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Last updated on September 24, 2017. This conference program is tentative and subject to change
Technical Program for Wednesday September 27, 2017
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WeAT1 , Room 109 |
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Model Learning for Control |
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Chair: Schoellig, Angela P. | Univ. of Toronto |
Co-Chair: Au, Tsz-Chiu | Ulsan National Inst. of Science and Tech |
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10:30-10:45, Paper WeAT1.1 | Add to My Program |
Multi-Robot Transfer Learning: A Dynamical System Perspective |
Helwa, Mohamed K. | Univ. of Toronto |
Schoellig, Angela P. | Univ. of Toronto |
Keywords: Model Learning for Control, Learning and Adaptive Systems
Abstract: Multi-robot transfer learning allows a robot to use data generated by a second, similar robot to improve its own behavior. The potential advantages are reducing the time of training and the unavoidable risks that exist during the training phase. Transfer learning algorithms aim to find an optimal transfer map between different robots. In this paper, we investigate, through a theoretical study of single-input single-output (SISO) systems, the properties of such optimal transfer maps. We first show that the optimal transfer learning map is, in general, a dynamic system. The main contribution of the paper is to provide an algorithm for determining the properties of this optimal dynamic map including its order and regressors (i.e., the variables it depends on). The proposed algorithm does not require detailed knowledge of the robots' dynamics, but relies on basic system properties easily obtainable through simple experimental tests. We validate the proposed algorithm experimentally through an example of transfer learning between two different quadrotor platforms. Experimental results show that an optimal dynamic map, with correct properties obtained from our proposed algorithm, achieves 60-70% reduction of transfer learning error compared to the cases when the data is directly transferred or transferred using an optimal static map.
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10:45-11:00, Paper WeAT1.2 | Add to My Program |
Data-Efficient Control Policy Search Using Residual Dynamics Learning |
Saveriano, Matteo | Tech. Univ. of Munich |
Yin, Yuchao | Tech. Univ. of Munich |
Falco, Pietro | Tech. Univ. of Munich |
Lee, Dongheui | Tech. Univ. of Munich |
Keywords: Model Learning for Control, Learning and Adaptive Systems, Motion Control
Abstract: In this work, we propose a model-based and data efficient approach for reinforcement learning. The main idea of our algorithm is to combine simulated and real rollouts to efficiently find an optimal control policy. While performing rollouts on the robot, we exploit sensory data to learn a probabilistic model of the residual difference between the measured state and the state predicted by a simplified model. The simplified model can be any dynamical system, from a very accurate system to a simple, linear one. The residual difference is learned with Gaussian processes. Hence, we assume that the difference between real and simplified model is Gaussian distributed, which is less strict than assuming that the real system is Gaussian distributed. The combination of the partial model and the learned residuals is exploited to predict the real system behavior and to search for an optimal policy. Simulations and experiments show that our approach significantly reduces the number of rollouts needed to find an optimal control policy for the real system.
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11:00-11:15, Paper WeAT1.3 | Add to My Program |
Online Multi-Target Learning of Inverse Dynamics Models for Computed-Torque Control of Compliant Manipulators |
Polydoros, Athanasios S. | Univ. of Innsbruck |
Boukas, Evangelos | Aalborg Univ. Copenhagen |
Nalpantidis, Lazaros | Aalborg Univ |
Keywords: Model Learning for Control, Learning and Adaptive Systems
Abstract: Inverse dynamics models are applied to a plethora of robot control tasks such as computed-torque control, which are essential for trajectory execution. The analytical derivation of such dynamics models for robotic manipulators can be challenging and depends on their physical characteristics. This paper proposes a machine learning approach for modeling inverse dynamics and provides information about its implementation on a physical robotic system. The proposed algorithm can perform online multi-target learning, thus allowing efficient implementations on real robots. Our approach has been tested both offline, on datasets captured from three different robotic systems and online, on a physical system. The proposed algorithm exhibits state-of-the-art performance in terms of generalization ability and convergence. Furthermore, it has been implemented within ROS for controlling a Baxter robot. Evaluation results show that its performance is comparable to the built-in inverse dynamics model of the robot.
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11:15-11:30, Paper WeAT1.4 | Add to My Program |
A New Data Source for Inverse Dynamics Learning |
Kappler, Daniel | Max-Planck Inst. for Intelligent Systems |
Meier, Franziska | Max Planck Inst. for Intelligent Systems |
Ratliff, Nathan | Lula Robotics Inc |
Schaal, Stefan | MPI Intelligent Systems & Univ. of Southern California |
Keywords: Model Learning for Control, Learning and Adaptive Systems
Abstract: Modern robotics is gravitating toward increasingly collaborative human robot interaction. Tools such as acceleration policies can naturally support the realization of reactive, adaptive, and compliant robots. These tools require us to model the system dynamics accurately -- a difficult task. The fundamental problem remains that simulation and reality diverge--we do not know how to accurately change a robot's state. Thus, recent research on improving inverse dynamics models has been focused on making use of machine learning techniques. Traditional learning techniques train on the actual realized accelerations, instead of the policy's desired accelerations, which is an indirect data source. Here we show how an additional training signal -- measured at the desired accelerations -- can be derived from a feedback control signal. This effectively creates a second data source for learning inverse dynamics models. Furthermore, we show how both the traditional and this new data source, can be used to train task-specific models of the inverse dynamics, when used independently or combined. We analyze the use of both data sources in simulation and demonstrate its effectiveness on a real-world robotic platform. We show that our system incrementally improves the learned inverse dynamics model, and when using both data sources combined converges more consistently and faster.
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11:30-11:45, Paper WeAT1.5 | Add to My Program |
Learning of Vehicular Performance Models for Longitudinal Motion Planning to Satisfy Arrival Requirements |
Nguyen, Ty | Ulsan National Inst. of Science and Tech |
Nguyen, Dung | Ulsan National Inst. of Science and Tech |
Au, Tsz-Chiu | Ulsan National Inst. of Science and Tech |
Keywords: Model Learning for Control, Learning and Adaptive Systems, Autonomous Vehicle Navigation
Abstract: Motion planning with predictable timing and velocity will enable a number of interesting applications such as autonomous intersection management (AIM). These planning algorithms depend on an accurate model of the performance of the vehicular controllers, which can be highly non-linear. Au et al. proposed a motion planning algorithm to satisfy the arrival requirements in AIM. However, they assumed that the performance models are given for every road and did not discuss how to learn these models. In this paper, we propose an instance-based learning approach to learn the performance models automatically, and argue that instance-based learning is suitable for this learning task because performance models for different roads can have a high correlation with each other. Moreover, an exploration strategy based on the principle of least effort is given to speed up the learning process. Our experiments showed that the instance-based learning method with distance-based exploration strategy offers a faster learning rate than the artificial neural network methods.
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11:45-12:00, Paper WeAT1.6 | Add to My Program |
Why Did the Robot Cross the Road? - Learning from Multi-Modal Sensor Data for Autonomous Road Crossing |
Radwan, Noha | Univ. of Freiburg |
Winterhalter, Wera | Univ. of Freiburg |
Dornhege, Christian | Univ. of Freiburg |
Burgard, Wolfram | Univ. of Freiburg |
Keywords: Autonomous Agents, Autonomous Vehicle Navigation, Sensor Fusion
Abstract: We consider the problem of developing robots that navigate like pedestrians on sidewalks through city centers for performing various tasks including delivery and surveillance. One particular challenge for such robots is crossing streets without pedestrian traffic lights. To solve this task the robot has to decide based on its sensory input if the road is clear. In this work, we propose a novel multi-modal learning approach for the problem of autonomous street crossing. Our approach solely relies on laser and radar data and learns a classifier based on Random Forests to predict when it is safe to cross the road. We present extensive experimental evaluations using real-world data collected from multiple street crossing situations which demonstrate that our approach yields a safe and accurate street crossing behavior and generalizes well over different types of situations. A comparison to alternative methods demonstrates the advantages of our approach.
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WeAT2 , Room 111 |
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Compliant Joint/Mechanism I |
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Chair: Gupta, Kamal | Simon Fraser Univ |
Co-Chair: Tsagarakis, Nikos | Istituto Italiano Di Tecnologia |
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10:30-10:45, Paper WeAT2.1 | Add to My Program |
Human-Inspired Compliant Strategy for Peg-In-Hole Assembly Using Environmental Constraint and Coarse Force Information |
Li, Xiaoqing | Univ. of Science and Tech. Beijing |
Li, Rui | Inst. of Automation, Chinese Acad. of Sciences |
Qiao, Hong | Inst. of Automation, Chinese Acad. of Sciences |
Ma, Chao | Univ. of Science and Tech. Beijing |
Li, Liang | Beijing Inst. of Spacecraft System Engineering |
Keywords: Compliant Assembly, Industrial Robots
Abstract: Automated assembly, especially peg-in-hole insertion, is a common task in manufacturing. In particular, the high-precision assembly is achieved by high-precision manipulator and sensing system. However, uncertainty and various parts for assembly are still challenges for robotic assembly, especially for low-precision robot and sensors. It is noteworthy that human can implement assembly tasks although the precision of the arm and hand is not comparable with a common industrial robot, in which process compliance is the key characteristic of their motion. In this paper, we present a human-inspired compliant strategy for peg-in-hole assembly task using the environmental constraint and coarse force information. In the proposed strategy, a constraint region is designed for motion planning and utilized for eliminating the uncertainty of the initial positioning error of the peg. Force sensor is applied to sense the contact force of which the direction is used to adjust the movement of the peg. Therefore, high-precision sensor is not necessarily required. Inspired by human compliant assembly, a from coarse to fine adjustment strategy is executed. The contribution of our strategy is that high precision assembly task can be solved by low precision system. The constraint region and force guided directional adjustment have increased the robustness of the system. The strategy is carried out in simulation for round peg-in-hole assembly task. The experimental results show that the assembly task can be successfully completed and demonstrate the effectiveness of our strategy.
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10:45-11:00, Paper WeAT2.2 | Add to My Program |
Development and Control of a Variable Stiffness Actuator Using a Variable Radius Gear Transmission Mechanism |
Chang, Handdeut | KAIST |
Kim, Sangjoon J. | KAIST |
Na, Youngjin | Korea Advanced Inst. of Science and Tech. (KAIST) |
Park, Junghoon | KAIST |
Kim, Jung | KAIST |
Keywords: Compliant Joint/Mechanism, Biologically-Inspired Robots, Physical Human-Robot Interaction
Abstract: The closer distance between robots and human partners in the same space makes compliant robots essential in these days. While torque sensor based impedance control scheme suffers insufficient bandwidth, musculoskeletal systems can achieve similar ability with smaller resources by using mechanically guaranteed dynamics. In this study, inspired by active stiffness mechanism of biological muscle, we developed a variable stiffness actuator which can realize precise joint stiffness without torque sensor based feedback control. The actuator consists of two antagonistically allocated DC motors with a variable radius gear transmission mechanism. The equilibrium position and joint stiffness can be independently controlled adjusting the activation level of motors by feedforward control. Theoretically predicted stiffness is realized well in both static and dynamic condition. In this paper, the design, functional principle and control of the actuator are introduced with analytical investigation.
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11:00-11:15, Paper WeAT2.3 | Add to My Program |
Control of a Variable Stiffness Joint for Catching a Moving Object |
Bhole, Ajinkya | Birla Inst. of Tech. and Science, Pilani, Rajasthan |
Kumle, Julian | Univ. of Twente |
Groothuis, Stefan S. | Mourik International B.V |
Carloni, Raffaella | Univ. of Twente |
Keywords: Compliant Joint/Mechanism, Compliance and Impedance Control
Abstract: The paper presents a control method to catch a moving object with a joint actuated by means of a variable stiffness actuator. The controller is designed such that the variable stiffness joint acts as a virtual damper that absorbs the kinetic energy of the moving object. The virtual damping and the output stiffness of the variable stiffness actuator are the control variables. To obtain a critically damped system, the damping coefficient is scheduled on both the output stiffness and the inertia of the system. Experiments on the rotational variable stiffness actuator vsaUT-II validate the control method.
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11:15-11:30, Paper WeAT2.4 | Add to My Program |
What Is the Torque Bandwidth of This Actuator? |
Malzahn, Jörn | Istituto Italiano Di Tecnologia |
Kashiri, Navvab | Istituto Italiano Di Tecnologia |
Roozing, Wesley | Istituto Italiano Di Tecnologia |
Tsagarakis, Nikos | Istituto Italiano Di Tecnologia |
Caldwell, Darwin G. | Istituto Italiano Di Tecnologia |
Keywords: Compliant Joint/Mechanism, Force Control, Compliance and Impedance Control
Abstract: The paper proposes a method to assess the feasible torque bandwidth for electrically driven torque controllable actuators over its entire torque amplitude range. The method solely relies on the knowledge of hardware parameters and thereby determines the physically feasible torque control bandwidth at a given torque amplitude, independent of a controller. The method yields torque-frequency diagrams that are suitable to benchmark torque controllers, formulate actuator design specifications and compare as well as select actuators for a specific torque control application. The paper exemplifies the method on a WALK-MAN leg actuator with locked actuator output and the more practical case of a varying load inertia.
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11:30-11:45, Paper WeAT2.5 | Add to My Program |
On the Stiffness Selection for Torque Controlled Series-Elastic Actuators |
Roozing, Wesley | Istituto Italiano Di Tecnologia |
Malzahn, Jörn | Istituto Italiano Di Tecnologia |
Kashiri, Navvab | Istituto Italiano Di Tecnologia |
Caldwell, Darwin G. | Istituto Italiano Di Tecnologia |
Tsagarakis, Nikos | Istituto Italiano Di Tecnologia |
Keywords: Compliant Joint/Mechanism, Force Control
Abstract: Series-elastic actuators are quickly becoming the core component of robots operating in real world environments, allowing for robust, safe, torque controlled robots. This paper investigates the influence of the selected stiffness and control parameters. By consolidating several analyses, it is shown two opposing criteria exist for the choice of stiffness: lowering stiffness increases actuator transparency, while increasing stiffness increases torque tracking bandwidth. This fact is used in the context of impedance rendering to propose an optimal stiffness selection criterion that maximises the renderable impedance frequency. This provides a concrete method for choosing stiffness based on the application of the joint. Extensive simulation and experimental results are presented that validate the analyses.
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11:45-12:00, Paper WeAT2.6 | Add to My Program |
Design and Analysis of Planar Rotary Springs |
Georgiev, Nikola | Caltech |
Burdick, Joel | California Inst. of Tech |
Keywords: Compliant Joint/Mechanism, Mechanism Design, Product Design, Development and Prototyping
Abstract: This paper is concerned with the analysis, design, and prototyping of rotary planar springs for robotics applications such as rotary series elastic actuators, or mechanical couplings. The key contribution is the development of a mathematical model, based on curved beam theory, that allows rapid design, analysis, and optimization of rotary springs that have arbitrary arm shape. The paper also introduces methods to reduce the spring mass via composite arm structures, or arm cutouts. A prototype is designed, analyzed and tested to demonstrate the validity of the model.
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WeAT3 , Room 116 |
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Manipulation |
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Chair: Lee, Su-Lin | Imperial Coll. London |
Co-Chair: Piater, Justus | Univ. of Innsbruck |
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10:30-10:45, Paper WeAT3.1 | Add to My Program |
Robust Constraint-Based Robot Control for Bimanual Cap Rotation |
Parigi-Polverini, Matteo | Pol. Di Milano |
Zanchettin, Andrea Maria | Pol. Di Milano |
Incocciati, Francesco | Pol. Di Milano |
Rocco, Paolo | Pol. Di Milano |
Keywords: Dual Arm Manipulation, Compliant Assembly, Force Control
Abstract: In this work a constraint-based control approach is proposed in order to perform a cap rotation task with a dual- arm robot. The method relies on the introduction of a robust specification for the constraint on the interaction force arising during the task, accounting for robot-environment contact model uncertainties, in addition to force measurement noise and surface uncertainties. Experiments have been performed on an ABB dual-arm prototype robot to validate the proposed approach in a cap assembly task, employing a model-based sensorless observer of the interaction forces.
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10:45-11:00, Paper WeAT3.2 | Add to My Program |
Inverse Dynamics Control of Bimanual Object Manipulation Using Orthogonal Decomposition: An Analytic Approach |
Shahbazi Aghbelagh, Mohammad | Istituto Italiano Di Tecnologia (IIT) |
Lee, Jinoh | Fondazione Istituto Italiano Di Tecnologia |
Caldwell, Darwin G. | Istituto Italiano Di Tecnologia |
Tsagarakis, Nikos | Istituto Italiano Di Tecnologia |
Keywords: Dual Arm Manipulation, Dynamics, Motion Control of Manipulators
Abstract: In this paper, the well-known problem of codependence between inverse dynamics torque and contact force in bimanual object manipulation is addressed. The common contact constraint, namely rigid grasping, is exploited to decompose the set of dynamics equations into two orthogonally decoupled sets. Subsequently, the inverse dynamics control is formulated in a sub-manifold that is independent of the contact force, leading to analytically correct solutions that do not need to resort to common approximations for the aforementioned codependence problem. The contact force is also analytically computed and, therefore, can be optimally distributed using the torque redundancy. Relying on this prediction is most significant in situations where a force sensor at the end-effector is not present or is faulty. Even in the availability of sensory data, the predicted force may be used to correct typically noisy or delayed when filtered measurements, resulting in improved robustness. Simulation experiments on a planar bimanual manipulation model are presented.
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11:00-11:15, Paper WeAT3.3 | Add to My Program |
A Vision-Guided Multi-Robot Cooperation Framework for Learning-By-Demonstration and Task Reproduction |
Huang, Bidan | Imperial Coll. London |
Ye, Menglong | Imperial Coll. London |
Lee, Su-Lin | Imperial Coll. London |
Yang, Guang-Zhong | Imperial Coll. London |
Keywords: Dual Arm Manipulation, Intelligent and Flexible Manufacturing, Learning from Demonstration
Abstract: This paper presents a vision-based learning-by-demonstration approach for multi-robot manipulation. With this method, a vision system is involved in both the task demonstration and reproduction stages, and the speed and accuracy of the task reproduction are adapted according to the context of the demonstration. An expert first demonstrates how to use tools to perform a task, while the tool motion is observed using a vision system. The demonstrations are then encoded using a statistical model to generate a reference motion trajectory. Equipped with the same tools and the learned model, the robot is guided by vision to reproduce the task. The task performance was evaluated in terms of both accuracy and speed. However, simply increasing the robot's speed could decrease the reproduction accuracy. To this end, a dual-rate Kalman filter is employed to compensate for latency between the robot and vision system. More importantly, the robot speed is adapted according to the learned motion model. We demonstrate the effectiveness of our approach by performing two tasks: a trajectory reproduction task and a bimanual sewing task. We show that using our vision-based approach, the robots can conduct effective learning by demonstrations and perform accurate and fast task reproduction. The proposed approach is generalisable to other manipulation tasks, where bimanual or multi-robot cooperation is required.
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11:15-11:30, Paper WeAT3.4 | Add to My Program |
Extracting Bimanual Synergies with Reinforcement Learning |
Luck, Kevin Sebastian | Arizona State Univ |
Ben Amor, Heni | Arizona State Univ |
Keywords: Dual Arm Manipulation, Learning and Adaptive Systems
Abstract: Motor synergies are an important concept in human motor control. Through the co-activation of multiple muscles, complex motion involving many degrees-of-freedom can be generated. However, leveraging this concept in robotics typically entails using human data that may be incompatible for the kinematics of the robot. In this paper, our goal is to enable a robot to identify synergies for low-dimensional control using trial-and-error only. We discuss how synergies can be learned through latent space policy search and introduce an extension of the algorithm for the re-use of previously learned synergies for exploration. The application of the algorithm on a bimanual manipulation task for the Baxter robot shows that performance can be increased by reusing learned synergies intra-task when learning to lift objects. But the reuse of synergies between two tasks with different objects did not lead to a significant improvement.
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11:30-11:45, Paper WeAT3.5 | Add to My Program |
Model-Free Precise In-Hand Manipulation with a 3d-Printed Tactile Gripper |
Ward-Cherrier, Benjamin | Univ. of Bristol |
Rojas, Nicolas | Imperial Coll. London |
Lepora, Nathan | Univ. of Bristol |
Keywords: Force and Tactile Sensing, Dexterous Manipulation, Grippers and Other End-Effectors
Abstract: The use of tactile feedback for precision manipulation in robotics still lags far behind human capabilities. This study has two principal aims: 1) To demonstrate in-hand reorientation of grasped objects through active tactile manipulation. 2) To present the development of a novel TacTip sensor and GR2 gripper platform for tactile manipulation. Through the use of Bayesian active perception algorithms, the system successfully achieved in-hand reorientation of cylinders of different diameters (20, 25, 30 and 35,mm) using tactile feedback. Average orientation errors along manipulation trajectories were below 5 deg. for all cylinders with reorientation ranges varying from 42 deg. to 67 deg. We also demonstrated an improvement in active tactile manipulation accuracy when using additional training data. Our methods for active tactile manipulation with the GR2 TacTip gripper are model-free, can be used to investigate principles of dexterous manipulation and could lead to essential advances in the areas of robotic tactile manipulation and tele-operated robots.
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11:45-12:00, Paper WeAT3.6 | Add to My Program |
Visual Task Outcome Verification Using Deep Learning |
Erkent, Ozgur | Innsbruck Univ |
Shukla, Dadhichi | Univ. of Innsbruck |
Piater, Justus | Univ. of Innsbruck |
Keywords: Visual Learning, Deep Learning in Robotics and Automation, Learning from Demonstration
Abstract: Manipulation tasks requiring high precision are difficult for reasons such as imprecise calibration and perceptual inaccuracies. We present a method for visual task outcome verification that provides an assessment of the task status as well as information for the robot to improve this status. The final status of the task is assessed as success, failure or in progress. We propose a deep learning strategy to learn the task with a small number of training episodes and without requiring the robot. A probabilistic, appearance-based pose estimation method is used to learn the demonstrated task. For real-data efficiency, synthetic training images are created around the trajectory of the demonstrated task. We show that our method can estimate the task status with high accuracy in several instances of different tasks, and demonstrate the accuracy of a high-precision task on a real robot.
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WeAT4 , Room 114 |
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Optimization and Optimal Control I |
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Chair: Hauser, Kris | Duke Univ |
Co-Chair: Hur, Pilwon | Texas A&M Univ |
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10:30-10:45, Paper WeAT4.1 | Add to My Program |
Landmark Guided Probabilistic Roadmaps |
Paden, Brian | MIT |
Nager, Yannik | ETH Zürich |
Frazzoli, Emilio | Massachusetts Inst. of Tech |
Keywords: Optimal Control, Motion and Trajectory Generation, Motion and Path Planning
Abstract: A landmark based heuristic is investigated for reducing query phase run-time of the probabilistic roadmap (PRM) motion planning method. The heuristic is generated by storing minimum spanning trees from a small number of vertices within the PRM graph and using these trees to approximate the cost of a shortest path between any two vertices of the graph. The intermediate step of preprocessing the graph increases the time and memory requirements of the classical motion planning technique in exchange for speeding up individual queries making the method advantageous in multi-query applications. This paper investigates these trade-offs on PRM graphs constructed in randomized environments as well as a practical manipulator simulation. We conclude that the method is preferable to Dijkstra's algorithm or the A* algorithm with conventional heuristics in multi-query applications.
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10:45-11:00, Paper WeAT4.2 | Add to My Program |
A Unified Control Method for Quadrotor Tail-Sitter UAVs in All Flight Modes: Hover, Transition, and Level Flight |
Zhou, Jinni | Hong Kong Univ. of Science and Tech |
Lyu, Ximin | Hong Kong Univ. of Science and Tech |
Li, Zexiang | Hong Kong Univ. of Science and Tech |
Shen, Shaojie | Hong Kong Univ. of Science and Tech |
Zhang, Fu | Hong Kong Univ. of Science and Tech |
Keywords: Optimization and Optimal Control, Aerial Systems: Mechanics and Control, Control Architectures and Programming
Abstract: This paper presents a unified control framework for controlling a quadrotor tail-sitter UAV. The most salient feature of this framework is its capability of uniformly treating the hovering and forward flight, and enabling continuous transition between these two modes, depending on the commanded velocity. The key part of this framework is a nonlinear solver that solves for the proper attitude and thrust that produces the required acceleration set by the position controller in an online fashion. The planned attitude and thrust are then achieved by an inner attitude controller that is global asymptotically stable. To characterize the aircraft aerodynamics, a full envelope wind tunnel test is performed on the full-scale quadrotor tail-sitter UAV. In addition to planning the attitude and thrust required by the position controller, this framework can also be used to analyze the UAV’s equilibrium state (trimmed condition), especially when wind gust is present. Finally, simulation results are presented to verify the controller’s capacity, and experiments are conducted to show the attitude controller’s performance.
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11:00-11:15, Paper WeAT4.3 | Add to My Program |
Occupancy Grid Based Distributed MPC for Mobile Robots |
Mehrez, Mohamed W. | Memorial Univ. in Newfoundland |
Sprodowski, Tobias | Univ. of Bremen |
Worthmann, Karl | Tech. Univ. Ilmenau |
Mann, George K. I. | Memorial Univ. of Newfoundland |
Gosine, Raymond G. | Memorial Univ. of Newfoundland |
Sagawa, Juliana Keiko | Production Engineering Department, Federal Univ. of São Car |
Pannek, Jürgen | Univ. Bremen |
Keywords: Optimization and Optimal Control, Distributed Robot Systems, Multi-Robot Systems
Abstract: In this paper, we introduce a novel approach of reducing the communication load in distributed model predictive control (DMPC) for mobile robots. The key idea is to project the predicted state trajectory onto a grid resulting in an occupancy grid prediction. This approach has the advantage of utilizing continuous optimization methods while only quantized information is exchanged. We consider non-holonomic mobile robots to numerically and experimentally investigate the proposed method.
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11:15-11:30, Paper WeAT4.4 | Add to My Program |
A Step towards Generating Human-Like Walking Gait Via Trajectory Optimization through Contact for a Bipedal Robot with One-Sided Springs on Toes |
Chao, Kenneth | Texas A&M |
Hur, Pilwon | Texas A&M Univ |
Keywords: Optimization and Optimal Control, Humanoid and Bipedal Locomotion, Motion and Path Planning
Abstract: Trajectory optimization with direct collocation are widely used in various bipedal walking studies, from dynamic simulation in biomechanics to efficient bipedal walking motion generation with multiple contact domains. Although the latter has gained popularity, most of the approaches in this field in general rely on pre-determined contact sequence (domains). This motivates us to use trajectory optimization through contact for generating an efficient and human-like walking gait, because this approach can automatically generate the contact sequence by solving a nonlinear program (NLP) with complementary constraints. However, in this approach the initial guess affects the result significantly, and the direct collocation with Euler method may not be accurate enough for the system dynamics. Therefore, we propose a modified framework and constraints to improve the generated results. We used a zero moment point (ZMP)-based flat-feet walking gait as an initial guess. We also show how to add virtual components like springs at ankle joints to alter the behavior of the resultant walking gait. In addition, considering the one-sided springs at the passive toe joints of the bipedal robot AMBER 3, additional complementary constraints are introduced for a better match of the full dynamics. The results of our modified approach with different constraint conditions are presented and discussed.
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11:30-11:45, Paper WeAT4.5 | Add to My Program |
A Data-Driven Indirect Method for Nonlinear Optimal Control |
Tang, Gao | Duke Univ |
Hauser, Kris | Duke Univ |
Keywords: Optimization and Optimal Control, Learning and Adaptive Systems, Motion and Path Planning
Abstract: Nonlinear optimal control problems are challenging to solve due to the prevalence of local minima that prevent convergence and/or optimality. This paper describes nearest-neighbors optimal control (NNOC), a data-driven framework for nonlinear optimal control using indirect methods. It determines initial guesses for new problems with the help of precomputed solutions to similar problems, retrieved using k-nearest neighbors. A sensitivity analysis technique is introduced to linearly approximate the variation of solutions between new and precomputed problems based on their variation of parameters. Experiments show that NNOC can obtain the global optimal solution orders of magnitude faster than standard random restart methods, and sensitivity analysis can further reduce the solving time almost by half. Examples are shown on two optimal control problems in vehicle control.
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11:45-12:00, Paper WeAT4.6 | Add to My Program |
Convexification and Real-Time On-Board Optimization for Agile Quad-Rotor Maneuvering and Obstacle Avoidance |
Szmuk, Michael | Univ. of Washington |
Pascucci, Carlo Alberto | Univ. of Washington |
Dueri, Daniel | Univ. of Washington |
Acikmese, Behcet | Univ. of Washington |
Keywords: Optimization and Optimal Control, Motion and Path Planning, Collision Avoidance
Abstract: In this paper, we apply lossless and successive convexification techniques and employ real-time on-board convex optimization to perform constrained motion planning for quad-rotors. In general, this problem is challenging for real-time on-board applications due to its non-convex nature. The ability to generate feasible trajectories quickly and reliably is central to operating high-performance aerial robots in populated spaces. Motivated by our earlier research on convexification of non-convex optimal control problems, we use these convexification techniques to cast the problems into one (or a sequence of) Second-Order Cone Programming (SOCP) problem(s). In doing so, we are able to attain our solutions by leveraging modern advances in Interior Point Method (IPM) algorithms. Here, we focus on 3-degree-of-freedom trajectory generation, whereby closed-loop control is used to track a translational trajectory computed on-board at the onset of the maneuver. To the best of our knowledge, this is the first demonstration of convexification techniques used in real-time on-board trajectory generation for high-performance quad-rotor flight. We present two example scenarios: (1) a case where lossless convexification is used to increase the available control envelope, thus enabling an agile flip maneuver, and (2) a case where both convexification techniques are used to compute a path through a flight space containing ellipsoidal keep-out zones. We present flight demonstration results obtained using the Autonomous Control Laboratory's (ACL's) custom quad-rotor platforms and SOCP optimization software. Additionally, computation timing statistics for the example scenarios obtained using a series of mobile ARM and Intel processors show a minimum mean computation time of 36.5 and 122.2 milliseconds, respectively.
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WeAT5 , Room 118 |
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Legged Robots III |
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Chair: Choi, Hyouk Ryeol | Sungkyunkwan Univ |
Co-Chair: Semini, Claudio | Istituto Italiano Di Tecnologia |
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10:30-10:45, Paper WeAT5.1 | Add to My Program |
Development of Experimental Legged Robot for Inspection and Disaster Response in Plants |
Yoshiike, Takahide | Honda R&D Co., Ltd |
Kuroda, Mitsuhide | Honda R&D Co., Ltd |
Ujino, Ryuma | Honda R&D Co., Ltd |
Kaneko, Hiroyuki | Honda R&D Co., Ltd |
Higuchi, Hirofumi | Honda R&D Co., Ltd |
Iwasaki, Shingo | Honda R&D Co., Ltd |
Kanemoto, Yoshiki | Honda R&D Co., Ltd |
Asatani, Minami | Honda R&D Co., Ltd |
Koshiishi, Takeshi | Honda R&D Co., Ltd |
Keywords: Climbing Robots, Legged Robots, Robotics in Hazardous Fields
Abstract: In this paper, a new experimental legged robot for inspection and disaster response in social infrastructures designed for humans, such as factories and power plants is presented. The robot has distinctive features to climb up and down ladders with a narrow cage, to pass through narrow environments, to move upon scattered debris at disaster sites and to deal with sudden and unexpected contact. The robot also satisfies environmental requirements related to dust, water and temperature. To implement environmental resistance to a slim body for movement in a narrow environment, cooling of heat sources such as CPUs is a serious problem. Therefore a new cooling structure for humanoid robots is proposed. The proposed robot experiments on the above features are also shown in this paper.
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10:45-11:00, Paper WeAT5.2 | Add to My Program |
A Leg Design Method for High Speed Quadrupedal Locomotion |
Dallas, Spyridon | National Tech. Univ. of Athens |
Machairas, Konstantinos | National Tech. Univ. of Athens |
Koutsoukis, Konstantinos | National Tech. Univ. of Athens |
Papadopoulos, Evangelos | National Tech. Univ. of Athens |
Keywords: Legged Robots, Mechanism Design, Motion Control
Abstract: This paper introduces a leg design method aiming at speed maximization for quadruped robots with two-segment compliant legs, in trotting and bounding. The proposed method is an effort to address the leg design challenge in a holistic way, exploiting the coupling between gait parameters, leg design parameters and hardware constraints, while remaining control scheme independent. Optimal body trajectories and footfalls are derived using a simplified centroidal dynamics model, whereas joint trajectories and torques are computed by a more complex dynamic model, incorporating actuation parameters and constraints. The method is applied using real robot parameters to yield an optimal leg design, validated through a realistic trotting simulation experiment. In this experiment, the robot achieves accelerating motion from stance towards the maximum speed predicted by the method.
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11:00-11:15, Paper WeAT5.3 | Add to My Program |
Foot Placement and Ankle Push-Off Control for the Orbital Stabilization of Bipedal Robots |
Zamani, Ali | Univ. of Texas at San Antonio |
Bhounsule, Pranav | Univ. of Texas at San Antonio |
Keywords: Legged Robots, Motion Control, Humanoid and Bipedal Locomotion
Abstract: The main motivation of this paper is to understand the role of foot placement and ankle push-off control in stabilizing bipedal gaits. We modify the simplest walker (heavy torso, light legs) by incorporating a hip spring, a hip actuator, and a telescopic linear actuator. We consider two stability criteria: one-step dead-beat stabilization for full correction of disturbance in a single step and exponential orbital stabilization using discrete control Lyapunov function. Our findings are as follows: (1) Both control strategies have almost similar robustness as measured by the number of steps walked on stochastic terrain before failure, but both strategies are more robust for changing terrain with step down and less robust for step up. (2) One step dead-beat stabilization is more energy-efficient than exponential stabilization. (3) Control strategy for step up is to decrease foot placement or maintain push-off and for step down is to increase foot placement or decrease the push-off. However, it is most energy-efficient to use foot placement control for step up and push-off control for step down.
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11:15-11:30, Paper WeAT5.4 | Add to My Program |
Online Payload Identification for Quadruped Robots |
Tournois, Guido Alexander | Delft Univ. of Tech |
Focchi, Michele | Fondazione Istituto Italiano Di Tecnologia |
Del Prete, Andrea | CNRS |
Orsolino, Romeo | Istituto Italiano Di Tecnologia |
Caldwell, Darwin G. | Istituto Italiano Di Tecnologia |
Semini, Claudio | Istituto Italiano Di Tecnologia |
Keywords: Legged Robots, Robust/Adaptive Control of Robotic Systems, Model Learning for Control
Abstract: The dynamic parameters of the leg links are not frequently altered during expeditions and therefore are best suitable to be identified offline. On the other hand, the trunk parameters depend on the different modules that will be mounted on the robot, like a motor to provide the hydraulic power, or different sets of cameras for perception. Based on this motivation, in this paper we propose two recursive approaches to online identify the position of the Center of Mass (CoM) of the robot trunk, when a payload change occurs. We will demonstrate the effectiveness of the proposed approaches analysing their robustness in simulation. Furthermore, experimental trials on our 80 kg quadruped robot HyQ, showed that the proposed strategies are applicable during locomotion to cope with big payload changes. These can create shifts on the CoM that can possibly hamper locomotion stability. In these cases our online identification strategy is able to promptly update the trunk model parameters in the planner/controller, enhancing the locomotion stability.
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11:30-11:45, Paper WeAT5.5 | Add to My Program |
Trajectory Design and Control of Quadruped Robot for Trotting Over Obstacles |
Lee, Young Hun | Sungkyunkwan Univ |
Lee, Yoon Haeng | Sungkyunkwan Univ |
Lee, Hyunyong | Sungskyunkwan Univ |
Phan, Luong Tin | Sungkyunkwan Univ |
Kang, Hansol | Sungkyunkwan Univ |
Kim, Uikyum | SungKyunKwan Univ |
Jeon, Jeongmin | Sungkyunkwan Univ |
Choi, Hyouk Ryeol | Sungkyunkwan Univ |
Keywords: Legged Robots, Motion Control, Motion and Path Planning
Abstract: Various control strategies using trajectory planning, object recognition and learning are researched for avoiding obstacles when legged robot is walking. In this paper, designed trajectory by using Non Uniform Basis Spline (NUBS) curve and control strategy, by using proposed trajectory, to effectively overcome obstacles are presented. The trajectory designed by NUBS curve has several advantages: 1) local modification, 2) tracking velocity control for each domain, and 3) low degree trajectory with a large number of control points. The robot gets remarkable effectiveness when these advantages are used to generate the trajectory for walking and overcoming obstacles. By implementation of the proposed control strategy, quadruped robot can walk over obstacles while keeping its gait, speed and balance without collision although adjusting relatively preferable state which is more suitable position or posture of the walking robot shortly before encountering obstacles is not required. The proposed trajectory and control strategy are discussed, and performance is validated through experimental evaluations.
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11:45-12:00, Paper WeAT5.6 | Add to My Program |
Active Stabilization of a Stiff Quadruped Robot Using Local Feedback |
Vasconcelos, Rui | Inst. Superior Técnico |
Hauser, Simon | Biorob, EPFL |
Dzeladini, Florin | EPFL, Biorob |
Mutlu, Mehmet | École Pol. Fédérale De Lausanne (EPFL) |
Horvat, Tomislav | EPFL |
Melo, Kamilo | EPFL |
Oliveira, Paulo | Inst. Superior Técnico |
Ijspeert, Auke | EPFL |
Keywords: Legged Robots, Sensor-based Control, Robust/Adaptive Control of Robotic Systems
Abstract: Animal locomotion exhibits all the features of complex non linear systems such as multi-stability, critical fluctuation, limit cycle behavior and chaos. Studying these aspects on real robots has been proved difficult and therefore results mostly rely on the use of computer simulation. Simple control approaches - based on phase oscillators - have been proposed and exhibit several of these features. In this work, we compare two types of controllers: (a) an open loop control approach based on phase oscillators and (b) the Tegotae-based closed loop extension of this controller. The first controller has been shown to exhibit synchronization features between the body and the controller when applied to a quadruped robot with compliant leg structures. In this contribution, we apply both controllers to the locomotion of a stiff quadruped structure. We show that the Tegotae-controller exhibits self-organizing behavior, such as spontaneous gait transition and critical fluctuation. Moreover, it exhibits features such as the ability to stabilize both asymmetric and symmetric morphological changes, despite the lack of compliance in the leg.
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WeAT6 , Room 121 |
Add to My Program |
RGBD Perception I |
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Chair: Kosecka, Jana | George Mason Univ |
Co-Chair: Lauri, Mikko | Univ. of Hamburg |
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10:30-10:45, Paper WeAT6.1 | Add to My Program |
M³Net: Multi-Scale Multi-Path Multi-Modal Fusion Network and Example Application to RGB-D Salient Object Detection |
Chen, Hao | City Univ. of Hong Kong |
Li, You-Fu | City Univ. of Hong Kong |
Su, Dan | City Univ. of Hong Kong |
Keywords: RGB-D Perception, Object detection, segmentation, categorization, Deep Learning in Robotics and Automation
Abstract: Fusing RGB and depth data is compelling in boosting performance for various robotic and computer vision tasks. Typically, the streams of RGB and depth information are merged into a single fusion point in an early or late stage to generate combined features or decisions. The single fusion point also means single fusion path, which is congested and inflexible to fuse all the information from different modalities. As a result, the fusion process is brute-force and consequently insufficient. To address this problem, we propose a multi-scale multi-path multi-modal fusion network (M³Net), in which the fusion path is scattered to diversify the contributions of each modality from global and local perspectives. Specially, the CNN streams of each modality are fused with a global understanding branch and meanwhile a local capturing branch. By filtering and regulating information flow in a multi-path way, the M3Net are equipped with more adaptive and flexible fusion mechanism, thus easing the gradient-based learning process, improving the directness and transparency of fusion process and simultaneously facilitating the fusion process with multi-scale perspectives. Comprehensive experiments on three benchmark datasets demonstrate the significant and consistent improvements of the proposed approach over state-of-the-art methods.
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10:45-11:00, Paper WeAT6.2 | Add to My Program |
Label Propagation in RGB-D Video |
Reza, Md | George Mason Univ |
Zheng, Hui | George Mason Univ |
Georgakis, Georgios | George Mason Univ |
Kosecka, Jana | George Mason Univ |
Keywords: RGB-D Perception, Object detection, segmentation, categorization, Semantic Scene Understanding
Abstract: We propose a new method for the propagation of semantic labels in RGB-D video of indoor scenes given a set of ground truth keyframes. Manual labeling of all pixels in every frame of a video sequence is labor intensive and costly, yet required for training and testing of semantic segmentation methods. The availability of video enables propagation of labels between the frames for obtaining large amounts of annotated pixels. While previous methods commonly used optical flow motion cues for label propagation, we present a novel approach using the camera poses and 3D point clouds for propagating the labels in superpixels computed on the unannotated frames of the sequence. The propagation task is formulated as an energy minimization problem in a Conditional Random Field (CRF). We performed experiments on the 8 video sequences from SUN3D dataset and showed superior performance to an optical flow based label propagation approach. Furthermore, we demonstrated that the propagated labels can be used to learn better models using data hungry deep convolutional neural network (DCNN) based approaches for the task of semantic segmentation. The approach demonstrates an increase in performance when the ground truth keyframes are combined with the propagated labels during training.
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11:00-11:15, Paper WeAT6.3 | Add to My Program |
Learning How a Tool Affords by Simulating 3D Models from the Web |
Abelha, Paulo | Univ. of Aberdeen |
Guerin, Frank | Univ. of Aberdeen |
Keywords: RGB-D Perception, Domestic Robots, Service Robots
Abstract: Robots performing everyday tasks such as cooking in a kitchen need to be able to deal with variations in the household tools that may be available. Given a particular task and a set of tools available, the robot needs to be able to assess which would be the best tool for the task, and also where to grasp that tool and how to orient it. This requires an understanding of what is important in a tool for a given task, and how the grasping and orientation relate to performance in the task. A robot can learn this by trying out many examples. This learning can be faster if these trials are done in simulation using tool models acquired from the Web. We provide a semi-automatic pipeline to process 3D models from the Web, allowing us to train from many different tools and their uses in simulation. We represent a tool object and its grasp and orientation using 21 parameters which capture the shapes and sizes of principal parts and the relationships among them. We then learn a ‘task function’ that maps this 21 parameter vector to a value describing how effective it is for a particular task. Our trained system can then process the unsegmented point cloud of a new tool and output a score and a way of using the tool for a particular task. We compare our approach with the closest one in the literature and show that we achieve significantly better results.
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11:15-11:30, Paper WeAT6.4 | Add to My Program |
Self-Supervised Online Learning of Appearance for 3D Tracking |
Lee, Bhoram | Univ. of Pennsylvania |
Lee, Daniel D. | Univ. of Pennsylvania |
Keywords: RGB-D Perception, Visual Tracking, Learning and Adaptive Systems
Abstract: This paper presents a self-supervised online learning approach for 3D object tracking that requires no pretraining of appearance. Our method focuses on selecting the most relevant parts of the RGBD input by continuously updating appearance classifiers in conjunction with the spatial occupancy of the target. Fine-grained regions selected via the learned bottom-up saliency, together with spatial cues of the 3D shape model, are used to identify and localize the target via shape registration. The subsequent 3-D pose estimate along with positive and negative labels from the registration are used for online learning appearance. The proposed method outperforms competing model-based tracking algorithms on public datasets as well as on a new motion scene dataset that we have collected.
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11:30-11:45, Paper WeAT6.5 | Add to My Program |
Saliency-Guided Adaptive Seeding for Supervoxel Segmentation |
Gao, Ge | Univ. of Hamburg |
Lauri, Mikko | Univ. of Hamburg |
Zhang, Jianwei | Univ. of Hamburg |
Frintrop, Simone | Univ. of Hamburg |
Keywords: RGB-D Perception, Object detection, segmentation, categorization, Computer Vision for Other Robotic Applications
Abstract: We propose a new saliency-guided method for generating supervoxels in 3D space. Rather than using an evenly distributed spatial seeding procedure, our method uses visual saliency to guide the process of supervoxel generation. This results in densely distributed, small, and precise supervoxels in salient regions which often contain objects, and larger supervoxels in less salient regions that often correspond to background. Our approach largely improves the quality of the resulting supervoxel segmentation in terms of boundary recall and undersegmentation error on publicly available benchmarks.
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11:45-12:00, Paper WeAT6.6 | Add to My Program |
Dense Piecewise Planar RGB-D SLAM for Indoor Environments |
Le, Phi-Hung | George Mason Univ |
Kosecka, Jana | George Mason Univ |
Keywords: RGB-D Perception, SLAM, Mapping
Abstract: The paper exploits weak Manhattan constraints to parse the structure of indoor environments from RGB-D video sequences in an online setting. We extend the previous approach for single view parsing of indoor scenes to video sequences and formulate the problem of recovering the floor plan of the environment as an optimal labeling problem solved using dynamic programming. The temporal continuity is enforced in a recursive setting, where labeling from previous frames is used as a prior term in the objective function. In addition to recovery of piecewise planar weak Manhattan structure of the extended environment, the orthogonality constraints are also exploited by visual odometry and pose graph optimization. This yields reliable estimates in the presence of large motions and absence of distinctive features to track. We evaluate our method on several challenging indoors sequences demonstrating accurate SLAM and dense mapping of low texture environments. On existing TUM benchmark we achieve competitive results with the alternative approaches which fail in our environments.
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WeAT7 , Room 122 |
Add to My Program |
Biomimetics I |
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Chair: Ma, Shugen | Ritsumeikan Univ |
Co-Chair: Brock, Oliver | Tech. Univ. Berlin |
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10:30-10:45, Paper WeAT7.1 | Add to My Program |
Curved Excavation by a Sub-Seafloor Excavation Robot |
Tadami, Naoaki | Chuo Univ |
Nagai, Mamoru | Chuo Univ |
Nakatake, Toyoharu | Chuo Univ |
Fujiwara, Ami | Chuo Univ |
Yamada, Yasuyuki | Chuo Univ |
Nakamura, Taro | Chuo Univ |
Yoshida, Hiroshi | Japan Agency for Marine-Earth Science and Tech |
Sawada, Hirotaka | JAXA |
Kubota, Takashi | Jaxa Isas |
Keywords: Biomimetics, Hydraulic/Pneumatic Actuators, Marine Robotics
Abstract: Sub-seafloor exploration is an important area of biological and geological research, and often requires samples of seafloor mud to be recovered. The minerals and marine sediments trapped in this mud are also potentially valuable resources. However, seabed exploration has been limited by the complexity and cost of the traditional equipment used. Wide area exploration can be made possible by deploying multiple robots to autonomously search beneath the ocean floor. In this study, we prototyped a sub-seafloor excavation robot for use in seabed exploration. The key system comprised a propulsion unit and an excavation unit that allow the robot to move freely within the seabed. We experimentally demonstrated the ability of the excavation robot to produce curved boreholes with a diameter of 160 mm, a turning radius of 1.67 m, and a depth of 613 mm. Our experimental results confirm that nonlinear excavation is possible using the excavation robot developed.
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10:45-11:00, Paper WeAT7.2 | Add to My Program |
Human Mimetic Forearm Design with Radioulnar Joint Using Miniature Bone-Muscle Modules and Its Applications |
Kawaharazuka, Kento | The Univ. of Tokyo |
Makino, Shogo | The Univ. of Tokyo |
Kawamura, Masaya | The Univ. of Tokyo |
Asano, Yuki | The Univ. of Tokyo |
Kakiuchi, Yohei | The Univ. of Tokyo |
Okada, Kei | The Univ. of Tokyo |
Inaba, Masayuki | The Univ. of Tokyo |
Keywords: Biomimetics, Humanoid Robots, Tendon/Wire Mechanisms
Abstract: The human forearm is composed of two long, thin bones called the radius and the ulna, and rotates using two axle joints. We aimed to develop a forearm based on the body proportion, weight ratio, muscle arrangement, and joint performance of the human body in order to bring out its benefits. For this, we need to miniaturize the muscle modules. To approach this task, we arranged two muscle motors inside one muscle module, and used the space effectively by utilizing common parts. In addition, we enabled the muscle module to also be used as the bone structure. Moreover, we used miniature motors and developed a way to dissipate the motor heat to the bone structure. Through these approaches, we succeeded in developing a forearm with a radioulnar joint based on the body proportion, weight ratio, muscle arrangement, and joint performance of the human body, while keeping maintainability and reliability. Also, we performed some motions such as soldering, opening a book, turning a screw, and badminton swinging using the benefits of the radioulnar structure, which have not been discussed before, and verified that Kengoro can realize skillful motions using the radioulnar joint like a human.
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11:00-11:15, Paper WeAT7.3 | Add to My Program |
An Underwater Electrosensor for Identifying Objects of Similar Volume and Aspect Ratio Using Convolution Neural Network |
Wang, Ke | Curtin Univ |
Do, Khac Duc | Univ. of Western Australia |
Cui, Lei | Curtin Univ |
Keywords: Biomimetics, Recognition, Deep Learning in Robotics and Automation
Abstract: Underwater electrosense is bio-inspired by weakly electric fishes that use an electric field to see the objects in the water. Current studies on engineering electrosense focus on designing sophisticated sensors and algorithms for emulating biological functions including localization and identification. This work aimed to develop a planar sensor equipped with a dense electrode array that is capable of providing accurate and dense data for identifying objects of similar volume and aspect ratio, which has been a challenge in underwater sensing. After sensor design and implementation were presented, convolutional neural networks (CNN), which are widely used in digital image recognition, was trained using both simulation and experimental data. In simulation, the overall success rate on identifying the sphere, cube, and rod is 92.6% by a 28x28 electrode array. In the preliminary experimental tests, a sensor with 16x16 electrode array achieved an overall success rate of 90.4% on identifying a sphere and a rod.
