Keywords: Autonomous search and rescue, Robotics and Automation for safety and security, Unmanned ground, aerial, and marine vehicles
Abstract: In this paper, we present a framework for online generation of safe trajectories directly on point clouds for autonomous quadrotor flight. Considering a quadrotor operating in unknown environments, we use a 3-D laser range finder for state estimation and simultaneously build a point cloud map of the environment. Based on the incrementally built point cloud map, we utilize the property of the fast nearest neighbor search in KD-tree and adopt the sampling-based path finding method to generate a flight corridor with safety guarantee in 3-D space.A trajectory generation method formulated in quadratically constrained quadratic programming (QCQP) is then used to generate trajectories that constrained entirely within the corridor. Our method runs onboard within 100 milliseconds,making it suitable for online re-planning. We integrate the proposed planning method with laser-based state estimation and mapping modules, and demonstrate the autonomous quadrotor flight in unknown indoor and outdoor environments.

Keywords: Multi-agent coordination, Autonomous search and rescue, Intelligent behaviors to improve robot performance and survivability
Abstract: This paper presents the visual localization subsystem of the ongoing EMILY project. This project aims to assist responders with establishing contact with drowning victims as quickly as possible through the use of a 1.3-meter autonomous unmanned surface vehicle (USV). Once victims are reached, the device can serve as a flotation device to support them. An unmanned aerial vehicle (UAV) provides a live video feed to responders and aids USV's navigation by visually estimating the USV's position and orientation. The movement of the UAV and the USV along with varying lighting, distance, and perspective make the task of estimating USV's position and orientation challenging. We present two implemented solutions for reliable visual localization, the first relying on color thresholding and contour detection, and the second using histograms, back-projection, and CamShift algorithm. The visual localization system was validated in four proof-of-concept field trials. Other unsuccessful methods are discussed.

Keywords: Unmanned ground, aerial, and marine vehicles, Manipulation, Robotics and Automation for safety and security
Abstract: One important issue of multirotor UAVs is their limited operational time due to their high power consumption. This issue may hinder the application of aerial robots for security purposes as their flight endurance can be exploited for just a finite amount of time, which is not necessarily sufficient in realistic surveillance scenarios. In order to achieve long endurance missions with multirotor UAVs, e.g. for crowd-surveillance, it can be beneficial to perch the UAV while it is operative to increase the operation time.

This work presents an aerial manipulator that allows for reliable and reversible perching of multirotor UAVs on smooth vertical surfaces, using a lightweight mechanism based on passive vacuum-cup technology and the absorption of aerial impacts. This contributes towards enabling drones to become more flexible security systems for long endurance missions, as it allows them to position themselves passively in the environment. In this work, the design of the aerial perching mechanism is presented, as well as the perching strategy performed to achieve reliable perching. Experimental results demonstrate the relevant capabilities of the system for a drone weighing approximately 1.8 kg, including stable perching on the environment, disarming the rotors and reliable take-off.

Keywords: Robotics and Automation for safety and security, Manipulation, Mechanisms, Mechatronics, and Embedded Control
Abstract: Since the 2011 Fukushima nuclear disaster in Japan, various types of humanoid robots have been developed. Although many researchers are trying to develop the robot technology, it is premature to deploy the robot to the real situation. The main reason is a lack of a manipulation performance. This paper suggests the new mechanism of the robot gripper. Torsion springs, an outer frame and a ballscrew are used to realize the new gripping mechanism. It is light-weight and resistant to external forces. This mechanism is useful especially for bipedal/quadrupedal transformable locomotive robots. Simulation and optimization are carried out by MATLAB 2014b. Six design parameters are chosen to minimize the required motor torque. SOLIDWORKS 2014 is used to obtain the robot hand model for the experiment. Experimental tests are done for validating the proposed