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11:15-11:30, Paper WeAT7.4 | Add to My Program |
Modelling and Analysis of the Passive Planar Rimless Wheel Mechanism in Universal Domain |
Jia, Wenchuan | Shanghai Univ |
Yang, Jiang | Shanghai Univ |
Bi, Liangyu | Shanghai Univ |
Zhang, Quan | Shanghai Univ |
Sun, Yi | Shanghai Univ |
Pu, Huayan | Shanghai Univ |
Ma, Shugen | Ritsumeikan Univ |
Keywords: Passive Walking, Kinematics, Legged Robots
Abstract: The planar rimless wheel (PRW) is a classic and simple passive dynamic mechanism to simulate biped walking, different simplified PRW models have respective descriptions and limited applications. This paper focus on constructing the general PRW model, and analyzing the intrinsic and mathematical relation between different PRW models. Based that, the limit cycle of symmetric PRW and asymmetric PRW are proposed separately. Moreover, the stability in universal domain are investigated in detail. Furthermore, simulation and experiment results show that the 2-period limit cycle motion of the asymmetric PRW is more effective, flexible and self-adaptive compared with regular rimless wheel, and more actual applications would be achieved by adopting the general model.
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11:30-11:45, Paper WeAT7.5 | Add to My Program |
Inclined Surface Locomotion Strategies for Spherical Tensegrity Robots |
Chen, Lee-Huang | Univ. OF CALIFORNIA BERKELEY |
Cera, Angelo Brian | UC Berkeley |
Zhu, Edward | UC Berkeley |
Edmunds, Riley | Univ. of California, Berkeley |
Rice, Franklin | Univ. of California, Berkeley |
Bronars, Antonia | UC Berkeley |
Tang, Ellande | UC Berkeley |
Malekshahi, Saunon Rod | Univ. of California, Berkeley |
Romero, Osvaldo | Univ. Nacional Autónoma De México |
Agogino, Adrian | UC Santa Cruz, NASA Ames Res. Center |
Agogino, Alice | Univ. of California Berkeley |
Keywords: Climbing Robots, Space Robotics and Automation, Underactuated Robots
Abstract: This paper presents a new teleoperated spherical tensegrity robot capable of performing locomotion on steep inclined surfaces. With a novel control scheme centered around the simultaneous actuation of multiple cables, the robot demonstrates robust climbing on inclined surfaces in hardware experiments and speeds significantly faster than previous spherical tensegrity models. This robot is an improvement over other iterations in the TT-series and the first tensegrity to achieve reliable locomotion on inclined surfaces of up to 24 degrees. We analyze locomotion in simulation and hardware under single and multi-cable actuation and introduce two novel multi-cable actuation policies, suited for steep incline climbing and speed, respectively. We propose compelling justifications for the increased dynamic ability of the robot and motivate development of optimization algorithms able to take advantage of the robot’s increased control authority.
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11:45-12:00, Paper WeAT7.6 | Add to My Program |
Handshakiness: Benchmarking for Human-Robot Hand Interactions |
Knoop, Espen | The Walt Disney Company |
Bächer, Moritz | Disney Res |
Wall, Vincent | TU Berlin |
Deimel, Raphael | TU Berlin |
Brock, Oliver | Tech. Univ. Berlin |
Beardsley, Paul | Disney Res. Zurich |
Keywords: Performance Evaluation and Benchmarking, Social Human-Robot Interaction, Physical Human-Robot Interaction
Abstract: Handshakes are common greetings, and humans therefore have strong priors of what a handshake should feel like. This makes it challenging to create compelling and realistic human-robot handshakes, necessitating the consideration of human haptic perception in the design of robot hands. At its most basic level, haptic perception is encoded by contact points and contact pressure distributions on the skin. This motivates our work on measuring the contact area and contact pressure in human handshaking interactions. We present two benchmarking experiments in this regard, measuring the contact locations in human-human/human-robot handshaking and the contact pressure distribution for handshakes with a sensorized palm. We present results from human studies with the benchmarking experiments, providing a baseline for comparison with robot hands as well as presenting new insights into human handshaking. We also show initial work in using these results for the evaluation of robot hands, and progressing towards iterative design of robot hands optimized for social hand interactions.
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WeAT8 , Room 202 |
Add to My Program |
Humanoid and Bipedal Locomotion I |
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Chair: Kheddar, Abderrahmane | CNRS-AIST JRL (Joint Robotics Lab. UMI3218/CRT |
Co-Chair: Suleiman, Wael | Univ. of Sherbrooke |
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10:30-10:45, Paper WeAT8.1 | Add to My Program |
Rotational Sliding Motion Generation for Humanoid Robot by Force Distribution in Each Contact Face |
Kojima, Kunio | The Univ. of Tokyo |
Nozawa, Shunichi | The Univ. of Tokyo |
Okada, Kei | The Univ. of Tokyo |
Inaba, Masayuki | The Univ. of Tokyo |
Ishiguro, Yasuhiro | The Univ. of Tokyo |
Sugai, Fumihito | The Univ. of Tokyo |
Kakiuchi, Yohei | The Univ. of Tokyo |
Keywords: Humanoid Robots, Humanoid and Bipedal Locomotion, Contact Modelling
Abstract: Recent studies have explored humanoid robots in contact with the environment in various ways. However, many of them assumed static rather than sliding contacts.Studies on humanoid shuffle motion planning have realized sliding motions, such as turning, but relied on quasi-static balance control. In this paper, we propose a dynamic balance control method for sliding contact motions.The proposed method consists of the Distributed Force Contact Constraint (D.F.C.C.), which describes rotational sliding contact constraints, and the Slide Friction Control (S.F.C.), which controls humanoid dynamic balance based on the Model Predictive Control by using the D.F.C.C. The D.F.C.C. segments a contact face into a grid of contact points and optimize the vertical component of the contact forces. This enables us to calculate the sliding friction forces at each contact point. The S.F.C. is the Model Predictive Control for distributing contact forces to each contact face considering sliding frictional dynamics. The D.F.C.C. is simple and easy to apply to the S.F.C. In our online stabilizer, we control not only a ZMP but also contact forces for realizing the contact force distributions planned in the S.F.C. Finally, we show our method's validity through the experiment using life-sized humanoid robot JAXON.
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10:45-11:00, Paper WeAT8.2 | Add to My Program |
Control Strategy and Implementation for a Humanoid Robot Pushing a Heavy Load on a Rolling Cart |
Hawley, Louis | Univ. of Sherbrooke |
Suleiman, Wael | Univ. of Sherbrooke |
Keywords: Humanoid Robots, Humanoid and Bipedal Locomotion, Legged Robots
Abstract: In this paper, we introduce a control strategy aimed at generating a stable walking pattern for a humanoid pushing a heavy load on a cart. In contrast to previous approaches that rely on force/torque sensors to measure the interaction between the robot and the pushed object, we present a simple model-based controller that can be implemented on most robots due to its computationally efficient design. Every aspect of the controller design is covered, from the formulation and validation of the dynamic model, to the implementation and validation on an actual humanoid robot. The experimental results show that the controller can efficiently make a NAO humanoid transport, in a stable way, the equivalent of its own weight on a rolling cart.
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11:00-11:15, Paper WeAT8.3 | Add to My Program |
3D Walking and Skating Motion Generation Using Divergent Component of Motion and Gauss Pseudospectral Method |
Takasugi, Noriaki | The Univ. of Tokyo |
Kojima, Kunio | The Univ. of Tokyo |
Nozawa, Shunichi | The Univ. of Tokyo |
Okada, Kei | The Univ. of Tokyo |
Inaba, Masayuki | The Univ. of Tokyo |
Keywords: Humanoid and Bipedal Locomotion, Humanoid Robots, Optimization and Optimal Control
Abstract: This paper presents a COM trajectory generation method for 3D walking and skating motion by nonlinear optimization. In our method, we solve the following problems: (1) dealing with both walking and skating motion in the same framework, (2) generating center of mass (COM) trajectory faster than execution time, (3) executing motion with large acceleration. For solving (1) and (2), we calculate the COM trajectory at every step and introduce frictional constraints to the Divergent Component of Motion as terminal conditions. By changing the terminal condition, we can generate both skating and walking motion. Besides, the nonlinear constrained optimization using Gauss Pseudospectral Method is introduced for solving (2) and (3). Thanks to this method, we generate the 3D COM trajectory considering contact constraints and kinematic constraints faster than execution time. Finally, the walking and skating experiment were carried out to confirm the effectiveness of our method using life-sized humanoid HRP-2. Applying the proposed method, HRP-2 could successfully walk at 0.4 [m/s] and skate at 1.0 [m/s].
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11:15-11:30, Paper WeAT8.4 | Add to My Program |
Frictional Constraints on the Sole of a Biped Robot When Slipping |
Takabayashi, Yusuke | Maebashi Inst. of Tech |
Ishihara, Kosuke | Maebashi Inst. of Tech |
Yoshioka, Masataka | National Inst. of Tech. Kochi Coll |
Liang, Hongbo | Maebashi Inst. of Tech |
Liu, Chang | Maebashi Inst. of Tech |
Zhu, Chi | Maebashi Inst. of Tech |
Keywords: Humanoid and Bipedal Locomotion, Humanoid Robots
Abstract: The traction force of any moving object on a floor is the frictional force between the object and the floor. Therefore, investigation of the frictional constraint is very important for such moving object on a floor as well as a biped walking robot. Conventionally, the study of frictional constraint of a biped robot was only constrained in translational slip, without considering rotational slip, which is actually important in actual biped walking. This is one of the causes the walking speed of biped robots lower than the one of human beings. In this paper, an evaluation method of frictional constraints for biped robots is proposed. The translational friction force and the twist frictional torque acting on the biped robot’s sole are both deduced and verified for single support phase. First, based on a biped robot model, an approach to calculate the frictional force and torque is deduced as the quantitative expression of frictional constraint. Then, the experimental verification method is designed and the proposed calculation approach is confirmed. Finally, the consideration of the result of experiments is discussed. This approach is expected to be used for helping the realization of fast biped walkings.
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11:30-11:45, Paper WeAT8.5 | Add to My Program |
Dynamic Walking Over Rough Terrains by Nonlinear Predictive Control of the Floating-Base Inverted Pendulum |
Caron, Stephane | Lirmm Cnrs |
Kheddar, Abderrahmane | CNRS-AIST JRL (Joint Robotics Lab. UMI3218/CRT |
Keywords: Humanoid and Bipedal Locomotion
Abstract: We present a real-time pattern generator for dynamic walking over rough terrains. Our method automatically finds step durations, a critical issue over rough terrains where they depend on terrain topology. To achieve this level of generality, we consider a Floating-base Inverted Pendulum (FIP) model where the center of mass can translate freely and the zero-tilting moment point is allowed to leave the contact surface. This model is equivalent to a linear inverted pendulum with variable center-of-mass height, but its equations of motion remain linear. Our solution then follows three steps: (i) we characterize the FIP contact-stability condition; (ii) we compute feedforward controls by solving a nonlinear optimization over receding-horizon FIP trajectories. Despite running at 30~Hz in a model-predictive fashion, simulations show that the latter is too slow to stabilize dynamic motions. To remedy this, we (iii) linearize FIP feedback control into a constrained linear-quadratic regulator that runs at 300~Hz. We finally demonstrate our solution in simulations with a model of the HRP-4 humanoid robot, including noise and delays over state estimation and foot force control.
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11:45-12:00, Paper WeAT8.6 | Add to My Program |
Almost Driftless Navigation of 3D Limit-Cycle Walking Bipeds |
Veer, Sushant | Univ. of Delaware |
Shafiee Motahar, Mohamad | Univ. of Delaware |
Poulakakis, Ioannis | Univ. of Delaware |
Keywords: Humanoid and Bipedal Locomotion, Legged Robots
Abstract: This paper presents a method for navigating 3D dynamically walking bipedal robots amidst obstacles. Our framework relies on composing gait primitives corresponding to limit-cycle locomotion behaviors and it produces nominal motion plans that are compatible with the system's dynamics and can be tracked with high fidelity. The low-level controllers of the biped are designed within the Hybrid Zero Dynamics (HZD) framework. Exploiting the dimensional reduction afforded by HZD and properties of invariant sets of switching systems among multiple equilibria, we obtain polynomial approximations of a reduced order Poincare map and of the net change of the center of mass location over a stride. These polynomials are then incorporated in a high-level Rapidly Exploring Random Tree (RRT) planner to generate nominal plans which are tracked by the biped with drastically low drifting errors, without adversely affecting the time for computation.
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WeAT9 , Room 204 |
Add to My Program |
Human Assistive Systems |
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Chair: Zecca, Massimiliano | Loughborough Univ |
Co-Chair: Artemiadis, Panagiotis | Arizona State Univ |
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10:30-10:45, Paper WeAT9.1 | Add to My Program |
Real-Time End-Effector Motion Behavior Planning Approach Using On-Line Point-Cloud Data towards a User Adaptive Assistive Bath Robot |
Dometios, Athanasios | National Tech. Univ. of Athens (NTUA) |
Papageorgiou, Xanthi S. | National Tech. Univ. of Athens |
Arvanitakis, Antonis | National Tech. Univ. of Athens |
Tzafestas, Costas S. | ICCS - Inst. of Communication and Computer Systems |
Maragos, Petros | National Tech. Univ. of Athens |
Keywords: Automation in Life Sciences: Biotechnology, Pharmaceutical and Health Care, Physically Assistive Devices, Service Robots
Abstract: Elderly people have particular needs in performing bathing activities, since these tasks require body flexibility. Our aim is to build an assistive robotic bath system, in order to increase the independence and safety of this procedure. Towards this end, the expertise of professional carers for bathing sequences and appropriate motions have to be adopted, in order to achieve natural, physical human - robot interaction. In this paper, a real-time end-effector motion planning method for an assistive bath robot, using on-line Point-Cloud information, is proposed. The visual feedback obtained from Kinect depth sensor is employed to adapt suitable washing paths to the user’s body part motion and deformable surface. We make use of a navigation function-based controller, with guarantied globally uniformly asymptotic stability, and bijective transformations for the adaptation of the paths. Experiments were conducted with a rigid rectangular object for validation purposes, while a male and a female subject took part to the experiment in order to evaluate and demonstrate the basic concepts of the proposed methodology.
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10:45-11:00, Paper WeAT9.2 | Add to My Program |
Towards a User-Adaptive Context-Aware Robotic Walker with a Pathological Gait Assessment System: First Experimental Study |
Chalvatzaki, Georgia | NATIONAL Tech. Univ. OF ATHENS |
Papageorgiou, Xanthi S. | National Tech. Univ. of Athens |
Tzafestas, Costas S. | ICCS - Inst. of Communication and Computer Systems |
Keywords: Automation in Life Sciences: Biotechnology, Pharmaceutical and Health Care, Physically Assistive Devices, Medical Robots and Systems
Abstract: When designing a user-friendly Mobility Assistive Device (MAD) for mobility constrained people, it is important to take into account the diverse spectrum of disabilities, which results into completely different needs to be covered by the MAD for each specific user. An intelligent adaptive behavior is necessary for the deployment of a MAD. In this work we present experimental results, using an in house developed methodology for estimating the gait of users with different mobility status while interacting with a robotic MAD. Our methodology uses a laser scanner, mounted on the MAD to track the legs positions using Particle Filters and Probabilistic Data Association (PDA-PF). The legs' states are fed to an HMM-based pathological gait cycle recognition system to compute in real-time the gait parameters that are crucial for the mobility status characterization of the user. We aim to show that a gait assessment system would be an important feedback for an intelligent MAD. Thus, we use this system to compare the gaits of the subjects using two different control settings of the MAD and we experimentally validate the ability of our system to recognize the impact of the control designs on the users' walking performance. The results demonstrate that a generic control scheme does not meet every patient's needs, and therefore, an Adaptive Context-Aware MAD (ACA MAD), that can understand the specific needs of the user, is important for enhancing the human-robot physical interaction.
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11:00-11:15, Paper WeAT9.3 | Add to My Program |
Supervisory Control of a DaVinci Surgical Robot |
Chow, Der-Lin | Case Western Res. Univ |
Xu, Peng | Case Western Res. Univ |
Tuna, Eser Erdem | Case Western Res. Univ |
Huang, Siqi | Case Western Res. Univ |
Cavusoglu, M. Cenk | Case Western Res. Univ |
Newman, Wyatt | Case Western Res. Univ |
Keywords: Automation in Life Sciences: Biotechnology, Pharmaceutical and Health Care, Surgical Robotics: Laparoscopy
Abstract: This paper presents an approach to supervisory control of a DaVinci surgical robot. At present, such robots are controlled by teleoperation, with dissimilar kinematics of the operator interface vs. the robot. As a result, it can be difficult for the operator to visualize the kinematic restrictions on the robot, particularly for desired extended, precise trajectories, such as circular needle driving. The interface presented here constitutes a means to elevate the operator from teleoperation mode to supervisory mode. The operator interacts directly with a point-cloud display, allowing selection of task specifications from which the system automatically computes and executes precise trajectories to achieve the task goals. The intent is to allow the operator to focus on task specifications and rely on automation to achieve faster and more precise execution.
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11:15-11:30, Paper WeAT9.4 | Add to My Program |
Step Sequence and Direction Detection of Four Square Step Test |
Kong, Weisheng | Waseda Univ |
Waaning, Lauren | Loughborough Univ |
Sessa, Salvatore | Waseda Univ |
Zecca, Massimiliano | Loughborough Univ |
Magistro, Daniele | Loughborough Univ |
Takeuchi, Hikaru | Tohoku Univ |
Kawashima, Ryuta | Tohoku Univ |
Takanishi, Atsuo | Waseda Univ |
Keywords: Automation in Life Sciences: Biotechnology, Pharmaceutical and Health Care, Health Care Management, Sensor Fusion
Abstract: Poor balance control and falls are big issues for older adults that due to aging decline have a lower postural balance and directional control in balance performance than younger age groups. The four square step test (FSST) was developed to evaluate rapid stepping that is often required when changing direction and avoiding obstacles while walking. However, previous researchers used only the total time as the assessment in the test. The aim of this paper is to objectively quantify the sequence and direction of the steps in FSST, by using two inertial sensors placed on both feet. An algorithm was developed to automatically segment the steps performed during the test, and calculate the stepping direction from the linear velocity of the foot. Experiments were conducted with 100 Japanese healthy older adults, where sensor data and video of 20 subjects were randomly subtracted for algorithm verification. The results showed that the algorithm succeeded for 71.7% trials in recognizing both the step sequence and step direction in FSST, while 90.2% of the detection failure could be excluded with an auto verification method.
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11:30-11:45, Paper WeAT9.5 | Add to My Program |
Multi-Modal Trip Hazard Affordance Detection on Construction Sites |
McMahon, Sean M | Queensland Univ. of Tech |
Sünderhauf, Niko | Queensland Univ. of Tech |
Upcroft, Ben | Queensland Univ. of Tech |
Milford, Michael J | Queensland Univ. of Tech |
Keywords: Robotics in Construction, Computer Vision for Other Robotic Applications, Visual Learning
Abstract: Trip hazards are a significant contributor to accidents on construction and manufacturing sites. Current safety inspections are labour intensive and limited by human fallibility,making automation of trip hazard detection appealing from both a safety and economic perspective. Trip hazards present an interesting challenge to modern learning techniques because they are defined as much by affordance as by object type; for example wires on a table are not a trip hazard, but can be if lying on the ground. To address these challenges, we conduct a comprehensive investigation into the performance characteristics of 11 different colour and depth fusion approaches,including 4 fusion and one non fusion approach; using colour and two types of depth images. Trained and tested on over 600 labelled trip hazards over 4 floors and 2000m 2 in an active construction site, this approach was able to differentiate between identical objects in different physical configurations.Outperforming a colour-only detector, our multi-modal trip detector fuses colour and depth information to achieve a 4% absolute improvement in F1-score. These investigative results and the extensive publicly available dataset moves us one step closer to assistive or fully automated safety inspection systems on construction sites.
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11:45-12:00, Paper WeAT9.6 | Add to My Program |
A Hybrid Brain-Machine Interface for Control of Robotic Swarms: Preliminary Results |
Karavas, George K. | Arizona State Univ |
Larsson, Daniel | Arizona State Univ |
Artemiadis, Panagiotis | Arizona State Univ |
Keywords: Brain Machine Interfaces
Abstract: Human Swarm Interaction (HSI) is a new field which relates to the effective control of robotic swarms by human operators and has received increased attention lately. Based on the approaches that have been proposed, it is evident that the control of swarms can become quite complicated. On the other hand, Brain Machine Interfaces (BMI) can offer intuitive control in a plethora of applications where other interfaces alone (e.g. joysticks) are inadequate or impractical, e.g. for people with motor disabilities. There are multiple types of BMI, but most of them rely on the analysis of ElectroEncephaloGraphic (EEG) signals. The authors have previously shown that swarm behaviors elicit specific brain activity on human subjects that observe them. Motivated by this result, in this work, we present preliminary results of a hybrid BMI that combines information from the brain and an external device. An algorithm for extracting information from the frequency domain of EEG signals that allows integration with the manual task of using a joystick is presented. The hybrid interface shows high accuracy and robustness when used as a brain-robot interface. Moreover, it allows for continuous control variables extracted from the EEG signals. Finally, its efficacy is proven across multiple subjects, while its performance is also demonstrated in the real-time control of a swarm of quadrotors.
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WeAT10 , Room 205 |
Add to My Program |
Object Detection, Segementation, and Categorization I |
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Chair: Triebel, Rudolph | Tech. Univ. Munich |
Co-Chair: Pham, Trung | The Univ. of Adelaide |
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10:30-10:45, Paper WeAT10.1 | Add to My Program |
Autonomous Meshing, Texturing and Recognition of Object Models with a Mobile Robot |
Ambrus, Rares | Royal Inst. of Tech. (KTH) Stockholm Sweden |
Bore, Nils | KTH Royal Inst. of Tech |
Folkesson, John | KTH |
Jensfelt, Patric | KTH - Royal Inst. of Tech |
Keywords: Object detection, segmentation, categorization, Autonomous Agents, Deep Learning in Robotics and Automation
Abstract: We present a system for creating object models from RGB-D views acquired autonomously by a mobile robot. We create high-quality textured meshes of the objects by approximating the underlying geometry with a Poisson surface. Our system employs two optimization steps, first registering the views spatially based on image features, and second aligning the RGB images to maximize photometric consistency with respect to the reconstructed mesh. We show that the resulting models can be used robustly for recognition by training a Convolutional Neural Network (CNN) on images rendered from the reconstructed meshes. We perform experiments on data collected autonomously by a mobile robot both in controlled and uncontrolled scenarios. We compare quantitatively and qualitatively to previous work to validate our approach.
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10:45-11:00, Paper WeAT10.2 | Add to My Program |
Meaningful Maps with Object-Oriented Semantic Mapping |
Sünderhauf, Niko | Queensland Univ. of Tech |
Pham, Trung | The Univ. of Adelaide |
Latif, Yasir | Univ. of Adelaide |
Milford, Michael J | Queensland Univ. of Tech |
Reid, Ian | Univ. of Adelaide |
Keywords: Object detection, segmentation, categorization, Mapping, Semantic Scene Understanding
Abstract: For intelligent robots to interact in meaningful ways with their environment, they must understand both the geometric and semantic properties of the scene surrounding them. The majority of research to date has addressed these mapping challenges separately, focusing on either geometric or semantic mapping. In this paper we address the problem of building environmental maps that include both semantically meaningful, object-level entities and point- or mesh-based geometrical representations. We simultaneously build geometric point cloud models of previously unseen instances of known object classes and create a map that contains these object models as central entities. Our system leverages sparse, feature-based RGB-D SLAM, image-based deep-learning object detection and 3D unsupervised segmentation.
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11:00-11:15, Paper WeAT10.3 | Add to My Program |
Selecting CNN Features for Online Learning of 3D Objects |
Ullrich, Monika | German Aerospace Center (DLR) |
Ali, Haider | Johns Hopkins Univ |
Durner, Maximilian | German Aerospace Center DLR |
Marton, Zoltan-Csaba | German Aerospace Center (DLR) |
Triebel, Rudolph | Tech. Univ. Munich |
Keywords: Object detection, segmentation, categorization, RGB-D Perception, Recognition
Abstract: We present a novel method for classifying 3D objects that is particularly tailored for the requirements in robotic applications. The major challenges here are the comparably small amount of available training data and the fact that often data is perceived in streams and not in fixed-size pools. Traditional state-of-the-art learning methods, however, require a large amount of training data, and their online learning capabilities are usually limited. Therefore, we propose a modality-specific selection of convolutional neural networks (CNN), pre-trained or fine-tuned, in combination with a classifier that is designed particularly for online learning from data streams, namely the Mondrian Forest (MF). We show that this combination of trained features obtained from a CNN can be improved further if a feature selection algorithm is applied. In our experiments, we use the resulting features both with a MF and a linear Support Vector Machine (SVM). With SVM we beat the state of the art on an RGB-D dataset, while with MF a strong result for active learning is achieved.
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11:15-11:30, Paper WeAT10.4 | Add to My Program |
Probabilistic 3D Multilabel Real-Time Mapping for Multi-Object Manipulation |
Wada, Kentaro | The Univ. of Tokyo |
Okada, Kei | The Univ. of Tokyo |
Inaba, Masayuki | The Univ. of Tokyo |
Keywords: Object detection, segmentation, categorization, RGB-D Perception, Perception for Grasping and Manipulation
Abstract: Probabilistic 3D map has been used for object segmentation with multiple camera viewpoints, however, con- ventional methods lack of real-time efficiency or functionality of multilabel object mapping. In this paper, we propose a method to generate three-dimensional map with multilabel occupancy in real-time. Extending our previous work in which only target label occupancy is mapped, we achieve multilabel object segmentation in a single looking around action. We evaluate our method by testing segmentation accuracy with 39 different ob- jects, and applying to robotic manipulation of multiple objects in the experiments. Our mapping-based method outperforms the conventional registration-based method: 40 - 96% relative to 12.6 mean IU3d, and the robot successfuly recognizes (86.9%) and manipulates multiple objects (60.7%) in an environment with heavy occlusions.
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11:30-11:45, Paper WeAT10.5 | Add to My Program |
What Makes a Place? Building Bespoke Place Dependent Object Detectors for Robotics |
Hawke, Jeffrey | Univ. of Oxford |
Bewley, Alex | Univ. of Oxford |
Posner, Ingmar | Oxford Univ |
Keywords: Object detection, segmentation, categorization, Visual Learning, Computer Vision for Transportation
Abstract: This paper is about enabling robots to improve their perceptual performance through repeated use in their operating environment, creating local expert detectors fitted to the places through which a robot moves. We leverage the concept of 'experiences' in visual perception for robotics, accounting for bias in the data a robot sees by fitting object detector models to a particular 'place'. The key question we seek to answer in this paper is simply: how do we define a place? We build bespoke pedestrian detector models for autonomous driving, highlighting the necessary trade off between generalisation and model capacity as we vary the extent of the 'place' we fit to. We demonstrate a sizeable performance gain over a current state-of-the-art detector when using computationally lightweight bespoke place-fitted detector models.
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11:45-12:00, Paper WeAT10.6 | Add to My Program |
MFNet: Towards Real-Time Semantic Segmentation for Autonomous Vehicles with Multi-Spectral Scenes |
Ha, Qishen | The Univ. of Tokyo |
Watanabe, Kohei | The Univ. of Tokyo |
Karasawa, Takumi | The Univ. of Tokyo |
Ushiku, Yoshitaka | Grad School of Information Science & Tech. the Univ |
Harada, Tatsuya | The Univ. of Tokyo |
Keywords: Object detection, segmentation, categorization, Computer Vision for Transportation, Autonomous Vehicle Navigation
Abstract: This work addresses the semantic segmentation of images of street scenes for autonomous vehicles based on a new RGB-Thermal dataset, which is also introduced in this paper. An increasing interest in self-driving vehicles has necessitated the adaptation of semantic segmentation for self-driving systems. However, recent research relating to semantic segmentation is mainly based on RGB images acquired during times of poor visibility at night and under adverse weather conditions. Furthermore, most of these methods only focused on improving performance while ignoring time consumption. The aforementioned problems prompted us to propose new convolutional neural network architecture for multi-spectral image segmentation that enables the segmentation accuracy to be retained during real-time operation. We benchmarked our method by creating an RGB-Thermal dataset in which thermal and RGB images are combined. We showed that the segmentation accuracy was significantly increased by adding thermal infrared information.
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WeAT11 , Room 207 |
Add to My Program |
Aerial Systems: Mechanics and Control I |
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Chair: Papanikolopoulos, Nikos | Univ. of Minnesota |
Co-Chair: Shen, Shaojie | Hong Kong Univ. of Science and Tech |
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10:30-10:45, Paper WeAT11.1 | Add to My Program |
A Unified Approach to Configuration-Based Dynamic Analysis of Quadcopters for Optimal Stability |
Hedayatpour, Mojtaba | Univ. of Regina |
Mehrandezh, Mehran | Univ. of Regina |
Janabi-Sharifi, Farrokh | Ryerson Univ |
Keywords: Aerial Systems: Mechanics and Control, Underactuated Robots
Abstract: A special type of rotary-wing Unmanned Aerial Vehicles (UAV), called Quadcopter have prevailed to the civilian use for the past decade. They have gained significant amount of attention within the UAV community for their redundancy and ease of control, despite the fact that they fall under an under-actuated system category. They come in a variety of configurations. The "+" and "x" configurations were introduced first. Literature pertinent to these two configurations is vast. However, in this paper, we define 6 additional possible configurations for a Quadcopter that can be built under either "+" or "x" setup. These configurations can be achieved by changing the angle that the axis of rotation for rotors make with the main body, i.e., fuselage. This would also change the location of the COM with respect to the propellers which can add to the overall stability. A comprehensive dynamic model for all these configurations is developed for the first time. The overall stability for these configurations are addressed. In particular, it is shown that one configuration can lead to the most statically-stable platform by adopting damping motion in Roll/Pitch/Yaw, which is described for the first time to the best of our knowledge.
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10:45-11:00, Paper WeAT11.2 | Add to My Program |
Wall Contact by Octo-Rotor UAV with One DoF Manipulator for Bridge Inspection |
Ikeda, Takahiro | Meijo Univ |
Yasui, Shogo | Meijo Univ |
Fujihara, Motoharu | Meijo Univ |
Ohara, Kenichi | Meijo Univ |
Ashizawa, Reiji | Meijo Univ |
Ichikawa, Akihiko | Meijo Univ |
Okino, Akihisa | Okino Industries, LTD |
Oomichi, Takeo | Meijo Univ |
Fukuda, Toshio | Meijo Univ |
Keywords: Aerial Systems: Mechanics and Control, Aerial Systems: Applications, Robotics in Construction
Abstract: This paper describes a octo-rotor unmanned aerial vehicle (UAV) with one degree of freedom (DoF) manipulator for bridge inspection. The UAV has an ability to contact bridge pier to conduct hammering test. To control contact force applied by the UAV to the bridge pier, one DoF is enough for the manipulator implemented on the UAV. A preliminary experiment shows that the force is proportional to the pitch angle of the UAV when it contacts the bridge pier. A bridge pier contact experiment shows that our developed UAV can control contact force between its end-effector and the bridge pier; mean error of the contact force is 4.27[N] (S.D. is 3.64 [N]) against 20[N] desired force.
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11:00-11:15, Paper WeAT11.3 | Add to My Program |
Enabling Robot Assisted Landing of Heavy UAV Rotorcraft Via Combined Control and Workload Sharing |
Maier, Moritz | German Aerospace Center (DLR) |
Kondak, Konstantin | German Aerospace Center |
Ott, Christian | German Aerospace Center (DLR) |
Keywords: Aerial Systems: Mechanics and Control, Motion Control of Manipulators, Redundant Robots
Abstract: In this paper, a tracking control approach for robot assisted landing of UAV rotorcraft, such as multicopters and helicopters, is presented. The aim is to safely land these type of flying vehicles under side wind conditions and on moving surfaces using a robot manipulator arm mounted on the ground. In our previous work, we have considered light UAVs compared to the robot's payload capabilities. In this work, we present a method that enables to realize robot assisted landing for arbitrary combinations of aerial vehicles and robot arms. We show that the combined system is overactuated. This allows to distribute the workload and enables to assist heavy rotorcraft, whose weight would otherwise exceed the nominal payload of the robot arm. The performance of the controller is evaluated in numerical simulations as well as in experiments using a custom-built hexacopter and a KUKA/DLR light-weight robot.
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11:15-11:30, Paper WeAT11.4 | Add to My Program |
A Hierarchical Control Approach for a Quadrotor Tail-Sitter VTOL UAV and Experimental Verification |
Lyu, Ximin | Hong Kong Univ. of Science and Tech |
Gu, Haowei | Hong Kong Univ. of Science and Tech |
Zhou, Jinni | Hong Kong Univ. of Science and Tech |
Li, Zexiang | Hong Kong Univ. of Science and Tech |
Shen, Shaojie | Hong Kong Univ. of Science and Tech |
Zhang, Fu | Hong Kong Univ. of Science and Tech |
Keywords: Aerial Systems: Mechanics and Control, Control Architectures and Programming, Dynamics
Abstract: We present a hierarchical control approach that can be used to fulfill autonomous flight, including vertical takeoff, landing, hovering, transition, and level flight, of a quadrotor tail-sitter vertical takeoff and landing unmanned aerial vehicle (VTOL UAV). A unified attitude controller, together with a moment allocation scheme between elevons and motor differential thrust, is developed for all flight modes. A comparison study via real flight tests is performed to verify the effectiveness of using elevons in addition to motor differential thrust. With the well-designed switch scheme proposed in this paper, the aircraft can transit between different flight modes with negligible altitude drop or gain. Intensive flight tests have been performed to verify the effectiveness of the proposed control approach in both manual and fully autonomous flight mode.
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11:30-11:45, Paper WeAT11.5 | Add to My Program |
Energy Characterization of a Transformable Solar-Powered Unmanned Aerial Vehicle |
Jenson, Devon | Cse, Umn |
D'Sa, Ruben | Univ. of Minnesota |
Henderson, Travis | Cse, Umn |
Kilian, Jack | Cse, Umn |
Schulz, Bobby | Univ. of Minnesota Twin Cities |
Papanikolopoulos, Nikos | Univ. of Minnesota |
Keywords: Aerial Systems: Mechanics and Control, Aerial Systems: Applications
Abstract: Given the wide variety of flight conditions typically encountered by fixed-wing aerial vehicles, the flight performance of a solar unmanned aerial vehicle (SUAV) depends on many factors. Predicting the performance for a given application requires characterization of both system and environmental components. Furthermore, a UAV with a transformable airframe increases the number of characterizable states. Proposed in [1] is a SUAV capable of transforming between quad-rotor and fixed-wing configurations. Each state has a unique set of capabilities which result in significant differences with respect to power consumption and solar panel orientation, increasing the design limitations on various system components. This paper characterizes the solar radiation, propulsion system, and power electronics for both quad-rotor and fixed-wing states. Clear-sky and solar panel models are used to predict the power available for a given location and time. The propulsion system is modeled to predict power consumption for a given mass and considers the optimum propeller pitch. Custom power electronics are modeled and simulated to determine conversion efficiencies and battery sizes required to lift a given payload. The overall system model is discussed for specific applications and is compared with experimental flight data.
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11:45-12:00, Paper WeAT11.6 | Add to My Program |
A Small Hybrid Ground-Air Vehicle Concept |
Morton, Scott | Univ. of Minnesota |
Papanikolopoulos, Nikos | Univ. of Minnesota |
Keywords: Aerial Systems: Mechanics and Control, Aerial Systems: Applications
Abstract: Small robots benefit from the ability to go places where humans cannot and are attractive for numerous practical reasons such as portability and manufacturing simplicity. However, with smaller scale comes more difficulty traversing rough terrain, especially for robots which use wheel-based locomotion. Previous approaches to overcome this drawback have included auxiliary mechanisms such as jumping, transformations of the robot or its appendages, and alternative forms of locomotion such as aerial flight capability. This paper presents a small scale robot that is capable of both ground travel and aerial flight. These locomotion types, in combination, allow for efficient ground-based movement as well as the ability to overcome obstacles or explore otherwise unreachable locations through air travel. The novel aspect of this approach is a transformation between ground and air configurations which allows flight components to be stowed safely within the robot frame while in ground mode. This feature offers advantages over previous approaches such as a highly compact ground configuration and protection of delicate flight hardware when not in use. In this paper the concept is compared to other approaches to address ground robot mobility drawbacks and a detailed design is presented with a focus on the transformation between these modes. Lastly, a fully functional prototype is presented which is capable of ground and air locomotion and the transformation between these configurations.
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WeAT12 , Room 208 |
Add to My Program |
Agricultural Robotics I |
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Chair: Bhattacharya, Sourabh | Iowa State Univ |
Co-Chair: Dayoub, Feras | Queensland Univ. of Tech |
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10:30-10:45, Paper WeAT12.1 | Add to My Program |
Semi-Supervised Online Visual Crop and Weed Classification in Precision Farming Exploiting Plant Arrangement |
Lottes, Philipp | Univ. of Bonn |
Stachniss, Cyrill | Univ. of Bonn |
Keywords: Robotics in Agriculture and Forestry, Field Robots
Abstract: Precision farming robots offer a great potential for reducing the amount of agro-chemicals that is required in the fields through a targeted, per-plant intervention. To achieve this, robots must be able to reliably distinguish crops from weeds on different fields and across growth stages. In this paper, we tackle the problem of separating crops from weeds reliably while requiring only a minimal amount of training data through a semi-supervised approach. We exploit the fact that most crops are planted in rows with a similar spacing along the row, which in turn can be used to initialize a vision-based classifier requiring only minimal user efforts to adapt it to a new field. We implemented our approach using C++ and ROS and thoroughly tested it on real farm robots operating in different countries. The experiments presented in this paper show that with around 1 min of labeling time, we can achieve classification results with an accuracy of more than 95% in real sugar beet fields in Germany and Switzerland.
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10:45-11:00, Paper WeAT12.2 | Add to My Program |
Online Detection of Occluded Plant Stalks for Manipulation |
Jenkins, Merritt | Carnegie Mellon Univ |
Kantor, George | Carnegie Mellon Univ |
Keywords: Robotics in Agriculture and Forestry, Field Robots, Object detection, segmentation, categorization
Abstract: This paper describes an algorithm for visually detecting crop stalks in-situ. Field-based crop stalk detection is a challenging computer vision problem due to occlusion by leaves, similarity of color and texture between stalks and surrounding foliage, and high stalk density within rows. Detecting stalks for grasping adds further challenges such as computation time and computing hardware. The proposed algorithm utilizes multiple stereo images taken from an unmanned ground vehicle and exploits geometric features specific to stalks such as vertical continuity, height, and the direction of surface normals. The described hardware and software pipeline is capable of detecting stalks for a manipulator grasp in approximately 12 seconds, and preliminary results show that hardware improvements can reduce detection time to 4 seconds. The algorithm is tested on 378 point clouds generated from 916 images of Sorghum bicolor, a grain crop. Performance is evaluated according to two methods, demonstrating precision greater than 93%.
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11:00-11:15, Paper WeAT12.3 | Add to My Program |
Smart Autonomous Grain Carts for Harvesting-On-Demand |
Tian, Yan | Iowa State Univ |
Bhattacharya, Sourabh | Iowa State Univ |
Keywords: Autonomous Agents, Path Planning for Multiple Mobile Robots or Agents, Agricultural Automation
Abstract: In this work, we address the problem of centralized scheduling and motion planning for multiple grain carts with finite capacity that serve a group of combine harvesters engaged in a harvesting operation. First, we solve a facility location problem of finding the optimal depot position to minimize the distance traveled by the grain carts. Next, we formulate the scheduling problem as a constraint satisfaction problem. For a rectangular field, we present two schemes which allow the grain carts to unload all the combine harvesters without interrupting the harvesting activity. Finally, for both schemes, we present a relation between the physical parameters of the vehicles that need to be satisfied in order to meet the scheduling constraints.
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11:15-11:30, Paper WeAT12.4 | Add to My Program |
A Transplantable System for Weed Classification by Agricultural Robotics |
Hall, David | Queensland Univ. of Tech |
Dayoub, Feras | Queensland Univ. of Tech |
Perez, Tristan | Queensland Univ. of Tech |
McCool, Christopher Steven | Queensland Univ. of Tech |
Keywords: Computer Vision for Automation, Robotics in Agriculture and Forestry
Abstract: This work presents a rapidly deployable system for automated precision weeding with minimal human labeling time. This overcomes a limiting factor in robotic precision weeding related to the use of vision-based classification systems trained for species that may not be relevant to specific farms. We present a novel approach to overcome this problem by employing unsupervised weed scouting, weed-group labeling, and finally, weed classification that is trained on the labeled scouting data. This work demonstrates a novel labeling approach designed to maximize labeling accuracy whilst needing to label as few images as possible. The labeling approach is able to provide the best classification results of any of the examined exemplar-based labeling approaches whilst needing to label over seven times fewer images than full data labeling.
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11:30-11:45, Paper WeAT12.5 | Add to My Program |
In-Field Segmentation and Identification of Plant Structures Using 3D Imaging |
Sodhi, Paloma | Carnegie Mellon Univ |
Vijayarangan, Srinivasan | Carnegie Mellon Univ |
Wettergreen, David | Carnegie Mellon Univ |
Keywords: Robotics in Agriculture and Forestry, Agricultural Automation, Computer Vision for Automation
Abstract: Automatically correlating plant observable characteristics to their underlying genetics will streamline selection methods in plant breeding. Measurement of plant observable characteristics is called phenotyping, and knowing plant phenotypes accurately and throughout a plant's growth is central to making breeding decisions. In-field plant phenotyping in an automated and noninvasive manner is hence crucial to accelerating plant breeding methods. However, most of the existing methods on plant phenotyping using visual imaging are confined to controlled greenhouse environments. This paper presents an automated method of mapping 2D images collected in an outdoor sorghum field to segmented 3D plant units that are of interest for phenotyping. This method leverages multiple horizontal and vertical viewpoints while capturing 2D images from a robotic platform so as to generate in-field 3D reconstructions of the sorghum plant. We develop and quantitatively evaluate segmentation methods on these 3D reconstructions and also compare against reconstructions obtained from a controlled greenhouse environment. We present analysis that contrasts the role of purely local geometric features and the effect of addition of global context in both datasets. This work furthers capabilities of in-field phenotyping which paves the way forward for plant biologists to study the coupled effect of genetics and environment on improving crop yields.
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11:45-12:00, Paper WeAT12.6 | Add to My Program |
Automatic Model Based Dataset Generation for Fast and Accurate Crop and Weeds Detection |
Di Cicco, Maurilio | Sapienza Univ. of Rome |
Potena, Ciro | Sapienza Univ. of Rome |
Grisetti, Giorgio | Sapienza Univ. of Rome |
Pretto, Alberto | Sapienza Univ. of Rome |
Keywords: Robotics in Agriculture and Forestry, Agricultural Automation, Computer Vision for Other Robotic Applications
Abstract: Selective weeding is one of the key challenges in the field of agriculture robotics. To accomplish this task, a farm robot should be able to accurately detect plants and to distinguish them between crop and weeds. Most of the promising state-of-the-art approaches make use of appearance-based models trained on large annotated datasets. Unfortunately, creating large agricultural datasets with pixel-level annotations is an extremely time consuming task, actually penalizing the usage of data-driven techniques. In this paper, we face this problem by proposing a novel and effective approach that aims to dramatically minimize the human intervention needed to train the detection and classification algorithms. The idea is to procedurally generate large synthetic training datasets randomizing the key features of the target environment (i.e., crop and weed species, type of soil, light conditions). More specifically, by tuning these model parameters, and exploiting a few real-world textures, it is possible to render a large amount of realistic views of an artificial agricultural scenario with no effort. The generated data can be directly used to train the model or to supplement real-world images. We validate the proposed methodology by using as testbed a modern deep learning based image segmentation architecture. We compare the classification results obtained using both real and synthetic images as training data. The reported results confirm the effectiveness and the potentiality of our approach.
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WeAT13 , Room 211 |
Add to My Program |
Motion and Path Planning V |
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Chair: Manocha, Dinesh | Univ. of North Carolina at Chapel Hill |
Co-Chair: Dai, Ran | Iowa State Univ |
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10:30-10:45, Paper WeAT13.1 | Add to My Program |
Towards Planning and Control of Hybrid Systems with Limit Cycle Using LQR Trees |
Rajasekaran, Siddharthan | Worcester Pol. Inst |
Natarajan, Ramkumar | Worcester Pol. Inst |
Taylor, Jonathan D. | Carnegie Mellon Univ |
Keywords: Hybrid Logical/Dynamical Planning and Verification, Optimization and Optimal Control, Motion and Path Planning
Abstract: We present a multi-query recovery policy for a hybrid system with goal limit cycle. The sample trajectories and the hybrid limit cycle of the dynamical system are stabilized using locally valid Time Varying LQR controller policies which probabilistically cover a bounded region of state space. The original LQR Tree algorithm builds such trees for non-linear static and non-hybrid systems like a pendulum or a cart-pole. We leverage the idea of LQR trees to plan with a continuous control set, unlike methods that rely on discretization like dynamic programming to plan for hybrid dynamical systems where it is hard to capture the exact event of discrete transition. We test the algorithm on a compass gait model by stabilizing a dynamic walking hybrid limit cycle with point foot contact from random initial conditions. We show results from the simulation where the system comes back to a stable behavior with initial position or velocity perturbation and noise.
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10:45-11:00, Paper WeAT13.2 | Add to My Program |
Ergodic Coverage in Constrained Environments Using Stochastic Trajectory Optimization |
Ayvali, Elif | Carnegie Mellon Univ |
Salman, Hadi | Carnegie Mellon Univ |
Choset, Howie | Carnegie Mellon Univ |
Keywords: Motion and Path Planning, Multi-Robot Systems, Optimization and Optimal Control
Abstract: In search and surveillance applications in robotics, it is intuitive to spatially distribute robot trajectories with respect to the probability of locating targets in the domain. Ergodic coverage is one such approach to trajectory planning in which a robot is directed such that the percentage of time spent in a region is in proportion to the probability of locating targets in that region. In this work, we extend the ergodic coverage algorithm to robots operating in constrained environments and present a formulation that can capture sensor footprint and avoid obstacles and restricted areas in the domain. We demonstrate that our formulation easily extends to coordination of multiple robots equipped with different sensing capabilities to perform ergodic coverage of a domain.
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11:00-11:15, Paper WeAT13.3 | Add to My Program |
Sampling-Based Coverage Motion Planning for Industrial Inspection Application with Redundant Robotic System |
Jing, Wei | Carnegie Mellon Univ |
Polden, Joseph | Singapore Inst. of Manufacturing Tech. (SIMTech) |
Goh, Chun Fan | Carnegie Mellon Univ |
Rajaraman, Mabaran | Carnegie Mellon Univ |
Lin, Wei | SIMTech, A*STAR |
Shimada, Kenji | Carnegie Mellon Univ |
Keywords: Motion and Path Planning, Task Planning, Planning, Scheduling and Coordination
Abstract: This paper presents a novel sampling-based motion planning method for shape inspection applications with a redundant robotic system. In this paper, a 7-Degree-of-Freedom (DOF) redundant robotic system consisting of a 6-DOF manipulator and a 1-DOF turntable is used for the industrial inspection problem. A Set Covering Problem (SCP) is formulated to select suitable viewpoints that satisfy the inspection requirements, and a Generalized Travelling Salesman Problem (GTSP) is formulated to determine both the robot poses and the visiting sequences. While previous studies solve the two problems separately, we formulate the SCP and GTSP problems as a combined sequencing SC-GTSP problem. A Random-Key Genetic Algorithm (RKGA) is then used to solve the combined SC-GTSP problem in a one-step optimization process. To validate the effectiveness of our method, we applied the proposed method to several motion planning cases. The results show that the proposed method outperforms the previous approaches by requiring up to 28.1% less total inspection time.
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11:15-11:30, Paper WeAT13.4 | Add to My Program |
Static Force Distribution and Orientation Control for a Rover with an Actively Articulated Suspension System |
Cordes, Florian | DFKI Robotics Innovation Center Bremen |
Babu, Ajish | German Res. Center for Artificial Intelligence (DFKI) |
Kirchner, Frank | Univ. of Bremen |
Keywords: Space Robotics and Automation, Motion Control, Legged Robots
Abstract: This paper presents the control strategies used to adapt the actively articulated suspension system of the rover SherpaTT to irregular terrain. Experimental validation of the approach with the physical system is conducted and presented. The coordinated control of the legs constituting the suspension system is encapsulated in a Ground Adaption Process (GAP) that operates independently from high level motion commands. The GAP makes use of force and orientation measurements to control the suspension system with 20 active degrees of freedom. The active suspension is used to achieve multi-objective terrain adaption encompassing (i) active force distribution at the wheel-ground contact points, (ii) keeping all wheels in permanent ground contact, and (iii) body orientation wrt gravity.
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11:30-11:45, Paper WeAT13.5 | Add to My Program |
Probabilistic Prioritization of Movement Primitives |
Paraschos, Alexandros | Tech. Univ. Darmstadt |
Lioutikov, Rudolf | Tech. Univ. Darmstadt |
Peters, Jan | Tech. Univ. Darmstadt |
Neumann, Gerhard | Univ. of Lincoln |
Keywords: Learning from Demonstration
Abstract: Movement prioritization is a common approach to combine controllers of different tasks for redundant robots, where each task is assigned a priority. The priorities of the tasks are often hand-tuned or the result of an optimization, but seldomly learned from data. This paper combines Bayesian task prioritization with probabilistic movement primitives to prioritize full motion sequences that are learned from demonstrations. Probabilistic movement primitives (ProMPs) can encode distributions of movements over full motion sequences and provide control laws to exactly follow these distributions. The probabilistic formulation allows for a natural application of Bayesian task prioritization. We extend the ProMP controllers with an additional feedback component that accounts inaccuracies in following the distribution and allows for a more robust prioritization of primitives. We demonstrate how the task priorities can be obtained from imitation learning and how different primitives can be combined to solve even unseen task-combinations. Due to the prioritization, our approach can efficiently learn a combination of tasks without requiring individual models per task combination. Further, our approach can adapt an existing primitive library by prioritizing additional controllers, for example, for implementing obstacle avoidance. Hence, the need of retraining the whole library is avoided in many cases. We evaluate our approach on reaching movements under constraints with redundant simulated planar robots and two physical robot platforms, humanoid robot ``iCub'' and a humanoid robot arm.
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11:45-12:00, Paper WeAT13.6 | Add to My Program |
Mission Planning for a Multi-Robot Team with a Solar-Powered Charging Station |
Kingry, Nathaniel | Iowa State Univ |
Liu, Yen-Chen | Iowa State Univ |
Simon, Benjamin | Iowa State Univ |
Bang, Yun Qi | Iowa State Univ |
Dai, Ran | Iowa State Univ |
Keywords: Energy and Environment-Aware Automation, Motion and Path Planning, Multi-Robot Systems
Abstract: This paper presents a mission planning problem for a cooperative team of unmanned ground vehicles (UGVs), which includes multiple rovers and a solar-powered mobile charging station. The team is required to start at an initial point and visit a series of objective points before arriving at the final point selected from the set of objective points, where the UGVs will be charged from the solar-powered mobile charging station. This mission is represented as a multi-Hamiltonian Path Problem (mHPP). In order to effectively coordinate the team, an understanding of the mission environment is first obtained by generating a scalar field representation of the solar insolation of the environment from a visual-spectrum image. Then, a cascaded heuristic optimization algorithm, using modified genetic algorithm and particle swarm optimization, is used to generate a time-optimized mission plan for the team of UGVs, which guides each UGV to its assigned objective points and then rendezvous at the final charging location while guaranteeing compliance with the net energy gain constraint. The feasibility and efficiency of the proposed algorithm are verified using an experimental testbed and constructed indoor simulation environments.
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WeAT14 , Room 217 |
Add to My Program |
Humanoid Locomotion |
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Chair: Poulakakis, Ioannis | Univ. of Delaware |
Co-Chair: Asano, Fumihiko | Japan Advanced Inst. of Science and Tech |
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10:30-10:45, Paper WeAT14.1 | Add to My Program |
Distributed Torque Estimation Toward Low-Latency Variable Stiffness Control for Gear-Driven Torque Sensorless Humanoid |
Nagamatsu, Yuya | The Univ. of Tokyo |
Shirai, Takuma | Tokyo Univ |
Suzuki, Hiroto | The Univ. of Tokyo |
Kakiuchi, Yohei | The Univ. of Tokyo |
Okada, Kei | The Univ. of Tokyo |
Inaba, Masayuki | The Univ. of Tokyo |
Keywords: Humanoid Robots, Force Control, Legged Robots
Abstract: This paper explains low-latency joint torque feedback control based on torque estimation on each joint for gear-driven humanoid robots with harmonic drives. Force control of gear-driven robots has an advantage in its fully variable stiffness in comparison with elastic robots. However, feedback latency makes gear-driven robots vulnerable to impact rising in several milliseconds. It would be resolved by low-latency torque feedback loop in a single joint, but torque sensors are too large for life-sized humanoid robots. We estimate joint torque from motor current and rotation observed in each joint, and give artificial elasticity to joints using compliance control and shock absorption control. Our controller performance is demonstrated by landing experiments.
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10:45-11:00, Paper WeAT14.2 | Add to My Program |
MPC-Based Humanoid Pursuit-Evasion in the Presence of Obstacles |
De Simone, Daniele | Sapienza Univ. of Rome |
Scianca, Nicola | Sapienza Univ. of Rome |
Ferrari, Paolo | Sapienza Univ. of Rome |
Lanari, Leonardo | Sapienza Univ. of Rome |
Oriolo, Giuseppe | Sapienza Univ. of Rome |
Keywords: Humanoid and Bipedal Locomotion, Reactive and Sensor-Based Planning, Humanoid Robots
Abstract: We consider a pursuit-evasion problem between humanoids in the presence of obstacles. In our scenario, the pursuer enters the safety area of the evader headed for collision, while the latter executes a fast evasive motion. Control schemes are designed for both the pursuer and the evader. They are structurally identical, although the objectives are different: the pursuer tries to align its direction of motion with the line-of-sight to the evader, whereas the evader tries to move in a direction orthogonal to the line-of-sight to the pursuer. At the core of the control architecture is a Model Predictive Control scheme for generating a stable gait. This allows for the inclusion of workspace obstacles, which we take into account at two levels: during the determination of the footsteps orientation and as an explicit MPC constraint. We illustrate the results with simulations on NAO humanoids.
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11:00-11:15, Paper WeAT14.3 | Add to My Program |
Steering a 3D Limit-Cycle Biped for Collaboration with a Leader |
Shafiee Motahar, Mohamad | Univ. of Delaware |
Veer, Sushant | Univ. of Delaware |
Poulakakis, Ioannis | Univ. of Delaware |
Keywords: Humanoid and Bipedal Locomotion, Physical Human-Robot Interaction, Legged Robots
Abstract: This paper presents a control method for steering three dimensional (3D) dynamically walking bipeds that are engaged in cooperative tasks such as object transportation. Towards achieving safe interaction with a leading human (or robot) collaborator, the walking biped is required to exhibit compliance at the port of interaction, while simultaneously adapting its walking pattern in response to the perceived interaction forces. To address these issues, we propose a method that fuses impedance control of the biped's arm with position control of its legs in a way that the biped adaptively modifies its stepping pattern according to the collaborator's intentions. The method is applied on a 3D bipedal robot that is driven in the workspace by a collaborator, whose intention is communicated to the biped through the interaction force.
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11:15-11:30, Paper WeAT14.4 | Add to My Program |
2D Omnidirectional Navigation of a Biped Robot Based on an Egocentric Orbit Following |
Atsuta, Hiroshi | Osaka Univ |
Sugihara, Tomomichi | Graduate School of Engineering, Osaka Univ |
Keywords: Humanoid and Bipedal Locomotion, Humanoid Robots, Motion Control
Abstract: This paper addresses an omnidirectional locomotion control to make a biped robot walk back and forth, turn to any direction, move sideways and carry out them seamlessly. This is achieved by integrating smooth-path-tracking and lateral walking controllers that have been proposed by the authors, which is not straightforward because the path tracking is designed to converge to a referential path while the lateral walking aims to go away from the path. It can be avoided by extending the path-tracking controller to consecutively redraw the orbit that passes the middle of the feet. The proposed controller is designed completely in the robot-centric frame, namely, all the references and the manipulated variables are represented from the robot's viewpoint so that the operator can issue the referential values in the first-person view. Additionally, as the robot is ruled by neither a plan of footsteps nor time-dependent trajectories, it can flexibly respond to various perturbations. The validity of the proposed controller is investigated through computer simulations and an application to navigation of the robot is also shown.
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11:30-11:45, Paper WeAT14.5 | Add to My Program |
Biped Walking Stabilization Based on Foot Placement Control Using Capture Point Feedback |
Jeong, Hyobin | KAIST |
Sim, Okkee | KAIST |
Bae, HyoIn | KAIST, HuboLab |
Lee, Kang Kyu | KAIST Hubolab |
Oh, Jaesung | KAIST |
Oh, Jun Ho | Korea Advanced Inst. of Sci. and Tech |
Keywords: Humanoid Robots, Legged Robots, Sensor-based Control
Abstract: In this paper we introduce a biped foot placement controller based on capture point (CP) feedback control. This capture point feedback controller generates desired Zero Moment Point (ZMP) according to current capture point error. We call this desired ZMP as Control-ZMP (cZMP). Using this cZMP, we constructed (i) a disturbance adapting walking pattern generator, (ii) an ankle torque reference generator, (iii) a landing foot position adjustor and, (iv) a step time adjustor. By applying these controllers, the biped system becomes robust over uneven terrain and external pushing disturbances. We considered cZMP as a key indicator of bipedal walking stability. If the cZMP is within the support polygon, the robot will track the cZMP by using (i) and (ii). If the cZMP is outside of the support polygon, the robot will change footstep position and time by using (iii) and (iv) (COM pattern will be changed by (i) too). Capture point dynamics is described based on a linear inverted pendulum (LIP) model. The performance of the suggested control algorithm is validated in the Choreonoid simulator with a model of DRC-HUBO+ [11], [12].
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11:45-12:00, Paper WeAT14.6 | Add to My Program |
Modeling and Analysis of Sliding Passive Dynamic Walking with Semicircular Feet Considering Impulsive Frictional Effect |
Asano, Fumihiko | Japan Advanced Inst. of Science and Tech |
Harata, Yuji | Hiroshima Univ |
Keywords: Passive Walking, Legged Robots, Dynamics
Abstract: This paper discusses the condition necessary for achieving stable passive-dynamic walking of a compass-like biped robot with semicircular feet on a slippery downhill, and analyzes the fundamental gait properties through numerical simulations. First, we introduce the semicircular-footed compass model and develop the equation of motion, holonomic constraint condition, and equation of collision considering the effect of impulsive frictional force. The paradox in transformation of the impulsive frictional force effect is also discussed. Second, we numerically show that short- and long-period sliding passive compass gaits can be generated under the same condition except the initial condition, and the sliding directions of the fore foot immediately after impact in the two gaits are different from each other. Furthermore, we conduct parametric studies to understand the change tendency of the fundamental gait properties with respect to the system parameters such as the foot radius and frictional coefficient. The simulation results show that the effect of semicircular feet makes it possible for the passive biped to walk on slippery downhill stably in the absence of the hip-damper.
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WeAT15 , Room 215 |
Add to My Program |
Aerial I |
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Chair: Furukawa, Tomonari | Virginia Pol. Inst. and State Univ |
Co-Chair: Waslander, Steven Lake | Univ. of Waterloo |
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10:30-10:45, Paper WeAT15.1 | Add to My Program |
Aerial Image Based Heading Correction for a Large Scale SLAM in an Urban Canyon |
Roh, Hyunchul | KAIST |
Jeong, Jinyong | KAIST |
Kim, Ayoung | Korea Advanced Inst. of Science Tech |
Keywords: SLAM, Localization, Field Robots
Abstract: This paper presents an effective solution for 3D urban map generation using aerial images as prior information for Simultaneous Localization and Mapping (SLAM). The research targets urban canyons where Global Positioning System (GPS) signals are highly sporadic and erroneous. As a solution for urban canyon mapping, this study proposes aerial imagebased heading correction and kinematics considered odometry modeling. Aerial images often suffer from being significantly askew due to the height of structures and viewpoint changes, preventing direct integration with SLAM. However, we found that the direction of the structural edges were still valid, despite slanted building images. Making use of this property, this paper proposes a heading correction method using aerial images. As heading error is a critical factor in SLAM when mapping large areas, the proposed heading correction method substantially reduces estimation errors. Aiming for large urban area mapping, this paper also focuses on sensor modeling for odometry and GPS data. In odometry generation, mobile robot kinematics is considered by incorporating wheel diameter and base distance uncertainties into odometry covariance modeling. Results are presented from various types of urban areas over a path 28 km in length. For thorough validation, we ran the algorithm on three urban areas with differing degrees of GPS availability and structural complexity: a downtown area with medium complexity, a building complex, and the downtown area of a large city.
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10:45-11:00, Paper WeAT15.2 | Add to My Program |
Image-Based UAV Localization Using Interval Methods |
Kenmogne, Ide-Flore | INRIA |
Drevelle, Vincent | Univ. De Rennes 1, IRISA, INRIA Rennes |
Marchand, Eric | Univ. De Rennes 1, IRISA, INRIA Rennes |
Keywords: Localization, Computer Vision for Other Robotic Applications, Sensor Fusion
Abstract: This paper proposes an image-based localization method that enables to estimate a bounded domain of the pose of an unmanned aerial vehicle (UAV) from uncertain measurements of known landmarks in the image. The approach computes a domain that should contain the actual robot pose, assuming bounded image measurement errors and landmark position uncertainty. It relies on interval analysis and constraint propagation techniques to rigorously back-propagate the errors through the non-linear observation model. Attitude information from onboard sensors is merged with image observations to reduce the pose uncertainty domain, along with prediction based on velocity measurements. As tracking landmarks in the image is prone to errors, the proposed method also enable fault detection from measurement inconsistencies. This method is tested using a quadcopter UAV with an onboard camera.
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11:00-11:15, Paper WeAT15.3 | Add to My Program |
Distance Function Based 6DOF Localization for Unmanned Aerial Vehicles in GPS Denied Environments |
Unicomb, James | Univ. of Tech. Sydney |
Dantanarayana, Lakshitha | Univ. of Tech. Sydney |
Arukgoda, Janindu | Univ. of Tech. Sydney |
Ranasinghe, Ravindra | Univ. of Tech. Sydney |
Dissanayake, Gamini | Univ. of Tech. Sydney |
Furukawa, Tomonari | Virginia Pol. Inst. and State Univ |
Keywords: Localization, Aerial Systems: Perception and Autonomy, Sensor Fusion
Abstract: This paper presents an algorithm for localizing an unmanned aerial vehicle (UAV) in GPS denied environments. Localization is performed with respect to a pre-built map of the environment represented using the distance function of a binary mosaic, avoiding the need for extraction and explicit matching of visual features. Edges extracted from images acquired by an onboard camera are projected to the map to compute an error metric that indicates the misalignment between the predicted and true pose of the UAV. A constrained extended Kalman filter (EKF) framework is used to generate an estimate of the full 6-DOF location of the UAV by enforcing the condition that the distance function values are zero when there is no misalignment. Use of an EKF also makes it possible to seamlessly incorporate information from any other system on the UAV, for example, from its auto-pilot, a height sensor or an optical flow sensor. Experiments using a hexarotor UAV both in a simulation environment and in the field are presented to demonstrate the effectiveness of the proposed algorithm.
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11:15-11:30, Paper WeAT15.4 | Add to My Program |
Circular Formation Control of Fixed-Wing UAVs with Constant Speeds |
Garcia de Marina, Hector | Ec. Nationale De L'aviation Civil (ENAC) |
Sun, Zhiyong | Australian National Univ |
Bronz, Murat | ENAC |
Hattenberger, Gautier | ENAC, French Civil Aviation Univ |
Keywords: Multi-Robot Systems, Aerial Systems: Mechanics and Control, Cooperating Robots
Abstract: In this paper we propose an algorithm for stabilizing circular formations of fixed-wing UAVs with constant speeds. The algorithm is based on the idea of tracking circles with different radii in order to control the inter-vehicle phases with respect to a target circumference. We prove that the origin of the error dynamics of the inter-vehicle phases is exponentially stable. Furthermore, thanks to the stability properties of the guidance vector field that guides the vehicles, the algorithm can be extended to other closed trajectories. One of the main advantages of this approach is that the algorithm guarantees the confinement of the team in a specific area, even when communications or sensing among vehicles are lost. We show the effectiveness of the algorithm with an actual formation flight of three aircraft. The algorithm is ready to use for the general public in the open-source Paparazzi autopilot.
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11:30-11:45, Paper WeAT15.5 | Add to My Program |
A Decision-Theoretic Approach to Detection-Based Target Search with a UAV |
Gupta, Aayush | Saratoga High School |
Bessonov, Daniel | Saratoga High School |
Li, Patrick | Saratoga High School |
Keywords: Autonomous Vehicle Navigation, AI-Based Methods, Autonomous Agents
Abstract: Search and rescue missions and surveillance require finding targets in a large area. These tasks often use unmanned aerial vehicles (UAVs) with cameras to detect and move towards a target. However, common UAV approaches make two simplifying assumptions. First, they assume that observations made from different heights are deterministically correct. In practice, observations are noisy, with the noise increasing as the height used for observations increases. Second, they assume that a motion command executes correctly, which may not happen due to wind and other environmental factors. To address these, we propose a sequential algorithm that determines actions in real time based on observations, using partially observable Markov decision processes (POMDPs). Our formulation handles both observations and motion uncertainty and errors. We run offline simulations and learn a policy. This policy is run on a UAV to find the target efficiently. We employ a novel compact formulation to represent the coordinates of the drone relative to the target coordinates. Our POMDP policy finds the target up to 3.4 times faster when compared to a heuristic policy.
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11:45-12:00, Paper WeAT15.6 | Add to My Program |
Using a Quadrotor to Track a Moving Target with Arbitrary Relative Motion Patterns |
Chen, Jing | Hong Kong Univ. of Science and Tech |
Shen, Shaojie | Hong Kong Univ. of Science and Tech |
Keywords: Aerial Systems: Perception and Autonomy, Motion and Path Planning, Visual Tracking
Abstract: We propose a novel approach for safe tracking of a moving target in cluttered environments using a quadrotor. The key contribution of our work is a formulation that enables the generation of safe and dynamical feasible tracking trajectories that satisfy arbitrary relative motion patterns (circling, parallel tracking, undirectional tracking, etc.) with respect to the target. In our framework, forming the desired relative motion pattern between the quadrotor and the target only requires a generative function that specifies relative positions at different time instants. Our method generates samples to fit a piecewise-polynomial representation of the desired relative motion pattern and embeds it into a cost function for solving valid tracking trajectories via quadratic programming. Collision avoidance is achieved by squeezing the trajectory into a collision-free flight corridor, and dynamical feasibility is achieved by enforcing bounds on corresponding derivatives. Both of which can be written as linear constraints for the quadratic programming. Our approach is lightweight and can be implemented for real-time target tracking. We use a simulated cluttered environment and multiple desired relative motion patterns to demonstrate the performance of the proposed approach.
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WeAT16 , Room 220 |
Add to My Program |
Reactive and Sensor-Based Planning I |
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Chair: Kleiner, Alexander | Irobot |
Co-Chair: Englot, Brendan | Stevens Inst. of Tech |
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10:30-10:45, Paper WeAT16.1 | Add to My Program |
Belief Roadmap Search: Advances in Optimal and Efficient Planning under Uncertainty |
Shan, Tixiao | Stevens Inst. of Tech |
Englot, Brendan | Stevens Inst. of Tech |
Keywords: Reactive and Sensor-Based Planning, Motion and Path Planning, Autonomous Vehicle Navigation
Abstract: We characterize and propose advances in the technique of Belief Roadmap Search (BRMS), the process of searching a roadmap in belief space for robot motion planning under localization uncertainty. We discuss the conditions required for optimal substructure in the single-source search of a roadmap in belief space, demonstrating that there are several desirable cost functions for which this property cannot be achieved. Practical performance issues of BRMS are discussed, including the implications of a commonly-used anti-cycling rule, and the computational complexity realized in practical applications of the technique. We propose a best-first implementation of BRMS, in contrast to the standard breadth-first implementation, which we show to improve the computational cost of search by up to 49% by eliminating unnecessary node expansions - the mechanics of both approaches are compared in detail. A variety of motion planning examples are explored.
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10:45-11:00, Paper WeAT16.2 | Add to My Program |
Reactive Synthesis for Finite Tasks under Resource Constraints |
He, Keliang | Rice Univ |
Lahijanian, Morteza | Univ. of Oxford |
Kavraki, Lydia | Rice Univ |
Moshe, Vardi | Rice Univ |
Keywords: Formal Methods for Robotics, Reactive and Sensor-Based Planning, Task Planning
Abstract: There are many applications where robots have to operate in environments that other agents can change. In such cases, it is desirable for the robot to achieve a given highlevel task despite interference. Ideally, the robot must decide its next action as it observes the changes in the world, i.e. act reactively. In this paper, we consider a reactive planning problem for finite robotic tasks with resource constraints. The task is represented using a temporal logic for finite behaviors and the robot must achieve the task using limited resources under all possible finite sequences of moves of other agents. We present a formulation for this problem and an approach based on quantitative games. The efficacy of the approach is demonstrated through a manipulation case study.
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11:00-11:15, Paper WeAT16.3 | Add to My Program |
Probabilistic Nod Generation Model Based on Estimated Utterance Categories |
Liu, Chaoran | Osaka Univ |
Ishi, Carlos Toshinori | ATR |
Ishiguro, Hiroshi | Osaka Univ |
Keywords: Robot Audition, Gesture, Posture, Social Spaces and Facial Expressions, Humanoid Robots
Abstract: We propose a probabilistic model that generates nod motions based on utterance categories estimated from the speech input. The model comprises two main blocks. In the first block, dialogue act-related categories are estimated from the input speech. Considering the correlations between dialogue acts and head motions, the utterances are classified into three categories having distinct nod distributions. Linguistic information extracted from the input speech is fed to a cluster of classifiers which are combined to estimate the utterance categories. In the second block, nod motion parameters are generated based on the categories estimated by the classifiers. The nod motion parameters are represented as probability distribution functions (PDFs) inferred from human motion data. By using speech energy features, the parameters are sampled from the PDFs belonging to the estimated categories. Subjective experiment results indicate that the motions generated by our proposed approach are considered more natural than those of a previous model using fixed nod shapes and hand-labeled utterance categories.
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11:15-11:30, Paper WeAT16.4 | Add to My Program |
Visual Navigation with Efficient ConvNet Features |
Jaspers, Hanno | Univ. of the Bundeswehr Munich |
Fassbender, Dennis | Univ. of the Bundeswehr Munich |
Wuensche, Hans J | UniBw Munich |
Keywords: Visual-Based Navigation, Deep Learning in Robotics and Automation, Autonomous Vehicle Navigation
Abstract: In this paper, we propose a system for autonomous vehicle following without a line of sight. From monocular camera images, the leading vehicle extracts scene descriptors which it transmits to the following vehicle by means of vehicle-to-vehicle (V2V) communication. The follower is able to recognize the scenes using its own camera and follow autonomously. A particle filter framework is employed for jump-free localization on the driven path of the leading vehicle. We compare the performance of different place features for accurate localization on a custom application-oriented dataset and evaluate methods to reduce the feature size for low-bandwidth V2V communication, while maintaining and even improving the recognition performance. Real-world results demonstrate the applicability of our system.
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11:30-11:45, Paper WeAT16.5 | Add to My Program |
A Solution to Room-By-Room Coverage for Autonomous Cleaning Robots |
Kleiner, Alexander | Irobot |
Baravalle, Rodrigo Guillermo | Irobot, CIFASIS-CONICET, Lab. for System Dynamics and Sign |
Kolling, Andreas | Irobot Corp |
Pilotti, Pablo | Irobot |
Munich, Mario Enrique | Irobot |
Keywords: Domestic Robots, Robot Companions
Abstract: We introduce RoomSeg, a novel method for segmenting occupancy grid maps into regions that represent rooms and corridors in the real world. The segmentation is utilized for systematic room-by-room cleaning on autonomous vacuum cleaners running in private homes. RoomSeg is based on automated clutter removal and watershed segmentation on grid maps. Segmented regions are merged into rooms by semantic decision rules. Presented experimental results clearly indicate the efficiency and accuracy of the approach when compared with state of the art methods. When deployed on cleaning robots, a substantial decrease in mission time can be achieved.
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11:45-12:00, Paper WeAT16.6 | Add to My Program |
Viscosity-Based Height Reflex for Workspace Augmentation for Quadrupedal Locomotion on Rough Terrain |
Focchi, Michele | Fondazione Istituto Italiano Di Tecnologia |
Featherstone, Roy | Istituto Italiano Di Tecnologia |
Orsolino, Romeo | Istituto Italiano Di Tecnologia |
Semini, Claudio | Istituto Italiano Di Tecnologia |
Caldwell, Darwin G. | Istituto Italiano Di Tecnologia |
Keywords: Reactive and Sensor-Based Planning, Legged Robots, Underactuated Robots
Abstract: We propose a reactive locomotion strategy, called height reflex, that is useful to address big elevation changes in the terrain (e.g. when a quadruped robot has to step down from a high platform). In these cases the swing leg can lose mobility creating issues in the subsequent steps. The height reflex is a foot trajectory replanning strategy that redistributes the swing motion (in a smart way) to the stance legs to ”lower” the whole trunk and to aid the foothold searching motion. To spread the motion we exploit a massless link model of the robot with virtual dampers at the joints, which is used to replan the feet trajectories. The proposed approach is able to incorporate kinematic limits, it is easy-to-tune, computationally efficient and suitable for real-time implementations. The reflex is implemented and experimentally evaluated on the 80 kg hydraulic quadruped HyQ. With our approach we were able to address high steps, up to 24 cm which is 30% of HyQ leg length and 53% of its retractable leg range.
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WeAT17 , Room 221 |
Add to My Program |
Redundant Robotics |
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Chair: Takanishi, Atsuo | Waseda Univ |
Co-Chair: Kovecses, Jozsef | McGill Univ |
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10:30-10:45, Paper WeAT17.1 | Add to My Program |
Linear Actuator Robots: Differential Kinematics, Controllability, and Algorithms for Locomotion and Shape Morphing |
Usevitch, Nathan | Stanford |
Hammond, Zachary | Stanford Univ |
Follmer, Sean | Stanford Univ |
Schwager, Mac | Stanford Univ |
Keywords: Redundant Robots, Parallel Robots, Kinematics
Abstract: We consider a class of robotic systems composed of high elongation linear actuators connected at universal joints. We derive the differential kinematics of such robots, and formalize concepts of controllability based on graph rigidity. Control methods are then developed for two separate applications: locomotion and shape morphing. The control algorithm in both cases solves a series of linearly constrained quadratic programs at each time step to minimize an objective function while ensuring physical feasibility. We present simulation results for locomotion along a prescribed path, and morphing to a target shape.
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10:45-11:00, Paper WeAT17.2 | Add to My Program |
Interactive Null Space Control for Intuitively Interpretable Reconfiguration of Redundant Manipulators |
Mansfeld, Nico | German Aerospace Center (DLR) |
Beck, Fabian | German Aerospace Center (DLR) |
Dietrich, Alexander | German Aerospace Center (DLR) |
Haddadin, Sami | Leibniz Univ. Hanover |
Keywords: Redundant Robots, Physical Human-Robot Interaction, Motion and Path Planning
Abstract: Kinematic redundancy is a characteristic and beneficial property in collaborative robots nowadays as it enhances the flexibility and dexterity of the system. While the robot is manipulating an object, it is often necessary to kinematically reconfigure the robot, for example, when it obstructs the human. For this, internal or so-called null space motions can be carried out which do not affect the main task. In general, it is desirable that the human coworker can anticipate how the robot will move at any time. However, for null space motions this is typically not the case as they are non-intuitive and not suitable for interaction. In this work, we develop intuitive null space interaction behaviors for redundant manipulators, where the human can easily guide the robot. We want to provide users with a tool, that is straightforward to implement and solves real-world problems effectively. Two practical applications for an eight- and ten-DOF robot demonstrate the performance of the proposed method.
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11:00-11:15, Paper WeAT17.3 | Add to My Program |
A Survey on Precision of Redundantly Actuated DELTA-Type Parallel Kinematic Mechanisms |
Shahidi, Seyed Amirreza | RWTH Aachen Univ |
Lorenz, Michael | RWTH Aachen Univ |
Charaf Eddine, Sami | RWTH Aachen Univ |
Hüsing, Mathias | RWTH Aachen Univ |
Corves, Burkhard | RWTH Aachen Univ |
Keywords: Redundant Robots, Parallel Robots, Flexible Robots
Abstract: Precision is an important feature in modern robotics and manipulation technology. Elevation of the robot's end-effector precision depends on different features as stiffness, tolerance etc. which should be considered during the synthesis and design phase of the manipulator. The focus of this study is on the structural stiffness of parallel kinematic manipulators (PKM) exhibiting actuation redundancy. It is determined how the stiffness depends on physical and geometrical characteristics of the manipulator and how it is possible to take advantage of redundancy to enhance the stiffness of the manipulator. It is shown that redundantly actuated PKM (RA-PKM) with components made of softer and accordingly lighter materials demonstrate comparable stiffness to the non-redundant manipulators which consequently decrease the required energy for moving the dead-load in operation. Based on the model built in this study, optimizations are conducted and manipulators with optimal morphologies for different tasks are introduced. As a case study, RA-PKM of type n-RRPaRs are considered.
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11:15-11:30, Paper WeAT17.4 | Add to My Program |
A Method to Enforce Stiff Constraints in the Simulation of Articulated Multibody Systems |
Hewlett, Joseph | McGill Univ |
Kovecses, Jozsef | McGill Univ |
Angeles, Jorge | McGill Univ |
Keywords: Simulation and Animation, Formal Methods for Robotics, Dynamics
Abstract: We propose a novel integrator for implementing bilateral constraints in multibody simulation using variational integrator methods. We first construct a variational penalty method, which is used to enforce a constraint. The penalty term is simulated using an asynchronous variational integrator, allowing the penalty part of the system to be simulated using a smaller time step. We compute the Discrete Euler-Lagrange (DEL) equations for an equivalent penalty term with a larger time step and then use this rescaled system in the aforementioned variational penalty method, thereby enforcing the constraints. This enables us to incorporate some of the behavior of a very stiff system, which would only be stable on the small time scale, into the system on the large time scale. The effect is better adherence to the constraints, at a larger time step. We demonstrate the method with a simulation of a chain of rigid bodies. We then discuss the potential applications of the integrator and highlight how the work can be used to better interpret the tuned values of the coefficients used in penalty formulations.
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11:30-11:45, Paper WeAT17.5 | Add to My Program |
Improving the Performance of Biomechanically Safe Velocity Control for Redundant Robots through Reflected Mass Minimization |
Mansfeld, Nico | German Aerospace Center (DLR) |
Djellab, Badis | German Aerospace Center (DLR) |
Raldua Veuthey, Jaime | German Aerospace Center (DLR) |
Beck, Fabian | German Aerospace Center (DLR) |
Ott, Christian | German Aerospace Center (DLR) |
Haddadin, Sami | Leibniz Univ. Hanover |
Keywords: Robot Safety, Physical Human-Robot Interaction, Redundant Robots
Abstract: Ensuring safety is a primary goal in physical human-robot interaction. In various collision experiments it was found that the robot's effective mass, velocity, and geometry are the key parameters which influence the human injury severity during an impact. Recently, a velocity controller was proposed that limits the robot speed to a biomechanically safe value, taking into account the mass and the curvature in the direction of movement for a given point of interest. The mass and the geometry depend on the mechanical design, however, the effective mass also depends on the robot configuration. In this paper, we exploit the redundant degree(s) of freedom of a joint torque controlled seven- and eight-DOF robot to minimize the effective mass without affecting the desired Cartesian end-effector trajectory and with the goal to improve the performance of the safe velocity controller at the same time. Given recent results in robotics injury analysis, we analyze when such a redundancy resolution scheme actually improves safety. For the considered robots, we find reflected mass extrema that can be obtained by null space motions, and propose a real-time, torque-based redundancy resolution scheme, which is finally verified in experiments.
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11:45-12:00, Paper WeAT17.6 | Add to My Program |
A Four-Limbed Disaster-Response Robot Having High Mobility Capabilities in Extreme Environments |
Hashimoto, Kenji | Waseda Univ |
Matsuzawa, Takashi | Waseda Univ |
Teramachi, Tomotaka | Waseda Univ |
Uryu, Kazuhiro | Waseda Univ |
Sun, Xiao | Waseda Univ |
Hamamoto, Shinya | Waseda Univ |
Koizumi, Ayanori | Waseda Univ |
Takanishi, Atsuo | Waseda Univ |
Keywords: Legged Robots, Search and Rescue Robots, Robotics in Hazardous Fields
Abstract: This paper describes a novel four-limbed robot having high mobility capability in extreme environments. At disaster sites, there are various types of environments where a robot must move such as rough terrain with possibility of collapse, narrow places, stairs, vertical ladders and so forth. In this paper, first we categorized extreme environments based on three indexes: unevenness, narrowness, and inclination. To move in such extreme environments, we proposed a four-limbed robot having various locomotion styles such as bipedal/quadrupedal walking, crawling and ladder climbing. The main contribution of this paper is the concept and hardware design of the four-limbed robot. We developed a prototype of the four-limbed robot having commonly structured limbs. The number of DoF for the whole body is 29, with 7-DoFs in each limb and 1-DoF in the trunk. The robot weight is 110 kg, and the height is 1,290 mm when standing on two legs. The end-effector has hook-like shape. Verification of the prototype robot is conducted through simulations and experiments.
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WeAT18 , Room 223 |
Add to My Program |
Failure Detection and Recovery |
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Chair: Tang, Hui | Guangdong Univ. of Tech |
Co-Chair: Rojas, Juan | Guangdong Univ. of Tech |
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10:30-10:45, Paper WeAT18.1 | Add to My Program |
A Multimodal Execution Monitor with Anomaly Classification for Robot-Assisted Feeding |
Park, Daehyung | Georgia Inst. of Tech |
Kim, HoKeun | Georgia Inst. of Tech |
Hoshi, Yuuna | Georgia Inst. of Tech |
Erickson, Zackory | Georgia Inst. of Tech |
Kapusta, Ariel | Georgia Inst. of Tech |
Kemp, Charlie | Georgia Inst. of Tech |
Keywords: Failure Detection and Recovery, Learning and Adaptive Systems, Service Robots
Abstract: Activities of daily living (ADLs) are important for quality of life. Robotic assistance offers the opportunity for people with disabilities to perform ADLs on their own. However, when a complex semi-autonomous system provides real-world assistance, occasional anomalies are likely to occur. Robots that can detect, classify and respond appropriately to common anomalies have the potential to provide more effective and safer assistance. We introduce a multimodal execution monitor to detect and classify anomalous executions when robots operate near humans. Our system builds on our past work on multimodal anomaly detection. Our new monitor classifies the type and cause of common anomalies using an artificial neural network. We implemented and evaluated our execution monitor in the context of robot-assisted feeding with a general-purpose mobile manipulator. In our evaluations, our monitor outperformed baseline methods from the literature. It succeeded in detecting 12 common anomalies from 8 able-bodied participants with 83% accuracy and classifying the types and causes of the detected anomalies with 90% and 81% accuracies, respectively. We then performed an in-home evaluation with Henry Evans, a person with severe quadriplegia. With our system, Henry successfully fed himself while the monitor detected, classified the types, and classified the causes of anomalies with 86%, 90%, and 54% accuracy, respectively.
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10:45-11:00, Paper WeAT18.2 | Add to My Program |
Force-Sensorless Fault Tolerant Detection and Switching Control of Tendon-Driven Mechanisms with Redundant Tendons |
Suehiro, Kiichi | Kubota Coporation |
Ozawa, Ryuta | Ritsumeikan Univ |
Van Heerden, Kirill | Ritsumeikan Univ |
Keywords: Tendon/Wire Mechanism, Failure Detection and Recovery, Motion Control
Abstract: Tendons in tendon-driven mechanisms are relatively weak components and sometimes break. This paper proposes a detection method of tendon breakage and a switching control system for tendon-driven mechanisms with redundant tendons. The detection method immediately detects the tendon breakage from the kinematic information of the tendons. The switching control system compensates the control performance by only using the remaining tendons. We experimentally confirm that virtual tendon stretch in a breakage case is adequently larger than that in a normal case to detect the breakage from the kinematic information and the switching controller improves the tracking performance when a tendon is broken.
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11:00-11:15, Paper WeAT18.3 | Add to My Program |
Structure and Performance Analysis of the 7! Robots Generated from an Optimally Fault Tolerant Jacobian |
Xie, Biyun | Colorado State Univ |
Maciejewski, Anthony A. | Colorado State Univ |
Keywords: Redundant Robots, Kinematics, Failure Detection and Recovery
Abstract: A measure of local fault tolerance for kinemati- cally redundant robots has previously been defined based on the properties of the singular values of the Jacobian matrix. Based on these measures, one can determine a Jacobian that is optimal. Because these measures are solely based on the singular values of the Jacobian, permutation of the columns does not affect the optimality. Therefore, when one generates a kinematic robot design from this optimal Jacobian, there will be 7! robot designs with the same locally optimal fault tolerant property. The work described here shows how to analyze and organize the kinematic structure of these 7! designs in terms of their Denvavit and Hartenberg (DH) parameters. Furthermore, global fault tolerant measures are defined in order to evaluate the different designs. It is shown that robot designs that are very similar in terms of DH parameters, e.g., robots generated from Jacobians where the columns are in reverse order, can have very different global properties. Finally, a computationally efficient approach to calculate the global pre- and post-failure dexterity measures is presented and used to identify two Pareto optimal robot designs. The workspaces for these optimal designs are also shown.
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11:15-11:30, Paper WeAT18.4 | Add to My Program |
Online Robot Introspection Via Wrench-Based Action Grammars |
Rojas, Juan | Guangdong Univ. of Tech |
Luo, Shuangqi | Guangdong Univ. of Tech |
Zhu, DingQiao | Sun Yat Sen Univ |
Huang, Zhenjie | Sun Yat Sen Univ |
Lin, Hongbin | Guangdong Univ. of Tech |
Du, Yunlong | Sun Yat Sen Univ |
Kuàng, Wen Wei | Sun Yat Sen Univ |
Harada, Kensuke | Osaka Univ |
Keywords: Assembly, Failure Detection and Recovery, Recognition
Abstract: Robotic failure is all too common in unstructured robot tasks. Despite well-designed controllers, robots often fail due to unexpected events. Robots under a sense-plan-act paradigm do not have an additional loop to check their actions. In this work, we present a principled methodology to bootstrap online robot introspection for contact tasks. In effect, we seek to enable the robot to recognize and expect its behavior, else detect anomalies. We postulated that noisy wrench data inherently contains patterns that can be effectively represented by a vocabulary. The vocabulary is obtained by segmenting and encoding data. And when wrench information represents a sequence of sub-tasks, the vocabulary represents a set of words or sentence and provides a unique identifier. The grammar, which can also include unexpected events, was classified both offline and online for simulated and real robot experiments. Multi-class Support Vector Machines (SVMs) were used offline, while online probabilistic SVMs were used to give temporal confidence to the introspection result. Our work's contribution is the presentation of a generalizable online semantic scheme that enables a robot to understand its high-level state whether nominal or anomalous. It is shown to work in offline and online scenarios for a particularly challenging contact task: snap assemblies. We perform the snap assembly in one-arm simulated and real one-arm experiments and a simulated two-arm experiment. The data set itself is also fully available online and provides a valuable resource by itself for this type of contact task. Our verification mechanism can be used by high-level planners or reasoning systems to enable intelligent failure recovery or determine the next most optimal manipulation skill to be used. Supplemental information, code, data, and other supporting documentation can be found at [1].
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11:30-11:45, Paper WeAT18.5 | Add to My Program |
Viewpoint Selection for Visual Failure Detection |
Saran, Akanksha | Univ. of Texas at Austin |
Lakic, Branka | Duke Univ |
Majumdar, Srinjoy | Univ. of Texas at Austin |
Hess, Juergen Michael | Robert Bosch LLC |
Niekum, Scott | Univ. of Texas at Austin |
Keywords: Failure Detection and Recovery, Computer Vision for Other Robotic Applications
Abstract: The visual difference between outcomes in many robotics tasks is often subtle, such as the tip of a screw being near a hole versus in the hole. Furthermore, these small differences are often only observable from certain viewpoints or may even require information from multiple viewpoints to fully verify. We introduce and compare three approaches to selecting viewpoints for verifying successful execution of tasks: (1) a random forest-based method that discovers highly informative fine-grained visual features, (2) SVM models trained on features extracted from pre-trained convolutional neural networks, and (3) an active, hybrid approach that uses the above methods for two-stage multi-viewpoint classification. These approaches are experimentally validated on an IKEA furniture assembly task and a quadrotor surveillance domain.
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11:45-12:00, Paper WeAT18.6 | Add to My Program |
Towards Adaptive Semantic Subscriptions for Stream Reasoning in the Robot Operating System |
de Leng, Daniel | Linköping Univ |
Heintz, Fredrik | Linköping Univ |
Keywords: Failure Detection and Recovery, Learning and Adaptive Systems, Planning, Scheduling and Coordination
Abstract: Modern robotic systems often consist of a growing set of information-producing components that need to be appropriately connected for the system to function properly. This is commonly done manually or through relatively simple scripts by specifying explicitly which components to connect. However, this process is cumbersome and error-prone, does not scale well as more components are introduced, and lacks flexibility and robustness at run-time. This paper presents an algorithm for setting up and maintaining implicit subscriptions to information through its semantics rather than its source, which we call semantic subscriptions. The proposed algorithm automatically reconfigures the system when necessary in response to changes at run-time, making the semantic subscriptions adaptive to changing circumstances. To illustrate the effectiveness of adaptive semantic subscriptions, we present a case study with two SoftBank Robotics NAO robots for handling the cases when a component stops working and when new components, in this case a second robot, become available. The solution has been implemented as part of a stream reasoning framework integrated with the Robot Operating System (ROS).
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WeAmPo , Ballroom Foyer |
Add to My Program |
Wednesday Posters AM |
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Chair: Lim, Angelica | SoftBank Robotics Europe |
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10:00-10:30, Paper WeAmPo.1 | Add to My Program |
Evo-ROS: Integrating Evolutionary Robotics and ROS |
Moore, Jared | Grand Valley State Univ |
Clark, Anthony | Missouri State Univ |
Simon, Glen | Michigan State Univ |
McKinley, Philip | Michigan State Univ |
Keywords: Control Architectures and Programming, Collision Avoidance, Autonomous Vehicle Navigation
Abstract: We introduce Evo-ROS, a framework combining evolutionary search and ROS/Gazebo-based simulation. The framework enables researchers and developers to take advantage of evolutionary search during design. Evolutionary algorithms can be applied to many aspects of robot development, including optimal configuration and placement of sensors and actuators, generation of compensatory behavior in case of failed/faulty components, and detection of “unlikely-but-possible” situations that might cause system failure.
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10:00-10:30, Paper WeAmPo.2 | Add to My Program |
Unsupervised Spatial-Semantic Maps for Human-Robot Collaboration in Communication-Constrained Environments |
Doherty, Kevin | Massachusetts Inst. of Tech |
Girdhar, Yogesh | Woods Hole Oceanographic Inst |
Keywords: Semantic Scene Understanding, Cognitive Human-Robot Interaction, Marine Robotics
Abstract: Many applications of robots in space and underwater exploration can benefit from real-time human telepresence. Such environments, however, impose drastic constraints on data transmission, limiting the utility of both the human and the robot. Semantic maps can provide useful context to an operator, but previous methods in semantic mapping rely on supervised learning methods that require a fixed and known set of classes. We make use of topic modeling to learn a spatial-semantic map in an unsupervised way, transmitting only anomalous images and representative topic images. This allows a human operator to interpret the learned topics, and therefore map content, without requiring a trained model, so that the operator may aid in decision-making or exploration.
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10:00-10:30, Paper WeAmPo.3 | Add to My Program |
Performance Boost with Hybrid Cloud Robotics |
Farokhi, Soodeh | C2RO | Coll. Cloud Robotics |
Vargas, Aldo | C2RO | Coll. Cloud Robotics |
Khanbeigi, Nazli | C2RO Robotics |
Fox, Geoffrey | Indiana Univ |
Keywords: Distributed Robot Systems, Object detection, segmentation, categorization, SLAM
Abstract: Since its emergence in 2010, cloud robotics has been a major trend in today’s robotics, however, there are some real-time robotics applications for mobile robots that are not able to use this paradigm due to their sensitive latency requirements. In this paper, hybrid cloud robotics is proposed as a processing model utilizing both edge and cloud computing in robotics. This model is implemented for two computation intensive algorithms, object recognition and SLAM, for a robot with a light single-board computer on-board.
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10:00-10:30, Paper WeAmPo.4 | Add to My Program |
IKBT: Autonomous Symbolic Inverse Kinematics Solver |
Zhang, Dianmu | Univ. of Washington |
Hannaford, Blake | Univ. of Washington |
Keywords: AI-Based Methods, Kinematics
Abstract: Symbolic inverse kinematics analysis solves the problem of how to control the robot joints to achieve desired end effector location. It is a non-trivial task critical for any robot design. While there are many numerical packages for inverse kinematics, they share common flaws including, finding only one of the multiple solutions, requirement of a starting value, dependence on the starting value, and problems with convergence near singular configurations. Up till now, closed-form symbolic inverse kinematics analysis was generally handled by human experts, because of the high-level mathematical reasoning needed. Our major contributions to automate closed-form kinematics solving are: 1. We built an expert system -called "IKBT"- that solves inverse kinematics automatically without human supervision or input, using Behavior Tree, a control frame work used in game AI and robotics control. 2. We incorporated knowledge that frequently used (by human experts) when solving inverse kinematics into leaf nodes of the behavior tree. These knowledge nodes are independent of degree-of-freedoms (DOFs), applicable to any robot. 3. Our expert system can solve complicated robots, such as 6-DOF commercial robot manipulator PUMA. IKBT achieved a general success rate of 80% on all 20+ test robots. 4. On average, IKBT generates solutions for one robot in a few seconds - the same work load usually takes human experts 30 minutes to hours to solve. 5. IKBT generates a dependency graph of joint variables after solving, includes all possible solutions. Contrary to the common belief, we discovered that solution tree is often insufficient to represent the intricate dependencies among joint variables - a graph is more suitable to fulfill this role. 6. IKBT has several defining advantages including applicability to any robot, extensible toolbox, up-to-date and easy to implement language (Python), and limited dependency limited only to a few libraries. These characteristics will spur the wild adaption of IKBT into robotics research community, as well as initiate changes in curriculum design.
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10:00-10:30, Paper WeAmPo.5 | Add to My Program |
Closed-Loop Force Control of BLDC Motors with Applications to Multi-Rotor Aerial Vehicles |
Chung, Joseph | Johns Hopkins Univ |
Garimella, Gowtham | Johns Hopkins Univ |
Sheckells, Matthew | Johns Hopkins Univ |
Kobilarov, Marin | Johns Hopkins Univ |
Keywords: Aerial Systems: Mechanics and Control, Force Control, Aerial Systems: Applications
Abstract: This work proposes a feedback controller for regulating the thrust produced by Brushless Direct Control (BLDC) motors using feedback from a load-cell attached to the base of the motor. The direct control of mechanical thrust provides stable control under external disturbances from wind and objects in the surroundings. Experiments have shown that the controller is able to track reference thrust trajectories accurately. This controller can also be used with different motors, propellers and battery voltages without additional calibration.
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10:00-10:30, Paper WeAmPo.6 | Add to My Program |
Robotics Education for K-12 Students for Enhancing Skill Sets Prior to Entering University |
Nabeel, Muhammad | Korea Univ. of Tech. and Education |
Ovais Latifee, Hiba | NED Univ. |
Naqi, Obaid | EDVON |
Aqeel, Kashan | EDVON |
Sheikh, Huzaifa | EDVON |
Arshad, Muhammad | EDVON |
Khurram, Muhammad | NED Univ. |
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10:00-10:30, Paper WeAmPo.7 | Add to My Program |
How Robots Help Eradicate Rework in the Industry |
Reed, Benjamin | Veerum Inc |
Ramesh, Megnath | Veerum Inc |
Keywords: Robotics in Construction, Big Data in Robotics and Automation, Field Robots
Abstract: Industrial rework is a huge problem in large scale capital projects, as it is a waste of time, money and resources. Veerum’s mission is to eliminate rework using autonomous robots and AI technology to create a “Digital Twin” of the project. This can be used to keep a project on schedule and on budget, by identifying and resolving issues during design, fabrication, logistics, and construction phases in capital projects. Veerum’s long term vision is an autonomous construction procedure with an AI deploying & managing robot to build the world’s critical infrastructure.
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10:00-10:30, Paper WeAmPo.8 | Add to My Program |
Interval Capture Basin for Robust Robotic Collision Avoidance |
Le Menec, Stephane | MBDA |
Keywords: Collision Avoidance, Reactive and Sensor-Based Planning, Robot Safety
Abstract: Viability theory provides a set of concepts and algorithms to study uncertain continuous dynamic systems under viability (or state) constraints. Interval computation is about guaranteed numerical methods for approximating sets. The main tool to be used is based on the idea of enclosing real numbers in intervals and real vectors in boxes. Refined interval techniques as contractor programming and guaranteed integration allow to implement the viability kernel and the capture basin algorithms. Results are provided considering the kinematics of the game of two cars. Viability kernel and capture basin algorithms are used to compute backward reachable sets which are differential game capture zones assuming predefined maximum time horizons. Then, collision avoidance between two non cooperative ground mobile robots is performed based on the backward reachable sets mentioned above. Keywords: Non Cooperative Differential Games, Pursuit-Evasion Games, Backward Reachable Sets, Level Sets of the Value Function, Viability Theory, Viability Kernel, Capture Basin, Interval Computing, Contractor Programming, Collision Avoidance, Game of Two Identical Cars, Robotics.
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10:00-10:30, Paper WeAmPo.9 | Add to My Program |
ROS 2 Security |
DiLuoffo, Vincenzo | Worcester Pol. Inst. (WPI) |
Michalson, William R. | Worcester Pol. Inst |
Sunar, Berk | Worcester Pol. Inst. (WPI) |
Keywords: Distributed Robot Systems, Sensor Fusion, Deep Learning in Robotics and Automation
Abstract: Abstract— It is no secret that robotic systems are expanding into many human roles or to augmentation of human roles. The Robot Operating System (ROS) is an open source standard for the robotic industry, that enables locomotion, manipulation, navigation, and recognition tasks by integrating sensors, motors and controllers into reusable modules over a distributed messaging architecture. As reliance on robotic systems increases, these systems become high value targets, for example in autonomous vehicles where human life is at risk. The original ROS implementations were not designed to mitigate the security risks associated with hostile actors. ROS 2, the next generation of the Robot Operating System, addresses this shortcoming, leveraging Data Distributed Services (DDS) for its messaging architecture and DDS security extension for its data protection in motion. This paper provides a systematic review of ROS 2 and identifies potential risks for this new robotic system paradigm. A ROS 2 robotic system is layered from the hardware which includes sensors, motors and controllers to the software layers which includes the Operating System (OS), security services, protocols, messaging and the cognitive layer for observation, learning and action. Since ROS 2 and security are new considerations for robotics systems as they move from the laboratory into the mainstream, many questions emerge regarding what needs to be secure vs non secure, and is this an all or nothing model. Another concern is the performance vs security models, since latency and throughput are critical to real-time robotic functionality. The ROS 2 security model protects a number of the robotic layers, but concerns are identified when compared to a holistic security model.
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10:00-10:30, Paper WeAmPo.10 | Add to My Program |
Registration of Lidar-Based Point Cloud Maps Using Spatial Position of Visual Features |
Kim, Jaeseung | Yonsei Univ |
Shin, Minhwan | Yonsei Univ |
Jeong, Jongmin | Yonsei Univ |
Park, Jin Bae | Yonsei Univ |
Ikeuchi, Katsushi | Microsoft |
Sinha, Sudipta | Microsoft Res |
Keywords: Mapping, RGB-D Perception, Range Sensing
Abstract: We propose a novel registration method of 3D point cloud maps. Navigation based on 3D point cloud maps is the one of the most important technologies in unmanned vehicle field. To combine and extend the 3D maps, ICP method has been used widely, but this method takes long computation time when aligning large scale maps which include a lot of points. Therefore, a point cloud map registration method which precisely register two maps using low-cost cameras is proposed. By combining odometry information derived from the mapping procedure and the 3D position of the image feature points, location of the coexisting places in both maps are extracted. Then, the transform between the origin of each map can be estimated.
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10:00-10:30, Paper WeAmPo.11 | Add to My Program |
Origami Wheel Transformer: A Variable Diameter Wheel-Drive Robot Using an Origami Structure |
Lee, Dae-young | Seoul National Univ |
Cho, Kyu-Jin | Seoul National Univ. Biorobotics Lab |
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10:00-10:30, Paper WeAmPo.12 | Add to My Program |
Learning Deformable Linear Object with Finite Element and Real-Time Measurements of the 3D Deformation |
Zhang, Tianxue | THE CHINESE Univ. OF HONGKONG |
Liu, Yunhui | Chinese Univ. of Hong Kong |
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10:00-10:30, Paper WeAmPo.13 | Add to My Program |
Accurate and Robust Micro Sun Sensor Using Black Sun Effect |
Lee, Sukhan | Sungkyunkwan Univ |
Saleem, Rashid | Sungkyunkwan Univ |
Kim, Jaewoong | SungKyunKwan Univ |
Keywords: Computer Vision for Other Robotic Applications, Field Robots
Abstract: Limp darkening is an optical phenomenon that causes the center of a celestial star like the sun to appear brighter than the overall circular disk. This leads to, so called, the black sun effect where the CMOS pixel imaging the sun center becomes oversaturated and darkened instead due to the electron overspill under saturation. This paper presents a novel sun sensor extracting the sun vector accurately and robustly based on a micro size, 1mmx1mmx1.74mm, of CMOS camera. The black sun effect allows the sun center to be accurately extracted even under the sun image appearing irregular and noisy due to glares. The sun center is localized precisely by the iterative extraction of corners within the sun glare while removing out any spurious corners. The proposed sun sensor is implemented in the following two application modes: 1) a stationary mode targeted for tracking the sun for heliostats or solar panels with a single image sensor configuration and 2) a non-stationary mode targeted for determining the orientation of space rovers with six sun sensors configured in the icosahedron geometry of 23mmx23mmx12mm in size. For the stationary mode, we obtained the accuracy of 0.1° by combining the sun sensor measurement with the sun vector prediction in a Kalman filter framework. For the non-stationary mode, we obtained the accuracy of 0.3° by fusing the measurements from three sun sensors available at any instant of time. Experiments indicate that the sun vector extraction takes an average of 85msec. This paper shows that a compact size, highly cost-effective, yet highly accurate and robust sun sensor can be made available for various applications.
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10:00-10:30, Paper WeAmPo.14 | Add to My Program |
Grasping with Wet Adhesion: Preliminary Approach |
Ho, Van | Japan Advanced Inst. of Science and Tech |
Huynh, Ngoc Van | Japan Advanced Inst. of Science and Tech |
Keywords: Soft Material Robotics, Gripper and Other End-Effectors, Grasping
Abstract: Locking two surfaces with minimum normal force may result in safe grasping of objects in robotic hands. This paper presents a preliminary approach on design and analysis of a bio-inspired soft pad that enhances the adhesion with the environment by morphological optimization of its surface at micro-scale. The design principle is originated from the biological wet attachment of a tree-frog toes and surrounding environment caused by capillary force and surface tension of a secretion film between the toe and the surface. We fabricated soft pad that was deposited with a similar morphological network by molding process on a silicon substrate with etching technique. With wet adhesion was considered in robotic grasping, this research is expected to be applied in wet and high-moisture environment.
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10:00-10:30, Paper WeAmPo.15 | Add to My Program |
End to End Memory Networks for Planning |
Khan, Arbaaz | Univ. of Pennsylvania |
Zhang, Clark | Univ. of Pennsylvania |
Atanasov, Nikolay | Univ. of Pennsylvania |
Karydis, Konstantinos | Univ. of California, Riverside |
Kumar, Vijay | Univ. of Pennsylvania |
Lee, Daniel D. | Univ. of Pennsylvania |
Keywords: Deep Learning in Robotics and Automation, Motion and Path Planning
Abstract: A planning task can be thought of as a loop process that contains a two-step problem. In the first step, the agent perceives its environment. In the second step, the agent executes an action based on the perceived environment. Such emph{perception-action} loops can be successfully learned by using tools from the area of deep learning However, in planning problems, the optimal actions are sequential in nature. Purely convolutional architectures (CNNs) perform poorly when applied to planning problems due to the reactive nature of the policies learned by them. The complexity of this problem is compounded when the environment is only partially observable as is the case with most real world tasks. It has been shown that when learning how to plan in such environments, it becomes necessary to use memory to retain information about states visited. Using recurrent networks to store past information and learn optimal control has been explored before. Recent advances in memory augmented networks have shown that it is beneficial to use external memory with write operators that can be learned by a neural network over. We are specifically interested in the differentiable neural computer architecture. Using this as motivation we split our planning problem into two levels. At a lower level, we use an approximation of the value iteration algorithm within a convolutional networks to learn optimal plans on the partially observed environments. At a higher level, another network controller interfaced with an external memory takes in these locally optimal plans and a sparse representation of the environment as its input and produces plans that are optimal globally. We show impressive results with this network when trained with supervised labels on grid worlds. We also test our hypothesis that the network learns the structure of the environment by testing it on maps with cul-de-sacs or tunnels with a dead end where the agent must explore it all the way to the end when it sees the dead end and retraces its steps. Generating supervised labels is not always easy and are often not consistent (two pilots flying the same course with a drone can have vastly different control policies). Reinforcement learning can be a good alternative to allowing the agent to learn the control policy on its own. This does not work in environments that have a sparse reward structure. In reinforcement learning the agents uses the reward signal from the environment to update its policy. Environments where the reward is only received when the agent reaches the goal could be several time steps away. To solve this we introduce deep reward shaping that gives the agents small rewards when its uncertainty is high forcing it to explore the environment. By adding this exploration module, we show our agent is able to learn how to navigate simple 2D grid worlds, graphs as well as complex 3D environments with sparse rewards.
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10:00-10:30, Paper WeAmPo.16 | Add to My Program |
Musical Audio Signal Restoration Using Bi-Directional LSTM |
Taniguchi, Ryosuke | Tokyo Inst. of Tech |
Hoshiba, Kotaro | Tokyo Inst. of Tech |
Nakadai, Kazuhiro | Honda Res. Inst. Japan Co., Ltd |
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10:00-10:30, Paper WeAmPo.17 | Add to My Program |
A Neuromorphic System for Tactile Pattern Recognition Using Extreme Learning Machine |
Rasouli, Mahdi | National Univ. of Singapore |
Cabibihan, John-John | Qatar Univ |
Thakor, Nitish | National Univ. of Singapore |
Keywords: Prosthetics and Exoskeletons, Force and Tactile Sensing, AI-Based Methods
Abstract: We present a large area tactile sensor module that integrates sensors with processing circuits. This system comprises a piezoresistive fabric material as the sensor that emulates the skin, an interface that produces spike patterns that emulate the neural signals from the mechanoreceptors in the skin, and an extreme learning Machine (ELM) chip for computing and pattern recognition. We demonstrate recognition capability of our system in several tactile pattern recognition tasks, including object recognition and texture categorization. Benefiting from intrinsic advantages of biologically-inspired event-driven systems and massively parallel processing capabilities of the ELM chip, the proposed architecture offers a fast and energy-efficient alternative for processing tactile information. Moreover, it provides the opportunity for development of low-cost tactile modules for prosthetic and robotic applications.
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10:00-10:30, Paper WeAmPo.18 | Add to My Program |
A Decentralized Trust-Minimized Cloud Robotics Architecture |
Simovic, Alessandro | Univ. of Zurich |
Kaestner, Ralf | ETH Zurich |
Rufli, Martin | IBM Res. GmbH |
Keywords: Distributed Robot Systems, Big Data in Robotics and Automation, Software, Middleware and Programming Environments
Abstract: We introduce a novel, decentralized architecture facilitating consensual, blockchain-secured computation and verification of data / knowledge. Through the integration of (i) a decentralized content-addressable storage system, (ii) a decentralized communication and time stamping server, and (iii) a decentralized computation module, it enables a scalable, transparent, and semantically interoperable cloud robotics ecosystem, capable of powering the emerging internet of robots.
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10:00-10:30, Paper WeAmPo.19 | Add to My Program |
Human-Inspired Internal Models for Robot Arm Motions |
Luo, Dingsheng | Peking Univ |
Hu, Fan | Peking Univ |
Zhang, Tao | Peking Univ |
Deng, Yian | Peking Univ |
Nie, Mengxi | Peking Univ |
Wu, Xihong | Peking Univ |
Keywords: Manipulation Planning, Learning and Adaptive Systems, Grasping
Abstract: Researches in cognitive science reveal that human central nervous system internally simulates dynamic behavior of the motor system using internal models. Being inspired, in this research, how to better develop the internal models for robot arm motion control in a human-inspired manner is discussed. Developing the internal models is essentially establishing mappings between motor command and body state, where the mapping from motor onto state is called forward model (FM) and the reverse one is named inverse model (IM). Considering that human proprioception plays an important role for the development of internal models, we propose to use autoencoder neural network to establish the proprioception of robots, and the internal models are then learned based on the proprioception. To evaluate the proprioception based internal models, two types of FM and three different structures of IM are compared respectively. Acting like human, all the models are trained in a developmental manner along with the self-produced arm babbling (unconscious arm movements). Experimental results indicate that borrowing mechanism from human proprioception does help to improve the performance of both FM and IM. Additionally, an integrated framework involving the FM and IM is further proposed for several arm motion control tasks, i.e. reaching, grasping and placing, and the results on our PKU-HR6.0 humanoid robot consistently demonstrate the effectiveness.
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10:00-10:30, Paper WeAmPo.20 | Add to My Program |
A High Torque Modular Actuator Design for a Lower Limb Exoskeleton |
Grandmaison, Christian | Inst. of Biomedical Engineering - UNB |
Quinn, Nathan | Univ. of New Brunswick |
Losier, Yves | Univ. of New Brunswick |
Sensinger, Jonathon | Univ. of New Brunswick |
Keywords: Mechanism Design, Prosthetics and Exoskeletons, Rehabilitation Robotics
Abstract: The current generation of commercially available exoskeletons used in lower limb rehabilitation or as walking assistants provide power at both hips and knees, although not at the ankles. Due to unactuated ankles, existing exoskeletons produce a compensated walking pattern, limiting their walking speeds and efficiency of gait. This work presents the design of a reconfigurable modular actuator design, where the same mechanism is used to efficiently power the hip, knee, and ankle in the sagittal plane. A novel ball screw support assembly was designed allowing an in-line motor to be used in a compact and robust design. To reduce hardware cost, the actuator design is modular, so that the same assembly can be reconfigured to the hip, knee, and ankle. Although biomechanical requirements while walking (speed & torque) vary considerably between each lower-limb joint, the reconfigurable design takes advantage of the variance in the range of motions to provide for more speed or torque as appropriate. This is achieved by changing the anchor point of the driving link in our offset slider-crank mechanism. The linear actuation is achieved with a ball screw, and is directly coupled to a 100W brushless DC motor. Managing the axial load generated in a compact and lightweight manner required a novel custom solution. A compact ball screw linear assembly was achieved through the design of a novel mechanical coupling between the motor shaft and ball screw. This allows for placing angular contact bearings on the outer diameter of the coupling, thereby making the total length of the linear assembly shorter while able to withstand high loads. A single joint prototype has been fabricated and tested. The full assembly is currently under fabrication. This lower-limb exoskeleton will be used to test a self-aligning joint length adjustment method, and investigate novel control strategies on this six active degrees of freedom system.
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10:00-10:30, Paper WeAmPo.21 | Add to My Program |
Implementation of an Autonomous Mobile Platform for Loading Explosives in Mining Applications |
Tavares Ferreira, Jhony Alan | Vale Inst. of Tech. - ITV |
Xavier Fidêncio, Aline | Vale Inst. of Tech |
Azpúrua, Héctor Ignacio | Univ. Federal De Minas Gerais |
Freitas, Gustavo Medeiros | ITV - Inst. Tecnológico Vale |
Miola, Wilson | VALE Inst. OF Tech |
Keywords: Mining Robotics, Field Robots, Robotics in Hazardous Fields
Abstract: The development of mining technologies has grown significantly in recent years. For mining companies, the adoption of new technologies on automation and remote operation represents a significant opportunity for gains in productivity and safety. This paper describes the development of an integrated solution for autonomous explosive loading applied to mining processes. This method can reduce or eliminate the risks to which operators are exposed in environments such as rock blast areas. The proposed solution was validated with simulated and real tests. Tests were carried out in a laboratory, using a mobile platform with a robotic arm.
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10:00-10:30, Paper WeAmPo.22 | Add to My Program |
Applications of Hardware Embedded Reduced Intricacy (HERI) Hand |
Ren, Zeyu | Istituto Italiano Di Tecnologia |
Zhou, Chengxu | Fondazione Istituto Italiano Di Tecnologia |
Tsagarakis, Nikos | Istituto Italiano Di Tecnologia |
Keywords: Tendon/Wire Mechanisms, Underactuated Robots, Multifingered Hands
Abstract: Multiple grasping applications based on the Hardware Embedded Reduced Intricacy (HERI) Hand [1], which demonstrates balanced dexterous finger manipulation as well as powerful grasping of common objects, will be presented in this track.
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10:00-10:30, Paper WeAmPo.23 | Add to My Program |
Research on the Third Arm: Proposal of a Face Vector Interface for Voluntary and Intuitive Control of a Wearable Robot Arm |
Iwasaki, Yukiko | Waseda Univ |
Iwata, Hiroyasu | Waseda Univ |
Keywords: Wearable Robots, Human-Centered Robotics, Virtual Reality and Interfaces
Abstract: The "Third Arm", a new type of wearable robot arm is proposed to help people who wants to perform two concurrent tasks in daily life. To be useful in various, complex, and unpredictable tasks such as occurred in housework at homes or displaying goods at shops, the Third Arm should be not only controlled autonomously by its artificial intelligence, but also operative by humans voluntarily and intuitively. However, it is difficult to operate the Third Arm because humans could not use their both hands and arms for operation under dual-task situations. Therefore, we proposed a "face vector" interface as the original solution for operating the Third Arm. A face vector is a modality to instruct the target object voluntarily and intuitively. The three-dimensional coordinates of target object from humans could be get by measuring the direction of a human’s face and the distance between the object surface and a human’s face, using gyro sensors and distance sensors. Combining the object instruction by a face vector with the motion instruction by a voice command or machine learning systems, people can easily operate the Third Arm without using their hands and arms, and their eyes can be free to move between the main work and the other work. However, it is considered that there is the error distance of object instruction because a face vector is invisible. In addition, it is considered that the efficiency of a main task is affected by the cognitive load of a face vector interface because humans must pay attention for two different tasks simultaneously. Therefore, we evaluate the error distance and cognitive load of a proposed face vector interface for voluntariness and intuitiveness. The experiment was conducted in the environment of a real world and a virtual reality. To easy recognize of a point that humans are now instructing by their face vector, we made a visual biofeedback of a face vector using laser pointer. To build a dual-task situation, the wooden blocks discrimination task by touching their shapes as a main task, and pointing at objects by their face vector as a sub task. The required time of main tasks and the error distance of object instructions in sub tasks are recorded in conditions of with and without a visual biofeedback and single-task and dual-task situations. The results show that the error distance could be significantly decreased by showing a visual biofeedback in both single-task and dual-task situations. On the other hand, the results also show that the efficiency of a main work could be significantly decreased only when humans are showed a visual biofeedback. These results indicate that a visual biofeedback function could increase the accuracy of object instructions but decrease the work efficiency of dual-task situations. Therefore, a face vector could be useful as the interface of voluntary and intuitive object instructions for the Third Arm if a visual biofeedback function could be adjustable depending on users or situations.
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10:00-10:30, Paper WeAmPo.24 | Add to My Program |
Towards a Cooperative Method for 3D Magnetic Maps Generation Using Small and Autonomous Aerial Robots |
Azpúrua, Héctor Ignacio | Univ. Federal De Minas Gerais |
Potje, Guilherme Augusto | Univ. Federal De Minas Gerais |
Frota Rezeck, Paulo Alfredo | Federal Univ. of Minas Gerais |
Freitas, Gustavo Medeiros | ITV - Inst. Tecnológico Vale |
Uzeda Garcia, Luis Guilherme | Inst. Tecnológico Vale |
Nascimento, Erickson | Univ. Federal De Minas Gerais (UFMG) |
Guimarães Macharet, Douglas | Univ. Federal De Minas Gerais |
Campos, Mario Montenegro | Univ. Federal De Minas Gerais |
Pimentel, Bruno | Univ. Federal De Minas Gerais |
Keywords: Aerial Systems: Applications, Autonomous Vehicle Navigation, Mapping
Abstract: In this proposal, we deal with the problem of generating 3D magnetic maps using cooperative and autonomous aerial robots. We propose a novel approach for autonomous mapping using a custom fluxgate magnetometer and multiple commercial cameras embedded on the aerial platforms. We also present a novel method for generating a Digital Magnetic Elevation Model (DEM) from the gathered data. Our method was validated in simulation and real experiments. Results have shown high accuracy in the measurements generated from the DEM model and an accurate estimated magnetic representation of metal objects placed in a test scenario.
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10:00-10:30, Paper WeAmPo.25 | Add to My Program |
High Precision Control of 3D Printed Field Robots in the Presence of Unknown Traction Coefficients |
Kayacan, Erkan | Univ. of Illinois at Urbana-Champaign |
Chowdhary, Girish | Univ. of Illinois at Urbana Champaign |
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10:00-10:30, Paper WeAmPo.26 | Add to My Program |
Towards a Robust Control Paradigm for Steady-State and Transient Walking with Active Transfemoral Prostheses |
Rezazadeh, Siavash | Univ. of Texas at Dallas |
Gregg, Robert D. | Univ. of Texas at Dallas |
Keywords: Prosthetics and Exoskeletons, Legged Robots, Rehabilitation Robotics
Abstract: In this work, we show that a control paradigm based on a special combination of holonomic and nonholonomic virtual constraints results in stable walking with an active transfemoral prosthesis and enables the subject to comfortably manage rapid changes in speed and other walking attributes.
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10:00-10:30, Paper WeAmPo.27 | Add to My Program |
Development of a Miniature, Low-Cost Robot for a Laboratory-Scale Underwater Collectives Testbed |
Berlinger, Florian | Harvard Univ |
Dusek, Jeff | Harvard Univ |
Gauci, Melvin | Harvard Univ |
Nagpal, Radhika | Harvard Univ |
Keywords: Marine Robotics, Biologically-Inspired Robots
Abstract: The long-term goal of this project is to provide a complete, laboratory-scale testbed that significantly lowers the barrier to entry for this area of research, which would serve as a stepping-stone for real world implementations. This testbed will consist of a robot that has all the required sensing, communication, and locomotion capabilities to operate in a collective, but is low-cost and small enough that large-scale collectives can be achieved with only modest robotic and infrastructure cost. The current research phase focuses on the physical design and locomotion system of such a robot, although some sensing capabilities have been added to validate the locomotion capabilities. The robot is 100 mm in the longest dimension and has a component cost of 100. The robot is highly maneuverable in 3D, being capable of forward and backward swimming, in-place rotation, and vertical ascent and descent.
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10:00-10:30, Paper WeAmPo.28 | Add to My Program |
Machine Learning for Prediction of Communication Strength for Relay UAV Trajectory Planner |
Ladosz, Pawel | Loughborough Univ |
Oh, Hyondong | UNIST |
Chen, Wenhua | Loughborough Univ |
Keywords: Aerial Systems: Applications, Networked Robots, Learning and Adaptive Systems
Abstract: This poster focuses on the use of Gaussian Process (GP) to predict air-to-ground communication strength for UAV relay in urban environments. In particular, Gaussian Process is used to learn inaccuracies in communication model and effects of line of sight obstructions for support of a trajectory planner. Two implementations are discussed. First where UAV performs back and forth search pattern to learn communication model which is then used for trajectory planning. Second where data collection and trajectory planner is run simultaneously. It is shown that Second implementation benefits from being able to start relay mission immediately, while second offers higher communication improvements.
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10:00-10:30, Paper WeAmPo.29 | Add to My Program |
Coordination, Symmetry and Grouping of Redundant Movement Strategies |
Huzaifa, Umer | Univ. of Illinois at Urbana-Champaign |
LaViers, Amy | Univ. of Illinois at Urbana-Champaign |
Keywords: Biologically-Inspired Robots, Motion and Path Planning, Legged Robots
Abstract: Recreating complex, coordinated movements exhibited by humans is not a well-understood process. There are methods present in the literature for coordinated movement based on the relative distance between multiple limbs. A method is presented for generating different trajectories through configuration space between an initial and a final pose. This method is based on a concept from Laban/Bartenieff Movement Studies that describes large, body-level coordinated movement strategies, called Patterns of Body Organization. This set of patterns is used as a basis of human movements, meaning that a different pattern choice between two fixed poses gives different movements. An example pattern in humans, Upper-Lower, is used when diving in a pool where the swimmer orients its limbs to make two distinct limb groups divided at the waist and coordinates them for a successful dive.
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10:00-10:30, Paper WeAmPo.30 | Add to My Program |
Aerial Robots: An Impact Study of Human-Drone Interaction to Accompany People |
Garrell, Anais | UPC-CSIC |
Sanfeliu, Alberto | Univ. Pol. De Cataluyna |
Keywords: Social Human-Robot Interaction, Aerial Systems: Applications
Abstract: Nowadays, it can be observed an extensive progress in the field of human robot interaction. Both aerial and ground robots are working on a large range of applications, for instances, human robot assistance, robot acting as a companion, or ageing care. Despite this progress, the interaction between autonomous aerial robots and non-trained humans is one of the most difficult challenges which researchers are starting to investigate. Thanks to modern systems of perception and control, the research on aerial robots has also grown substantially. This research paves the way for a near future wherein aerial and ground robots interact with people in houses, streets, or retail environments in order to perform specific tasks. One of the first works to address human drone interaction (HDI) was presented in [1]. In this research, the aerial robot is used to extend human abilities, for example, by enhancing the human’s field of view to report accidents or anomalies. Moreover, in [2] the authors proposed a flying drone acting as a personal companion to support people in emergency situations. To enable reliable human-drone interaction, a communication channel is required a phone, or gestural control [3]. Nevertheless, there are few feedback techniques for HDI. Some recent works studied head movements and propeller noise in order to present emotional states [4]. We presented previously in [5] a navigation model suitable for accompanying people in a comfortable manner, whereby aerial robots could navigate with people in indoor and outdoor environments alike. To accomplish this goal, we have seen that the interaction between robots and humans plays a key role, because robots should act in accordance with human motion and observe the interactive forces, which enable the robot navigate side-by-side with a human. The side-by-side navigation is a subject of study where efforts are mainly focused on the development of autonomous companion robots capable of performing human-robot interactions in a more natural way [6]. Nevertheless, these works were developed for ground robots. Similarly, other works for robot companion introduce mediating factors, such as person’s individual experience with robots [13], however the experiments were conducted on controlled areas with no dynamic obstacles nor people. With regards to aerial robots, the research on robots accompanying people is relatively minimal, [1], [3]. Furthermore, the works have been mainly devoted to simple robotics tasks with little interaction between the robot and the person. Unlike previous works for ground robots, in [5], we propose a new robot companion approach for aerial robots in urban environments. Our current efforts are focused on study the impact of robots navigating and accompanying people in urban areas, looking for the optimal configuration of the pair human-drone and the study of the personal space the robot should consider to develop the task as comfortable as possible.
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10:00-10:30, Paper WeAmPo.31 | Add to My Program |
Dynamic Whole Body Imitation of Human Motions in Humanoid Robot |
Sripada, Aditya Sudhakar | SRM Univ |
Ramayee, Harish Asokan | SRM Univ |
Ramasamy, Sridhar | Assistant Professor, SRM Univ |
Warrier, Abhishek | SRM Univ |
Keywords: Telerobotics and Teleoperation, Humanoid Robots
Abstract: This work presents a system that enables a humanoid robot to imitate complex human motions real-time while walking. To capture human motions, a Microsoft Kinect Depth sensor is used. Unlike the cumbersome motion capture suits, the sensor makes the system more comfortable to interact with. The user does not have to wear any special suit. The skeleton data is extracted from the Kinect which is processed to generate the robot's joint angles. Robot Operating System (ROS) is used for the communication between the various parts of the code to achieve minimal latency. Thus the robot imitates the human in real-time with negligible lag. Unlike most of the human motion imitation systems, this system is not stationary. The robot can walk while imitating human motions. The lower body motions of the user are also captured by the Kinect and processed, and modified slightly to attain maximum stability while placing steps. When the user is in a single support phase in between steps, the foot trajectories of the robot that satisfy the ZMP criterion are obtained by cubic interpolation and the gait is generated. At any given point in time, the robot's feet are placed in such a way that the center of mass lies over the support polygon.
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10:00-10:30, Paper WeAmPo.32 | Add to My Program |
A Platform-Invariant Architecture for High-Level Spatial Robotic Commands |
Huzaifa, Umer | Univ. of Illinois at Urbana-Champaign |
Jang Sher, Anum | Univ. of Illinois at Urbana-Champaign |
Jain, Varun | Univ. of Illinois at Urbana-Champaign |
Li, Jialu | Univ. of Illinois at Urbana-Champaign |
Zurawski, Alex | Univ. of Illinois at Urbana-Champaign |
LaViers, Amy | Univ. of Illinois at Urbana-Champaign |
Keywords: Human-Centered Robotics, Telerobotics and Teleoperation, Gesture, Posture, Social Spaces and Facial Expressions
Abstract: In many human-robot-interaction and robot teleoperation scenarios, it is difficult to convey spatial commands to the robot. In a model-driven approach, there are generic parameterization approaches, such as Unified Robot Description Format (URDF), for platforms to define different poses. Another example is DH parameters for the class of robotic manipulators. Here, we present a representation framework of high-level, spatial commands that specifies many joint angles with relatively few parameters based on a spatial architecture. This is inspired from the Body and Space categories in Laban/ Bartenieff Movement Studies (LBMS). Moreover, this framework can be extended to any platform.
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10:00-10:30, Paper WeAmPo.33 | Add to My Program |
Design of Shoe Plate and Experimental Validation for Small Hopping Rover on Granular Media |
Maeda, Takao | Chuo Univ |
Kunii, Yasuharu | Chuo Univ |
Yoshikawa, Kent | JAXA |
Otsuki, Masatsugu | Japan Aerospace Exploration Agency |
Yoshimitsu, Tetsuo | Japan Aerospace Exploration Agency |
Kubota, Takashi | Jaxa Isas |
Keywords: Space Robotics and Automation, Mechanism Design, Field Robots
Abstract: This paper describes the design method of the shoe plate of the hopping mechanism for the small hopping rover which travels on the moon, Mars, and asteroid surfaces. For efficient hopping, the design of a shoe plate with low slip is important. To design a push plate with a small amount of slip on the granular media for a stable and efficient hopping, it is necessary to know the reaction force received from the ground. In this paper, we describe the force estimation method of shoe plate design based on Resistive Force Theory, and calculate the reaction force when the shoe plate pressing the soil. Finally, the force acts on the shoe plate is verified using 3D printed experimental equipment.
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10:00-10:30, Paper WeAmPo.34 | Add to My Program |
Operator-Centered Human-Robot Interaction for Robotic Intervention in Harsh and Hazardous Environments |
Lunghi, Giacomo | CERN |
Di Castro, Mario | CERN |
Marin, Raul | Jaume I Univ |
Masi, Alessandro | CERN (European Organization for Nuclear Res |
Keywords: Telerobotics and Teleoperation, Human-Centered Automation, Industrial Robots
Abstract: During the latest years the use of robotic systems for dangerous intervention for replacing humans is becoming of global interest. Several situations require intervening in the minimum amount of time in a dangerous environment (presence of high risks, high temperatures, high radiation, oxygen deficiency etc) and robots can prevent the exposure of humans to such hazards. Therefore several robots have been developed for various scenarios such as search and rescue, bomb disposal, inspection and maintenance in hazardous environments, surveillance etc. For the development of such robots there are various aspects to take in to account: the reliability of the robot, the communication with it, the mechanical parts, the sensors, the control and the interface between the operator and the robot. In the research field, a lot of effort has been put on control, both of robotic platforms and manipulators, sensors, and communication. The industries instead, focused more on the mechanical aspects (robustness, payload etc.) and the reliability of the system. A key-point in the development of a robotic system is the interface between the robot and the operator. Industrial robots usually come with a specific control panel which allow to operate that specific robot and none else. The use of these robots is usually complicated and requires a lot of training from the operator. On the research side, a lot of effort have been put on how to provide a proper feedback to the operator while controlling the robot, for example by using haptic devices. Nevertheless, a complete study on a Human-Robot Interaction system was never done. A Human-Robot Interaction system should not only take into account the control methods, the communication with the robot and the display of the information, but it should be developed operator-centered, considering his/her possible inexperience, mistakes, confusion, stress and tiredness. This work aims to apply techniques used for the development of Graphical User Interfaces for the creation of a Human-Robot Interface (HRI) which is multimodal, adaptable, usable and learnable and which provides a complete environment for inspection, telemanipulation, data collection and training. The HRI is currently developed, used and tested at CERN, the European Center for Nuclear Research, for robotic interventions in the accelerator complex which is composed by more than 50 km of underground tunnels presenting several hazards such as high radiation, high temperature, oxygen deficiencies but also low luminosity and contamination risks.
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10:00-10:30, Paper WeAmPo.35 | Add to My Program |
Learning Point-To-Point Motions Using Partial Contraction Analysis |
Ravichandar, Harish chaandar | Univ. of Connecticut |
Salehi, Iman | Univ. of Connecticut |
Dani, Ashwin | Univ. of Connecticut |
Keywords: Learning from Demonstration, Learning and Adaptive Systems, Motion and Path Planning
Abstract: An algorithm called GMM-CDSP that learns the dynamics of point-to-point motions from demonstrated data is presented. The motion trajectories are modeled using an autonomous nonlinear system with partially contracting behavior. To accommodate the variability in demonstration data, Gaussian mixture models (GMM) are used to represent the motion dynamics. The parameters of the GMM are learned subject to the constraints derived from partial contraction analysis, which yields state-dependent constraints. A novel relaxation approach, inspired by sum of square (SOS) decomposition, is proposed to eliminate the state dependence on the constraints. The GMM-CDSP algorithm is evaluated on a shape-learning-and-drawing task using the Baxter robot platform and also compared with two state-of-the-art learning-from-demonstrations algorithms.
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10:00-10:30, Paper WeAmPo.36 | Add to My Program |
Integrated 3D Sensing and Augmented-Reality for Teleoperation |
Park, Young Soo | Argonne National Lab |
Kim, Joohee | Illinois Inst. of Tech |
Choi, Byung-Seon | Korea Atomic Energy Res. Inst |
Keywords: Telerobotics and Teleoperation, Virtual Reality and Interfaces, Mapping
Abstract: This paper presents a current development of an enhancing teleoperation method by integrating augmented-reality for robot manipulators for tasks in hazardous and safety critical environment. Also a key to success of such integration is a new model reconstruction algorithm with high resolution dynamic tracking capability. The proposed innovation will allow deploying simple and robust robots in remote sites performing precise and dexterous manipulation under teleoperation.
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10:00-10:30, Paper WeAmPo.37 | Add to My Program |
Serpentine Robotic Tails for Maneuvering and Stabilizing Mobile Robots |
Rone, William | Virginia Tech |
Saab, Wael | Virginia Tech |
Ben-Tzvi, Pinhas | Virginia Tech |
Keywords: Biologically-Inspired Robots, Robust/Adaptive Control of Robotic Systems, Dynamics
Abstract: This poster will provide an overview of the recent and ongoing research in the Virginia Tech Robotics and Mechatronics Lab related to serpentine robotic tails. Three tail designs that utilizing different mechanisms for distributing actuation with a tail’s actuated segment will be presented and contrasted. The dynamic models utilized to simulate these tails will be presented, along with the controllers utilized to operate these tails. Case studies showing the tail’s ability to stabilize and maneuver bipedal and quadrupedal mobile robots will also be presented.
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10:00-10:30, Paper WeAmPo.38 | Add to My Program |
HeRo: An Open Platform for Robotics Research and Education |
Frota Rezeck, Paulo Alfredo | Federal Univ. of Minas Gerais |
Azpúrua, Héctor Ignacio | Univ. Federal De Minas Gerais |
Chaimowicz, Luiz | Federal Univ. of Minas Gerais |
Keywords: Education Robotics, Multi-Robot Systems, Swarms
Abstract: In this work, we present a novel platform for swarm robotics that is low cost, easy to assemble using off the shelf components and is deeply integrated with the most used robotic framework available today: ROS (Robot Operating System). The robotic platform is completely open, composed of a 3D printed body and open source software. We describe its architecture, present its main features and evaluate its functionalities executing real experiments using a couple of robots. We concluded that the proposed swarm platform is a feasible and usable system for education and research, given its reduced cost, easy to use, and small size.
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10:00-10:30, Paper WeAmPo.39 | Add to My Program |
Experimental Error Compensation of the Linear Inverted Pendulum Model for Humanoid Robot TEO |
Garcia, Juan Miguel | Carlos III Univ. of Madrid |
Martinez, Santiago | Univ. Carlos III De Madrid |
Pinel, Maria Dolores | Univ. Carlos III De Madrid |
Balaguer, Carlos | Univ. Carlos III De Madrid |
Keywords: Humanoid and Bipedal Locomotion, Model Learning for Control, Calibration and Identification
Abstract: Humanoid balance controllers are influenced by many deviations from the humanoid system itself and from the environment too. This work presents an experimental method to improve the Linear Inverted Pendulum Model (LIPM) used in balance control. Measuring the Zero Moment Point (ZMP) in the real system and comparing the results with theoretical values helps to model the ZMP deviation. These diferences are introduced in the control system by means of a 'scheduling map' for each working point, increasing the accuracy of the balance control.
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10:00-10:30, Paper WeAmPo.40 | Add to My Program |
Using Emergency Maps to Add Not yet Explored Places into SLAM |
Mielle, Malcolm | Örebro Univ |
Magnusson, Martin | Örebro Univ |
Andreasson, Henrik | Örebro Univ |
Lilienthal, Achim J. | Örebro Univ |
Keywords: Search and Rescue Robots, SLAM, Mapping
Abstract: While using robots in search and rescue missions would help ensure the safety of first responders, a key issue is the time needed by the robot to operate. Even though SLAM is faster and faster, it might still be too slow to enable the use of robots in critical situations. One way to speed up operation time is to use prior information. We aim at integrating emergency-maps into SLAM to complete the SLAM map with information about not yet explored part of the environment. By integrating prior information, we can speed up exploration time or provide valuable prior information for navigation, for example, in case of sensor blackout/failure. However, while extensively used by firemen in their operations, emergency maps are not easy to integrate in SLAM since they are often not up to date or with non consistent scales. The main challenge we are tackling is in dealing with the imperfect scale of the rough emergency maps and integrate it with the online SLAM map in addition to challenges due to incorrect matches between these two types of map. We developed a formulation of graph-based SLAM incorporating information from an emergency map into SLAM, and propose a novel optimization process adapted to this formulation. We extract corners from the emergency map and the SLAM map, in between which we find correspondences using a distance measure. We then build a graph representation associating information from the emergency map and the SLAM map. Corners in the emergency map, corners in the robot map, and robot poses are added as nodes in the graph, while odometry, corner observations, walls in the emergency map, and corner associations are added as edges. To conserve the topology of the emergency map, but correct its possible errors in scale, edges representing the emergency map's walls are given a covariance so that they are easy to extend or shrink but hard to rotate. Correspondences between corners represent a zero transformation for the optimization to match them as close as possible. The graph optimization is done by using a combination robust kernels. We first use the Huber kernel, to converge toward a good solution, followed by Dynamic Covariance Scaling, to handle the remaining errors. We demonstrate our system in an office environment. We run the SLAM online during the exploration. Using the map enhanced by information from the emergency map, the robot was able to plan the shortest path toward a place it has not yet explored. This capability can be a real asset in complex buildings where exploration can take up a long time. It can also reduce exploration time by avoiding exploration of dead-ends, or search of specific places since the robot knows where it is in the emergency map.
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10:00-10:30, Paper WeAmPo.41 | Add to My Program |
K-Means Geometric Deployment for Optimal Cooperative Coverage Algorithm in Cluttered Area for a Fleet of Quadrotors |
Bouzid, Yasser | Univ. D'evry Val D'essonne |
Bestaoui, Yasmina | Univ. of Evry |
Siguerdidjane, Houria | CentraleSupelec |
Keywords: Aerial Systems: Applications, Path Planning for Multiple Mobile Robots or Agents
Abstract: In this work, we propose a new geometric based deployment approach for a fleet of quadrotors. Our task is to perform a distributed sensing in order to accomplish a coverage mission in cluttered environment where each vehicle plays the role of a flying tunable sensor. The proposed algorithm yields an optimal coverage path for each aerial robot while avoiding the obstacles, such that the union of all paths generates the full coverage of the 2D damaged target area. This latter is covered if the robots cross the overall existing scarred points, called Points Of Interest (POIs) that are automatically generated using a mesh generation algorithm. The problem is solved considering K-means Multi-directional optimal Fixed Node Rapidly-exploring Random Tree (RRT*FN) based allocation. By means of the pair-wise costs between points, the overall shortest path for each quadrotor is obtained by solving a Traveling Salesman Problem (TSP) using Genetic Algorithms (GA).
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10:00-10:30, Paper WeAmPo.42 | Add to My Program |
SafeDrive: A Robust Lane Tracking System for Autonomous and Assisted Driving under Limited Visibility |
Mo, Jiawei | Univ. of Minnesota, Twin Cities |
Sattar, Junaed | Univ. of Minnesota |
Keywords: Computer Vision for Transportation, Intelligent Transportation Systems, Autonomous Vehicle Navigation
Abstract: Autonomous detection of lane markers improves road safety, and purely visual tracking is desirable for widespread vehicle compatibility and reducing sensor intrusion, cost, and energy consumption. However, visual approaches are often ineffective because of a number of factors, including but not limited to occlusion, poor weather conditions, and paint wear-off. We present an approach towards robust lane tracking for assisted and autonomous driving, particularly under poor visibility. Our method, named SafeDrive, attempts to improve visual lane detection approaches in drastically degraded visual conditions without relying on additional active sensors other than vision and location data, sensors that are readily available on a standard smartphone.
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WePmPo , Ballroom Foyer |
Add to My Program |
Wednesday Posters PM |
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Chair: Lim, Angelica | SoftBank Robotics Europe |
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16:00-16:30, Paper WePmPo.1 | Add to My Program |
Humanoid Hopping Based on Centroidal Dynamics and Heuristic Foot Placement |
Xin, Songyan | Istituto Italiano Di Tecnologia (IIT) |
You, Yangwei | Istituto Italiano Di Tecnologia |
Zhou, Chengxu | Fondazione Istituto Italiano Di Tecnologia |
Tsagarakis, Nikos | Istituto Italiano Di Tecnologia |
Keywords: Humanoid and Bipedal Locomotion, Humanoid Robots, Legged Robots
Abstract: Inspired by the motion of juggling a ball from one hand to the other, humanoid hopping motion actually can be treated as juggling its center of mass (CoM) from one leg to the other. In both cases, stance phase and flight phase are involved. During the stance phase, the CoM trajectories of humanoid hopping can be generated based on the juggling motion characteristics. During the flight phase, the CoM follows ballistic dynamics. However, the relative position of feet with respect to CoM can still be controlled for the incoming landing. The feet position can be calculated by a simple heuristic foot placement algorithm considering the current CoM state. Afterwards, the CoM and feet tracking tasks are accomplished by a torque controller based on the full dynamics of the robot with respect to kinematic and dynamic constraints. The feasibility of the proposed control method is fully addressed by different simulations.
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16:00-16:30, Paper WePmPo.2 | Add to My Program |
Long-Term Robotic Area Coverage Mission Planning |
Li, Bingxi | Michigan Tech. Univ |
Moridian, Barzin | Michigan Tech. Univ |
Mahmoudian, Nina | Michigan Tech. Univ |
Keywords: Planning, Scheduling and Coordination, Path Planning for Multiple Mobile Robots or Agents
Abstract: The persistent operation of robotic missions is contingent on the smart use of energy. This work provides a solution in the intersection of trajectory optimization and energy autonomy for robotic area coverage missions. In this paper, a mission planning method is proposed that generates trajectories for mobile robots and locations of static charging stations for repeated battery replenishment through the mission. The method takes the working robots specifications and environmental constraints into consideration and can adapt to covering regions with different priorities. Systematic simulation experimentation has proven the effectiveness of the developed algorithm in area coverage and handling environmental constraints. In-lab aerial coverage scenario experiments illustrate the application of the obtained trajectories.
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16:00-16:30, Paper WePmPo.3 | Add to My Program |
Underwater Cave Mapping: Stereo Visual SLAM with IMU and Sonar |
Rahman, Sharmin | Univ. of South Carolina |
Quattrini Li, Alberto | Univ. of South Carolina |
Rekleitis, Ioannis | Univ. of South Carolina |
Keywords: SLAM, Sensor Fusion, Visual-Based Navigation
Abstract: This paper presents a real-time simultaneous localization and mapping (SLAM) algorithm for underwater cave combining visual data from a stereo camera with the angular velocity and linear acceleration data from Inertial Measurement Unit (IMU) and sonar data.
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16:00-16:30, Paper WePmPo.4 | Add to My Program |
Early Studies of a Transmission Mechanism for MR-Guided Interventions |
Zhao, Haoran | Univ. of Houston |
Liu, Xin | Univ. of Houston |
Zaid, Habib | Univ. of Houston |
Shah, Dipan J. | Houston Methodist DeBakey Heart & Vascular Center |
Heffernan, Michael | GuidaBot, LLC |
Becker, Aaron | Univ. of Houston |
Tsekos, Nikolaos | Univ. of Houston |
Keywords: Medical Robots and Systems, Mechanism Design, Model Learning for Control
Abstract: Magnetic resonance imaging (MRI)-guided, manipulator-assisted interventions have the potential to improve patient outcomes. This work presents a force transmission mechanism, called solid-media transmission (SMT), for actuating manipulators inside MRI scanners. The SMT mechanism is based on conduits filled with spheres and spacers made of a nonmagnetic, nonconductive material that forms a backbone for bidirectional transmission. Early modeling and experimental studies assessed SMT and identified limitations and improvements. Simulations demonstrated the detrimental role of friction, which can be alleviated with a choice of low friction material and long spacers. However, the length of the spacer is limited by the desired bending of the conduit. A closed-loop control law was implemented to drive the SMT. The 3rd order system fit ratio is 92.3%. A 1-m long SMT was experimentally tested under this closed-loop controller with heuristically set parameters using a customized benchtop setup. For commanded displacements of 1 to 50 mm, the SMT-actuated 1 degree of freedom stage exhibited sub-millimeter accuracy, which ranged from 0.109±0.057 mm to 0.045±0.029 mm depending on the commanded displacement. However, such accuracy required long control times inversely proportional to displacement ranging 7.56±1.85 s to 2.53±0.11 s. This was attributed to friction as well as backlash which is due to the suboptimal packing of the media. In MR studies, a 4-m long SMT-actuated 1 DoF manipulator was powered by a servo motor located inside the scanner room but outside the 5 Gauss line of the magnet. With shielding and filtering, the SNR of MR images during the operation of the servo motor and SMT-actuation was found to be 89±9% of the control case.
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16:00-16:30, Paper WePmPo.5 | Add to My Program |
Cognitive Mapping, Spatial Awareness and Goal Memory for a Mobile Robot Navigation System |
Zeno, Peter | Univ. of Bridgeport |
Patel, Sarosh | Univ. of Bridgeport |
Sobh, Tarek | Univ. of Bridgeport |
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16:00-16:30, Paper WePmPo.6 | Add to My Program |
Evaluation Methodology for Teleoperation Interfaces |
Xavier Fidêncio, Aline | Vale Inst. of Tech |
Tavares Ferreira, Jhony Alan | Vale Inst. of Tech. - ITV |
Freitas, Gustavo | Federal Univ. of Rio De Janeiro |
de Barros Monteiro, Paulo Marcos | Federal Univ. of Ouro Preto |
Azpúrua, Héctor Ignacio | Univ. Federal De Minas Gerais |
Rigueira Campos, Felipe | Univ. Federal De Ouro Preto |
Miola, Wilson | VALE Inst. OF Tech |
Keywords: Mining Robotics, Telerobotics and Teleoperation, Haptics and Haptic Interfaces
Abstract: In the mining industry, achieving a consistent and efficient production process has always been crucial. Therefore, the utilization of teleoperation techniques rises as a relevant solution to the problem. However, besides the development of teleoperation interfaces, it is also important to evaluate its suitability to the user. Hence, this paper presents the application of a methodology for evaluating such interfaces. A simplified experiment was conducted in a controlled environment using a mobile platform driven through obstacles with a teleoperation interface consisting of video and haptic devices. Results indicate that the utilization of such methodology can significantly contribute to the development of robust teleoperation interfaces.
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16:00-16:30, Paper WePmPo.7 | Add to My Program |
Interactive Perception Based on Gaussian Process Classification Applied to Household Object Recognition & Sorting |
Khan, Aamir | Univ. of Glasgow |
Aragon-Camarasa, Gerardo | Univ. of Glasgow |
Siebert, Jan Paul | Univ. of Glasgow |
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16:00-16:30, Paper WePmPo.8 | Add to My Program |
Learning a Visuomotor Controller for Real World Robotic Grasping Using Simulated Depth Images |
Viereck, Ulrich | Northeastern Univ |
ten Pas, Andreas | Northeastern Univ |
Saenko, Kate | ICSI & UC Berkeley EECS |
Platt, Robert | Northeastern Univ |
Keywords: Grasping, Deep Learning in Robotics and Automation, Perception for Grasping and Manipulation
Abstract: We want to build robots that are useful in unstructured real world applications, such as doing work in the household. Grasping in particular is an important skill in this domain, yet it remains a challenge. One of the key hurdles is handling unexpected changes or motion in the objects being grasped and kinematic noise or other errors in the robot. This paper proposes an approach to learning a closed-loop controller for robotic grasping that dynamically guides the gripper to the object. We use a wrist-mounted sensor to acquire depth images in front of the gripper and train a convolutional neural network to learn a distance function to true grasps for grasp configurations over an image. The training sensor data is generated in simulation, a major advantage over previous work that uses real robot experience, which is costly to obtain. Despite being trained in simulation, our approach works well on real noisy sensor images. We compare our controller in simulated and real robot experiments to a strong baseline for grasp pose detection, and find that our approach significantly outperforms the baseline in the presence of kinematic noise, perceptual errors and disturbances of the object during grasping.
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16:00-16:30, Paper WePmPo.9 | Add to My Program |
Category Level Pick and Place Using Deep Reinforcement Learning |
Gualtieri, Marcus | Northeastern Univ |
ten Pas, Andreas | Northeastern Univ |
Platt, Robert | Northeastern Univ |
Keywords: Perception for Grasping and Manipulation, Deep Learning in Robotics and Automation
Abstract: In this work we address the problem of robotic pick and place, where the robot is given a point cloud and an object category identification (e.g. bottles, mugs), and where the robot must place the object in a desired way. For example the robot must pick a bottle out of the clutter and place it upright, collision-free, and not so high that it falls over after being released. Our approach to the problem is to formulate it as a Markov decision process (MDP) and apply reinforcement learning (RL) methods to train the robot in simulation. We utilize our previous grasp detection work to provide the robot with a sampling of grasps to choose from for the pick action. The place action is chosen from a set of fixed place poses. As in DQN, an artificial neural network (ANN) is used to parameterize an approximation of the action-value function (Q-function). In training, the robot updates its Q-function through trial and error, essentially learning which grasps and places to choose. An off-the-shelf motion planner is used to plan the motions to the grasp and place poses. Our approach has several advantages over previous attempts. First, our method can handle novel object instances within a category, whereas others require a model of the manipulated object. Second, it works well in clutter, which is a challenging scenario for perception. And finally, the MDP/RL framework allows for easy extension to more complex problems, such as where re-grasping and re-placing steps are required. (For example, a mug is initially upside-down and must be flipped before it can be grasped from the mouth -- a precondition for placing it upright in a deep box.) The robot was able to quickly learn to place bottles and mugs in simulation. We also evaluated the trained ANN on a real robot with novel test objects.
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16:00-16:30, Paper WePmPo.10 | Add to My Program |
Autonomous UAVs for Structural Health Monitoring Using Ultrawide Band Beacons |
Dong Ho, Kang | Univ. of Manitoba |
Cha, Young-Jin | Univ. of Manitoba |
Keywords: Aerial Systems: Applications, Environment Monitoring and Management, Localization
Abstract: Civil infrastructures are essential to ensuring the ongoing functionality of human living environments. In order to make sure that aging infrastructures do not experience catastrophic failures, however, they require continuous monitoring and maintenance. Traditionally, visual inspection has been carried out to monitor the health of structures. However, assessments conducted by trained inspectors and monitoring methods using sensing systems based on contact sensors on the structures are costly and inefficient due to the number of inspectors and sensors required. To date, data acquisition using unmanned aerial vehicles (UAVs) equipped with cameras has been popular, and a great deal of research has been done concerning the use of UAVs for the visual inspection of infrastructures. However, UAVs require skilled pilots or a global positioning system (GPS) for autonomous flight. Unfortunately, for some parts of the structure, GPS cannot be used for the autonomous flight of the UAV. For example, the GPS signal beneath a bridge is unreliable, but this is one of the critical locations that should be inspected to monitor and ensure structural health. In order to explore a solution to this difficulty, this study examines an autonomous UAV method using ultra wide band beacons. As an exemplar of structural damage, concrete cracks were detected successfully using a deep convolutional neural network by processing the video data collected from the autonomous UAV.
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16:00-16:30, Paper WePmPo.11 | Add to My Program |
Robust Real-Time Hands-And-Face Detection for Human Robot Interaction |
MohaimenianPour, SeyedMehdi (Sepehr) | Simon Fraser Univ |
Vaughan, Richard | Simon Fraser Univ |
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16:00-16:30, Paper WePmPo.12 | Add to My Program |
Soft Pneumatic Actuator Skin for Wearable Bidirectional Tactile Interface |
Sonar, Harshal | Indian Inst. of Tech. Bombay |
Joshi, Sagar | Indian Inst. of Tech. Bombay |
Robertson, Matthew | EPFL |
Paik, Jamie | Ec. Pol. Federale De Lausanne |
Keywords: Haptics and Haptic Interfaces, Soft Material Robotics, Wearable Robots
Abstract: We propose a soft pneumatic actuator (SPA) based thin, stretchable and wearable device that can be safely placed on the skin to provide a modulable and high fidelity haptic feedback. The compliant `SPA-skin' device is capable of producing high frequency (0- 100 Hz) vibrations with modulable amplitude (0- 4 mm) controlled through integrated sensing of vibrations using low profile PZT sesors.
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16:00-16:30, Paper WePmPo.13 | Add to My Program |
Experimental Validation of Dynamic Legged Locomotion Utilizing a Single-DOF Robotic Leg |
Kamidi, Vinaykarthik | Robotics and Mechatronics Lab |
Ben-Tzvi, Pinhas | Virginia Tech |
Keywords: Legged Robots, Underactuated Robots, Kinematics
Abstract: Robotic legged locomotion has seen tremendous development in recent years. However, very few robots have shown dynamic locomotive capabilities and operational robustness while executing gaits at high-speed, such as the MIT Cheetah, the ETH StarlETH, and the IIT HYQ. These impressive successes are the result of complex structural designs and elaborate control schemes. This poster presents the recent and ongoing research undertaken at the Virginia Tech Robotics and Mechatronics lab with the intent to reduce the complexity of robotic legged systems for high-speed dynamic locomotion. The details of the novel leg mechanism will be highlighted, along with the design evolution of the leg through optimization. Experiments and its results obtained through the prototype showing that the leg is capable of performing dynamic locomotive gaits are presented.
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16:00-16:30, Paper WePmPo.14 | Add to My Program |
New Medical Robotics Standards – Aiming for Autonomous Systems |
Haidegger, Tamas | Obuda Univ. (OU) |
Rudas, Imre J. | Óbuda Univ |
Keywords: Medical Robots and Systems, Robot Safety, Surgical Robotics: Planning
Abstract: Autonomy is a fundamental attribute of robotics, yet it is one of the hardest terms to define, assess and regulate. Autonomy probably poses the greatest safety challenge within the medical field. AI methods and decision support systems are playing an increasing role in all domains of healthcare, and their breakthrough in medical robotics is just around the corner, assuming a safe regulatory framework can be developed. Supporting these trends, a new generation of robotics standards is emerging both in the IEEE and in the ISO/IEC domain, already focusing on the big challenge of the future medical systems: autonomy. This work provides a brief overview of the brand new standards targeting this complex area. The importance of standardization had become paramount in the medical domain, since that is believed to be the best way to increase safety systematically. Harmonized global standards and regulatory frameworks are offering ways to product certification through standardized testing requirements and protocols. However, until very recently, a huge gap existed, since the traditional robotics standards excluded service robots and medical robots, particularly. In the past 7 years, a joint working group of robotic experts was addressing this problem, and this year, the very first ISO/IEC joint Technical Report (TR) on the problem of autonomy for medical electrical systems (MES) (including robots) appeared. This is a first step towards the standardized assessment of robot capabilities, primarily focusing on their autonomous functions, while practical guidelines on methods for robot categorization and certification are also on the horizon. The new TR offers an unambiguous solution to describe and assess the autonomous capabilities of an MES. Relying on some earlier work in the field of industrial automation and service robotics, the TR recommends the parametrization of Degree of Autonomy (DoA) along four cognition-related functions of a system, which are affecting capabilities of an MES to Generate, Execute, Monitor and Select an option related to a robot task. Each of these functions can be driven by a human or a computed, which would then lead to the objective assessment of the DoA of the full system. DoA can vary from low to high, with zero meaning “no autonomy”, and the other end of the scale meaning a “full autonomy” system. DoA can be classified at different granularity levels, depending on where and how the above safety functions are implemented. Basic safety & essential performance for surgical robots The IEC TC 62/SC 62D joint committee worked to provide a practical degree of safety for surgical robots, resulting in a brand new standard to be published later this year. It defines the basic types of surgical robots and tools, and identifies integrated components. The standard collects all relevant mechanical and thermal hazards, along with the fault conditions of the equipment and the required usability trials.
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16:00-16:30, Paper WePmPo.15 | Add to My Program |
Smartphone-Based Interfaces for Articulated Robots |
Rodriguez, Diego | Univ. De Los Andes |
Perez Quintero, Camilo Alfonso | Univ. of Alberta |
Jagersand, Martin | Univ. of Alberta |
Figueroa, Pablo | Univ. of Los Andes |
Keywords: Mobile Manipulation, Service Robots, Virtual Reality and Interfaces
Abstract: This work shows the development of three smarphone-based interfaces to teleoperate a Barrett WAM arm and hand to pick-and-place an object in a particular location. Visual feedback is provided by streaming video of the robot's workspace to the smartphone. Based on our designs and experimental evaluation, we develop intuitions about the advantages of smartphone-based interfaces.
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16:00-16:30, Paper WePmPo.16 | Add to My Program |
Robust Grasp Planning Using Domain Randomization and Deep Generative Models |
Tobin, Joshua | UC Berkeley |
Duan, Yan | Univ. of California Berkeley |
Welinder, Peter | California Inst. of Tech |
Zaremba, Wojciech | OpenAI |
Abbeel, Pieter | UC Berkeley |
Keywords: Deep Learning in Robotics and Automation, Grasping, Perception for Grasping and Manipulation
Abstract: Deep learning-based grasp planning has made strong progress the past several years due to algorithmic improvements and increased data availability. However, state-of-the-art models are often trained on only hundreds or thousands of unique object instances, and as a result frequently do not generalize perfectly to previously unseen objects at test time. In this work, we explore a novel data generation pipeline for training a deep neural network to perform grasp planning that applies the idea of domain randomization to object synthesis. We generate millions of unique, non-realistic randomly generated objects with a range of physics and appearance properties, and train a deep neural network entirely in simulation to perform grasp planning on these objects. Since the distribution of robust grasps for a given object can be highly multimodal, we propose an autoregressive grasp planning model that maps an image of an object to a probability distribution p_{theta} where p_{theta}(g) corresponds to the probability that the grasp g is the most robust for that object. Our model allows us to sample grasps efficiently at test time (or avoid sampling entirely), a critical design criterion for scaling deep-learning based grasp planning to higher dimensional human-like end effectors that can have 20 or more degrees of freedom. We currently have preliminary results exploring these ideas in simulation, and plan to also test them on hardware.
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16:00-16:30, Paper WePmPo.17 | Add to My Program |
Feasibility of Automated Assessment of Manual Dexterity in Parkinson's |
Oña Simbaña, Edwin Daniel | Univ. Carlos III of Madrid |
Jardon Huete, Alberto | Univ. CARLOS III DE MADRID |
Balaguer, Carlos | Univ. Carlos III De Madrid |
Keywords: Computer Vision for Automation, Health Care Management, Human-Centered Automation
Abstract: In previous work, an automatic assessment system was presented for the evaluation of patient progress and effectiveness of the therapy, that is based on the Box and Blocks Test (BBT) of manual dexterity. In this article, a study of the feasibility to use in Parkinson treatment is presented. The results advocates the use of automated methods in physical rehabilitation assessment.
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16:00-16:30, Paper WePmPo.18 | Add to My Program |
Unsupervised Learning of Hierarchical Models for Hand-Object Interactions Using Tactile Glove |
Xie, Xu | UCLA |
Liu, Hangxin | Univ. of California, Los Angeles |
Edmonds, Mark | Univ. of California, Los Angeles |
Gao, Feng | Univ. of California, Los Angeles |
Qi, Siyuan | Univ. of California, Los Angeles |
Zhu, Yixin | Univ. of California, Los Angeles |
Rothrock, Brandon | Jet Propulsion Lab. California Inst. of Tech |
Zhu, Song-Chun | UCLA |
Keywords: AI-Based Methods, Haptics and Haptic Interfaces, Task Planning
Abstract: Contact forces of the hand are visually unobservable, but they play a crucial role in understanding hand-object interactions. We propose an unsupervised learning framework to learn a hierarchical model, Temporal And-Or graph (T-AOG), for hand-object interactions. The interactions are captured using a tactile glove that measures both hand pose and contact forces. Force vectors are extracted as features from the raw sensory input of poses and forces, and segmented by clustering. The T-AOG is induced in an unsupervised manner. Experiments show that our method achieves a high accuracy in terms of segmentation and labeling.
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16:00-16:30, Paper WePmPo.19 | Add to My Program |
Textile Identification Using Fingertip Motion and 3D Force Sensors in an Open-Source Gripper |
von Drigalski, Felix Wolf Hans Erich | Nara Inst. of Science and Tech |
Gall, Marcus | Karlsruhe Inst. of Tech. - KIT |
Cho, Sung-Gwi | Nara Inst. of Science and Tech |
Ding, Ming | Nara Inst. of Science and Tech |
Takamatsu, Jun | Nara Inst. of Science and Tech |
Ogasawara, Tsukasa | Nara Inst. of Science and Tech |
Asfour, Tamim | Karlsruhe Inst. of Tech. (KIT) |
Keywords: Gripper and Other End-Effectors, Force and Tactile Sensing, Haptics and Haptic Interfaces
Abstract: We show that to obtain tactile information about and recognize a textile, a robot gripper's fingertips together can be rubbed together in a human-inspired exploratory motion. Our method not only recognizes 18 different materials with over 94% accuracy, but also distinguishes between one and multiple layers of the same material.
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16:00-16:30, Paper WePmPo.20 | Add to My Program |
Swarming in ROS: From Design to Practical Deployment |
St-Onge, David | Ec. Pol. De Montreal |
Varadharajan, Vivek shankar | Pol. Montréal |
Beltrame, Giovanni | Ec. Pol. De Montreal |
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16:00-16:30, Paper WePmPo.21 | Add to My Program |
Biologically Inspired Dynamic Object Tracking by Mobile Robots with a Neuromorphic Vision Sensor |
Mishra, Abhishek | SiNAPSE, NUS |
Ghosh, Rohan | National Univ. of Singapore |
Thakor, Nitish | National Univ. of Singapore |
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16:00-16:30, Paper WePmPo.22 | Add to My Program |
Fast Multi-Contact Frictional Rigid Dynamics |
Li, Sheng | Peking Univ |
Zhang, Tianxiang | Peking Univ |
Wang, Guoping | Peking Univ |
Sun, Hanqiu | CUHK |
Manocha, Dinesh | Univ. of North Carolina at Chapel Hill |
Keywords: Contact Modelling, Simulation and Animation
Abstract: We present an interactive and stable multi-contact dynamic simulation algorithm for rigid bodies. Our approach is based on fast frictional dynamics (FFD) [14], which is designed for large sets of non-convex rigid bodies. We use a new friction model that performs velocity-level multi-contact simulation using impulse decomposition. Moreover, we accurately handle friction at each contact point using contact distribution and frictional impulse solvers, which also account for relative motion. We evaluate our algorithm’s performance on many complex multi-body benchmarks with thousands of contacts.In practice, our dynamics simulation algorithm takes a few milliseconds per timestep and exhibits more stable behaviors.
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16:00-16:30, Paper WePmPo.23 | Add to My Program |
Minimally Invasive Soft Robotic Tissue Manipulator for Safe Autonomous Surgery |
Schroeder, Tyler | Univ. of Maryland |
Opfermann, Justin | Children's National Medical Center |
Sachyani, Ela | Hebrew Univ. of Jerusalem |
Yuanfang, Zhang | Singapore Univ. of Tech. and Design |
Ge, Qi | Singapore Univ. of Tech. and Design |
Magdassi, Shlomo | Hebrew Univ. of Jerusalem |
Krieger, Axel | Univ. of Maryland |
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16:00-16:30, Paper WePmPo.24 | Add to My Program |
Development of a Smaller Size Modular Unit for Soft Robotics |
Lee, Jun-Young | Seoul National Univ |
Cho, Kyu-Jin | Seoul National Univ. Biorobotics Lab |
Keywords: Soft Material Robotics, Cellular and Modular Robots, Gripper and Other End-Effectors
Abstract: Abstract— In previous research, “SoBL”, a fast-build modularized design block for soft robotics, was introduced to overcome maintenance problems and simplify rapidly prototyping of soft robots. In this paper, a smaller size SoBL unit based on previous research was introduced. A three fingered soft gripper was assembled with the smaller size SoBL units and tested to pick up off-the-shelf mechanical components. This test showed the feasibility of design variation of SoBL units in terms of scale. In future, we hope that diversity of SoBL would be expanded in terms of both scale and unit designs for the bottom-up design concept of soft robotics. I. INTRODUCTION Field of soft robotics changes robots from relatively hard structures to soft and flexible structures. Most of the soft robots were fabricated with molding and casting process with elastomers [1], [2]. Comparing to traditional hard material based robots, soft robots fabricated with these methods have difficulties in maintenance and prototyping. To overcome these problems, “SoBL”, modular units for soft robotics, was introduced in our previous research [3]. In this paper, the smaller size of the SoBL unit was introduced. With the small SoBL units, the three fingered soft gripper was assembled and tested for check feasibility on a different scale. The gripper could securely pick up small mechanical components and shift their locations. II. DESIGN AND FABRICATION Based on the square shaped bending unit of SoBL in our previous research, the size of the unit was reduced by half. Connecting between units was maintained as screw-thread but redesigned for the changed size of the unit. A three fingered soft gripper was assembled with these size reduced units as shown in Figure 1 (a). Each finger was assembled with three units and a fingertip was assembled at the end of fingers. The gripper attached to the soft manipulator which was assembled with independent bending units. III. EXPERIMENTS The three fingered soft gripper was tested to grasp small objects. The gripper was actuated with around 30 kPa of air pressure. All three fingers shared an air channel, therefore, the fingers of the gripper were actuated simultaneously. At first, the gripper was tested with an off-the-shelf M3 nut (Figure 1(b)). Thanks to the fingertips, the gripper safely picked up and move the nut. In addition, the gripper also tested to pick up both an off-the-shelf M3 nut and a 10 mm long M3 bolt. As shown in Figure 1 (c), the gripper also could safely pick up and move both nut and bolt, simultaneously. IV. CONCLUSION In this paper, the small size modular unit for soft robotics was introduced and tested by assembling the three fingered soft gripper. This shows the feasibility of design variation of SoBL units in terms of scales. In future, we hope SoBL set enlarged in terms of scale and unit designs for bottom-up design concept of soft robotics.
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16:00-16:30, Paper WePmPo.25 | Add to My Program |
A Tip-Extending Catheter for Endovascular Surgery |
Hawkes, Elliot Wright | Univ. of California, Santa Barbara |
Morimoto, Tania K. | Stanford Univ |
Simpson, Cole Stewart | Stanford Univ |
Heit, Jeremey | Stanford Medical School |
Keywords: Flexible Robots, Medical Robots and Systems, Surgical Robotics: Steerable Catheters/Needles
Abstract: Access inside the human body is a challenge for minimally invasive surgery. For endovascular surgery (ES), push- catheters are inserted via an artery in the groin and pushed through the vasculature to gain access to distal arteries, including the arteries of the brain. Push-catheters, however, have limited ability to make sharp turns, and therefore may inadvertently damage the vessels. Here we describe a novel tip-extending catheter that grows through vessels in a manner analogous to how plants grow, termed Vascular Internal Navigation by Extension (VINE). The VINE catheter efficiently navigates tight turns and extreme angles due to its low bending stiffness and lack of sliding friction with vessel walls. Further, the soft, growing construction of VINE catheters results in reduced force on the leading edge, potentially reducing the risk of arterial injury compared to standard push-catheters. Our work helps advance the accessibility of ES tools and the speed and safety of ES.
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16:00-16:30, Paper WePmPo.26 | Add to My Program |
DeepIntent: Adversarial Learning for Modeling Pedestrian Intent in Autonomous Driving Interactions |
Gujjar, Pratik | Simon Fraser Univ |
Vaughan, Richard | Simon Fraser Univ |
Keywords: Human-Centered Robotics, Autonomous Vehicle Navigation, Deep Learning in Robotics and Automation
Abstract: Drivers and pedestrians engage in non-verbal and social cues to signal their intent, which is crucial to their interactions in traffic scenarios. We propose to learn such cues and model a pedestrian's intent with a Generative Adversarial Network. The learnt model then predicts actions likely to be performed 400-600 ms in the future. Responding to adverse actions in advance, we tread towards full autonomy.
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16:00-16:30, Paper WePmPo.27 | Add to My Program |
End-To-End Learning of Optical-Flow and Correlation Filters for Visual Tracking |
Zhu, Zheng | Inst. of Automation, Chinese Acad. of Sciences |
Li, Jianquan | Inst. of Automation, Chinese Acad. of Sciences |
Keywords: Visual Tracking
Abstract: Visual object tracking, which tracks a specified target in a changing video sequence automatically, is a fundamental problem in many aspects such as visual analytics, automatic driving, pose estimation and et al. Recently, the correlation filter-based tracking methods have been paid more attention to solve the problem of high computational costs. Correlation operations can be performed by element-wise multiplications using discrete Fourier transform in frequency domain, and discrete Fourier transform can be computed by the efficient fast Fourier transform in practice. This property of correlation filters makes it efficient for fast training and detection in visual tracking. However, most of correlation filters only use appearance features, ignoring motion information. We derive the back-propagation of correlation filters and combine the FlowNet into the network. Specifically, the correlation filters subnetwork explains for one-order information, and the flow subnetwork encodes the second-order information. The overall network are training end-to-end to ensure top tracking performance.
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16:00-16:30, Paper WePmPo.28 | Add to My Program |
CNN Based SLAM for Monitoring Coral Reef |
Modasshir, Md | Univ. of South Carolina |
Rekleitis, Ioannis | Univ. of South Carolina |
Keywords: Deep Learning in Robotics and Automation, Localization, SLAM
Abstract: Our proposed method makes SLAM in underwater more reliable and efficient by focusing on hard immobile coral species for visual features. The proposed method also eliminates features from unreliable objects. In order to provide such prior knowledge, we developed a convolutional neural network based classifier. We have collected coral reef footage from Barbados and the videos were annotated by experts. The CNN classifier was trained on the annotated data. This classifier can provide class activation map which can be converted to binary mask. The mask will help limiting extraction of visual features to image areas containing hard coral species providing the much needed prior knowledge to SLAM for localizing AUV.
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16:00-16:30, Paper WePmPo.29 | Add to My Program |
Mobility Analysis of a Speleologist Robot with Flexible Locomotion System |
Santos Rocha, Filipe Augusto | Inst. TECNOLOGICO VALE |
Freitas, Gustavo | Federal Univ. of Rio De Janeiro |
Magalhães, Paulo Henrique Vieira | Univ. Federal De Ouro Preto |
Miola, Wilson | VALE Inst. OF Tech |
Araujo, Ramon Nunes | Vale S.A |
Brandi, Iuri Viana | Vale S.A |
Keywords: Mining Robotics, Mechanism Design, Simulation and Animation
Abstract: One of the great motivations in the development of robots is to use them in dangerous environments. For mobile devices, it is empirical to be familiar with the locomotion system in use.This allows to understand its capabilities and limitations in order to guarantee the mission success and the devices integrity. The robot used in this paper has an interchangeable locomotion system that allows the device to move with legs, wheels, tracks or hybrid configurations. This proposal analyses mobility characteristics of divers locomotion modes employed by the same robot and then compares their performances. Tests were performed to collect locomotion data using a simulator and a real prototype. Many concepts predicted in the simulation were validated with the real robot. Finally, a comparison of the different locomotion characteristics is obtained.
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16:00-16:30, Paper WePmPo.30 | Add to My Program |
“Human-Like” Emergent Behavior in an Evolved Agent for a Cooperative Shepherding Task |
Nalepka, Patrick | Univ. of Cincinnati |
Patil, Gaurav | Univ. of Cincinnati |
Annand, Colin | Univ. of Cincinnati |
Weber, Brian | Univ. of Cincinnati |
Kallen, Rachel W | Center for Cognition Action & Perception, Univ. of Cincinna |
Minai, Ali | Univ. of Cincinnati |
Richardson, Michael | Univ. of Cincinnati |
Keywords: Learning and Adaptive Systems, Cooperating Robots, Social Human-Robot Interaction
Abstract: We used an evolutionary algorithm to optimize the parameters for an artificial agent model which can perform a cooperative herding task with either a human partner or another artificial agent. The algorithm evolved agents that could herd simulated sheep in a randomly-generated dynamical environment. We utilized different graded fitness functions to vary the amount of herding “success” to determine whether the agents would adopt similar strategies to human learners as they progress through the experiment. Results indicated that, like humans, the artificial agent was able to evolve from one mode of fixed-point behavior to an oscillatory regime when the model was limited to how quickly it could move and the demands for success increased. We tested one of these agents alongside human novices. A majority (80%) of participants learned the more optimal, oscillatory behavior. Further, a majority of participants (70%) were mistaken to believing they were playing with a human instead of the evolved agent.
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16:00-16:30, Paper WePmPo.31 | Add to My Program |
Exploring Communicative Arm Motion for Human-Robot Interaction |
Kebude, Dogancan | Koc Univ |
Sezgin, Tevfik Metin | Koc Univ |
Akgun, Baris | Koc Univ |
Keywords: Cognitive Human-Robot Interaction, Human-Centered Robotics
Abstract: This paper investigates subtle communicative cues in human reaching motions to be utilized in collaborative human-robot interaction scenarios. An experiment with 14 participants was performed in which each participant is asked to reach to grasp one of two cylindrical objects which are placed in four different configurations. The experiment had two conditions; (1) control condition where the participant reaches an object with no observer and (2) test condition where the participant is encouraged to exhibit communicative motion with an observer present. The experiments were only video recorded and no other sensors were placed in order to create an as natural environment as possible for the participants. The video recordings were annotated and analyzed to measure total action duration, time to maximum hand-aperture, and the relative time to maximum hand-aperture. The results show that some of these measures differ significantly between conditions. Some participants also exhibit grasp modality differences and slight exaggeration between the conditions. Furthermore, a post-experiment survey suggests that some differences might be unconscious. These findings show that subtle cues may be important in communicative motion generation and should be considered in human-robot interaction scenarios. The paper concludes by suggesting the use of the findings in developing algorithms and robotic systems.
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16:00-16:30, Paper WePmPo.32 | Add to My Program |
Robust Adaptive Control of Quadrotor System with Uncertainties and Limited Authority |
Emran, Bara | The Univ. of British Columbia |
Najjaran, Homayoun | Univ. of British Columbia |
Keywords: Robust/Adaptive Control of Robotic Systems, Aerial Systems: Mechanics and Control, Neural and Fuzzy Control
Abstract: robust adaptive nonlinear control system consisting of a neural network approximation and a modified reference model is considered for small quadrotors. Quadrotor systems, like any dynamical system, suffer from the presence of uncertainties in their model and parameters which may lead the system to instability or inaccuracy. In addition, the presence of input constraints in quadrotor systems violates the assumption of the control system to be affine in its control signal. Consequently, these problems add additional challenges and complicate designing the control system. The proposed control algorithm combined an adaptive neural network with the reference model modification techniques to overcome the mentioned difficulties. The proposed control system allows the quadrotor system to follow a designed path despite the system’s uncertainties, disturbances, and actuator saturation. In addition, the stability of the proposed controller is proven within the region of interest and validated using simulation and experimental setup.
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16:00-16:30, Paper WePmPo.33 | Add to My Program |
Training Wheels: Two-Phase Supervised and Reinforcement Transfer Learning Applied to Map Exploration |
Nikdel, Payam | Simon Fraser Univ |
Shrestha, Rakesh | Simon Fraser Univ |
Vaughan, Richard | Simon Fraser Univ |
Shamshirdar, Faraz | Simon Fraser Univ |
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16:00-16:30, Paper WePmPo.34 | Add to My Program |
Event-Based Robust Feature Detector under Dynamic Lighting Conditions |
Lee, Alex | Korea Advanced Inst. of Science and Tech. (KAIST) |
Kim, Ayoung | Korea Advanced Inst. of Science Tech |
Keywords: Visual Tracking, Robust/Adaptive Control of Robotic Systems, Recognition
Abstract: In this paper, we propose an event-based feature extraction and tracking method for high dynamic-ranged environments. Unlike other Visual Odometry (VO) methods that utilize frame-wise image data from the complementary metal- oxide-semiconductor (CMOS) sensors, we use data from event-based vision sensors. While only providing pixel-wise temporal intensity changes, the Dynamic Vision Sensor (DVS) robustly performs in higher dynamic ranges than a conventional charge- coupled device (CCD) sensor. This characteristic enables the DVS to achieve nearly no loss of pixel information even under drastic light condition changes. To exploit the obtained events in a VO, we introduce an event-based feature-extraction method and its descriptor, to robustly track features and lower the position error of VO in high dynamic-range environments.
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16:00-16:30, Paper WePmPo.35 | Add to My Program |
FlatFish - a Compact Resident AUV |
Mimoso, Geovane | SENAI CIMATEC |
Trocoli, Tiago | Brazilian Inst. of Robotics, SENAI CIMATEC |
Neves, Gustavo | Brazilian Inst. of Robotics, SENAI CIMATEC |
Cesar, Diego | Brazilian Inst. of Robotics, SENAI CIMATEC |
Cerqueira, Romulo | Brazilian Inst. of Robotics, SENAI CIMATEC |
Britto, João | Brazilian Inst. of Robotics, SENAI CIMATEC |
Silva, Lucas | Brazilian Inst. of Robotics, SENAI CIMATEC |
Santos, Jessivaldo | Brazilian Inst. of Robotics, SENAI CIMATEC |
Brito, Rafael | Brazilian Inst. of Robotics, SENAI CIMATEC |
Arjones, Gabriel | Brazilian Inst. of Robotics, SENAI CIMATEC |
Lima, Camila | Brazilian Inst. of Robotics, SENAI CIMATEC |
Albiez, Jan | Brazilian Inst. of Robotics, SENAI CIMATEC |
Reis, Marco | Brazilian Inst. of Robotics, SENAI CIMATEC |
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16:00-16:30, Paper WePmPo.36 | Add to My Program |
Simple and Fast Pointing Gesture Detection in RGB-D Images |
Azari, Bita | Simon Fraser Univ |
MohaimenianPour, SeyedMehdi (Sepehr) | Simon Fraser Univ |
Vaughan, Richard | Simon Fraser Univ |
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16:00-16:30, Paper WePmPo.37 | Add to My Program |
Towards Full Autonomy for Humanoid Robots |
Jagtap, Vinayak | Worcester Pol. Inst |
Gavarraju, Sumanth Nirmal | Worcester Pol. Inst |
Agarwal, Shlok | Worcester Pol. Inst |
Kejriwal, Sahil | Worcester Pol. Inst |
Devadoss, Samyuktha | Worcester Pol. Inst |
Gennert, Michael | Worcester Pol. Inst |
Keywords: Humanoid Robots, Space Robotics and Automation
Abstract: In this work we present design and implementation of a robust state machine that provides full autonomy over known tasks to Valkyrie R5 robot along with the ability for operator to override state machine commands.
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16:00-16:30, Paper WePmPo.38 | Add to My Program |
Efficient Factor Graph Fusion for Multi-Robot Mapping |
Natarajan, Ramkumar | Worcester Pol. Inst |
Gennert, Michael | Worcester Pol. Inst |
Keywords: SLAM, Multi-Robot Systems, Mapping
Abstract: This work presents a novel method currently being developed to efficiently factorize the combination of multiple factor graphs having common variables of estimation. Recent factor graph formulation for Simultaneous Localization and Mapping (SLAM) like Incremental Smoothing and Mapping using the Bayes tree (ISAM2) has been very successful and garnered much attention. Variable ordering, a well-known technique in linear algebra is employed for efficiently solving the factor graph. Our primary contribution in this work is to reuse the variable ordering of the graphs being combined to find the ordering of the fused graph called fusion ordering. In the case of mapping, multiple robots provide a great advantage over single robot by providing a faster map coverage and better estimation quality. This coupled with an inevitable increase in the number of robots around us produce a demand for faster algorithms. For example, a city full of self-driving cars could exhibit a "friendly" gesture by pooling their observation measurements rapidly to plan a traffic free navigation. By reusing the variable ordering of the parent graphs we were able to produce an order-of-magnitude difference in the time required for solving the fused graph. A formal verification is attempted to show that the proposed strategy does not violate any of the relevant standards. The fusion ordering is experimented on the standard dataset used in the sparse linear algebra community called SuiteSparse and a real-world multi-robot AP Hill dataset.
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16:00-16:30, Paper WePmPo.39 | Add to My Program |
Glass and Non-Glass Objects Classification Using Laser Rangefinders for Mobile Robots in Indoor Environments |
Jiang, Jun | The Univ. of Tokyo |
Miyagusuku, Renato | The Univ. of Tokyo |
Yamashita, Atsushi | The Univ. of Tokyo |
Asama, Hajime | The Univ. of Tokyo |
Keywords: Localization, Object detection, segmentation, categorization, AI-Based Methods
Abstract: In this paper we propose a method to classify glass and non-glass objects for mobile robots navigating in indoor environments using laser rangefinders. The classification results are used to build a glass grid map. Specifically, the proposed classifier, which is based on a 4-layer neural network, employs the LR's received intensity, the measured distance and the incident angle to classify glass and non-glass objects in the mapped environment. The validity of the proposed method has been tested experimentally. Preliminary experimental results shown the accuracy of the proposed solution to accurately classify glass and no-glass objects.
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16:00-16:30, Paper WePmPo.40 | Add to My Program |
On-Line Tracking and Ejection System for Investigating Dynamic Behavior of Running Insects |
Kawahara, Tomohiro | Kyushu Inst. of Tech |
Sato, Daiki | Kyushu Inst. of Tech |
Ahmad, Belal | Kyushu Inst. of Tech |
Ohtsuka, Hirofumi | National Inst. of Tech. Kumamoto Coll |
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16:00-16:30, Paper WePmPo.41 | Add to My Program |
Touchscreen Visual Servo Hopping: A Low-Attention UAV Interface |
Ghasemi Toudeshki, Amirmasoud | Simon Fraser Univ |
Vaughan, Richard | Simon Fraser Univ |
Keywords: Aerial Systems: Applications, Social Human-Robot Interaction, Visual Servoing
Abstract: We demonstrate a very simple touchscreen user interface whereby from a sparse series of user touch-screen inputs, a robot performs visual servo ‘hops’ from target to target and can reliably arrive at a distant, small, initially invisible target from hundreds of meters away. We demonstrate the method on a real robot.
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16:00-16:30, Paper WePmPo.42 | Add to My Program |
Flexible Links for Flexible Interaction |
D'Imperio, Mariapaola | Istituto Italiano Di Tecnologia |
Ludovico, Daniele | Pol. Di Torino |
Pizzamiglio, Cristiano | Pol. Di Torino/DIMEAS |
Canali, Carlo | Department of Advanced Robotics, Istituto Italiano Di Tecnologia |
Muscolo, Giovanni Gerardo | Italian Inst. of Tech |
Caldwell, Darwin G. | Istituto Italiano Di Tecnologia |
Cannella, Ferdinando | Istituto Italiano Di Tecnologia |
Keywords: Flexible Robots, Compliant Joint/Mechanism, Industrial Robots
Abstract: The robots interaction has been studied since the creation of them, because they share the environment with other objects or humans. The solutions have to face both the safety and the efficiency (in terms of speed and accuracy) because the robot will be even more used for helping or substitute the repetitive jobs in industrial plants. These two characteristics often are apparently in contrast, because the high speed or heavy payload look as the dangerous in case of impact. In this work a compliant approach is presented, but the flexibility is not implemented into the control, but into the links. The robot is built in elastic material to permit the deformation during the contact with other bodies. At same time the control deals with this compliance and then both the accuracy and speed is still guarantee.
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WeBT1 , Room 109 |
Add to My Program |
Deep Learning |
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Chair: He, Hongsheng | Univ. of Tennessee |
Co-Chair: Sa, Inkyu | ETH Zurich |
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14:30-14:45, Paper WeBT1.1 | Add to My Program |
Towards Visual Ego-Motion Learning in Robots |
Pillai, Sudeep | MIT |
Leonard, John | MIT |
Keywords: Visual Learning, Deep Learning in Robotics and Automation, Visual-Based Navigation
Abstract: Many model-based Visual Odometry (VO) algo- rithms have been proposed in the past decade, often restricted to the type of camera optics, or the underlying motion manifold observed. We envision robots to be able to learn and perform these tasks, in a minimally supervised setting, as they gain more experience. To this end, we propose a fully trainable solution to visual ego-motion estimation for varied camera optics. We propose a visual ego-motion learning architecture that maps observed optical flow vectors to an ego-motion density estimate via a Mixture Density Network (MDN). By modeling the architecture as a Conditional Variational Autoencoder (C-VAE), our model is able to provide introspective reasoning and prediction for ego-motion induced scene-flow. Additionally, our proposed model is especially amenable to bootstrapped ego-motion learning in robots where the supervision in ego-motion estimation for a particular camera sensor can be obtained from standard navigation-based sensor fusion strategies (GPS/INS and wheel-odometry fusion). Through experiments, we show the utility of our proposed approach in enabling the concept of self-supervised learning for visual ego-motion estimation in autonomous robots.
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14:45-15:00, Paper WeBT1.2 | Add to My Program |
Robots That Anticipate Pain: Anticipating Physical Perturbations from Visual Cues through Deep Predictive Models |
Sur, Indranil | SRI International |
Ben Amor, Heni | Arizona State Univ |
Keywords: Robot Safety, RGB-D Perception, Cognitive Human-Robot Interaction
Abstract: To ensure system integrity, robots need to proactively avoid any unwanted physical perturbation that may cause damage to the underlying hardware. In this paper, we investigate a machine learning approach that allows robots to anticipate impending physical perturbations from perceptual cues. In contrast to other approaches that require knowledge about sources of perturbation to be encoded before deployment, our method is based on experiential learning. Robots learn to associate visual cues with subsequent physical perturbations and contacts. In turn, these extracted visual cues are then used to predict potential future perturbations acting on the robot. To this end, we introduce a novel deep network architecture which combines multiple sub-networks for dealing with robot dynamics and perceptual input from the environment. We present a self-supervised approach for training the system that does not require any labeling of training data. Extensive experiments in a human-robot interaction task show that a robot can learn to predict physical contact by a human interaction partner without any prior information or labeling.
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15:00-15:15, Paper WeBT1.3 | Add to My Program |
Control of a Quadrotor with Reinforcement Learning |
Hwangbo, Jemin | Swiss Federal Inst. of Tech. Zurich |
Sa, Inkyu | ETH Zurich |
Siegwart, Roland | ETH Zurich |
Hutter, Marco | ETH Zurich |
Keywords: Deep Learning in Robotics and Automation, Aerial Systems: Mechanics and Control, AI-Based Methods
Abstract: In this paper, we present a method to control a quadrotor with a neural network trained using reinforcement learning techniques. The proposed network directly maps state to thrust forces making any predefined control structure obso- lete for training. Moreover, we present a new learning algorithm which differs from the existing ones in certain aspects. Our algorithm is conservative but stable for complicated tasks. Therefore, it is more applicable to controlling a quadrotor than existing algorithms. We demonstrate the performance of the trained policy both in simulation and with a real quadrotor. Experiments show that our policy network can react to step response relatively accurately. With the same policy, we also demonstrate that we can stabilize the quadrotor in the air even under very harsh initialization (manually throwing it upside- down in the air with an initial velocity of 5 m/s). Computation time of evaluating the policy is only 7 μs per time step which is two orders of magnitude less than common trajectory optimization algorithms with an approximated model.
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15:15-15:30, Paper WeBT1.4 | Add to My Program |
Deep Visual Gravity Vector Detection for Unmanned Aircraft Attitude Estimation |
Ellingson, Gary | Brigham Young Univ |
Wingate, David | Brigham Young Univ |
McLain, T.W. | Bringham Young Univ |
Keywords: Deep Learning in Robotics and Automation, Visual Learning, Sensor Fusion
Abstract: This paper demonstrates a feasible method for using a deep neural network as a sensor to estimate the attitude of a flying vehicle using only flight video. A dataset of still images and associated gravity vectors was collected and used to perform supervised learning. The network builds on a previously trained network and was trained to be able to approximate the attitude of the camera with an average error of about 8 degrees. Flight test video was recorded and processed with a relatively simple visual odometry method. The aircraft attitude is then estimated with the visual odometry as the state propagation and network providing the attitude measurement in an extended Kalman filter. Results show that the proposed method of having the neural network provide a gravity vector attitude measurement from the flight imagery reduces the standard deviation of the attitude error by approximately 12 times compared to a baseline approach.
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15:30-15:45, Paper WeBT1.5 | Add to My Program |
Learning Deep Visual Object Models from Noisy Web Data: How to Make It Work |
Massouh, Nizar | Sapienza Rome Univ |
Babiloni, Francesca | Sapienza Rome Univ |
Tommasi, Tatiana | Univ. of Rome Sapienza |
Young, Jay | Univ. of Birmingham |
Hawes, Nick | Univ. of Birmingham |
Caputo, Barbara | Sapienza Univ |
Keywords: Recognition, Object detection, segmentation, categorization, Deep Learning in Robotics and Automation
Abstract: Deep networks thrive when trained on large scale data collections. This has given ImageNet a central role in the development of deep architectures for visual object classification. However, ImageNet was created during a specific period in time, and as such it is prone to aging, as well as dataset bias issues. Moving beyond fixed training datasets will lead to more robust visual systems, especially when deployed on robots in new environments which must train on the objects they encounter there. To make this possible, it is important to break free from the need for manual annotators. Recent work has begun to investigate how to use the massive amount of images available on the Web in place of manual image annotations. We contribute to this research thread with two findings: (1) a study correlating a given level of noisily labels to the expected drop in accuracy, for two deep architectures, on two different types of noise, that clearly identifies GoogLeNet as a suitable architecture for learning from Web data; (2) a recipe for the creation of Web datasets with minimal noise and maximum visual variability, based on a visual and natural language processing concept expansion strategy. By combining these two results, we obtain a method for learning powerful deep object models automatically from the Web. We confirm the effectiveness of our approach through object categorization experiments using our Web-derived version of ImageNet on a popular robot vision benchmark database, and on a lifelong object discovery task on a mobile robot.
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15:45-16:00, Paper WeBT1.6 | Add to My Program |
Learning Deep NBNN Representations for Robust Place Categorization |
Mancini, Massimiliano | Sapienza Univ. of Rome |
Rota Bulò, Samuel | Fondazione Bruno Kessler |
Ricci, Elisa | Univ. of Perugia |
Caputo, Barbara | Sapienza Univ |
Keywords: Recognition, Visual Learning, Semantic Scene Understanding
Abstract: This paper presents an approach for semantic place categorization using data obtained from RGB cameras. Previous studies on visual place recognition and classification have shown that, by considering features derived from pre-trained Convolutional Neural Networks (CNNs) in combination with part-based classification models, high recognition accuracy can be achieved, even in presence of occlusions and severe viewpoint changes. Inspired by these works, we propose to exploit local deep representations, representing images as set of regions applying a Na"{i}ve Bayes Nearest Neighbor (NBNN) model for image classification. As opposed to previous methods where CNNs are merely used as feature extractors, our approach seamlessly integrates the NBNN model into a fully-convolutional neural network.
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WeBT2 , Room 111 |
Add to My Program |
Compliant Joint/Mechanism II |
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Chair: Kashiri, Navvab | Istituto Italiano Di Tecnologia |
Co-Chair: Tsagarakis, Nikos | Istituto Italiano Di Tecnologia |
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14:30-14:45, Paper WeBT2.1 | Add to My Program |
Tribot: A Deployable, Self-Righting and Multi-Locomotive Origami Robot |
Zhakypov, Zhenishbek | École Pol. Fédérale De Lausanne |
Belke, Christoph H. | École Pol. Fédérale De Lausanne |
Paik, Jamie | Ec. Pol. Federale De Lausanne |
Keywords: Compliant Joint/Mechanism, Flexible Robots, Legged Robots
Abstract: There are several challenges in down-sizing robots for transportation deployment, diversification of locomotion capabilities tuned for various terrains, and rapid and on-demand manufacturing. In this paper we propose an origami-inspired method of addressing these key issues by designing and manufacturing a foldable, deployable, and self-righting version of the origami robot Tribot. Our latest Tribot prototype can jump as high as 215 mm, five times its height, and roll consecutively on any of its edges with an average step size of 55 mm. The 4 g robot self-deploys nine times of its size when released. A compliant roll cage ensures that the robot self-rights onto two legs after jumping or being deployed and also protects the robot from impacts. A description of our prototype and its design, locomotion modes, and fabrication is followed by demonstrations of its key features.
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14:45-15:00, Paper WeBT2.2 | Add to My Program |
COCrIP: Compliant OmniCrawler In-Pipeline Robot |
Singh, Akash | Visvesvaraya National Inst. of Tech |
Sachdeva, Enna | IIIT Hyderabad |
Sarkar, Abhishek | International Inst. of Information Tech. Hyderabad |
Krishna, Madhava | IIIT Hyderabad |
Keywords: Compliant Joint/Mechanism, Mechanism Design, Compliant Assembly
Abstract: This paper presents a modular in-pipeline climbing robot with a novel compliant foldable OmniCrawler mechanism. The circular cross-section of OmniCrawler module enables a holonomic motion to facilitate the alignment of the robot to steer in the direction of bends. Additionally, the crawler mechanism provides a fair amount of traction, even on slippery surfaces. These advantages of crawler modules have been further supplemented by incorporating active compliance in the module itself which helps to negotiate sharp bends in small diameter pipes. The robot has a series of 3 such compliant foldable modules interconnected by the links via passive joints. For the desirable pipe diameter and curvature of the bends, the spring stiffness values for each passive joint is determined by formulating a constrained optimization problem using the quasi-static model of the robot. Moreover, a minimum friction coefficient value between the module-pipe surface which can be vertically climbed by the robot without slipping is estimated. The numerical simulation results have further been validated by experiments on real robot prototype.
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15:00-15:15, Paper WeBT2.3 | Add to My Program |
Development of a Human Size and Strength Compliant Bi-Manual Platform for Realistic Heavy Manipulation Tasks |
Baccelliere, Lorenzo | Istituto Italiano Di Tecnologia |
Kashiri, Navvab | Istituto Italiano Di Tecnologia |
Muratore, Luca | Italian Inst. of Tech |
Laurenzi, Arturo | Istituto Italiano Di Tecnologia |
Kamedula, Malgorzata | Istituto Italiano Di Tecnologia |
Margan, Alessio | Istituto Italiano Di Tecnologia |
Cordasco, Stefano | Istituto Italiano Di Tecnologia (IIT) |
Malzahn, Jörn | Istituto Italiano Di Tecnologia |
Tsagarakis, Nikos | Istituto Italiano Di Tecnologia |
Keywords: Compliant Joint/Mechanism, Compliant Assembly, Mechanism Design
Abstract: Developing a high physical performance robotic manipulation platform with considerable power density, strength and resilience is not a trivial task and frequently leads to heavy and bulky systems unable to meet the application requirements, i.e. such robots should have human body size compatibility to work in infrastructures designed for humans. In this work we present a new high performance human size and weight compatible bi-manual manipulation platform that demonstrates notable physical strength and power capabilities. To attain this performance, design features including custom high performance elastic drives and robust light weight structure principles were considered resulting in large payload to robot mass ratio that is greater than 1.5 for short time heavy payloads. The design principles and mechanics of the upper body bi-manual robot are presented providing details on the solutions adopted for the various mechatronics components. The performance of the system actuation and the strength capacity of the overall platform is verified through the execution of heavy payload motion and impact experiments.
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15:15-15:30, Paper WeBT2.4 | Add to My Program |
Open-Loop Torque Control of Series Clutch Actuators with a High Torque to Weight Ratio |
Wang, Yushi | Waseda Univ |
Schmitz, Alexander | Waseda Univ |
Kobayashi, Kento | Waseda Univ |
Alvarez Lopez, Javier Alejandro | Waseda Univ. Sugano Lab |
Matsuo, Yuki | Waseda Univ |
Sakamoto, Yoshihiro | Waseda Univ |
Sugano, Shigeki | Waseda Univ |
Wang, Wei | Waseda Univ |
Keywords: Compliance and Impedance Control, Force Control, Robot Safety
Abstract: For robots that act outside of tightly controlled environments, force control is often better suited than position control. Series clutch actuators, used without an elastic element, can achieve excellent position control or can be used as a force/torque source. Clutches based on different physical principles can be employed; while recently a lot of research has been performed on clutches based on magnetorheological fluid (MR fluid), they still have a relatively low torque to weight ratio, which makes the integration into robots difficult. In industrial applications magnetic particle clutches are preferred, as they have proven their reliability, but they are even heavier for the same torque. Friction clutches have a higher torque to weight ratio, but are generally considered to be difficult to control. The goal of this research is to evaluate series clutch actuators with a high torque to weight ratio for open-loop torque control and collision safety. First, the characteristics of electromagnetically controlled clutches based on friction, MR fluid and magnetic particles are profiled. Subsequently, simple model-based open loop torque control is implemented and the hysteresis, step response, and frequency response is evaluated. The friction clutch has a higher hysteresis and torque variation than the other clutches, but a faster step response and a comparable frequency response. Collision experiments are conducted and the results show that also for collisions the torque can be controlled. Furthermore, in contact free motion, by using clutch settings that fulfill the dynamic torque requirements, unhindered position control is feasible, and by using torque limits that are only slighter higher than the dynamic requirements, safer actuation can be achieved. In conclusion, electromagnetically controlled friction clutches not only have a high torque to weight ratio (in our case 8 Nm/0.32 kg), but are also a viable option for torque control.
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15:30-15:45, Paper WeBT2.5 | Add to My Program |
Soft Fluidic Rotary Actuator with Improved Actuation Properties |
Fraś, Jan | Industrial Res. Inst. for Automation and Measurements |
Noh, Yohan | King's Coll. London |
Wurdemann, Helge Arne | Univ. Coll. London |
Althoefer, Kaspar | Queen Mary Univ. of London |
Keywords: Flexible Robots, Soft Material Robotics, Hydraulic/Pneumatic Actuators
Abstract: The constantly increasing amount of machines operating in the vicinity of humans makes it necessary to rethink the design approach for such machines to ensure that they are safe when interacting with humans. Traditional mechanisms are rigid and heavy and as such considered unsuitable, even dangerous when a controlled physical contact with humans is desired. A huge improvement in terms of safe human-robot interaction has been achieved by a radically new approach to robotics - soft material robotics. These new robots are made of compliant materials that render them safe when compared to the conventional rigid-link robots. This undeniable advantage of compliance and softness is paired with a number of drawbacks. One of them is that a complex and sophisticated controller is required to move a soft robot into the desired positions or along a desired trajectory, especially with external forces being present. In this paper we propose an improved soft fluidic rotary actuator composed of silicone rubber and fiber-based reinforcement. The actuator is cheap and easily manufactured providing near linear actuation properties when compared to pneumatic actuators presented elsewhere. The paper presents the actuator design, manufacturing process and a mathematical model of the actuator behavior as well as an experimental validation of the model. Four different actuator types are compared including a square-shaped and three differently reinforced cylindrical actuators.
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15:45-16:00, Paper WeBT2.6 | Add to My Program |
Flexible Ultrasonic Motor Using an Output Coil Spring Slider |
Kanada, Ayato | Toyohashi Univ. of Tech |
Mashimo, Tomoaki | Toyohashi Univ. of Tech |
Terashima, Kazuhiko | Toyohashi Univ. of Tech |
Keywords: Flexible Robots
Abstract: We present a flexible ultrasonic motor that generates linear motion as a novel soft actuator. This motor is comprised of a single cube stator with a through-hole, and a flexible coil spring inserted into the hole. The coil spring, which has a diameter of 10 mm and length of 200 mm, is translated by a vibration generated in the stator. A preload between the stator and the coil spring is important for improving the motor performance. The coil spring inserted into the stator hole generates the preload by expanding in a radial direction. We build a prototype flexible ultrasonic motor, and examine its basic performance parameters such as thrust force, velocity, response time, resolution and flexibility. To demonstrate flexibility, we show the stable thrust force and velocity even when the coil spring is bent to a bending radius of 15 mm.
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WeBT3 , Room 116 |
Add to My Program |
Planning |
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Chair: Rekleitis, Ioannis | Univ. of South Carolina |
Co-Chair: Dudek, Gregory | McGill Univ |
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14:30-14:45, Paper WeBT3.1 | Add to My Program |
The Matroid Team Surviving Orienteers Problem: Constrained Routing of Heterogeneous Teams with Risky Traversal |
Jorgensen, Stefan | Stanford Univ |
Chen, Robert | Northrop Grumman |
Milam, Mark B. | California Inst. of Tech |
Pavone, Marco | Stanford Univ |
Keywords: Path Planning for Multiple Mobile Robots or Agents, Robotics in Hazardous Fields, Search and Rescue Robots
Abstract: Consider a setting where robots must visit sites represented as nodes in a graph, but each robot may fail when traversing an edge. The goal is to find a set of paths for a team of robots which maximizes the expected number of nodes collectively visited, while guaranteeing that the paths satisfy a notion of "independence'' formalized by a matroid (e.g. limits on team size, number of visits to regions), and that the probabilities that each robot survives to its destination are above a given threshold. We call this problem the Matroid Team Surviving Orienteers (MTSO) problem, which has broad applications such as environmental monitoring in risky regions and search and rescue in dangerous conditions. We present the MTSO formally and detail numerous examples of matroids in a path planning context. We then propose an approximate greedy algorithm for selecting a feasible set of paths and prove that the value of the output is within a factor p_s/(p_s+lambda) of the optimum, where p_s is the per-robot survival probability threshold and 1/lambda < 1 is the approximation factor of an oracle routine for the well known orienteering problem. We demonstrate the efficiency of our approach by applying it to a scenario where a team of robots must gather information while avoiding pirates in the Coral Triangle.
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14:45-15:00, Paper WeBT3.2 | Add to My Program |
Semi-Boustrophedon Coverage with a Dubins Vehicle |
Lewis, Jeremy | Univ. of South Carolina |
Edwards, William | Univ. of South Carolina |
Benson, Kelly | Univ. of South Carolina |
Rekleitis, Ioannis | Univ. of South Carolina |
O'Kane, Jason | Univ. of South Carolina |
Keywords: Nonholonomic Motion Planning, Motion and Path Planning, Computational Geometry
Abstract: This paper addresses the problem of generating coverage paths---that is, paths that pass within some sensor footprint of every point in an environment---for vehicles with Dubins motion constraints. We extend previous work that solves this coverage problem as a traveling salesman problem (TSP) by introducing a practical heuristic algorithm to reduce runtime while maintaining near-optimal path length. Furthermore, we show that generating an optimal coverage path is NP-hard by reducing from the Exact Cover problem, which provides justification for our algorithm's conversion of Dubins coverage instances to TSP instances. Extensive experiments demonstrate that the algorithm does indeed produce length paths comparable to optimal in significantly less time. %
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15:00-15:15, Paper WeBT3.3 | Add to My Program |
A Study on Efficient Motion Design for Redundantly Actuated Parallel Kinematic Manipulators |
Lorenz, Michael | RWTH Aachen Univ |
Paris, Jascha Normen | RWTH Aachen Univ |
Haschke, Tobias | RWTH Aachen Univ |
Schöler, Frederic Jean-Francois | RWTH Aachen Univ |
Hüsing, Mathias | RWTH Aachen Univ |
Corves, Burkhard | RWTH Aachen Univ |
Keywords: Motion and Path Planning, Redundant Robots, Parallel Robots
Abstract: The increasing energy consumption within the industrial sector causes great concerns among numerous countries. Accordingly, an extensive reorientation towards an energy-efficient facility and processes design is essential for innovative production systems. In terms of automated object manipulation, energy efficiency significantly is affected by the physical design as well as by the dynamic characteristics of the manipulator. Since the influence on physical design parameters often is limited, a great impact on energy-efficiency of innovative manufacturing systems may result from an intelligent task management and suitable motion strategies. This contribution identifies energy-efficiency potentials for industrial manipulators in terms of motion design and redundant actuator configurations. In this context, an efficient trajectory planning algorithm is proposed, estimating the energy demand of object manipulation tasks in consideration of dynamic motion parameters as well as redundant actuator configurations. For this purpose, the geometric path as well as the motion law of given trajectories are optimized by a spatial displacement of predefined nodes and by an adjustment of corresponding time intervals. In order to verify its generality, the presented method is applied to the spatial n PRPaR manipulator exhibiting actuation redundancy. According results show a significant energy reduction, establishing high potentials for an increased efficiency of industrial robots.
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15:15-15:30, Paper WeBT3.4 | Add to My Program |
On Close Enough Orienteering Problem with Dubins Vehicle |
Faigl, Jan | Czech Tech. Univ. in Prague |
Pěnička, Robert | Czech Tech. Univ. in Prague |
Keywords: Nonholonomic Motion Planning, Motion and Path Planning, Planning, Scheduling and Coordination
Abstract: In this paper, we address a generalization of the Orienteering Problem (OP) for curvature-constrained vehicles and to problems where it is allowed to collect a reward associated to each target location within a specified distance from the target. The addressed problem combines challenges of the combinatorial optimization of the OP (to select the most rewarding targets and find the optimal sequence to visit them) with the continuous optimization related to the determination of the waypoint locations and suitable headings at the waypoints for the considered Dubins vehicle such that the curvature-constrained path does not exceed the given travel budget and the sum of the collected rewards is maximized. The proposed generalization is called the Close Enough Dubins Orienteering Problem (CEDOP) and novel unsupervised learning approach is proposed to address computational requirements of this challenging planning problem. Based on the presented results, the proposed approach is feasible and provides a bit worse solution of CEDOP than the existing combinatorial approach but with significantly lower computational requirements.
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15:30-15:45, Paper WeBT3.5 | Add to My Program |
Topologically Distinct Trajectory Predictions for Probabilistic Pursuit |
Shkurti, Florian | McGill Univ |
Dudek, Gregory | McGill Univ |
Keywords: Motion and Path Planning, Multi-Robot Systems, Motion Control
Abstract: We address the integrated planning and control problem that enables a single follower robot (the ``photographer'') to maintain a moving target (the ``subject'') in its field of view for as long as possible. We propose a real-time pursuit algorithm that seamlessly handles the often neglected, yet unavoidable, scenario in which the target escapes the follower's field of view; a scenario that simple, reactive controllers are ill-equipped to handle. Our algorithm aims to minimize the expected time until visual contact is re-established, which enables the photographer to track the subject for as long as possible, even in the presence of loss of visibility. At the core of our pursuit algorithm is an efficient method for sampling plausible trajectories from different homotopy classes. We do this by generating topologically distinct shortest paths by using the Voronoi diagram. We use these paths to make informed, model-based predictions of the likely future locations of the target, given a history of observations. Given these predictions, our algorithm produces pursuit trajectories that approximately optimize the likelihood of recovering visual contact. We show that constraining the predictive pursuit problem to the space of homotopy classes condenses the expanse of possibilities that our algorithm must consider, which enables target tracking in large occupancy grids, as opposed to many POMDP methods that are contrained to small environments. We benchmark the tracking behavior of our algorithm against the baseline of human subjects who performed the same set of pursuit tasks in simulation, as well as against two other pursuit algorithms that only take into account paths from a single homotopy class. We show that considering homotopy alternatives in 2D pursuit improves the tracking performance and that our algorithm does at least as well as humans in most pursuit scenarios.
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15:45-16:00, Paper WeBT3.6 | Add to My Program |
Towards Optical Biopsy of Olfactory Cells Using Concentric Tube Robots with Follow-The-Leader Deployment |
Girerd, Cedric | ICube AVR, FEMTO-ST |
Rabenorosoa, Kanty | FEMTO-ST Inst |
Rougeot, Patrick | Univ. of Franche-Comté, FEMTO-ST Inst |
Renaud, Pierre | ICube AVR |
Keywords: Medical Robots and Systems, Surgical Robotics: Steerable Catheters/Needles
Abstract: In this paper, we propose to take advantage of concentric tube robots (CTR) properties to design a robotic system for optical biopsies with fiber-based imaging modalities. Follow-the-leader (FTL) deployment, with CTR body following its tip, is being integrated as a design constraint in order to minimize the device invasiveness. A design procedure is proposed and developed in the context of olfactory cell inspection. Stability issues of CTR are considered with theoretical validation of FTL deployment. Finally, an experimental assessment in lab conditions is being conducted that includes the device deployment and the reproduction of scanning task for imaging. The whole surface to be inspected can be accessed, and 20 micrometers resolution of the CTR tip is observed.
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WeBT4 , Room 114 |
Add to My Program |
Optimization and Optimal Control II |
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Chair: Kyrki, Ville | Aalto Univ |
Co-Chair: Pajarinen, Joni | TU Darmstadt |
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14:30-14:45, Paper WeBT4.1 | Add to My Program |
Scalable Sparsification for Efficient Decision Making under Uncertainty in High Dimensional State Spaces |
Elimelech, Khen | Tech. – Israel Inst. of Tech |
Indelman, Vadim | Tech. - Israel Inst. of Tech |
Keywords: Optimization and Optimal Control, Motion and Path Planning, SLAM
Abstract: In this paper we introduce a novel sparsification method for efficient decision making under uncertainty and belief space planning in high dimensional state spaces. By using a sparse version of the state's information matrix, we are able to improve the high computational cost of examination of all candidate actions. We also present an in-depth analysis for the general case of approximated decision making, and use it in order to set bounds over the induced error in potential revenue. The scalability of the method allows balancing between the degree of sparsification and the tolerance for this error, in order to maximize its benefits. The approach differs from recent methods by focusing on improving the decision making process directly, and not as a byproduct of a sparsification of the state inference. Eventually, we demonstrate the superiority of the approach in a SLAM simulation, where we manage to maintain the accuracy of the solution, while demonstrating a significant improvement in run time.
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14:45-15:00, Paper WeBT4.2 | Add to My Program |
Constrained Unscented Dynamic Programming |
Plancher, Brian | Harvard Univ |
Manchester, Zachary | School of Engineering and Applied Sciences, Harvard Univ |
Kuindersma, Scott | Harvard Univ |
Keywords: Optimization and Optimal Control, Motion and Path Planning, Underactuated Robots
Abstract: Differential Dynamic Programming (DDP) has become a popular approach to performing trajectory optimization for complex, underactuated robots. However, DDP presents two practical challenges. First, the evaluation of dynamics derivatives during optimization creates a computational bottleneck, particularly in implementations that capture second-order dynamic effects. Second, constraints on the states (e.g., boundary conditions, collision constraints, etc.) require additional care since the state trajectory is implicitly defined from the inputs and dynamics. This paper addresses both of these problems by building on recent work on Unscented Dynamic Programming (UDP)---which eliminates dynamics derivative computations in DDP---to support general nonlinear state and input constraints using an augmented Lagrangian. The resulting algorithm has the same computational cost as first-order penalty-based DDP variants, but can achieve constraint satisfaction to high precision without the numerical ill-conditioning associated with penalty methods. We present results demonstrating its favorable performance on several simulated robot systems including a quadrotor and 7-DoF robot arm.
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15:00-15:15, Paper WeBT4.3 | Add to My Program |
Kinodynamic Trajectory Optimization and Control for Car-Like Robots |
Rösmann, Christoph | TU Dortmund Univ |
Hoffmann, Frank | Tech. Univ. Dortmund |
Bertram, Torsten | Tech. Univ. Dortmund |
Keywords: Optimization and Optimal Control, Nonholonomic Motion Planning, Motion and Path Planning
Abstract: This paper presents a novel generic formulation of Timed-Elastic-Bands for efficient online motion planning of car-like robots. The planning problem is defined in terms of a finite-dimensional and sparse optimization problem subject to the robots kinodynamic constraints and obstacle avoidance. Control actions are implicitly included in the optimized trajectory. Reliable navigation in dynamic environments is accomplished by augmenting the inner optimization loop with state feedback. The predictive control scheme is real-time capable and responds to obstacles within the robot's perceptual field. Navigation in large and complex environments is achieved in a pure pursuit fashion by requesting intermediate goals from a global planner. Requirements on the initial global path are fairly mild, compliance with the robot kinematics is not required. A comparative analysis with Reeds and Shepp curves and investigation of prototypical car maneuvers illustrate the advantages of the approach.
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15:15-15:30, Paper WeBT4.4 | Add to My Program |
A Systematic Analysis of Spring Symmetry on Optimality of Antagonistic Variable Stiffness Actuation |
Kamadan, Abdullah | Sabanci Univ |
Kiziltas, Gullu | Sabanci Univ |
Patoglu, Volkan | Sabanci Univ |
Keywords: Optimization and Optimal Control, Prosthetics and Exoskeletons, Compliance and Impedance Control
Abstract: We present a systematic co-design optimization framework that enables comparison of antagonist variable stiffness actuators (VSA) with and without spring symmetry constraints. The proposed framework promotes a fair comparative analysis by maintaining design continuity among system-optimal designs of symmetric and asymmetric VSA configurations. Through a case study of a VSA-powered knee prosthesis, we not only demonstrate that co-design of robots driven by VSAs can provide important performance benefits with respect to sub-system level control-optimal designs, but also provide evidence that relaxing symmetry constraints for certain periodic tasks can result in substantial advantages in performance. Our systematic comparative analysis justifies the use of asymmetric stiffness arrangements for antagonistic VSA-powered robotic systems performing periodic tasks.
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15:30-15:45, Paper WeBT4.5 | Add to My Program |
Hybrid Control Trajectory Optimization under Uncertainty |
Pajarinen, Joni | TU Darmstadt |
Kyrki, Ville | Aalto Univ |
Koval, Michael | Carnegie Mellon Univ |
Srinivasa, Siddhartha | Carnegie Mellon Univ |
Peters, Jan | Tech. Univ. Darmstadt |
Neumann, Gerhard | Univ. of Lincoln |
Keywords: Optimization and Optimal Control
Abstract: Trajectory optimization is a fundamental problem in robotics. While optimization of continuous control trajectories is well developed, many applications require both discrete and continuous, i.e. hybrid controls. Finding an optimal sequence of hybrid controls is challenging due to the exponential explosion of discrete control combinations. Our method, based on Differential Dynamic Programming (DDP), circumvents this problem by incorporating discrete actions inside DDP: we first optimize continuous mixtures of discrete actions, and, subsequently force the mixtures into fully discrete actions. Moreover, we show how our approach can be extended to partially observable Markov decision processes (POMDPs) for trajectory planning under uncertainty. We validate the approach in a car driving problem where the robot has to switch discrete gears and in a box pushing application where the robot can switch the side of the box to push. The pose and the friction parameters of the pushed box are initially unknown and only indirectly observable.
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15:45-16:00, Paper WeBT4.6 | Add to My Program |
Fast Trajectory Optimization for Legged Robots Using Vertex-Based ZMP Constraints |
Winkler, Alexander, Wayne | ETH Zurich |
Farshidian, Farbod | ETH Zurich |
Pardo, Diego | ETH Zürich |
Neunert, Michael | ETH Zurich |
Buchli, Jonas | ETH Zurich |
Keywords: Legged Robots, Optimization and Optimal Control, Humanoid and Bipedal Locomotion
Abstract: This paper combines the fast Zero-Moment-Point (ZMP) approaches that work well in practice with the broader range of capabilities of a Trajectory Optimization formulation, by optimizing over body motion, footholds and Center of Pressure simultaneously. We introduce a vertex-based representation of the support-area constraint, which can treat arbitrarily oriented point-, line-, and area-contacts uniformly. This generalization allows us to create motions such as quadrupedal walking, trotting, bounding, pacing, combinations and transitions between these, limping, bipedal walking and push-recovery all with the same approach. This formulation constitutes a minimal representation of the physical laws (unilateral contact forces) and kinematic restrictions (range of motion) in legged locomotion, which allows us to generate diverse motions in less than a second. We demonstrate the feasibility of the generated motions on a real quadruped robot.
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WeBT5 , Room 118 |
Add to My Program |
Surgical Robotics I |
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Chair: Burgner-Kahrs, Jessica | Gottfried Wilhelm Leibniz Univ. Hannover |
Co-Chair: Stoyanov, Danail | Univ. Coll. London |
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14:30-14:45, Paper WeBT5.1 | Add to My Program |
Robotic Knot Tying through a Spatial Trajectory with a Visual Servoing System |
Lu, Bo | The Hong Kong Pol. Univ |
Chu, Henry | The Hong Kong Pol. Univ |
Cheng, Li | The Hong Kong Pol. Univ |
Keywords: Surgical Robotics: Laparoscopy, Computer Vision for Automation, Motion and Path Planning
Abstract: Robot assisted surgery has become increasingly popular with the rapid development of more sophisticated robotic systems. Nevertheless, there are still many tedious surgical tasks that remain to be performed manually by surgeons with high supervisions. One example is to tie a surgical knot during the surgery, which includes the processes of needle threading, suture looping, suture tail grasping and suture pulling. In this research, we present a new method for robotic suture looping process. This method is based on a spatial trajectory planning for the surgical instruments, where challenges such as suture slippage and potential collisions between the instruments could be eliminated. In contrast to conventional looping process, a dynamic control scheme is proposed to optimize the time and workspace required to complete the process. Vision information is incorporated in order to enable closed loop control of the robotic system with Linear Quadratic (LQ) controller. A series of experiments were conducted in order to examine the performance of the proposed control scheme and the results confirmed that surgical knots can be successfully tied robotically, offering new insights to the field of automated robot-assisted surgery.
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14:45-15:00, Paper WeBT5.2 | Add to My Program |
ToolNet: Holistically-Nested Real-Time Segmentation of Robotic Surgical Tools |
Garcia Peraza Herrera, Luis | Univ. Coll. London |
Li, Wenqi | Univ. Coll. London |
Fidon, Lucas | Univ. Coll. London |
Gruijthuijsen, Caspar | KU Leuven, Department of Mechanical Engineering |
Devreker, Alain | KU Leuven |
Attilakos, George | Univ. Coll. London Hospitals |
Deprest, Jan | Univ. Hospital Leuven |
Vander Poorten, Emmanuel B | Katholieke Univ. Leuven |
Stoyanov, Danail | Univ. Coll. London |
Vercauteren, Tom | Univ. Coll. London (UCL) |
Ourselin, Sebastien | Univ. Coll. London |
Keywords: Surgical Robotics: Laparoscopy, Deep Learning in Robotics and Automation, Medical Robots and Systems
Abstract: Real-time tool segmentation from endoscopic videos is an essential part of many computer-assisted robotic surgical systems and of critical importance in robotic surgical data science. We propose two novel deep learning architectures for automatic segmentation of non-rigid surgical instruments. Both methods take advantage of automated deep-learning-based multi-scale feature extraction while trying to maintain an accurate segmentation quality at all resolutions. The two proposed methods encode the multi-scale constraint inside the network architecture. The first proposed architecture enforces it by cascaded aggregation of predictions and the second proposed network does it by means of a holistically-nested architecture where the loss at each scale is taken into account for the optimization process. As the proposed methods are for real-time semantic labeling, both present a reduced number of parameters. We propose the use of parametric rectified linear units for semantic labeling in these small architectures to increase the regularization of the network while maintaining the segmentation accuracy. We compare the proposed architectures against state-of-the-art fully convolutional networks. We validate our methods using existing benchmark datasets, including ex vivo cases with phantom tissue and different robotic surgical instruments present in the scene. Our results show a statistically significant improved Dice Similarity Coefficient over previous instrument segmentation methods. We analyze our design choices and discuss the key drivers for improving accuracy.
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15:00-15:15, Paper WeBT5.3 | Add to My Program |
Magnetic Interactions of Neighbouring Stator Sets in Multi DOF Local Electromagnetic Actuation for Robotic Abdominal Surgery |
Leong, Ching Ying, Florence | Univ. of Melbourne |
Mohammadi, Alireza | The Univ. of Melbourne |
Tan, Ying | The Univ. of Melbourne |
Thiruchelvam, Dhan | Department of Surgery, Univ. of Melbourne at St Vincent's H |
Valdastri, Pietro | Vanderbilt Univ |
Oetomo, Denny | The Univ. of Melbourne |
Keywords: Surgical Robotics: Laparoscopy, Medical Robots and Systems
Abstract: This paper aims to characterise the magnetic interaction in neighbouring sets of local electromagnetic actuation (LEMA) actuators in a robotic platform for abdominal surgery. The analysis looks into the affect of the magnetic fields contributed by stator-rotor set (the actuation unit) located adjacent to the rotor of interest. Each rotor drives one of the DOFs on a surgical robotic device. In this study, a two-DOF setup is used for the magnetic interaction analysis, which can be expanded to general case n-DOF setup with the Principle of Superposition of magnetic fields from multiple sources. The magnetic model is then used to compute the dynamics of the system, which involves the equation of motion of the rotors and associated robotic mechanism it drives, and the actuator (electrical) model that takes into account the back EMF generated by the permanent magnet rotors. The magnetic field effect of the neighbouring set onto the rotor is observed by obtaining the speed response of the rotor through simulation so that the dynamic model can be validated against the experimental results. The outcomes are useful for the design specification of the LEMA system configuration, involving the feasible / pragmatic distance between the stator sets such that the interference is minimised, the design of the necessary control strategy.
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15:15-15:30, Paper WeBT5.4 | Add to My Program |
Dynamic Reconstruction of Deformable Soft-Tissue with Stereo Scope in Minimal Invasive Surgery |
Song, Jingwei | Univ. of Tech. Sydney |
Wang, Jun | Univ. of Tech. Sydney |
Zhao, Liang | Imperial Coll. London |
Huang, Shoudong | Univ. of Tech. Sydney |
Dissanayake, Gamini | Univ. of Tech. Sydney |
Keywords: Surgical Robotics: Laparoscopy, SLAM, Computer Vision for Medical Robotics
Abstract: In minimal invasive surgery, it is important to rebuild and visualize the latest deformed shape of soft-tissue surfaces to mitigate tissue damages. This paper proposes an innovative Simultaneous Localization and Mapping (SLAM) algorithm for deformable dense reconstruction of surfaces using a sequence of images from a stereoscope. We introduce a warping field based on the Embedded Deformation (ED) nodes with 3D shapes recovered from consecutive pairs of stereo images. The warping field is estimated by deforming the last updated model to the current live model. Our SLAM system can: (1) Incrementally build a live model by progressively fusing new observations with vivid accurate texture. (2) Estimate the deformed shape of unobserved region with the principle As-Rigid-As-Possible. (3) Show the consecutive shape of models. (4) Estimate the current relative pose between the soft-tissue and the scope. In-vivo experiments with publicly available datasets demonstrate that the 3D models can be incrementally built for different soft-tissues with different deformations from sequences of stereo images obtained by laparoscopes. Results show the potential clinical application of our SLAM system for providing surgeon useful shape and texture information in minimal invasive surgery.
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15:30-15:45, Paper WeBT5.5 | Add to My Program |
A Multi-Axis Force Sensor to Assess Tissue Properties in Real-Time |
Jones, Dominic | Univ. of Leeds |
Wang, Hongbo | Univ. of Leeds |
Alazmani, Ali | Univ. of Leeds |
Culmer, Peter Robert | Univ. of Leeds |
Keywords: Surgical Robotics: Laparoscopy, Soft Material Robotics, Force and Tactile Sensing
Abstract: Objective: This work presents a method for the use of a soft multi-axis force sensor to determine tissue trauma in Minimally Invasive Surgery. Despite recent developments, there is a lack of effective haptic sensing technology employed in instruments for Minimally Invasive Surgery (MIS). There is thus a clear clinical need to increase the provision of haptic feedback and to perform real-time analysis of haptic data to inform the surgical operator. This paper establishes a methodology for the capture of real-time data through use of an inexpensive prototype grasper. Fabricated using soft silicone and 3D printing, the sensor is able to precisely detect compressive and shear forces applied to the grasper face. The sensor is based upon a magnetic soft tactile sensor, using variations in the local magnetic field to determine force. The performance of the sensing element is assessed and a linear response was observed, with a max hysteresis error of 4.1% of the maximum range of the sensor. To assess the potential of the sensor for surgical sensing, a simulated grasping study was conducted using ex vivo porcine tissue. Two previously established metrics for prediction of tissue trauma were obtained and compared from recorded data. The normalized stress rate (kPa.mm-1) of compression and the normalized stress relaxation (ΔσR) were analyzed across repeated grasps. The sensor was able to obtain measures in agreement with previous research, demonstrating future potential for this approach. In summary this work demonstrates that inexpensive soft sensing systems can be used to instrument surgical tools and thus assess properties such as tissue health. This could help reduce surgical error and thus benefit patients.
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15:45-16:00, Paper WeBT5.6 | Add to My Program |
Sensing Slip of Grasped Wet, Conformable Objects |
Burkhard, Natalie | Stanford Univ |
Steger, Ryan | Intuitive Surgical |
Cutkosky, Mark | Stanford Univ |
Keywords: Surgical Robotics: Laparoscopy, Perception for Grasping and Manipulation, Force and Tactile Sensing
Abstract: Grasping and manipulation of biological tissue are crucial processes during minimally invasive surgery (MIS). To enable atraumatic and reliable grasping, it would be useful to detect slip. Because the grasped object (biological tissue) is moist, conformable, and delicate, and because the sensor must work in a surgical environment, this application requires a departure from conventional slip sensing methods. We present a technology and method based on hot-wire anemometry to detect slip while grasping wet, conformable materials and discuss how this approach may be extended to graspers used in robot-assisted surgery (RAS). We present our design and the results from characterization tests as well as experimental results that demonstrate its ability to detect planar direction of slip of wet, compliant objects.
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WeBT6 , Room 121 |
Add to My Program |
RGBD Perception II |
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Chair: Pronobis, Andrzej | Univ. of Washington |
Co-Chair: Rives, Patrick | INRIA |
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14:30-14:45, Paper WeBT6.1 | Add to My Program |
An Efficient Rotation and Translation Decoupled Initialization from Large Field of View Depth Images |
Martins, Renato | Inria |
Fernández-Moral, Eduardo | INRIA |
Rives, Patrick | INRIA |
Keywords: Omnidirectional Vision, RGB-D Perception, Range Sensing
Abstract: Image and point cloud registration methods compute the relative pose between two images. Commonly used registration algorithms are iterative and rely on the assumption that the motion between the images is small. In this work, we propose a fast pose estimation technique to compute a rough estimate of large motions between depth images, which can be used as initialization to dense registration methods. The main idea is to explore the properties given by planar surfaces with co-visibility and their normals from two distinct viewpoints. We present, in two decoupled stages, the rotation and then the translation estimation, both based on the normal vectors orientation and on the depth. These two stages are efficiently computed by using low resolution depth images and without any feature extraction/matching. We also analyze the limitations and observabilty of this approach, and its relationship to ICP point-to-plane. Notably, if the rotation is observable, at least five degrees of freedom can be estimated in the worst case. To demonstrate the effectiveness of the method, we evaluate the initialization technique in a set of challenging scenarios, comprising simulated spherical images from the Sponza Atrium model benchmark and real spherical indoor sequences.
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14:45-15:00, Paper WeBT6.2 | Add to My Program |
Extrinsic Calibration of Multiple RGB-D Cameras from Line Observations |
Perez-Yus, Alejandro | Univ. De Zaragoza |
Fernández-Moral, Eduardo | INRIA |
Lopez-Nicolas, Gonzalo | Univ. De Zaragoza |
Guerrero, Josechu | Univ. De Zaragoza |
Rives, Patrick | INRIA |
Keywords: RGB-D Perception, Sensor Fusion, Omnidirectional Vision
Abstract: This paper presents a novel method to estimate the relative poses between RGB and depth cameras without the requirement of an overlapping field of view, thus providing flexibility to calibrate a variety of sensor configurations. This calibration problem is relevant to robotic applications which can benefit of using several cameras to increase the field of view. In our approach, we extract and match lines of the scene in the RGB and depth cameras, and impose geometric constraints to find the relative poses between the sensors. An analysis of the observability of the problem is presented. We have validated our method in both synthetic and real scenarios with different camera configurations, demonstrating that our approach achieves good accuracy and is very simple to apply, in contrast with previous methods based on trajectory matching using visual odometry or SLAM.
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15:15-15:30, Paper WeBT6.4 | Add to My Program |
Sensor Fusion for Fiducial Tags: Highly Robust Pose Estimation from Single Frame RGBD |
Jin, Pengju | Carnegie Mellon Univ |
Matikainen, Pyry | Carnegie Mellon Univ |
Srinivasa, Siddhartha | Carnegie Mellon Univ |
Keywords: RGB-D Perception, Sensor Fusion, Computer Vision for Other Robotic Applications
Abstract: Although there is an abundance of planar fiducial-marker systems proposed for augmented reality and computer-vision purposes, using them to estimate the pose accurately in robotic applications where collected data are noisy remains a challenge. This is inherently a difficult problem because these fiducial marker systems work solely within the RGB image space and the resolution of cameras on robots is often constrained. As a result, small noise in the image would cause the tag's detection process to produce large pose estimation errors. This paper describes an algorithm that improves the pose estimation accuracy of square fiducial markers in difficult scenes by fusing information from RGB and depth sensors. The algorithm retains the high detection rate and low false positive rate characteristics of fiducial systems while making them much more robust to size, lighting and sensory noise for pose estimation. The improvements make the fiducial tags suitable for robotic tasks requiring high pose accuracy in the real world environment.
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15:30-15:45, Paper WeBT6.5 | Add to My Program |
Depth-Aware Convolutional Neural Networks for Accurate 3D Pose Estimation in RGB-D Images |
Porzi, Lorenzo | Mapillary |
Peñate-Sánchez, Adrián | Inst. De Robòtica I Informàtica Industrial, CSIC-UPC |
Ricci, Elisa | Univ. of Perugia |
Moreno-Noguer, Francesc | CSIC |
Keywords: RGB-D Perception, Computer Vision for Other Robotic Applications, Visual Tracking
Abstract: Most recent approaches to 3D pose estimation from RGB-D images address the problem in a two-stage pipeline. First, they learn a classifier –typically a random forest– to predict the position of each input pixel on the object surface. These estimates are then used to define an energy function that is minimized w.r.t. the object pose. In this paper, we focus on the first stage of the problem and propose a novel classifier based on a depth-aware Convolutional Neural Network. This classifier is able to learn a scale-adaptive regression model that yields very accurate pixel-level predictions, allowing to finally estimate the pose using a simple RANSAC-based scheme, with no need to optimize complex ad hoc energy functions. Our experiments on publicly available datasets show that our approach achieves remarkable improvements over state-of-the-art methods.
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15:45-16:00, Paper WeBT6.6 | Add to My Program |
SegICP: Integrated Deep Semantic Segmentation and Pose Estimation |
Wong, Jay M. | Draper |
Mariottini, Gian Luca | Draper Lab |
Torralba, Antonio | MIT |
Chipalkatty, Rahul | Georgia Inst. of Tech |
Kee, Vincent | Massachusetts Inst. of Tech |
Hebert, Mitchell | Univ. of Massachusetts Amherst |
Zhou, Bolei | MIT |
Le, Tiffany | MIT |
Schneider, Abraham | Charles Stark Draper Lab |
Johnson, David M.S. | Draper |
Wu, Jimmy | Massachusetts Inst. of Tech |
Wagner, Syler | The Charles Stark Draper Lab |
Keywords: RGB-D Perception, Localization, Learning and Adaptive Systems
Abstract: Recent robotic manipulation competitions have highlighted that sophisticated robots still struggle to achieve fast and reliable perception of task-relevant objects in complex, realistic scenarios. To improve these systems’ perceptive speed and robustness, we present SegICP, a novel integrated solution to object recognition and pose estimation. SegICP couples convolutional neural networks and multi-hypothesis point cloud registration to achieve both robust pixel-wise semantic segmentation as well as accurate and real-time 6-DOF pose estimation for relevant objects.Our architecture achieves 1 cm position error and < 5◦ angle error in real time without an initial seed. We evaluate and benchmark SegICP against an annotated dataset generated by motion capture.
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WeBT7 , Room 122 |
Add to My Program |
Biomimetics II |
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Chair: Shim, Youngbo | Mechatronics and Manufacturing Tech. Center, Samsung Elec |
Co-Chair: Jang, Junwon | Samsung Electronics Co., Ltd |
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14:30-14:45, Paper WeBT7.1 | Add to My Program |
Snake Robots in Contact with the Environment: Influence of the Friction on the Applied Wrench |
Reyes, Fabian | Ritsumeikan Univ |
Ma, Shugen | Ritsumeikan Univ |
Keywords: Biologically-Inspired Robots, Force Control, Contact Modelling
Abstract: Robots capable of both locomotion and interaction with the environment are necessary for robots to move from ideal laboratory situations to real applications. Snake robots have been researched for locomotion in unstructured environments due to its unique and adaptable gaits, however, they have not been used to interact with the environment in a dexterous manner, for example to grasp or push an object. In this paper, it is shown the effect of both the configuration of the snake robot (shape) and the friction between the snake robot and ground, on a wrench applied to another object. It is assumed that the snake robot has anisotropic friction with the ground, a property that has been proved to be essential for locomotion. The extreme case of no friction and ideal unbounded friction can be both studied at the same time, making the model and conclusions very versatile and possible to apply to any coefficient of friction. The model and metrics are tested in a study case.
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14:45-15:00, Paper WeBT7.2 | Add to My Program |
Long-Legged Hexapod Giacometti Robot Using Thin Soft McKibben Actuator |
Mohd Faudzi, Ahmad `Athif | Univ. Teknologi Malaysia |
Endo, Gen | Tokyo Inst. of Tech |
Kurumaya, Shunichi | Tokyo Inst. of Tech |
Suzumori, Koichi | Tokyo Inst. of Tech |
Keywords: Biomimetics, Biologically-Inspired Robots, Soft Material Robotics
Abstract: This letter introduces a lightweight hexapod robot, Giacometti robot, made with long and narrow legs following the Alberto Giacometti’s sculpture conception. The goal is achieved by, firstly, using multiple links with thin and soft McKibben actuators, and secondly, choosing a leg design which is narrow in comparison to its body’s length and height, unlike conventional robot design. By such design characteristic, the leg will exhibit elastic deformations due to the low stiffness property of the thin link structure. Then, we model the leg structure and conduct the deflection analysis to confirm the capability of the leg to perform walking motion. The high force to weight ratio characteristics of the actuator provided the ability to drive the system, as shown by a static model and further validated experimentally. To compensate for the high elastic structural flexibility of the legs, two walking gaits namely customized Wave gait and Giacometti gait were introduced. The robot could walk successfully with both gaits at a maximum speed of 0.005 m/s and 0.05 m/s, respectively. It is envisaged that the lightweight Giacometti robot design can be very useful in legged robotic exploration.
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15:00-15:15, Paper WeBT7.3 | Add to My Program |
Antagonist Inhibition Control in Redundant Tendon-Driven Structures Based on Human Reciprocal Innervation for Wide Range Limb Motion of Musculoskeletal Humanoids |
Kawaharazuka, Kento | The Univ. of Tokyo |
Kawamura, Masaya | The Univ. of Tokyo |
Makino, Shogo | The Univ. of Tokyo |
Asano, Yuki | The Univ. of Tokyo |
Okada, Kei | The Univ. of Tokyo |
Inaba, Masayuki | The Univ. of Tokyo |
Keywords: Biomimetics, Humanoid Robots, Tendon/Wire Mechanism
Abstract: The body structure of an anatomically correct tendon-driven musculoskeletal humanoid is complex, and the difference between its geometric model and the actual robot is very large because expressing the complex routes of tendon wires in a geometric model is very difficult. If we move a tendon-driven musculoskeletal humanoid by the tendon wire lengths of the geometric model, unintended muscle tension and slack will emerge. In some cases, this can lead to the wreckage of the actual robot. To solve this problem, we focused on reciprocal innervation in the human nervous system, and then implemented antagonist inhibition control (AIC) based on the reflex. This control makes it possible to avoid unnecessary internal muscle tension and slack of tendon wires caused by model error, and to perform wide range motion safely for a long time. To verify its effectiveness, we applied AIC to the upper limb of the tendon-driven musculoskeletal humanoid, Kengoro, and succeeded in dangling for 14 minutes and doing pull-ups.
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15:15-15:30, Paper WeBT7.4 | Add to My Program |
A Novel Modular Compliant Knee Joint Actuator for Use in Assistive and Rehabilitation Orthoses |
Bacek, Tomislav | Vrije Univ. Brussel |
Moltedo, Marta | Vrije Univ. Brussel |
Langlois, Kevin | VUB |
Rodriguez Guerrero, Carlos | Vrije Univ. Brussel |
Vanderborght, Bram | Vrije Univ. Brussel |
Lefeber, Dirk | Vrije Univ. Brussel |
Keywords: Wearable Robots, Prosthetics and Exoskeletons, Rehabilitation Robotics
Abstract: Despite significant advancements in the field of wearable robots (WRs), commercial WRs still use traditional direct-drive actuation units to power their joints. On the other hand, in research prototypes compliant actuators are increasingly being used to more adequately address the issues of safety, robustness, control and overall system efficiency. The advantages of mechanical compliance are exploited in a novel modular actuator prototype designed for the knee joint. Due to its modularity, the actuator can be implemented in a knee joint of a standalone or a multi-joint lower-limbs orthosis, for use in gait rehabilitation and/or walking assistance. Differently from any other actuator used in orthotic research prototypes, it combines a Variable Stiffness Actuator (VSA) and a Parallel Elasticity Actuation (PEA) unit in a single modular system. Although independent, the units are designed to work together in order to fully mimic dynamic behavior of the human knee joint. In this paper, design aspects and functional evaluation of the new actuator are presented and a rationale for such a design in biomechanics of the human knee joint is given. The VSA subsystem is characterized in a quasi- static benchmarking environment and the results showing main performance indicators are presented.
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15:30-15:45, Paper WeBT7.5 | Add to My Program |
Preliminary Study of Online Gait Recognizer for Lower Limb Exoskeletons |
Jang, Junwon | Samsung Electronics Co., Ltd |
Kim, Kyungrock | Samsung Advanced Inst. of Tech. (SAIT) |
Lee, Jusuk | Samsung Electronics Co., Ltd |
Lim, Bokman | Samsung Electronics Co., Ltd |
Cho, Joon-Kee | Samsung Advanced Inst. of Tech |
Shim, Youngbo | Samsung Electronics |
Keywords: Wearable Robots, Prosthetics and Exoskeletons, Rehabilitation Robotics
Abstract: We propose a novel two-tier gait recognizer using a minimal number of mechanical sensors built into a lower limb exoskeleton. The aim of this recognizer is to offer one-step selection of one of the actions ascending, descending, and level walking during five gaits (stair ascent/descent, slope ascent/descent, level walking). The proposed recognizer is executed at the moment of foot contact as estimated by an inertial measurement unit (IMU) on the pelvis without using direct foot sensors. The proposed recognizer selects the gait by using the relations between the angles formed by the hip and knee joints during the last step. As this study constitutes preliminary work for lower limb exoskeletons, we used a hip exoskeleton integrated with two wireless IMUs on the shank to set up the lower limb exoskeleton sensor configuration. Experiments were used to evaluate IMU-based foot contact estimation with respect to a foot sensor based on a force-sensitive resistor (FSR) for stairs, slopes, and level ground. In addition, we evaluated the performance of the proposed two-tier gait recognizer by using two healthy male subjects in various gait environments.
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15:45-16:00, Paper WeBT7.6 | Add to My Program |
A Pneumatic Artificial Muscle Manufactured Out of Self-Healing Polymers That Can Repair Macroscopic Damages |
Terryn, Seppe | Vrije Univ. Brussel (VUB) |
Brancart, Joost | Vrije Univ. Brussel (VUB) |
Lefeber, Dirk | Vrije Univ. Brussel - VUB |
Van Assche, Guy | Vrije Univ. Brussel (VUB) |
Vanderborght, Bram | Vrije Univ. Brussel |
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WeBT8 , Room 202 |
Add to My Program |
Humanoid and Bipedal Locomotion II |
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Chair: Poulakakis, Ioannis | Univ. of Delaware |
Co-Chair: Zanotto, Damiano | Stevens Inst. of Tech |
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14:30-14:45, Paper WeBT8.1 | Add to My Program |
Modeling Robot Geometries Like Molecules, Application to Fast Multi-Contact Posture Planning for Humanoids |
Faraji, Salman | EPFL |
Ijspeert, Auke | EPFL |
Keywords: Humanoid Robots, Kinematics, Optimization and Optimal Control
Abstract: Traditional joint-space models used to describe equations of motion for humanoid robots offer nice properties linked directly to the way these robots are built. However, from a computational point of view and convergence properties, these models are not the fastest when used in planning optimizations. In this paper, inspired by Cartesian coordinates used to model molecular structures, we propose a new modeling technique for humanoid robots. We represent robot segments by vectors and derive equations of motion for the full body. Using this methodology in a complex task of multi-contact posture planning with minimal joint torques, we set up optimization problems and analyze the performance. We demonstrate that compared to joint-space models that get trapped in local minima, the proposed vector-based model offers much faster computational speed and a suboptimal but unique final solution. The underlying principle lies in reducing the nonlinearity and exploiting the sparsity in the problem structure. Apart from the specific case study of posture optimization, these principles can make the proposed technique a promising candidate for many other optimization-based complex tasks in robotics.
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14:45-15:00, Paper WeBT8.2 | Add to My Program |
Estimating CoP Trajectories and Kinematic Gait Parameters in Walking and Running Using Instrumented Insoles |
Zhang, Huanghe | Stevens Inst. of Tech |
Zanotto, Damiano | Stevens Inst. of Tech |
Agrawal, Sunil | Columbia Univ |
Keywords: Human detection & tracking, Force and Tactile Sensing, Wearable Robots
Abstract: Quantitative analysis of the plantar pressure distribution during dynamic tasks can facilitate diagnosis of foot and ankle dysfunctions and prevent potential injuries by providing detailed information about weight bearing and weight shifting patterns. Traditional laboratory measurements are currently limited by high operating costs and lack of portability. The use of instrumented insoles capable of capturing kinematic and kinetic gait parameters as subjects perform out-of-the-lab dynamic activities is a promising approach to overcome these limitations. This letter introduces SportSole, a fully portable system that can measure spatiotemporal gait parameters and center of pressure (CoP) trajectories. Wearing the SportSole, nine able-bodied subjects completed a walking session followed by a running session, each consisting of 10 full laps along a 16-meter straight-line path. Accuracy and precision of CoP trajectories and kinematic parameters were assessed using an electronic walkway as the reference system. After calibration, mean deviations in the CoP were 0.61 ± 0.05 cm (RMSE ± SD) for walking and 0.72 ± 0.08 cm for running. Deviations in stride length, stride time, and velocity were 1.66 ± 0.18 cm, 0.006 ± 0.003 s, and 1.65 ± 0.10 cm/s for walking, 1.91 ± 0.19 cm, 0.01 ± 0.03 s, and 2.67 ± 0.38 cm/s for running. These promising results indicate that the proposed system has the potential to be used for out-of-the-lab gait analysis of walking and running.
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15:00-15:15, Paper WeBT8.3 | Add to My Program |
Adaptation of Limit-Cycle Walkers for Collaborative Tasks: A Supervisory Switching Control Approach |
Veer, Sushant | Univ. of Delaware |
Shafiee Motahar, Mohamad | Univ. of Delaware |
Poulakakis, Ioannis | Univ. of Delaware |
Keywords: Humanoid and Bipedal Locomotion, Legged Robots, Physical Human-Robot Interaction
Abstract: This paper presents a method to achieve online gait adaptation of a dynamically walking biped when collaborating with an external agent - either a human or a robot - acting as a leader. Adaptation occurs without any explicit information on the leader’s intended motion; only implicit information is used through the interaction force developed between the leader and the biped. An adaptive supervisory control scheme is proposed and guarantees for boundedness of the state despite switching under external force are provided. The supervisory controller leverages the availability of a library of exponentially stable limit-cycle gaits, and orchestrates switching among them in an online fashion to achieve adaptation. As a result, the range of leader speeds that the biped can adapt to is drastically enlarged while the leader’s effort is reduced.
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15:15-15:30, Paper WeBT8.4 | Add to My Program |
Optimal Control Based Push Recovery Strategy for the Icub Humanoid Robot with Series Elastic Actuators |
Hu, Yue | Heidelberg Univ |
Mombaur, Katja | Heidelberg Univ |
Keywords: Humanoid and Bipedal Locomotion, Optimization and Optimal Control, Humanoid Robots
Abstract: One of the biggest challenges of humanoid robots is to keep the balance at any moment, as they can be subject to different types of external perturbations. Therefore, push recovery is a relevant issue in humanoid robotics, which still represents an open challenge. In literature, the most used method is based on the capture point, where a reduced model of the robot is used to compute recovery motions. In this paper we want to explore the problem with a different approach, by using whole-body models combined with optimal control. The robot is subject to an external perturbation, which is taken into account in the system dynamics as continuous external force. Optimal control is used to generate whole-body recovery motions by using the whole-body dynamic model of the robot. Instead of the capture point criterion, we optimize for a stable motion that allows to perform recovery within one step, at the end of which the robot is in a state of zero velocity. We apply the method to the model of the humanoid robot HeiCub, where serial springs can be mounted in the knee and ankle pitch actuators to change them into Series Elastic Actuators (SEA). The recovery motion is computed for both the model with and without SEA.
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15:30-15:45, Paper WeBT8.5 | Add to My Program |
Generation of Locomotion Trajectories for Series Elastic and Viscoelastic Bipedal Robots |
Werner, Alexander | German Aerospace Center (DLR) |
Turlej, Wojciech | German Aerospace Center (DLR) |
Ott, Christian | German Aerospace Center (DLR) |
Keywords: Humanoid and Bipedal Locomotion, Optimization and Optimal Control, Legged Robots
Abstract: Series-elastic and viscoelastic robots can provide performance gains in applications with high dynamics. Harnessing these requires an understanding of the dynamics of the system, which can be gained using optimization-based methods. The result are motions which make optimal use of the intrinsic behavior, possibly exceeding the performance of an equivalent rigid-body robot. We present a collocation framework which enables both automatic computation of contact-switching patterns and allows the full utilization of the dynamics of the compliant system. The formulation also addresses the problem of redundant torque generation in viscoelastic actuators. The effectiveness of this method was demonstrated in simulations as well as experiments with a compliant bipedal robot. The approach is capable of providing gait primitives, longer gait sequences containing multiple steps as well as generating extremely dynamic motions, e.g. somersaults.
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15:45-16:00, Paper WeBT8.6 | Add to My Program |
Snapbot: A Reconfigurable Legged Robot |
Kim, Joohyung | Disney Res |
Alspach, Alexander | Disney Res |
Yamane, Katsu | Disney |
Keywords: Legged Robots, Cellular and Modular Robots, Mechanism Design
Abstract: We develop a reconfigurable legged robot, named Snapbot, to emulate configuration changes and various styles of legged locomotion. The body of Snapbot houses a microcontroller and a battery for untethered operation. The body also contains connections for communication and power to the modular legs. The legs can be attached to and detached from the body using magnetic mechanical couplings. In the center of this coupling, there is a multi-pin spring-loaded electrical connector that distributes power and transmits data between the controller and leg actuators. The locomotion algorithm is implemented on the microcontroller. The algorithm enables Snapbot to locomote in various configurations with one to six legs by recognizing configuration changes and selecting the locomotion method according to the current configuration. Snapbot will be utilized for further research on legged locomotion.
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WeBT9 , Room 204 |
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Calibration and Identification |
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Chair: Triebel, Rudolph | Tech. Univ. Munich |
Co-Chair: Chaumette, Francois | Inria Rennes-Bretagne Atlantique |
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14:30-14:45, Paper WeBT9.1 | Add to My Program |
A Method for Hand-Eye and Camera-To-Camera Calibration for Limited Fields of View |
Nissler, Christian | German Aerospace Center (DLR) |
Marton, Zoltan-Csaba | German Aerospace Center (DLR) |
Kisner, Hannes | Tech. Univ. Chemnitz |
Thomas, Ulrike | Tech. Univ. of Chemnitz |
Triebel, Rudolph | Tech. Univ. Munich |
Keywords: Calibration and Identification, Localization, Computer Vision for Automation
Abstract: In classical robot-camera calibration, a 6D transformation between the camera frame and the local frame of a robot is estimated by first observing a known calibration object from a number of different view points and then finding transformation parameters that minimize the reprojection error. The disadvantage with this is that often not all configurations can be reached by the end-effector, which leads to an inaccurate parameter estimation. Therefore, we propose a more versatile method based on the detection of oriented visual features, in our case AprilTags. From a collected number of such detections during a defined rotation of a joint, we fit a Bingham distribution by maximizing the observation likelihood of the detected orientations. After a tilt and a second rotation, a camera-to-joint transformation can be determined. In experiments with accurate ground truth available, we evaluate our approach in terms of precision and robustness, both for hand-eye/robot-camera and for camera-camera calibration, with classical solutions serving as a baseline.
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14:45-15:00, Paper WeBT9.2 | Add to My Program |
Comparison of Trajectory Parametrization Methods with Statistical Analysis for Dynamic Parameter Identification of Serial Robot |
Abu-Dakka, Fares J. | Istituto Italiano Di Tecnologia |
Diaz-Rodriguez, Miguel | Univ. De Los Andes |
Keywords: Calibration and Identification, Motion and Path Planning
Abstract: This paper introduces an approach for designing exciting trajectories for parameter identification of serial robots based on a combination of Fourier Series (FS) and Schroeder Phased Harmonic Sequence (SPHS). An initial estimation of the trajectory is designed for each link using SPHS. Afterwards, the initial trajectory enable to find the initial parameters of the FS which are fed to an optimization process that finds the optimal parameters of the FS used for identification purpose. Like this, we can take the advantages of both FS and SPHS and eliminate the disadvantages of each of them. Moreover, a comparison of results between; the proposed method, original FS, and SPHS is taking place to demonstrate the effectiveness of the new approach. In this vein, a one-way analysis of variance is conducted to compare whether there are significant improvement or not. An PA10 7DoF arm robot serves as test bed for conducting experiments. Findings shows that the optimal trajectory found through the proposed approach requires less computation time compared to original FS which can be an advantage for fast and robust identification.
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15:00-15:15, Paper WeBT9.3 | Add to My Program |
Adaptive Estimation of Measurement Bias in Six Degree of Freedom Inertial Measurement Units: Theory and Preliminary Simulation Evaluation |
Spielvogel, Andrew Robert | Johns Hopkins Univ |
Whitcomb, Louis | The Johns Hopkins Univ |
Keywords: Calibration and Identification, Sensor Fusion
Abstract: Six-degree of freedom (DOF) inertial measurement units (IMUs) are widely used for attitude estimation. However, such systems' accuracy is limited by the accuracy of calibration of bias, scale factors, and non-orthogonality of sensor measurements. This paper reports a stable adaptive estimator of measurement bias in six-DOF IMUs and preliminary simulation results employing a commercially available IMU comprising a 3-axis fiber optic gyroscope (FOG) with a 3-axis micro-electro-mechanical systems (MEMS) accelerometer. A stability proof of the adaptive estimator and preliminary numerical simulation results are reported. The simulation results for a rotating IMU configuration are promising, and further experimental evaluation and extension of the algorithm for the case of a translating IMU configuration typically found on moving robotic vehicles are needed.
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15:15-15:30, Paper WeBT9.4 | Add to My Program |
Optical Coherence Tomography Based 1D to 6D Eye-In-Hand Calibration |
Antoni, Sven-Thomas | Hamburg Univ. of Tech |
Otte, Christoph | Hamburg Univ. of Tech |
Savarimuthu, Thiusius Rajeeth | Univ. of Southern Denmark |
Rajput, Omer | Hamburg Univ. of Tech |
Schlaefer, Alexander | Hamburg Univ. of Tech |
Keywords: Calibration and Identification, Visual-Based Navigation, Surgical Robotics: Laparoscopy
Abstract: Optical coherence tomography (OCT) is an interferometric imaging modality with spatial resolution in the micrometer range. The OCT signal can be used to detect small structures to measure deformation or to characterize tissue. Moreover, OCT can be realized through a single optical fiber, i.e., it can be easily integrated with instruments. However, to use OCT for intra-operative guidance its spatial alignment needs to be established. Hence, we consider eye-in-hand calibration between the 1D OCT imaging and a 6D robotic position system. We present a method to perform pivot calibration for OCT and based on this introduce pivot+d, a new 1D to 6D eye-in-hand calibration. We provide detailed results on the convergence and accuracy of our method and use translational and rotational ground truth to show that our methods allow for sub millimeter positioning accuracy of an OCT beam with a robot. For pivot calibration we observe a mean translational error of 0.5161+-0.4549mm while pivot+d shows 0.3772+-0.2383mm. Additionally, pivot+d improves rotation detection by about 8° when compared to pivot calibration.
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15:30-15:45, Paper WeBT9.5 | Add to My Program |
A New Calibration Technique for Multi-Camera Systems of Limited Overlapping Field-Of-Views |
Xing, Ziran | ShanghaiTech Univ |
Yu, Jingyi | Univ. of Delaware |
Ma, Yi | Univ. of Illinois at Urbana-Champaign |
Keywords: Calibration and Identification
Abstract: State-of-the-art calibration methods typically choose to use a checkerboard as the calibration target for its simplicity and robustness. They however require the complete checkerboard be captured to break symmetry. More recent multi-camera systems such as Google Jump, Jaunt, and camera arrays have limited overlapping field-of-view (FoV) and having all cameras viewing the complete checkerboard is extremely difficult in reality. Tailored patterns such as CALTag[1] introduce new image features within the checker blocks for breaking symmetry but they also break the grid topology. We present a new technique using such patterned calibration targets for a broad range of multi-camera systems. Our key observation is that applying directional gradient filters yields to heterogeneous responses on grid vs. non-grid features: the former are isolated and the latter are highly inter-connected. We therefore apply a simple but highly efficient technique to eliminate non-grid outliers based on connected component analysis and gradient histograms. Finally, we recover the complete grid by approximating each local checkerboard as a parallelogram and imposing the topology constraint. We conduct comprehensive experiments on a number of recent multi-camera systems and our technique significantly outperforms the state-of-the-art in accuracy and robustness.
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15:45-16:00, Paper WeBT9.6 | Add to My Program |
Application of Response Surface Methodology for Performing Kinematic Calibration of a 3-PSS/S Parallel Kinematic Mechanism |
Rahman, Taufiq | Agile Sensor Tech. Inc |
Hicks, Dion | Memorial Univ. of Newfoundland |
Hossain, Mohammed Raju | Memorial Univ. of Newfoundland |
Krouglicof, Nicholas | Univ. of Prince Edward Island |
Keywords: Kinematics, Calibration and Identification, Parallel Robots
Abstract: Kinematic calibration of a robotic manipulator determines its fabricated dimensions that inevitably deviate, due to manufacturing tolerances, from the specified/designed geometry. Conventional calibration methods achieve this goal by deriving a system of constraint equations from the kinematic structure. Workspace coordinates and the corresponding joint space coordinates are experimentally obtained so that these constraint equations can be solved for the optimal geometric parameters that best fit the data. This paper proposes an alternative kinematic calibration method that leverages response surface methodology to obtain empirical models of direct and inverse kinematics from the same experimental data. The advantages the proposed method include nullifying the requirements of deriving constraint equations and performing joint sensor calibration. In addition, since the developed models are empirical in nature, whether closed-form solutions to the direct or the indirect model is available becomes conveniently inconsequential. Both physical and simulation experiments were conducted on a 3-PSS/S to evaluate the accuracy of the proposed method.
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WeBT10 , Room 205 |
Add to My Program |
Object Detection, Segementation, and Categorization II |
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Chair: Lizarralde, Fernando | Federal Univ. of Rio De Janeiro |
Co-Chair: MohaimenianPour, SeyedMehdi (Sepehr) | Simon Fraser Univ |
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14:30-14:45, Paper WeBT10.1 | Add to My Program |
Object-Based Affordances Detection with Convolutional Neural Networks and Dense Conditional Random Fields |
Nguyen, Anh | Inst. Italiano Di Tech |
Kanoulas, Dimitrios | Inst. Italiano Di Tecnologia |
Caldwell, Darwin G. | Istituto Italiano Di Tecnologia |
Tsagarakis, Nikos | Istituto Italiano Di Tecnologia |
Keywords: Object detection, segmentation, categorization, RGB-D Perception, Deep Learning in Robotics and Automation
Abstract: We present a new method to detect object affordances in real-world scenes using deep Convolutional Neural Networks (CNN), an object detector and dense Conditional Random Fields (CRF). Our system first trains an object detector to generate bounding box candidates from the images. A deep CNN is then used to learn the depth features from these bounding boxes. Finally, these feature maps are post-processed with dense CRF to improve the prediction along class boundaries. The experimental results on our new challenging dataset show that the proposed approach outperforms recent state-of-the-art methods by a substantial margin. Furthermore, from the detected affordances we introduce a grasping method that is robust to noisy data. We demonstrate the effectiveness of our framework on the full-size humanoid robot WALK-MAN using different objects in real-world scenarios.
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14:45-15:00, Paper WeBT10.2 | Add to My Program |
Efficient Stairway Detection and Modeling for Autonomous Robot Climbing |
Shu Chan, Derek Kevin | Federal Univ. of Rio De Janeiro |
Silva, Rôb Klér | Federal Univ. of Rio De Janeiro |
Monteiro, João Carlos | COPPE / Federal Univ. of Rio De Janeiro |
Lizarralde, Fernando | Federal Univ. of Rio De Janeiro |
Keywords: Object detection, segmentation, categorization, Climbing Robots, RGB-D Perception
Abstract: This paper presents an accurate and computationally efficient stairway detection algorithm, robust to measurement noise. While most similar methods depend heavily on detecting three-dimensional (3D) features, this work focuses on locating two-dimensional (2D) features embedded in 3D data. The main idea is: each stair is a sequence of lines with similar domain of definition, and the staircase is a sequence of such elements. To avoid unnecessary computations, an octree is used to down-sample the environment point-cloud data. The resulting centroids are stored in n arrays, each containing points with equal height. This effectively segments the 3D data into n 2D slices. The Hough transform is used to scan each array for lines. the remainder of the algorithm detects lines with the same domain of definition and determines if sequences that may correspond to stairways exist. If these sequences meet the required tolerances, then a staircase is detected. For each detected stairway a model that contains the width, height, depth, and amount of stairs is returned. The proposed algorithm is able to efficiently locate and model staircases on different poses and is robust to noise from the measured data, as indicated by the experimental results.
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15:00-15:15, Paper WeBT10.3 | Add to My Program |
A Variational Approach for 3D Object Classification with Retrieval of Missing Data |
Yu, Hyeonwoo | Seoul National Univ |
Lee, Beom-Hee | Seoul National Univ |
Keywords: Object detection, segmentation, categorization, Deep Learning in Robotics and Automation, Computer Vision for Other Robotic Applications
Abstract: In this paper, we propose a classification method for single views of 3D objects with missing data retrieval. A mobile robot equipped with RGB-D sensors basically obtains only single view information of a 3D scene. Therefore, large amount of information is missing by self-occlusion, which leads to severe restriction on the object classification exploiting the whole shapes of 3D objects. Humans can precisely identify the objects from single view since they already have concepts of the entire shape of 3D objects by learning process. Based on these concepts, humans can infer the entire shape and category of the object from a single view. Inspired from this, the proposed algorithm learns concepts in abbreviated form for the shapes of 3D objects, then infers the entire shape and object category from these concepts simultaneously. We apply a generative model based on variational auto-encoder (VAE) to learn the concepts for complex shapes of 3D objects. Our method is evaluated on 3D CAD model dataset, and also compared with other state-of-the-art methods.
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15:15-15:30, Paper WeBT10.4 | Add to My Program |
12, 000-Fps Multi-Object Detection Using HOG Descriptor and SVM Classifier |
Li, Jianquan | Inst. of Automation, Chinese Acad. of Sciences |
Yin, Yingjie | Inst. of Automation Chinese Acad. of Sciences |
Liu, Xilong | Chinese Acad. of Sciences |
Xu, De | Chinese Acdamy of Sciences |
Gu, Qingyi | Inst. of Automation, Chinese Acad. of Sciences |
Keywords: Object detection, segmentation, categorization, Visual Tracking
Abstract: This paper describes a high-frame-rate (HFR) vision system that can detect multiple objects in an image of 512x512 pixels at 12,000 frames per seconds (fps). An optimized algorithm is proposed based on conventional Histograms of Oriented Gradient (HOG) descriptor and Support Vector Machine (SVM) classifier algorithms for hardware implementation. By implementing the proposed algorithm on a field-programmable gate array (FPGA) of a high-speed vision platform, multi-object in an image can be detected at 12,000 fps under complex background. In hardware implementation, 64 pixels were processed in parallel with 80 MHz camera clock. Source image and detection results can be transferred to personal computer (PC) in real-time for recording or post-processing. Our developed HFR multi-object detection system was verified by performing several evaluations.
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15:30-15:45, Paper WeBT10.5 | Add to My Program |
Deep Learning of Directional Truncated Signed Distance Function for Robust 3D Object Recognition |
Liu, Hongsen | Chinese Acad. of Science |
Cong, Yang | Chinese Acad. of Science, China |
Wang, Shuai | Chinese Acad. of Science |
Fan, Huijie | Shenyang Inst. of Automation |
Tian, Dongying | Shenyang Inst. of Automation |
Tang, Yandong | Shenyang Inst. of Automation, CAS |
Keywords: Object detection, segmentation, categorization, Recognition
Abstract: In this paper, we develop a novel 3D object recognition algorithm to perform detection and pose estimation jointly. We focus on analyzing the advantages of the 3D point cloud relative to the RGB-D image and try to eliminate the unpredictability of output values that inevitably occurs in regression tasks. To achieve this, we first adopt the Truncated Signed Distance Function (TSDF) to encode the point cloud and extract low compact discriminative feature via unsupervised deep learning network. This approach can not only eliminate the dense scale sampling for offline model training but also reduce the distortion by mapping the 3D shape to the 2D plane and overcome the dependence on texture information. Then, we train a Hough forests to achieve multi-object detection and 6-DoF pose estimation simultaneously. In addition, we propose a robust multi-level verification strategy that effectively eliminates the unpredictability of output values which inevitably occurs in regression tasks. Experiments on public datasets demonstrate that our approach provides effective results comparable to the state-of-the-arts.
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15:45-16:00, Paper WeBT10.6 | Add to My Program |
Estimating Deformability of Objects Using Meshless Shape Matching |
Güler, Püren | KTH |
Pieropan, Alessandro | KTH |
Ishikawa, Masatoshi | Univ. of Tokyo |
Kragic, Danica | KTH |
Keywords: Calibration and Identification, Object detection, segmentation, categorization, Simulation and Animation
Abstract: Humans interact with deformable objects on a daily basis but this still represents a challenge for robots. To enable manipulation of and interaction with deformable objects, robots need to be able to extract and learn the deformability of objects both prior to and during the interaction. Physics-based models are commonly used to predict the physical properties of deformable objects and simulate their deformation accurately. The most popular simulation techniques are force-based models that need force measurements. In this paper, we explore the applicability of a geometry-based simulation method called meshless shape matching (MSM) for estimating the deformability of objects. The main advantages of MSM are its controllability and computational efficiency that make it popular in computer graphics to simulate complex interactions of multiple objects at the same time. Additionally, a useful feature of the MSM that differentiates it from other physics-based simulation is to be independent of force measurements that may not be available to a robotic framework lacking force/torque sensors. In this work, we design a method to estimate deformability based on certain properties, such as volume conversation. Using the finite element method (FEM) we create the ground truth deformability for various settings to evaluate our method. The experimental evaluation shows that our approach is able to accurately identify the deformability of testing objects, supporting the value of MSM for robotic applications.
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WeBT11 , Room 207 |
Add to My Program |
Aerial Systems: Mechanics and Control II |
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Chair: Nakadai, Kazuhiro | Honda Res. Inst. Japan Co., Ltd |
Co-Chair: Fuller, Sawyer | Univ. of Washington |
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14:30-14:45, Paper WeBT11.1 | Add to My Program |
Momentum Control of an Underactuated Flying Humanoid Robot |
Pucci, Daniele | Italian Inst. of Tech |
Traversaro, Silvio | Istituto Italiano Di Tecnologia |
Nori, Francesco | Istituto Italiano Di Tecnologia |
Keywords: Aerial Systems: Mechanics and Control, Humanoid Robots, Optimization and Optimal Control
Abstract: The paper takes the first step towards the development of a control framework for underactuated flying humanoid robots. These robots may thus have the capacities of flight, contact locomotion, and manipulation, and benefit from technologies and methods developed for Whole-Body Control and Aerial Manipulation. As in the case of quadrotors, we assume that the humanoid robot is powered by four thrust forces. For convenience, these forces are placed at the robot hands and feet. The control objective is defined as the asymptotic stabilization of the robot centroidal momentum. This objective allows us to track a desired trajectory for the robot center of mass and keep small errors between a reference orientation and the robot base frame. Stability and convergence of the robot momentum are shown to be in the sense of Lyapunov. Simulations carried out on a model of the humanoid robot iCub verify the soundness of the proposed approach.
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14:45-15:00, Paper WeBT11.2 | Add to My Program |
Quadrobee: Simulating Flapping Wing Aerial Vehicle Dynamics on a Quadrotor |
Chen, Yuyang | Univ. at Buffalo |
Fuller, Sawyer | Univ. of Washington |
Dantu, Karthik | Univ. of Buffalo |
Keywords: Aerial Systems: Mechanics and Control, Dynamics, Biologically-Inspired Robots
Abstract: The RoboBee is a novel insect-scale flapping wing Micro Aerial Vehicle that is envisioned to enable exciting applications. While recent results have demonstrated full control as well as biomimetic behaviors such as perching, more complex challenges such as perception and navigation still exist. Typically, challenges in perception-based control can only be solved by experimentation. However, such fly-size MAVs are not widely available to researchers at large due to its intricate manufacturing process and limited mechanical lifetime. To facilitate the development of perception and control algorithms of insect-scale MAVs, we explore an approach of simulating flapping wing aerial vehicle dynamics on a quad-rotor. This work performs detailed analysis of the transformation of control inputs, and demonstrates feasibility by numerically simulating basic flight patterns of models of a RoboBee as well as that of a scaled quad-rotor.
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15:00-15:15, Paper WeBT11.3 | Add to My Program |
An Intermediary Quaternion-Based Control for Trajectory Following Using a Quadrotor |
Marchand, Nicolas | GIPSA-Lab CNRS/U of Grenoble/INRIA |
Colmenares-Vázquez, Josue | Univ. De Grenoble, GIPSA-Lab |
Castillo, Pedro | Sorbonne Univ. Univ. De Tech. De Compiègne |
Gomez Balderas, Jose Ernesto | GIPSA-Lab |
Keywords: Aerial Systems: Mechanics and Control, Motion Control, Process Control
Abstract: This work uses the intermediary quaternions in the design of a backstepping control technique with integral properties in order to perform a trajectory following. Nowadays, in order to determine the orientation of a vehicle, most of the inertial systems of aircrafts can give directly the rotation matrix and taking advantage of this fact, the intermediary quaternions can be determined in a simple way from this matrix. Moreover, one specific orientation corresponds to only one intermediary quaternion and this helps to cope the unwinding phenomenon presented when working with the classical quaternions. The control algorithm is validated numerically and experimentally by the following of a circular trajectory. In addition, during the simulation part, it is added some external perturbations and white noise in order to test the robustness of the algorithm.
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15:15-15:30, Paper WeBT11.4 | Add to My Program |
Design, Modelling and Hovering Control of a Tail-Sitter with Single Thrust-Vectored Propeller |
Wang, Wufan | Tsinghua Univ |
Zhu, Jihong | Tsinghua Univ |
Kuang, Minchi | Tsinghua Univ |
Keywords: Aerial Systems: Mechanics and Control
Abstract: This paper focuses on the design, modelling and hovering control of a tail-sitter with single thrust-vectored propeller which possesses the inherent advantages of both fixed wing and rotary wing unmanned aerial vehicles (UAVs). The developed tail-sitter requires only the same number of actuators as a normal fixed wing aircraft and achieves attitude control through deflections of the thrust-vectored propeller and ailerons. Thrust vectoring is realized by mounting a simple gimbal mechanism beneath the propeller motor. Both the thrust vector model and aerodynamics model are established, which leads to a complete nonlinear model of the tail-sitter in hovering state. Quaternion is applied for attitude description to avoid the singularity problem and improve computation efficiency. Through reasonable assumptions, a simplified model of the tail-sitter is obtained, based on which a backstepping controller is designed using the Lyapunov stability theory. Experimental results are presented to demonstrate the effectiveness of the proposed control scheme.
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15:30-15:45, Paper WeBT11.5 | Add to My Program |
Multilinked Multirotor with Internal Communication System for Multiple Objects Transportation Based on Form Optimization Method |
Anzai, Tomoki | Univ. of Tokyo |
Zhao, Moju | The Univ. of Tokyo |
Chen, Xiangyu | The Univ. of Tokyo |
Shi, Fan | The Univ. of Tokyo |
Kawasaki, Koji | The Univ. of Tokyo |
Okada, Kei | The Univ. of Tokyo |
Inaba, Masayuki | The Univ. of Tokyo |
Keywords: Aerial Systems: Mechanics and Control, Aerial Systems: Applications, Motion Control
Abstract: In this paper, we show the achievement of a transformable aerial robot with internal communication system for multiple objects transportation. As it is not easy to make the flight endurance of an aerial robot longer, we study the problem to transport multiple objects at the same time to improve the efficiency of transportation. However, for conventional aerial robots, multiple objects transportation is difficult because the CoG position changes when the number of grasped objects changes, resulting in the instability of the flight. Therefore, to solve this problem, we focus on the multirotor with two-dimensional multilinks proposed in our previous work, which possesses the ability to modify the CoG position actively and can keep the flight stable. First, we introduce the hardware platform including the structure of link module and internal communication system to achieve the extensibility in terms of the link number. We then propose a method to find the optimal form for the multilinks based on the flight stability. Finally, we present experimental results which include aerial transformation and multiple objects transportation.
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WeBT12 , Room 208 |
Add to My Program |
Agricultural Robtics II |
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Chair: Kayacan, Erdal | Nanyang Tech. Univ |
Co-Chair: Kermani, Mehrdad R. | Univ. of Western Ontario |
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14:30-14:45, Paper WeBT12.1 | Add to My Program |
Individual Leaf Identification from a Two-Dimensional Monocotyledon Image Based on Phytomorphological Graph Reconstruction |
Lee, Sang-Wook | Korea Inst. of Science and Tech |
Kim, Jun-Sik | Korea Inst. of Science & Tech |
Keywords: Agricultural Automation, Object detection, segmentation, categorization, Computer Vision for Automation
Abstract: We aim to automatically identify all individual leaves in a monocotyledon image. Leaf identification is one of key technologies to acquire plant phenotypes such as a leaf length, a leaf count, and a growth rate. However, it is challenging to identify individual leaves from a monocotyledonous plant image due to their complicated occlusion and similar colors. We adopt a graph-theoretical approach to overcome the leaf occlusion and the color similarity between leaves, and apply a combinatorial optimization technique to simultaneously identify all individual leaves based on local and global characteristics of plants. We propose a plant-wide global optimization to identify all true leaves in a plant, which is formulated as a minimum path cover problem that we call the phytomorphological graph reconstruction. A phytomorphological graph of a plant image is a graph reflecting the plant's structure and is constructed through a plant region extraction and a skeletonization. All candidate leaf paths in the graph are extracted and their leaf path likelihoods are computed from the graph, where the leaf path likelihood means a measure of similarity with true leaves. The candidate leaf paths and their path likelihoods are used in the graph reconstruction process in order to find an optimal subset of the leaf paths which are similar to true leaves and can restore the phytomorphological graph as completely as possible. Experiments show that our proposed system effectively identifies individual leaves from a single 2-dimensional image of rice plants, which enables us to take an accurate and efficient high-throughput measurement of phenotypes for plants.
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14:45-15:00, Paper WeBT12.2 | Add to My Program |
Grasp Evaluation Method for Applying Static Loads Leading to Beam Failure |
Abdeetedal, Mahyar | Western Univ |
Kermani, Mehrdad R. | Univ. of Western Ontario |
Keywords: Robotics in Agriculture and Forestry, Agricultural Automation, Grasping
Abstract: This paper deals with the problem of purposefully failing or yielding an object by a robotic gripper. We propose a grasp quality measure fabricated for robotic harvesting in which picking a crop from its stem is desired. The proposed metric characterizes a suitable grasp configuration for systematically controlling the failure behavior of an object to break it at the desired location while avoiding damage on other areas. Our approach is based on failure task information and gripper wrench insertion capability. Failure task definition is accomplished using failure theories. Gripper wrench insertion capability is formulated by modeling the friction between the object and gripper. A new method inspired by human pre-manipulation process is introduced to utilize gripper itself as a friction measurement device. The provided friction model is capable of handling the anisotropic behavior of materials which is the case for fruits and vegetables. The evaluation method is formulated as a quasistatic grasp problem. Additionally, the general case of both fully-actuated and under-actuated grippers are considered. As a validation of the proposed evaluation method, experimental results for failing parts using Kuka Light-Weight Robot IV robot are presented.
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15:00-15:15, Paper WeBT12.3 | Add to My Program |
A Robotic Vision System to Measure Tree Traits |
Tabb, Amy | USDA-ARS-AFRS |
Medeiros, Henry | Marquette Univ |
Keywords: Agricultural Automation, Computer Vision for Automation, Field Robots
Abstract: The autonomous measurement of tree traits, such as branching structure, branch diameters, branch lengths, and branch angles, is required for tasks such as robotic pruning of trees as well as structural phenotyping. We propose a robotic vision system called the Robotic System for Tree Shape Estimation (RoTSE) to determine tree traits in field settings. The process is composed of the following stages: image acquisition with a mobile robot unit, segmentation, reconstruction, curve skeletonization, conversion to a graph representation, and then computation of traits. Quantitative and qualitative results on apple trees are shown in terms of accuracy, computation time, and robustness. Compared to ground truth measurements, the RoTSE produced the following estimates: branch diameter (mean-squared error 0.99 mm), branch length (mean-squared error 45.64 mm), and branch angle (mean-squared error 10.36 degrees). The average run time was 8.47 minutes when the voxel resolution was 3 mm^3.
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15:15-15:30, Paper WeBT12.4 | Add to My Program |
Grasping by Wrapping: Mechanical Design and Evaluation |
Ho, Van | Japan Advanced Inst. of Science and Tech |
Keywords: Gripper and Other End-Effectors, Soft Material Robotics, Grasping
Abstract: This paper presents an analysis of the design and operation of a non-articulated robotic hand, inspired by the multilayered structure. The hand is made of a non-stretchable thin film, the two ends of which are attached to a soft substrate, forming an enclosed wrinkled shape. When the substrate is elongated, the morphology of the hand changes varied, resulting in a "wrapping" form around the grasped object. This design is applicable to a wide range of objects that can be grasped by the robotic hand. The smallest and biggest sizes of the grasped object are determined by the morphological computation of the film during design of the hand. This design also reduces the uncertainty of position between the hand and the object; i.e., stable grasping can be maintained as long as the object fits within the enclosed form of the hand. A mechanism controlling the morphology of the film using only one actuator, and for grasping food products such as fruits, is proposed. Preliminary results show the potential of the hand's morphology in the design of soft robotic mechanisms.
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15:30-15:45, Paper WeBT12.5 | Add to My Program |
A Novel Building Post-Construction Quality Assessment Robot: Design and Prototyping |
Yan, Rui Jun | Ningbo Intelligent Manufacturing Industry Res. Inst |
Kayacan, Erdal | Nanyang Tech. Univ |
Chen, I-Ming | Nanyang Tech. Univ |
Tiong, Lee Kong | Nanyang Tech. Univ |
Keywords: Automation Technologies for Smart Cities, Robotics in Construction
Abstract: This paper describes the design and development of an automated construction quality assessment robot system (QuicaBot) for hollowness, crack, evenness, alignments and inclination problems. To the best of our knowledge, this work is the first attempt to pave the way towards a fully autonomous robotic system for post construction quality assessment of buildings. The main goal of the novel robot is twofold: to systematize the manual inspection work through automation resulting in more reliable and objective inspection reports, and to speed up the inspection process resulting in a cost reduction. Based-on our initial on-site tests, the developed robot increases the overall efficiency in all the aforementioned five problems.
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15:45-16:00, Paper WeBT12.6 | Add to My Program |
Active View Planning for Counting Apples in Orchards |
Roy, Pravakar | Univ. of Minnesota |
Isler, Volkan | Univ. of Minnesota |
Keywords: Agricultural Automation, Reactive and Sensor-Based Planning, Field Robots
Abstract: We consider an agricultural automation scenario where a robot, equipped with a camera mounted on a manipulator, is charged with counting the number of apples in an orchard. We focus on the subtask of planning views so as to accurately estimate the number of apples in an apple cluster. We present a method to efficiently enumerate combinatorially distinct world models and to compute the most likely model from one or more views. These are incorporated into single and multi-step planners. We evaluate these planners in simulation as well as with experiments on a real robot.
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WeBT13 , Room 211 |
Add to My Program |
Task Planning |
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Chair: Liu, Lantao | Indiana Univ |
Co-Chair: Rovida, Francesco | Aalborg Univ. Copenhagen |
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14:30-14:45, Paper WeBT13.1 | Add to My Program |
An Approach to Robot Task Learning and Planning with Loops |
Mokhtari, Vahid | Univ. of Aveiro |
Seabra Lopes, Luís | Univ. De Aveiro |
Pinho, Armando | Univ. of Aveiro |
Keywords: Task Planning, Robust/Adaptive Control of Robotic Systems, Learning from Demonstration
Abstract: This paper addresses robot task model learning and planning with loops. By detecting and modeling loops in solved tasks it is possible to learn and solve wider classes of problems. We extend our previous work on experience-based planning domains} in robotics to detect, represent and generate loops in action sequences. This approach provides methods for, (i) conceptualizing robot experiences possibly containing loops and learning high-level robot activity schemata with loops; and (ii) instantiating schemata with loops for solving problem instances of the same task with varying sets of objects. Demonstrations of this system in both real and simulated environments prove its potentialities.
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14:45-15:00, Paper WeBT13.2 | Add to My Program |
Synthesis of Correct-By-Construction Behavior Trees |
Colledanchise, Michele | KTH - the Royal Inst. of Tech |
Murray, Richard | California Inst. of Tech |
Ogren, Petter | Royal Inst. of Tech. (KTH) |
Keywords: Task Planning, Formal Methods for Robotics, Behaviour-Based Systems
Abstract: In this paper, we study the problem of synthesizing correct-by-construction Behavior Trees (BTs) controlling agents in adversarial environments. The proposed approach combines the modularity and reactivity of BTs with the formal guarantees of Linear Temporal Logic (LTL) methods. Given a set of admissible environment specifications, an agent model in form of a Finite Transition System and the desired task in form of an LTL formula, we synthesize a BT in polynomial time, that is guaranteed to correctly execute the desired task. To illustrate the approach, we present three examples of increasing complexity.
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15:00-15:15, Paper WeBT13.3 | Add to My Program |
Task-Based Behavior Generalization Via Manifold Clustering |
Garcia, Rafael | Federal Univ. of Rio Grande Do Sul |
C. da Silva, Bruno | Federal Univ. of Rio Grande Do Sul (UFRGS) |
Comba, João L. D. | Federal Univ. of Rio Grande Do Sul |
Keywords: Task Planning, Robust/Adaptive Control of Robotic Systems, Motion Control
Abstract: Machine learning algorithms can be expensive to deploy, in particular, those used in robotics applications that perform many variations of the same task. Solutions to one variation of a task may be found via Reinforcement Learning algorithms, and are typically modeled as a vector of N parameters encoding the robot’s behavior policy. When N is large or executing robot trials is time-consuming, searching in the space of solutions becomes prohibitively expensive. In this paper, we introduce a method that allows robots to generalize behaviors by analyzing solutions to a small number of previously-trained related tasks. This allows for approximate policies for novel tasks to be rapidly estimated. We present a method that achieves this type of generalization by performing nonlinear regression directly on the policy manifold — i.e., the solution space spanned as we change the parameters describing tasks. Because tasks are typically described by few parameters, the corresponding policy manifold has few degrees of freedom, which leads to low-dimensional surfaces. We exploit this property to construct a function that maps task parameters to policy parameters (a parameterized skill). Our method uses manifold clustering techniques to deal with discontinuous manifolds, a challenging situation arising from physical obstacles or robot constraints. We evaluate our method on a set of robot manipulation tasks and show that it can efficiently estimate policies for novel tasks from a small number of training examples.
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15:15-15:30, Paper WeBT13.4 | Add to My Program |
Identifying Good Poses When Doing Your Household Chores: Creation and Exploitation of Inverse Surface Reachability Maps |
Hertle, Andreas | Albert-Ludwigs-Univ. Freiburg |
Nebel, Bernhard | Albert-Ludwigs-Univ. Freiburg |
Keywords: Task Planning, Mobile Manipulation
Abstract: In current approaches to combined task and motion planning, usually symbolic planning and sampling based motion-planning are integrated. One problem is here to come up with good samples. We address the problem of identifying useful poses for a robot close to working surfaces such as tables or shelves. Our approach is based on reachability inversion which answers the question: where should the robot be located in order to reach a certain object? We extend the concept from point-based objects to flat polygonal surfaces in order to enable the robot to have a a good grasping position for many objects. Our approach allows to quickly sample multiple distinct poses for the robot from an prior computed distribution. Further we show how sampling from an inverse reachability distribution can be integrated into a CTAMP system.
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15:30-15:45, Paper WeBT13.5 | Add to My Program |
Combining Neural Networks and Tree Search for Task and Motion Planning in Challenging Environments |
Paxton, Chris | Johns Hopkins Univ |
Raman, Vasumathi | California Inst. of Tech |
Hager, Gregory | Johns Hopkins Univ |
Kobilarov, Marin | Johns Hopkins Univ |
Keywords: Task Planning, Deep Learning in Robotics and Automation, Formal Methods for Robotics
Abstract: Task and motion planning subject to Linear Temporal Logic (LTL) specifications in complex, dynamic environments requires efficient exploration of many possible future worlds. Model-free reinforcement learning has proven successful in a number of challenging tasks, but shows poor performance on those tasks that require long term planning. In this work, we integrate Monte Carlo Tree Search with hierarchical neural net policies trained on expressive LTL specifications. We use reinforcement learning to find deep neural networks representing both low-level control policies and task-level option policies that achieve high-level goals. The combination allows this architecture to generate safe and responsive motion plans that respect the LTL constraints. We demonstrate our approach in a simulated autonomous driving setting, where a vehicle must drive down a road in traffic, avoid collisions, and navigate an intersection, all while obeying given rules of the road.
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15:45-16:00, Paper WeBT13.6 | Add to My Program |
Clustering-Based Algorithms for Multi-Vehicle Task Assignment in a Time-Invariant Drift Field |
Bai, Xiaoshan | Univ. of Gronengin |
Yan, Weisheng | Northwestern Pol. Univ |
Cao, Ming | Univ. of Groningen |
Keywords: Task Planning, Optimization and Optimal Control, Path Planning for Multiple Mobile Robots or Agents
Abstract: This paper studies the multi-vehicle task assignment problem where several dispersed vehicles need to visit a set of target locations in a time-invariant drift field while trying to minimize the total travel time. Using optimal control theory, we first design a path planning algorithm to minimize the time for each vehicle to travel between two given locations in the drift field. The path planning algorithm provides the cost matrix for the target assignment, and generates routes once the target locations are assigned to a vehicle. Then, we propose several clustering strategies to assign the targets, and we use two metrics to determine the visiting sequence of the targets clustered to each vehicle. Mainly used to specify the minimum time for a vehicle to travel between any two target locations, the cost matrix is obtained using the path planning algorithm, and is in general asymmetric due to time-invariant currents of the drift field. We show that one of the clustering strategies can obtain a min-cost arborescence of the asymmetric target-vehicle graph where the weight of a directed edge between two vertices is the minimum travel time from one vertex to the other respecting the orientation. Using tools from graph theory, a lower bound on the optimal solution is found, which can be used to measure the proximity of a solution from the optimal. Furthermore, by integrating the target clustering strategies with the target visiting metrics, we obtain several task assignment algorithms. Among them, two algorithms guarantee that all the target locations will be visited within a computable maximal travel time, which is at most twice of the optimal when the cost matrix is symmetric. Finally, numerical simulations show that the algorithms can quickly lead to a solution that is close to the optimal.
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WeBT14 , Room 217 |
Add to My Program |
Environment Monitoring |
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Chair: Zhu, Delong | The Chinese Univ. of Hong Kong |
Co-Chair: Zhou, Mingxi | Memorial Univ. of Newfoundland |
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14:30-14:45, Paper WeBT14.1 | Add to My Program |
Design of a Leak Sensor for Operating Water Pipe Systems |
Wu, You | MIT |
Kim, Kristina | Massachusetts Inst. of Tech |
Finn-Henry, Michael | MIT |
Youcef-Toumi, Kamal | Massachusetts Inst. of Tech |
Keywords: Environment Monitoring and Management, Automation Technologies for Smart Cities
Abstract: Water pipe leakage is a common and significant problem around the world. In recent years, an increasing amount of effort has been put into developing effective leak detection solutions for water pipes. Among them, the pressure gradient based method developed at Massachusetts Institute of Technology excels for its sensitivity in low pressure, small diameter pipes. It can also work in both plastic and metallic pipes carrying gas or water. However, the method was only verified in static fluid pipes, and the previous sensor designs were unable to detect leaks when there is a significant water flow in the pipe. This is undesired as the inspection can only be performed when water service is shut down. A modeling analysis shows that fluid dynamic effects in the water pipe make the original sensors dynamics too slow to react to leaks. Moreover, this leak detection method is prone to false alarms such as obstacles in the pipes, but there is a lack of studies on this topic. In this paper, we present three things: the design of a new leak sensor that is fast enough to detect leaks in dynamic fluid environments, a prototype for 52mm-inner-diameter pipeline tested in an industrial facility, and a method to differentiate leaks from false alarms supported by the test results.
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14:45-15:00, Paper WeBT14.2 | Add to My Program |
Hawkeye: Open Source Framework for Field Surveillance |
Zhu, Delong | The Chinese Univ. of Hong Kong |
Du, Yegui | Harbin Inst. of Tech |
Lin, Yuan | The Univ. of Auckland |
Li, Hongxiang | Harbin Inst. of Tech |
Wang, Chaoqun | The Chinese Univ. of HongKong |
Xu, Xun | Univ. of Auckland |
Meng, Max Q.-H. | The Chinese Univ. of Hong Kong |
Keywords: Surveillance Systems, Visual Tracking, Visual Servoing
Abstract: Abstract— This paper introduces a generic framework for field surveillance using consumer rotorcrafts and ground vehicles. Building such an autonomous system comes with two key challenges in persistent perception and obstacle avoidance. We begin with explaining two core algorithms to solve the challenges: an auto-landing algorithm that enables a quadrotor to land on a moving ground vehicle at a speed of 6.00 m/s, and an obstacle avoidance algorithm that ensures the safety of the quadrotor during searching process. On the basis of these algorithms, the architecture and infrastructure of Hawkeye framework are presented as well. Hawkeye is designed to be a generic platform with extensibility that allows integration of other domain applications. We demonstrate the potential of Hawkeye framework in a simulated agriculture monitoring mission and report its performance at the end of the paper.
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15:00-15:15, Paper WeBT14.3 | Add to My Program |
Underwater Acoustic-Based Navigation towards Multi-Vehicle Operation and Adaptive Oceanographic Sampling |
Zhou, Mingxi | Memorial Univ. of Newfoundland |
Bachmayer, Ralf | Memorial Univ. of Newfoundland |
deYoung, Brad | Memorial Univ |
Keywords: Autonomous Vehicle Navigation, Multi-Robot Systems, Marine Robotics
Abstract: It is important to register oceanographic data into a geo-referenced coordinate system. Knowing the location of the sampling is critical. For a marine robotic network, the location of Unmanned Surface Vessels (USVs) can be measured using a Global Positioning System (GPS), however the navigation of Autonomous Underwater Vehicles (AUVs) is more challenging. In this paper, we present a method for determining the position of underwater vehicles from a moving USV using the relative range information provided by an Ultra-Short Baseline (USBL)/acoustic modem. The navigation method uses an Extended Kalman Filter (EKF) to update the states predicted from a model-based dead-reckoning technique. Since the vehicle model is relative to the surrounding fluid, we have introduced two environmental states in the state matrix. Such a modification allows us to quantify the effects induced by the ocean current on the vehicle's speed. Beyond that, the method uses a limited number of sensors, only attitude sensors and an USBL/acoustic modem, offering an alternative for AUVs without expensive instruments such as a Doppler Velocity Log (DVL) and an Inertial Measurement Unit (IMU). Experiments are conducted to evaluate the range-based navigation method on a hybrid Slocum underwater glider with an USV. As a result from the reference trial, the estimated glider position stays within the error of 15 meters comparing to the measured position of a surface buoy where the glider is attached. In the open-water trial, trajectories estimated from the range-based navigation are compared with dead-reckoning paths and current-compensated dead-reckoning paths (reference). As a result, the distance errors are bounded with the proposed navigation method while the dead-reckoning errors grow without bound.
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15:15-15:30, Paper WeBT14.4 | Add to My Program |
Robotic Experiments to Evaluate Ocean Plume Characteristics and Structure |
Fahad, Muhammad | Stevens Inst. of Tech |
Guo, Yi | Stevens Inst. of Tech |
Bingham, Brian | Naval Postgraduate School |
Krasnosky, Kristopher | Univ. of Hawaii at Manoa |
Fitzpatrick, Laura | Univ. of Hawaii at Manoa |
Aragon Sanabria, Fernando | Univ. of Hawaii at Manoa |
Keywords: Robotics in Hazardous Fields, Marine Robotics, Environment Monitoring and Management
Abstract: We present field experiment results of ocean plume surveys conducted with a robotic platform. In our experiments, Rhodamine dye was used to generate a chemical plume in a coastal environment, and an unmanned surface vessel equipped with fluorometer sensors was deployed to conduct plume surveys. We present plume front and cross sectional survey results, where the robot is driven along visible plume boundaries and plume cross sections, respectively. Datasets collected during the experiments are shown together with statistical parameters that quantify the fine-scale plume structure. Experimental evidence shows that the assumption of the existence of a continuous and fixed-value concentration curve used in existing theoretical work for plume front tracking appears too strong for real ocean plumes. The datasets provide characteristic parameters that can be used for further development and verification of simulation models of ocean pollution plumes.
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15:30-15:45, Paper WeBT14.5 | Add to My Program |
UAV Assisted USV Visual Navigation for Marine Mass Casualty Incident Response |
Xiao, Xuesu | Texas A&M Univ |
Dufek, Jan | Texas A&M Univ |
Woodbury, Tim | Texas A&M Univ |
Murphy, Robin | Texas A&M |
Keywords: Field Robots, Marine Robotics, Aerial Systems: Applications
Abstract: This research teams an Unmanned Surface Vehicle (USV) with an Unmanned Aerial Vehicle (UAV) to augment and automate marine mass casualty incident search and rescue in emergency response phase. The demand for real-time responsiveness of those missions requires fast and comprehensive situational awareness and precise operations, which are challenging to achieve because of the large area and the flat nature of the water field. The responders, drowning victims, and rescue vehicle are far apart and all located at the sea level. The long distances mean responders cannot clearly discern the rescue vehicle and victims from the surrounding water. Furthermore, being at the same elevation makes depth perception difficult. Rescue vehicle and victims at different distances from the responder will always appear to be close together. This makes it almost impossible for the responders to accurately drive the USV to the victims in time. This paper proposes the use of a UAV to compensate for the lack of elevation of the responders and to automate search and rescue operations. The benefit of this system is two fold: 1) the UAV provides responders with an overhead view of the field, covers larger area than direct visual, and allows more accurate perception of the situation, and 2) it automates the rescue process so that the responders can focus on task-level needs instead of tediously driving the USV to the victims. Thirty autonomous navigation trials in 4 rescue scenarios prove the first known successful implementation of a small UAV visually navigating a USV.
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15:45-16:00, Paper WeBT14.6 | Add to My Program |
Data-Driven Selective Sampling for Marine Vehicles Using Multi-Scale Paths |
Manjanna, Sandeep | McGill Univ |
Dudek, Gregory | McGill Univ |
Keywords: Environment Monitoring and Management, Field Robots, Marine Robotics
Abstract: This paper addresses adaptive coverage of a spatial field without prior knowledge. Our application in this paper is to cover a region of the sea surface using a robotic boat, although the algorithmic approach has wider applicability. We propose an anytime planning technique for efficient data gathering using point-sampling based on non-uniform data-driven coverage. Our goal is to sense a particular region of interest in the environment and be able to reconstruct the measured spatial field. Since there are autonomous agents involved, there is a need to consider the costs involved in terms of energy consumed and time required to finish the task. An ideal map of the scalar field requires complete coverage of the region, but can be approximated by a good sparse coverage strategy along with an efficient interpolation technique. We propose to optimize the trade off between the environmental field mapping and the costs (energy consumed, time spent, and distance traveled) associated with sensing. We present an anytime algorithm for sampling the environment adaptively by following a multi-scale path to produce a variable resolution map of the spatial field. We compare our approach to a traditional exhaustive survey approach and show that we are able to effectively represent a spatial field spending minimum energy. We present results that indicate our sampling technique gathering most informative samples with least travel. We validate our approach through simulations and test the system on real robots in the open ocean.
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WeBT15 , Room 215 |
Add to My Program |
Computer Vision for Robotic Applications I |
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Chair: Kheddar, Abderrahmane | CNRS-AIST JRL (Joint Robotics Lab. UMI3218/CRT |
Co-Chair: Civera, Javier | Univ. De Zaragoza |
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14:45-15:00, Paper WeBT15.2 | Add to My Program |
Indoor Scan2BIM: Building Information Models of House Interiors |
Murali, Srivathsan | ETH Zurich |
Speciale, Pablo | ETH |
Oswald, Martin R. | ETH Zurich |
Pollefeys, Marc | ETH Zurich |
Keywords: Computer Vision for Other Robotic Applications, Computational Geometry, Mapping
Abstract: We present a system to generate building information models (BIMs) of house interiors from 3D scans. The strength of our approach is its simplicity and low runtime which allows for mobile processing applications. We consider scans of single floor, Manhattan-like indoor scenes for which our method creates metric room layouts by detecting walls and performing a subsequent reasoning about their neighborhood relations. The output of our method is a 3D BIM with hierarchical semantic annotations for individual rooms being refined by walls, ceilings, floors and doors. A variety of experiments demonstrate the effectiveness of our approach. Our reconstruction results compare well to other state-of-art methods in both reconstruction quality as well as runtime.
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15:00-15:15, Paper WeBT15.3 | Add to My Program |
A Multimodal Dataset for Object Model Learning from Natural Human-Robot Interaction |
Azagra, Pablo | Univ. of Zaragoza |
Golemo, Florian | INRIA Bordeaux |
Mollard, Yoan | Inria |
Lopes, Manuel | Inst. Superior Tecnico |
Civera, Javier | Univ. De Zaragoza |
Murillo, Ana Cristina | Univ. of Zaragoza |
Keywords: Computer Vision for Other Robotic Applications, Object detection, segmentation, categorization, Visual Learning
Abstract: Learning object models in the wild from naturalhuman interactions is an essential ability for robots to per-form general tasks. In this paper we present a robocentricmultimodal dataset addressing this key challenge. Our datasetfocuses on interactions where the user teaches new objects to therobot in various ways. It contains synchronized recordings ofvisual (3 cameras) and audio data which provide a challengingevaluation framework for different tasks. Additionally, we present an end-to-end system that learnsobject models using object patches extracted from the recordednatural interactions. Our proposed pipeline follows these steps:(a) recognizing the interaction type, (b) detecting the objectthat the interaction is focusing on, and (c) learning the modelsfrom the extracted data. Our main contribution lies in the stepstowards identifying the target object patches of the images. Wedemonstrate the advantages of combining language and visualfeatures for the interaction recognition and use multiple viewsto improve the object modelling. Our experimental results show that our dataset is challengingdue to occlusions and domain change with respect to typicalobject learning frameworks. The performance of common out-of-the-box classifiers trained on our data is low. We demonstratethat our algorithm outperforms such baselines
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15:15-15:30, Paper WeBT15.4 | Add to My Program |
Nut Fastening with a Humanoid Robot |
Pfeiffer, Kai | CNRS-AIST JRL (Joint Robotic Lab. UMI3218/RL, Tsukuba, Ja |
Escande, Adrien | Cnrs-Aist Jrl Umi3218/rl |
Kheddar, Abderrahmane | CNRS-AIST JRL (Joint Robotics Lab. UMI3218/CRT |
Keywords: Computer Vision for Other Robotic Applications, Assembly, Sensor-based Control
Abstract: We study the HRP-2Kai humanoid robot's ability to conduct the precise industrial task of fastening bolts in aircraft production. Our contribution stands mainly in high integration of different modules within the whole-body Quadratic Programing-based controller that has not been yet confronted to tasks demanding high precision in the execution and tuning. This includes the use of a robust visual servoing algorithm which allows the robot to move autonomously to a desired target and the design of specific tasks and estimators: a learning and admittance control that enables the robot to interact smoothly with its environment, and a fast and safe method to autonomously detect correct tool on nut insertion. We then show that the controller indeed enables our humanoid robot to achieve such a high precision task.
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15:30-15:45, Paper WeBT15.5 | Add to My Program |
Attentional Masking for Pre-Trained Deep Networks |
Wallenberg, Marcus | Linkoping Univ |
Forssen, Per-Erik | Linkoping Univ |
Keywords: Computer Vision for Other Robotic Applications, Deep Learning in Robotics and Automation, Object detection, segmentation, categorization
Abstract: The ability to direct visual attention is a fundamental skill for seeing robots. Attention comes in two flavours: the gaze direction (overt attention) and attention to a specific part of the current field of view (covert attention), of which the latter is the focus of the present study. Specifically, we study the effects of attentional masking within pre-trained deep neural networks for the purpose of handling ambiguous scenes containing multiple objects. We investigate several variants of attentional masking on partially pre-trained deep neural networks and evaluate the effects on classification performance and sensitivity to attention mask errors in multi-object scenes. We find that a combined scheme consisting of multi-level masking and blending provides the best trade-off between classification accuracy and insensitivity to masking errors. This proposed approach is denoted multilayer continuous-valued convolutional feature masking (MC-CFM). For reasonably accurate masks it can suppress the influence of distracting objects and reach comparable classification performance to unmasked recognition in cases without distractors.
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15:45-16:00, Paper WeBT15.6 | Add to My Program |
Estimating the Leaf Area Index of Crops through the Evaluation of 3D Models |
Zermas, Dimitris | Cse, Umn |
Morellas, Vassilios | U. of Minnesota |
Mulla, David | Univ. of Minnesota |
Papanikolopoulos, Nikos | Univ. of Minnesota |
Keywords: Computer Vision for Other Robotic Applications, Computer Vision for Automation, Agricultural Automation
Abstract: Financial and social elements of modern societies are closely connected to the cultivation of corn. Due to the massive production of corn, deficiencies during the cultivation process directly translate to major financial losses. The early detection and treatment of crops deficiencies is thus a task of great significance. Towards an automated health condition assessment, this study introduces a scheme for the computation of plant health indices. Based on the 3D reconstruction of small batches of corn plants, an alternative to existing cumbersome Leaf Area Index (LAI) estimation methodologies is presented. The use of 3D models provides an elevated information content, when compared to planar methods, mainly due to the reduced loss attributed to leaf occlusions. High resolution images of corn stalks are collected and used to obtain 3D models of plants of interest. Based on the extracted 3D point clouds, an accurate calculation of the Leaf Area Index (LAI) of the plants is performed. An experimental validation (using artificially made corn plants used as ground truth of the LAI estimation), emulating real world scenarios, supports the efficacy of the proposed methodology. The conclusions of this work, suggest a fully automated scheme for information gathering in modern farms capable of replacing current labor intensive procedures, thus greatly impacting the timely detection of crop deficiencies.
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WeBT16 , Room 220 |
Add to My Program |
Reactive and Sensor-Based Planning II |
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Chair: Huber, Gerold | Tech. Univ. of Munich |
Co-Chair: Robuffo Giordano, Paolo | Centre National De La Recherche Scientifique (CNRS) |
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14:30-14:45, Paper WeBT16.1 | Add to My Program |
Cost-Aware Path Planning under Co-Safe Temporal Logic Specifications |
Cho, Kyunghoon | Seoul National Univ |
Suh, Junghun | Seoul National Univ |
Tomlin, Claire | UC Berkeley |
Oh, Songhwai | Seoul National Univ |
Keywords: Motion and Path Planning, Formal Methods in Robotics and Automation
Abstract: This paper presents a path planning algorithm for generating a cost-efficient path which satisfies mission requirements specified in linear temporal logic (LTL). We assume that a cost function is defined over the configuration space. Examples of a cost function include hazard levels, wireless connectivity, and energy consumption, to name a few. The proposed method consists of two parts: sampling-based cost-aware path planning considering the vehicle dynamics based on RRT*, and a high-level logic which determines how to extend the RRT tree based on spatio-temporal specifications of an LTL formula. In order to find a low-cost trajectory with computational efficiency, the proposed method expands the RRT tree with long extensions using cross entropy, while the rewiring step of RRT* is used to preserve the asymptotic optimality. In simulation and experiments, we show that the proposed method performs favorably compared to existing methods.
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14:45-15:00, Paper WeBT16.2 | Add to My Program |
An Online Trajectory Generator on SE(3) with Magnitude Constraints |
Huber, Gerold | Tech. Univ. of Munich |
Gabler, Volker | Tech. Univ. München |
Wollherr, Dirk | Tech. Univ. München |
Keywords: Motion and Path Planning, Physical Human-Robot Interaction, Collision Avoidance
Abstract: With the increasing demand of humans and robots collaborating in a confined workspace, it is essential that robots can react instantaneously to unforeseen events while respecting comfort of human co-workers. As the human pays especial attention to the end-effector movement rather than individual joints in such tasks, we argue that it is necessary to limit exactly these end-effector dynamics directly on SE(3), regardless of any specific coordinate system. Only then it is possible to constrain the robot end-effector in its absolute dynamic values, to enhance human comfort. Common online trajectory generators (OTGs) are either limited to single degrees of freedom (DOFs) or consider decoupled multi-DOF mainly in joint space. While these strategies can be directly applied to Cartesian coordinate systems by using Euler angles for orientation, constraining the change in Euler angles does not lead to the correct angular velocities. In this work we present a novel OTG with constraints on translational and rotational magnitudes on SE(3). Simulations as well as experiments on a KUKA LWR4+ show the potential contribution towards improved Human-Robot-Collaboration.
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15:00-15:15, Paper WeBT16.3 | Add to My Program |
Online Velocity Planner for Laser Guided Vehicles Subject to Safety Constraints |
Raineri, Marina | Univ. of Parma |
Perri, Simone | Univ. of Parma |
Guarino Lo Bianco, Corrado | Univ. of Parma |
Keywords: Reactive and Sensor-Based Planning, Collision Avoidance, Robot Safety
Abstract: Laser Guided Vehicles (LGV) are largely used in industrial contexts for the autonomous dispatching of huge loads. LGVs of automated warehouses are driven by supervisory systems which assign their tasks depending on the process demands. The vehicle workspace is partially structured and it is normally shared with several independent agents like other LGVs, or human operated forklifts, or humans which directly interact with the vehicle itself. For efficiency and for safety reasons, LGVs move along pre-defined paths so that, if an unexpected obstacle is detected, they must be promptly stopped so as to avoid impacts. As shown in the paper, the safety problem is normally handled by limiting the plant productivity. This is clearly an improper approach, which can be overcome by considering a novel velocity planning strategy. The one proposed in this paper guarantees high safety standards, thus preserving the physical integrity of human coworkers, by simultaneously improving the plant productivity.
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15:15-15:30, Paper WeBT16.4 | Add to My Program |
An Optical Tracking System Based on Hybrid Stereo/Single-View Registration and Controlled Cameras |
Cortes, Guillaume | Realyz |
Marchand, Eric | Univ. De Rennes 1, IRISA, INRIA Rennes |
Ardouin, Jérôme | Unafilliated |
Lecuyer, Anatole | INRIA |
Keywords: Visual Tracking, Computer Vision for Other Robotic Applications
Abstract: Optical tracking is widely used in robotics applications such as unmanned aerial vehicle (UAV) localization. Unfortunately, such systems require many cameras and are, consequently, expensive. In this paper, we propose an approach to considerably increase the optical tracking volume without adding cameras. First, when the target becomes no longer visible by at least two cameras we propose a single-view tracking mode which requires only one camera. Furthermore, we propose to rely on controlled cameras able to track the UAV all around the volume to provide 6DoF tracking data through multi-view registration. This is achieved by using a visual servoing scheme. The two methods can be combined in order to maximize the tracking volume. We propose a proof-of-concept of such an optical tracking system based on two consumer-grade cameras and a pan-tilt actuator and we used this approach on UAV localization.
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15:30-15:45, Paper WeBT16.5 | Add to My Program |
Exploration with Active Loop Closing: A Trade-Off between Exploration Efficiency and Map Quality |
Lehner, Hannah | German Aerospace Center (DLR) |
Schuster, Martin Johannes | German Aerospace Center (DLR) |
Bodenmueller, Tim | German Aerospace Center (DLR) |
Kriegel, Simon | German Aerospace Center (DLR) |
Keywords: Reactive and Sensor-Based Planning, SLAM, Autonomous Agents
Abstract: A robotic system for search and rescue missions needs to efficiently explore and map new areas. In this paper, we present an integrated exploration strategy with active loop closing, which balances between the exploration speed and map quality. Specifically, it finds a trade-off between moving towards unknown space to gather new information and revisiting previous locations to improve localization accuracy and map quality through loop closures. Our integrated exploration is built upon a submap-based 6D SLAM system. Loop closure constraints originate from pairwise submap matches, which allow the optimization of an underlying SLAM graph. During exploration, we employ the expected information gain as well as the robot's localization uncertainty estimates to weigh exploration and revisiting actions online. We introduce the match effect as the expected impact of a loop closure on global optimization and consider this novel criterion together with the match likelihood and cost when evaluating the utility of revisiting previous locations. To demonstrate our approach, we present simulated and real-world experiments, comparing two variants of our novel method to a frontier-based exploration.
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15:45-16:00, Paper WeBT16.6 | Add to My Program |
Vision-Based Minimum-Time Trajectory Generation for a Quadrotor UAV |
Penin, Bryan | Inria |
Spica, Riccardo | Stanford Univ |
Robuffo Giordano, Paolo | Centre National De La Recherche Scientifique (CNRS) |
Chaumette, Francois | Inria Rennes-Bretagne Atlantique |
Keywords: Reactive and Sensor-Based Planning, Aerial Systems: Mechanics and Control, Visual Servoing
Abstract: In this paper, we address the problem of using a camera with limited field of view for controlling the motion of a quadrotor in aggressive flight regimes. We present a minimum time trajectory planning method that guarantees visibility of the image features while allowing the robot to undertake aggressive motions for which the usual near-hovering assumption is violated. We exploit differential flatness and B-Splines to parametrize the system trajectories in terms of a finite number of control points, which can then be optimized by Sequential Quadratic Programming (SQP). The control strategy is similar to a Receding Horizon Control (RHC) approach for modifying online the reference trajectory in order to account for noise, disturbances and any non-modeled effect. The algorithm is validated in a physically realistic simulation environment.
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WeBT17 , Room 221 |
Add to My Program |
Soft Material Robotics V |
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Chair: Choi, Hyouk Ryeol | Sungkyunkwan Univ |
Co-Chair: Wang, Michael Yu | Hong Kong Univ. of Science & Tech |
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14:30-14:45, Paper WeBT17.1 | Add to My Program |
Differential Pressure Control of 3D Printed Soft Fluidic Actuators |
Kalisky, Tom | Univ. of California, San Diego |
Wang, Yueqi | Univ. of California, San Diego |
Shih, Benjamin | Univ. of California, San Diego |
Drotman, Dylan | Univ. of California, San Diego |
Jadhav, Saurabh | Univ. of California, San Diego |
Aronoff Spencer, Eliah | Uc San Diego |
Tolley, Michael Thomas | Univ. of California, San Diego |
Keywords: Soft Material Robotics, Hydraulic/Pneumatic Actuators, Mechanism Design
Abstract: Abstract—Fluidically actuated soft robots show a great promise for operation in sensitive and unknown environments due to their intrinsic compliance. However, most previous designs use either flow control systems that are noisy, inefficient, sensitive to leaks, and cannot achieve differential pressure (i.e. can only apply either positive or negative pressures with respect to atmospheric), or closed volume control systems that are not adaptable and prohibitively expensive. In this paper, we present a modular, low cost volume control system for differential pressure control of soft actuators. We use this system to actuate three-chamber 3D printed soft robotic modules. For this design, we find a 54% increase in achievable blocked force, and a significant increase in actuator workspace when using differential pressure actuation as compared to the use of only pressure or vacuum. The increased workspace allowed the robot to achieve complex tasks such as writing on a screen with a laser pointer or manipulating fragile objects. Furthermore, we demonstrate a self-healing capability of the combined system by using vacuum to actuate ruptured modules which were no longer responsive to positive pressure.
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14:45-15:00, Paper WeBT17.2 | Add to My Program |
Design and Fabrication of a Shape-Morphing Soft Pneumatic Actuator: Soft Robotic Pad |
Sun, Yi | National Univ. of Singapore |
Guo, Jin | National Univ. of Singapore |
Miller-Jackson, Tiana | National Univ. of Singapore |
Liang, Xinquan | National Univ. of Singapore |
Ang Jr, Marcelo H | National Univ. of Singapore |
Yeow, Chen-Hua | National Univ. of Singapore |
Keywords: Soft Material Robotics, Hydraulic/Pneumatic Actuators, Mechanism Design
Abstract: Silicone-based soft pneumatic actuator (SPA) is one of the key interests in soft robotic research. Currently, most of the SPAs bear a similar one-dimensional rod-like shape, regardless of their design and fabrication. There are few prototypes of SPAs with two-dimensional initial shapes, however, they are basically the linear combination of several one-dimensional SPAs. This paper presents a new class of silicone-based SPA named soft robotic pad (SRP). The SRP is shaped into a soft pad with a single flat air chamber and can generate different kinds of motions according to the internal constraint matrix within the SRP. In this paper, the design and fabrication of our SRPs are elaborated in detail, followed by the preliminary characterization of the different SRP prototypes. Although the current design is not optimized, our SRP prototypes prove the feasibility of the design and fabrication of a 2D shape-morphing SPA. With subsequent optimization, the SRP can work robustly in various real-world applications as strong flat artificial muscles for human joint rehabilitation, or as fins in marine robots.
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15:00-15:15, Paper WeBT17.3 | Add to My Program |
Soft Pneumatic Gelatin Actuator for Edible Robotics |
Shintake, Jun | École Pol. Fédérale De Lausanne |
Sonar, Harshal | Indian Inst. of Tech. Bombay |
Piskarev, Egor | EPFL |
Paik, Jamie | Ec. Pol. Federale De Lausanne |
Floreano, Dario | Ec. Pol. Federal, Lausanne |
Keywords: Soft Material Robotics, Hydraulic/Pneumatic Actuators, Search and Rescue Robots
Abstract: We present a fully edible pneumatic actuator based on gelatin-glycerol composite. The actuator is monolithic, fabricated via a molding process, and measures 90 mm in length, 20 mm in width, and 17 mm in thickness. Thanks to the composite mechanical characteristics similar to those of silicone elastomers, the actuator exhibits a bending angle of 170.3 ° and a blocked force of 0.34 N at the applied pressure of 25 kPa. These values are comparable to elastomer based pneumatic actuators. As a validation example, two actuators are integrated to form a gripper capable of handling various objects, highlighting the high performance and applicability of the edible actuator. These edible actuators, combined with other recent edible materials and electronics, could lay the foundation for a new type of edible robots.
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15:15-15:30, Paper WeBT17.4 | Add to My Program |
Euglenoid-Inspired Giant Shape Change for Highly Deformable Soft Robots |
Digumarti, Krishna Manaswi | Bristol Robotics Lab |
Conn, Andrew | Univ. of Bristol |
Rossiter, Jonathan | Univ. of Bristol |
Keywords: Soft Material Robotics, Biologically-Inspired Robots, Flexible robots
Abstract: Nature has exploited softness and compliance in many different forms, from large cephalopods to microbial bacteria and algae. In all these cases large body deformations are used for both object manipulation and locomotion. The great potential of Soft Robotics is to capture and replicate these capabilities in controllable robotic form. This paper presents the design of a bio-inspired actuator capable of achieving a large volumetric change. Inspired by the changes in body shape seen in the euglena Eutreptiella spirogyra during its characteristic locomotion, a novel soft pneumatic actuator has been designed which exploits the hyper-elastic properties of elastomers. We call this the Hyper-Elastic Bellows (HEB) actuator. The result is a structure that works under both positive and negative pressure to achieve euglenoid like multi-modal actuation. Axial expansion of 450% and a radial expansion of 80% have been observed, along with a volumetric change of 300 times. Further, the design of a segmented robot with multiple chambers is presented which demonstrates several of the characteristic shapes adopted by the euglenoid in its locomotion cycle. This work shows the potential of this new soft actuation mechanism to realise biomimetic soft robotics with giant shape changes.
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15:30-15:45, Paper WeBT17.5 | Add to My Program |
A Novel Bioinspired Hexapod Robot Developed by Soft Dielectric Elastomer Actuators |
Nguyen, Canh Toan | Sungkyunkwan Univ |
Phung, Hoa | Sungkyunkwan Univ |
Hoang, Phi Tien | Sungkyunkwan Univ |
Nguyen, Tien Dat | Sungkyunkwan Univ |
Jung, Hosang | Sungkyunkwan Univ |
Moon, Hyungpil | Sungkyunkwan Univ |
Koo, Ja Choon | Sungkyunkwan Univ |
Choi, Hyouk Ryeol | Sungkyunkwan Univ |
Keywords: Soft Material Robotics, Biomimetics, Legged Robots
Abstract: This paper presents a hexapod crawling robot which has bioinspired design and locomotion posture from the insects. The robot, called S-Hex II, is an upgraded version of the different printable monolithic hexapod robot which is named as S-Hex I. The S-Hex II is studied for the project of developing mesoscale walking robots actuated by the soft dielectric elastomer actuators. In comparison with the S-Hex I, the S-Hex II owns smaller dimension, lighter weight, and significantly faster walking speed. We improve and increase the total number of degree-of-freedom (DOF) of the soft dielectric elastomer actuators (DEAs) from 3, used in the S-Hex I, up to 5, employed in the S-Hex II, and that provides the promising versatile locomotion ability to the S-Hex II robot. This robot has successfully demonstrated the back and forth ambulation on the flat terrain using the alternating tripod gait at the walking speed of 52 mm/s (approximately 0.35 body-lengths per second) and 7 Hz of actuation frequency.
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15:45-16:00, Paper WeBT17.6 | Add to My Program |
Design and Development of a Soft Gripper with Topology Optimization |
Zhang, Hongying | National Univ. of Singapore |
Wang, Michael Yu | Hong Kong Univ. of Science & Tech |
Chen, Feifei | National Univ. of Singapore |
Wang, Yiqiang | Hong Kong Univ. of Science and Tech |
Senthil Kumar, A. | National Univ. of Singapore |
Fuh, Jerry | National Univ. of Singapore |
Keywords: Soft Material Robotics, Additive Manufacturing, Gripper and Other End-Effectors
Abstract: Soft robots, primarily made out of intrinsically soft materials, have flourished greatly in the past decade due to their advantages such as flexibility and adaptability over rigid-bodied robots. A rich repertoire of soft robots designed from intuitive or biomimetic approaches have been developed to provide new solutions for robots. However, these design approaches are limited by the designers’ experience and inspiration, and a systematic design methodology for soft robots is still missing. We tackle this issue by mathematically recasting the design problem under the framework of topology optimization problem. To demonstrate the effectiveness of the proposed methodology, in this paper, we develop a pneumatically actuated soft gripper consisting of three fingers, each finger is able to undergo a free travel bending and deliver a grasping force. Hence, each gripper finger is designed as a continuum compliant mechanism to achieve its maximal bending deformation. The proposed soft gripper with complex shape is directly fabricated through 3D printing technology. Experimental results show that the deflected soft finger is able to achieve a 〖41〗^° free travel bending and generate 0.68N blocked force upon 0.11MPa actuation pressure. This work represents an important step towards the goal of designing soft robots automatically.
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WeBT18 , Room 223 |
Add to My Program |
Marine Robotics II |
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Chair: Ma, Shugen | Ritsumeikan Univ |
Co-Chair: Dudek, Gregory | McGill Univ |
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14:30-14:45, Paper WeBT18.1 | Add to My Program |
Experimental Verification of the Oscillating Paddling Gait for an Epaddle-EGM Amphibious Locomotion Mechanism |
Shen, Yayi | Ritsumeikan Univ |
Sun, Yi | Shanghai Univ |
Pu, Huayan | Shanghai Univ |
Ma, Shugen | Ritsumeikan Univ |
Keywords: Search and Rescue Robots, Field Robots
Abstract: An eccentric paddle locomotion mechanism based on the epicyclic gear mechanism (ePaddle-EGM) which was proposed to enhance the mobility of amphibious robots in multi-terrain tasks, can perform various terrestrial and aquatic gaits. Two of feasible aquatic gaits are the rotational paddling gait and the oscillating paddling gait. The former one has been studied in our previous work, and a capacity of generating vectored thrust has been found. In this paper, we focus on the oscillating paddling gait by measuring the generated thrusts of the gait on an ePaddle-EGM prototype module. Experimental results verify that the oscillating paddling gait can generate vectored thrust by changing the location of the paddle shaft as well. Furthermore, we compare the oscillating paddling gait with the rotational paddling gait at the vectored thrusting property, magnitude of the thrust, and the gait efficiency.
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14:45-15:00, Paper WeBT18.2 | Add to My Program |
FACON: A Flow-Aided Cooperative Navigation Scheme |
Song, Zhuoyuan | Univ. of Florida |
Mohseni, Kamran | Univ. of Florida at Gainesville |
Keywords: Marine Robotics, Sensor Fusion, Multi-Robot Systems
Abstract: Navigation for autonomous underwater vehicles (AUVs) in mid-depth water column is notoriously challenging due to the lack of features for reference. In this paper, we propose a flow-aided cooperative navigation (FACON) strategy to improve the navigation performance of a team of AUVs when neither frequent surfacing nor persistent bottom-locking is available. Preloaded ocean current forecasts are referenced by each individual vehicle as it performs dead-reckoning with an inertial navigation system and measures relative current velocities during navigation. A marginalized particle filter is applied by each AUV to track its location, velocity, sensor biases, and local flow perturbation unresolved by the ocean forecast. Meanwhile, AUVs perform distributed cooperative localization based on relative pose measurements and asynchronized local communication when they enter the communication range of one another. Opportunistic information fusion among AUVs is realized through covariance intersection. The performance of the flow-aided navigation scheme of a single AUV is analyzed within a simulated experiment based on field test data. The feasibility of FACON is discussed through simulation in a turbulent, multi-gyre flow field.
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15:00-15:15, Paper WeBT18.3 | Add to My Program |
Design and Adaptive Depth Control of a Micro Diving Agent |
Solowjow, Eugen | Hamburg Univ. of Tech |
Lange, Johann | Hamburg Univ. of Tech |
Pick, Marc-André | Hamburg Univ. of Tech |
Bessa, Wallace M. | Hamburg Univ. of Tech |
Kreuzer, Edwin | Hamburg Univ. of Tech |
Keywords: Marine Robotics, Neural and Fuzzy Control, Robust/Adaptive Control of Robotic Systems
Abstract: This paper presents an autonomous micro diving agent called ADA. It consists of off-the-shelf components and features opensource hardware and firmware. It can be applied as a testbed for depth controllers and as a mobile sensor platform for research or in industrial tanks. We propose a depth controller that is light enough to run on embedded hardware. The adopted approach is based on the feedback linearization method and enhanced by an adaptive fuzzy algorithm to cope with modeling inaccuracies. In experiments performed in a wave tank, the adaptive fuzzy scheme shows the ability to deal with both depth regulation and depth profile tracking. ADA is even able to hold on to dynamic isobars despite external disturbances. We demonstrate that under the influence of waves, ADA describes orbital motions similar to water particles.
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15:15-15:30, Paper WeBT18.4 | Add to My Program |
A Biomimetic Underwater Soft Robot Inspired by Cephalopod Mollusc |
Shen, Zhong | The Univ. of Hong Kong |
Wang, Zheng | The Univ. of Hong Kong |
Na, Junhan | The Univ. of Hong Kong |
Keywords: Marine Robotics, Hydraulic/Pneumatic Actuators, Flexible robots
Abstract: This paper presents a biomimetic underwater soft robot design with novel propulsion and maneuvering mechanisms. The robot design took inspirations from cephalopod molluscs. The proposed robot comprises of a soft mantle structure with multiple built-in soft actuators, is could deform to provide steering and maneuverability for underwater locomotion. Smart sensors are embedded into the soft mantle to provide realtime feedback to the controller. Underwater thrust is generated by a novel vortex-based soft tail mechanism also inspired by molluscs. The tail mechanism incorporates an electric motor sealed inside a continuum chamber, and rotational motion from the motor is transmitted to the soft-bodied tentacles which generate a vortex to produce thrust. The resulting soft robot is incorporated in a seamless body, while both propulsion and steering are generated by soft-body deformation. To investigate the novel vortex-based biomimetic propulsion generation mechanism, an analytical model was developed to capture the relation between input motor speed and the resulting thrust force. The entire robot was fabricated using 3D-printing and soft-material molding. The fabricated robot components and the assembled system were both validated through experiments. The results show that the mollusk-inspired robot could achieve underwater maneuverability with very low input power, and the measured results match well with the proposed analytical mode. The proposed design could easily be repeated by anyone with access to a consumer-grade 3D printer, enabling a wide range of biomimetic robot enthusiasts to investigate in the new mechanism for underwater propulsion and maneuvering.
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15:30-15:45, Paper WeBT18.5 | Add to My Program |
Study of Sweep Angle Effect on Thrust Generation of Oscillatory Pectoral Fins |
Chew, Chee Meng | National Univ. of Singapore |
Arastehfar, Soheil | National Univ. of Singapore |
Gunawan, Gunawan | National Univ. of Singapore |
Yeo, Khoon Seng | National Univ. of Singapore |
Keywords: Biomimetics, Marine Robotics
Abstract: Manta ray’s pectoral fins have been a great source of inspiration for propulsive mechanism of autonomous underwater vehicles, due to their propulsive capability. The geometry (shape) and flexibility factors of these fins have been hypothesized to be determinants of the propulsive capability of the fins in terms of thrust generation. In particular, the sweep angle factor has been omitted from previous studies, where it has been commonly set to about 30 degrees. This paper investigates the effects of sweep angle on thrust generation of oscillatory pectoral fins. Forty different fins were designed and fabricated to be experimented in a water channel, which involved measurement of thrust generated by the fins. The experiment was conducted under free stream (0.5 m/s) and still water conditions. Five different sweep angles (0, 10, 20, 30, 40 degrees) were incorporated into eight base designs of different flexibility characteristics to make up the 40 fins. To consider only sweep angle, other geometrical factors were not varied. Within the range of the sweep angle considered, the experimental results showed that sweep angle has no significant influence on the fins’ thrust generation, under both free stream and still water conditions. Overall, it can be concluded that sweep angle may not be a determinant of oscillatory pectoral fins’ thrust generation.
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15:45-16:00, Paper WeBT18.6 | Add to My Program |
Self-Reconfiguration of Modular Underwater Robots Using an Energy Heuristic |
Furno, Lidia | Tech. Univ. of Denmark |
Blanke, Mogens | Tech. Univ. of Denmark |
Galeazzi, Roberto | Tech. Univ. of Denmark |
Christensen, David Johan | Tech. Univ. of Denmark |
Keywords: Cellular and Modular Robots, Marine Robotics
Abstract: This paper investigates self-reconfiguration of a modular robotic system, which consists of a cluster of modular vehicles that can attach to each other by a connection mechanism. Thereby, they can form a desired morphology to meet task specific requirements. Reconfiguration can be needed due to limitations from dimensions of passable corridors for an underwater maintenance task, for supplemental instrumentation that is available on a particular robot, or as remedial action if one robot in a cluster suffers from malfunction. Being crucial for autonomous underwater vehicles, energy consumed is employed as a heuristic. The paper shows how the Basic Theta* algorithm can be guided by an energy criterion to calculate a transition from start- to goal morphology. Individual robots are guided while minimizing the overall energy for propulsion and for balancing restoring forces and moments in morphologies. The properties of the proposed self-reconfiguration algorithm are evaluated through simulations and preliminary model tank experiments. The energy based heuristic for reconfiguration is compared to a traditional solution that minimizes the Euclidean distance.
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WeCT1 , Room 109 |
Add to My Program |
Mobile Manipulation and Path Planning |
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Chair: Asfour, Tamim | Karlsruhe Inst. of Tech. (KIT) |
Co-Chair: Fraisse, Philippe | LIRMM |
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16:30-16:45, Paper WeCT1.1 | Add to My Program |
A Combined Approach for Robot Placement and Coverage Path Planning for Mobile Manipulation |
Paus, Fabian | Karlsruhe Inst. of Tech. (KIT) |
Kaiser, Peter | Karlsruhe Inst. of Tech. (KIT) |
Vahrenkamp, Nikolaus | Karlsruhe Inst. of Tech. (KIT) |
Asfour, Tamim | Karlsruhe Inst. of Tech. (KIT) |
Keywords: Mobile Manipulation, Manipulation Planning, Humanoid Robots
Abstract: Robotic coverage path planning describes the problem of determining a configuration space trajectory for successively covering a specified workspace target area with the robot's end-effector. Performing coverage path planning for mobile robots further requires solving the problem of robot placement, i.e. determining of suitable robot base positions to perform the task. Finding an optimal solution is hard as both problems cannot be solved independently. Combined robot placement and coverage planning is particularly interesting if repositioning of the robot is costly or if simultaneous repositioning and end-effector motion is not desired. In this paper, we present a general approach for combined robot placement and coverage path planning that takes constraints like collision avoidance and static stability into account. In contrast to related approaches, we focus on mobile manipulation tasks that require a fixed placement for executing coverage trajectory segments. The approach is evaluated in two scenarios that exemplify the broad range of possible applications: The coverage of a building facade using a robotic manlift and the coverage of an industrial conveyer belt for maintenance tasks using the humanoid robot ARMAR-III.
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16:45-17:00, Paper WeCT1.2 | Add to My Program |
A Framework for Intuitive Collaboration with a Mobile Manipulator |
Navarro, Benjamin | Univ. of Orléans |
Cherubini, Andrea | LIRMM - Univ. De Montpellier CNRS |
Fonte, Aicha | Univ. of Orleans |
Poisson, Gérard | Univ. D'orléans |
Fraisse, Philippe | LIRMM |
Keywords: Mobile Manipulation, Physical Human-Robot Interaction, Redundant Robots
Abstract: In this paper, we present a control strategy that enables intuitive physical human-robot collaboration with mobile manipulators equipped with an omnidirectional base. When interacting with a human operator, intuitiveness of operation is a major concern. To this end, we propose a redundancy solution that allows the mobile base to be fixed when working locally and moves it only when the robot approaches a set of constraints. These constraints include distance to singular poses, minimum of manipulability and distance to objects and angular deviation. Experimental results with a Kuka LWR4 arm mounted on a Neobotix MPO700 mobile base validate the proposed approach.
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17:00-17:15, Paper WeCT1.3 | Add to My Program |
Dynamically Decoupling Base and End-Effector Motion for Mobile Manipulation Using Visual-Inertial Sensing |
Sandy, Timothy | ETH Zürich |
Buchli, Jonas | ETH Zurich |
Keywords: Mobile Manipulation, Sensor-based Control, Motion Control of Manipulators
Abstract: In this work we present a co-located task space sensing and control system designed to control the end-effector motion of a mobile manipulator in the presence of dynamic and unknown base motion. We present a method for generating end-effector motion estimates at 1 kilohertz for use in real time control through visual-inertial sensor fusion. We show that a Moving Horizon Estimator outperforms Kalman filter-based methods in generating accurate predictive estimates for use in real time. We use this estimator to close a task space control loop directly at the end-effector, assuming no prior knowledge of the base pose and motion. We demonstrate the performance of this system on a hydraulically actuated arm which performs task-space tracking tasks in the presence of significant unknown base motion.
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17:15-17:30, Paper WeCT1.4 | Add to My Program |
Deformed State Lattice Planning |
Ren, Zhongqiang | Carnegie Mellon Univ |
Gong, Chaohui | Carnegie Mellon Univ |
Choset, Howie | Carnegie Mellon Univ |
Keywords: Motion and Path Planning
Abstract: Search-based planning that uses a state lattice has been successfully applied in many applications but its utility is limited when confronted with complex problems represented by a lattice with many nodes and edges with high branching factor. However, in many seemingly complex problems, proper “form-fitting” can reduce the number of nodes and edges needed to represent the problems, provides a concise state lattice and therefore simplifies the computation. This paper proposes a planning framework which strikes to identify concise representations of problems, creates such “form-fitting” state lattice on which a more concise search can take place. In a sense, we take a conventional state lattice and map it onto a deformed space, and then the motion primitives and heuristics follow. Since the contribution of the paper is not the search approach but rather the means by which the lattice is deformed, any search-based planner can then be easily changed to a corresponding deformed version with no increase in time complexity. This paper demonstrate the benifits of the approach which includes 1) planned path can be followed with few changes in motion primitives and thus can provide global smoothness of planned path; 2) fewer states are expanded and thus shorter time to search solution in state space is required, and 3) fewer states are expanded and thus less memory is required to save the state lattice. We demonstrate the benefit of the proposed approach in illustrative toy examples, as well as robot experiments.
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17:30-17:45, Paper WeCT1.5 | Add to My Program |
Online RRT* and Online FMT*: Rapid Replanning with Dynamic Cost |
Chandler, Bryant | Brigham Young Univ |
Goodrich, Michael A. | Brigham Young Univ |
Keywords: Motion and Path Planning
Abstract: Traditional path-planning involves (1) choosing start and goal points, (2) calculating a path, and (3) following that path. There are, however, many real world scenarios where an agent might need to change its goal and replan, which frequently includes expensively calculating a new path from scratch. We propose an adaptation to RRT* that locally rewires the RRT* tree as the robot moves and path costs change. Local rewiring takes advantage of information already existing in the tree and makes small adaptations that accommodate changes. Rewiring adds computational overhead during robot travel, but allows replanning in real time with approximately constant overhead. Empirical studies demonstrate that computational costs are lower than alternative replanners in 2D worlds with moderate obstacle density, and the resulting paths approach optimality as more time is allowed to replan.
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17:45-18:00, Paper WeCT1.6 | Add to My Program |
Learning Foresighted People Following under Occlusions |
Bayoumi, AbdElMoniem | Univ. of Bonn |
Karkowski, Philipp | Univ. of Bonn |
Bennewitz, Maren | Univ. of Bonn |
Keywords: Motion and Path Planning
Abstract: In many situations, users walk on typical paths between specific destinations at which the service of a mobile robot is needed. Depending on the environment and the paths, step-by-step following of the human might not be the optimal solution since better paths for the robot exist. We propose to perform a prediction about the human's future movements and use this information in a reinforcement learning framework to generate foresighted navigation actions for the robot. Since frequent occlusions of the human will occur due to obstacles and the robot's constrained field of view, the estimate about the humans's position and the prediction of the next destination are affected by uncertainty. Our approach deals with such situations by explicitly considering occlusions in the reward function such that the robot automatically considers to execute actions to get the human in its field of view. We show in simulated and real-world experiments that our technique leads to significantly shorter paths compared to an approach in which the robot always tries to closely follow the user and, additionally, can handle occlusions.
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WeCT2 , Room 111 |
Add to My Program |
Mechanism Design |
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Chair: Choi, Hyouk Ryeol | Sungkyunkwan Univ |
Co-Chair: Sugahara, Yusuke | Tokyo Inst. of Tech |
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16:30-16:45, Paper WeCT2.1 | Add to My Program |
A Novel POWERPACK for Robotic Application, Integrated Torque Sensor, Harmonic Drive and Motor |
Kim, Yong Bum | Sungskyunkwan Univ |
Kim, Uikyum | SungKyunKwan Univ |
Seok, Dong-Yeop | Sungkyunkwan Univ |
So, JinHo | Sungkyunkwan Univ |
Lee, Yoon Haeng | Sungkyunkwan Univ |
Choi, Hyouk Ryeol | Sungkyunkwan Univ |
Keywords: Mechanism Design, Force and Tactile Sensing, Force Control
Abstract: Force-sensing system represents one of the vital components of robotic systems for physical interaction performances. This system is facilitated by the force controllable actuators. However, to make a force controllable actuator, it is still a challenging subject for the majority of the robotic system. This paper proposes a novel POWERPACK unit integrated a torque sensor, a harmonic drive and a motor for enabling the force control. The torque sensing element is based on the capacitance sensing to achieve a compact and a simple structure. In this research, reveals the practical details of the POWERPACK and evaluates the performance of the actuator unit.
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16:45-17:00, Paper WeCT2.2 | Add to My Program |
Development and Grasp Analysis of a Sensorized Underactuated Finger |
Abdeetedal, Mahyar | Western Univ |
Kermani, Mehrdad R. | Univ. of Western Ontario |
Keywords: Mechanism Design, Force and Tactile Sensing, Underactuated Robots
Abstract: This paper presents the design and evaluation of a new sensorized underactuated self-adaptive finger. Our design incorporates a two degrees-of-freedom (DOF) parallel based underactuated mechanism with an embedded load cell for contact force measurement and a trimmer potentiometer to acquire the joint variables. Integration of the sensors leads to tactile feedback fidelity without compromising the finger size and complexity which results in efficient and robust functionality. The particular rounded shape of the distal phalanx and high equilibrium position enable the finger to deliver both precision and power grasps. The effectiveness of our design is verified theoretically and through experimental results demonstrating its shape adaptability, and tactile capability.
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17:00-17:15, Paper WeCT2.3 | Add to My Program |
A Human-Powered Joint Drive Mechanism Using Regenerative Clutches |
Sugahara, Yusuke | Tokyo Inst. of Tech |
Kikui, Kensuke | Tokyo Inst. of Tech |
Endo, Mitsuru | Nihon Univ |
Okamoto, Jun | Tokyo Women's Medical Univ |
Matsuura, Daisuke | Tokyo Inst. of Tech |
Takeda, Yukio | Tokyo Inst. of Tech |
Keywords: Mechanism Design, Human Factors and Human-in-the-Loop, Physical Human-Robot Interaction
Abstract: In this paper, a development of a single DOF joint drive mechanism using regenerative servo clutches is described. The regenerative servo clutch is a kind of a clutch developed by the authors which consists of a regenerative brake and a differential gear mechanism, and it can control the transmitted torque by controlling the regenerative brake torque. The joint drive mechanism developed in this study is the system which can perform the servo control of the angle of the output shaft using the externally provided constant-speed power directly, by controlling the transmitted torque by using the two regenerative servo clutches for normal and reverse rotation. Through the experimental results, the effectiveness of the developed mechanism and controller was confirmed.
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17:15-17:30, Paper WeCT2.4 | Add to My Program |
Design and Analysis of a Novel Planar Robotic Leg for High-Speed Locomotion |
Kamidi, Vinaykarthik | Robotics and Mechatronics Lab |
Saab, Wael | Virginia Tech |
Ben-Tzvi, Pinhas | Virginia Tech |
Keywords: Mechanism Design, Legged Robots
Abstract: This paper presents the mechanical design and analysis of a novel leg mechanism that has only one active degree of freedom (DOF). The proposed mechanism is intended towards simplifying the mechanical and control complexity identified with the robotic legs implemented on quadrupedal platforms capable of dynamic locomotion. First, a survey of high-speed and reduced DOF legged robotic systems is presented to elucidate the design challenges and determine system requirements. Drawing from these requirements, a novel design of a six-bar leg mechanism with a single DOF is proposed. The novelty of the mechanism lies in its ability to trace a path that accommodates the execution of trot-gait by the quadrupedal platform realized by integrating the proposed leg. The kinematics of the mechanism is formulated and a multi-body model is used to perform a series of case studies on the sensitivity of the foot trajectory to the leg’s dimensional parameters. Preliminary work on optimization of the foot trajectory is then performed. This research will ultimately assist the future design of quadrupedal robots to test the ability of spatial robotic tails in stabilizing and maneuvering the platform.
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17:30-17:45, Paper WeCT2.5 | Add to My Program |
Design Optimization of a Direct-Drive Linear Actuator Assistive Device for Stroke |
Haji Hosseinnejad, Soroosh | Univ. of Auckland |
Besier, Thor F. | Auckland Bioengineering Inst |
Taberner, Andrew J. | Univ. of Auckland |
Ruddy, Bryan P. | Univ. of Auckland |
Keywords: Mechanism Design, Prosthetics and Exoskeletons, Rehabilitation Robotics
Abstract: We present the conceptual design for a single degree-of-freedom shoulder assistive robot powered by a direct-drive linear electric motor. Such actuators offer high bandwidth and inherent force transparency, advantageous properties for an assistive device, but traditionally have inadequate force densities. We develop a model to describe the interaction between the robot kinematics and the actuator performance, and find the optimal actuator configuration. We also demonstrate the ability of a single design of such a device to fit a wide range of patients, and determine indicative power and mass specifications for the actuator. The resulting power and mass levels of approximately 1 kg and 130 W are well within the feasible range for a wearable device.
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17:45-18:00, Paper WeCT2.6 | Add to My Program |
3D Printable Origami Twisted Tower: Design, Fabrication, and Robot Embodiment |
Liu, Tao | Case Western Res. Univ |
Wang, Yanzhou | Case Western Res. Univ |
Lee, Kiju | Case Western Res. Univ |
Keywords: Mechanism Design, Tendon/Wire Mechanism, Kinematics
Abstract: This paper presents a novel robotic mechanism inspired by origami and its fabrication method using 3D printing. The selected twisted tower design shows unique structural and geometrical properties that enable bending and linear motions, and therefore, can be suitable for various robotic applications. However, fabrication of this origami design requires a complex sequence of paper folding and assembling by hand, which cannot be automated by currently existing manufacturing technologies. To fabricate this structure via 3D printing, the twisted tower is reconstructed in a computer aided design (CAD) model. The CAD model is then 3D printed using two different materials – a flexible material for creases and a rigid material for surfaces. The 3D printed structure preserves the geometrical properties of the original tower. Associated kinematics and workspace analysis are also presented in this paper. The 3D printed tower is then embodied into a robotic arm to physically demonstrate its potential utility.
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WeCT3 , Room 116 |
Add to My Program |
Force Control and Tactile Sensing |
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Chair: Niemeyer, Günter | Disney Res |
Co-Chair: Lepora, Nathan | Univ. of Bristol |
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16:30-16:45, Paper WeCT3.1 | Add to My Program |
Object Exploration Using Vision and Active Touch |
Yang, Chuanyu | Univ. of Bristol |
Lepora, Nathan | Univ. of Bristol |
Keywords: Force and Tactile Sensing, Biomimetics
Abstract: Achieving object exploration with passive vision and active touch has been under investigation for thirty years. We build upon recent progress in biomimetic active touch that combines perception via Bayesian evidence accumulation with controlling the tactile sensor using perceived stimulus location. Here, passive vision is combined with active touch by providing a visual prior for each perceptual decision, with the precision of this prior setting the relative contribution of each modality. The performance is examined on an edge following task using a tactile fingertip (the TacTip) mounted on a robot arm. We find that the quality of exploration is a U-shaped function of the relative contribution of vision and touch; moreover, multi-modal performance is more robust, completing the contour when touch alone fails. The overall system has several parallels with biological theories of perception, and thus plausibly represents a robot model of visuo-tactile exploration in humans.
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16:45-17:00, Paper WeCT3.2 | Add to My Program |
Multilayered Center-Of-Pressure Sensors for Robot Fingertips and Adaptive Feedback Control |
Suzuki, Yosuke | Kanazawa Univ |
Keywords: Force and Tactile Sensing, Multifingered Hands, Robust/Adaptive Control of Robotic Systems
Abstract: This paper proposes a sheet-shaped force sensor for covering a robot fingertip. The sensor consists of flexible materials and can be adaptively designed to the shape of the fingertip. When a load acts on the sensor, the contact position and both normal and tangential forces can be detected. Experimental results show the sensor characteristics as follows: the contact position can be estimated in high accuracy if it is enough separated from the boundary of the sensing area, the normal force up to 4N can be estimated independent with the contact position, and the tangential force can be estimated by calibration while the sensitivity remains to be improved. This paper also presents two feedback control laws of a robot finger mounted with the proposed sensor. One is to keep both a contact position and normal force at constant to a target object, and the other is to keep rolling contact even if the object moves while touching. The availability of the control laws are confirmed through motion experiments.
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17:00-17:15, Paper WeCT3.3 | Add to My Program |
A Tactile-Based Framework for Active Object Learning and Discrimination Using Multi-Modal Robotic Skin |
Kaboli, Mohsen | Tech. Univ. of Munich (TUM) |
Feng, Di | Tech. Univ. of Munich |
Yao, Kunpeng | Tech. Univ. of Munich |
Lanillos, Pablo | Tech. Univ. München |
Cheng, Gordon | Tech. Univ. of Munich |
Keywords: Force and Tactile Sensing, Recognition
Abstract: In this paper, we propose a complete probabilistic tactile-based framework to enable robots to autonomously explore unknown workspaces and recognize objects based on their physical properties. Our framework consists of three components: (1) an active pre-touch strategy to efficiently explore unknown workspaces; (2) an active touch learning method to learn about unknown objects based on their physical properties (surface texture, stiffness, and thermal conductivity) with the least number of training samples; and (3) an active touch algorithm for object discrimination, which selects the most informative exploratory action to apply to the object, so that the robot can efficiently distinguish between objects with a few number of actions. Our proposed framework was experimentally evaluated using a robotic arm equipped with multimodal artificial skin. The robot with the active pre-touch method reduced the uncertainty of the workspace up to 30% and 70% compared to uniform and random strategies, respectively. By means of the active touch learning algorithm, the robot used 50% fewer samples to achieve the same learning accuracy than the baseline methods. By taking advantage of the prior knowledge obtained during the learning process, the robot actively discriminated objects with an improvement of 10% recognition accuracy compare to the random action selection approach.
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17:15-17:30, Paper WeCT3.4 | Add to My Program |
Toward Torque Control of a KUKA LBR IIWA for Physical Human-Robot Interaction |
Chawda, Vinay | The Walt Disney Company |
Niemeyer, Günter | Disney Res |
Keywords: Force Control, Industrial Robots, Physical Human-Robot Interaction
Abstract: In this paper we examine joint torque tracking as well as estimation of external torques for the KUKA Lightweight Robot (LBR) IIWA. To support physical human-robot interaction tasks, we need smooth estimation that allows detection of delicate external events and good control to hide inertial forces. Unfortunately a transmission nonlinearity in the motor to joint gearing injects vibrations and limits the performance of the built-in torque controller and observer. We confirm the nonlinearity to be a spatially periodic deflection between the motor and joint. Identification of this behavior allows us to generate more accurate joint position measurements. We also design a matching spatial filter to remove the vibrations from joint torque measurements. Experiments on an LBR IIWA show that compensating for the nonlinearity provides smoother external torque estimates and improves the torque tracking performance. Furthermore, we are able to increase the gain margin more than three fold over the built-in controller.
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17:30-17:45, Paper WeCT3.5 | Add to My Program |
Robust Set Invariance for Implicit Robot Force Control in Presence of Contact Model Uncertainty |
Parigi-Polverini, Matteo | Pol. Di Milano |
Nicolis, Davide | Pol. Di Milano |
Zanchettin, Andrea Maria | Pol. Di Milano |
Rocco, Paolo | Pol. Di Milano |
Keywords: Force Control, Robust/Adaptive Control of Robotic Systems, Optimization and Optimal Control
Abstract: The present paper exploits set invariance theory to address the problem of robot implicit force control in presence of stiffness uncertainty in the interaction model. A numerical approach is introduced to compute the invariance function for constraints with arbitrary relative degree. The method is then applied to robot force control, enhancing force regulation performance, in terms of steady state error and convergence speed, despite model mismatch and measurement noise. Its effectiveness is experimentally validated and compared to previous results of set invariance control on a hybrid force/position task performed with a 6 degrees of freedom industrial robot equipped with a force/torque sensor.
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17:45-18:00, Paper WeCT3.6 | Add to My Program |
Haptic Guidance in Dynamic Environments Using Optimal Reciprocal Collision Avoidance |
Lisini Baldi, Tommaso | Univ. of Siena |
Scheggi, Stefano | Univ. of Twente |
Aggravi, Marco | Univ. of Siena |
Prattichizzo, Domenico | Univ. of Siena |
Keywords: Haptics and Haptic Interfaces, Human-Centered Robotics
Abstract: Human guidance in situation with poor/no visibility, such as assistive or search-and-rescue scenarios, is a challenging task. In this paper, we address the problem of guiding users along collision-free paths in dynamic environments, assuming that they cannot rely on hearing and vision. The proposed approach relies on haptic stimuli to provide effective directional cues to the subjects. The navigation policy presented in this study exploits the nonholonomic nature of human locomotion in goal directed paths, which leads to an intuitive guidance mechanism. In order to dynamically generate motion controls which guide the subjects along collision-free paths, we adapt the Optimal Reciprocal Collision Avoidance for non-holonomic agents to our specific problem. The collision avoidance algorithm takes into account the haptic stimuli which can be displayed to the users and the motion uncertainty of the users when reacting to the provided stimuli. The proposed algorithm is evaluated in three different dynamic scenarios. A total of 18 blindfolded human subjects are asked to follow haptic cues in order to reach a target area while avoiding real static obstacles and moving users. Three metrics such as time to reach the goal, length of the trajectories, and minimal distance from the obstacles are considered to compare results obtained using this approach and experiments performed without visual impairments. Experimental results reveal that blindfolded subjects are successfully able to avoid collisions and safely reach the target in all the performed trials.
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WeCT4 , Room 114 |
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Simulation and Animation |
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Chair: Manocha, Dinesh | Univ. of North Carolina at Chapel Hill |
Co-Chair: Li, Sheng | Peking Univ |
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16:30-16:45, Paper WeCT4.1 | Add to My Program |
Visualizing Robot Behaviors As Automated Video Annotations: A Case Study in Robot Soccer |
Zhu, Danny | Carnegie Mellon Univ |
Veloso, Manuela | Carnegie Mellon Univ |
Keywords: Simulation and Animation, Autonomous Agents, Cognitive Human-Robot Interaction
Abstract: Autonomous mobile robots continuously perceive the world, plan or replan to achieve objectives, and execute the selected actions. Videos of autonomous robots are often naturally used to aid in replaying and demonstrating robot performance. However, plain videos contain no information about the ongoing internals of the robots. In this work, we contribute an approach to automate the overlay of visual annotations on videos of robots' execution to capture information underlying their reasoning. We concretely focus our presentation on the complex robot soccer domain, where the high speed of the robots' execution results from action planning for collaboration and response to the adversary.
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16:45-17:00, Paper WeCT4.2 | Add to My Program |
Fast Simulation of Vehicles with Non-Deformable Tracks |
Pecka, Martin | Czech Tech. Univ. in Prague |
Zimmermann, Karel | Czech Tech. Univ. Prague |
Svoboda, Tomas | Faculty of Electrical Engineering, Czech Tech. Univ. In |
Keywords: Simulation and Animation, Collision Avoidance, Autonomous Vehicle Navigation
Abstract: This paper presents a novel technique that allows for both computationally fast and sufficiently plausible simulation of vehicles with non-deformable tracks. The method is based on an effect we have called Contact Surface Motion. A comparison with several other methods for simulation of tracked vehicle dynamics is presented with the aim to evaluate methods that are available off-the-shelf or with minimum effort in general-purpose robotics simulators. The proposed method is implemented as a plugin for the open-source physics-based simulator Gazebo using the Open Dynamics Engine.
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17:00-17:15, Paper WeCT4.3 | Add to My Program |
Multi-Contact Frictional Rigid Dynamics Using Impulse Decomposition |
Li, Sheng | Peking Univ |
Zhang, Tianxiang | Peking Univ |
Wang, Guoping | Peking Univ |
Sun, Hanqiu | CUHK |
Manocha, Dinesh | Univ. of North Carolina at Chapel Hill |
Keywords: Simulation and Animation, Contact Modelling
Abstract: We present an interactive and stable multi-contact dynamic simulation algorithm for rigid bodies. Our approach is based on fast frictional dynamics (FFD) [15], which is designed for large sets of non-convex rigid bodies. We use a new friction model that performs velocity-level multi-contact simulation using impulse decomposition. Moreover, we accurately handle friction at each contact point using contact distribution and frictional impulse solvers, which also account for relative motion. We evaluate our algorithm’s performance on many complex multi-body benchmarks with thousands of contacts. In practice, our dynamics simulation algorithm takes a few milliseconds per timestep and exhibits more stable behaviors.
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17:15-17:30, Paper WeCT4.4 | Add to My Program |
Loosely-Constrained Volumetric Contact Force Computation for Rigid Body Simulation |
Wakisaka, Naoki | Osaka Univ |
Sugihara, Tomomichi | Graduate School of Engineering, Osaka Univ |
Keywords: Simulation and Animation, Dynamics
Abstract: A novel method to compute the contact force in forward dynamics simulation of rigid bodies based on contact volume is proposed. The conventional methods are based on contact vertices, where the normal and tangential directions are estimated with respect to each pair of facets or facet and vertex of colliding bodies. However, the normal direction is intrinsically determined based on the solid deformation. This paper proposes a novel method that combines the constraint-based method and the volumetric intersection computation. Since the method estimates a 6-axis resultant force directly, there are two problems that are how to predict the preferred deformation of the volume and how to confirm the friction limit. The idea is to apply the least-square method for the former and to check if the computed force can be resolved into each stress within the friction limit. The proposed method checks the condition with linear programming method through a pyramidal approximation.
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17:30-17:45, Paper WeCT4.5 | Add to My Program |
Evaluation of Regular Planar Meshes for Modular Active Cell Robots (MACROs) |
Nawroj, Ahsan | Yale Univ |
Dollar, Aaron | Yale Univ |
Keywords: Cellular and Modular Robots, Simulation and Animation
Abstract: In this paper we investigate a series of candidate regular planar mesh geometries in terms of their suitability for utilization as mesh primitives for constructing compliant robotic structures. In prior work, we established a framework of compliant, articulate robotic meshes, termed Modular Active Cell Robots (MACROs), created from contractile Shape Memory Alloy linear-actuators (Active Cells). In this paper, we examine how to utilize these MACROs and othe | |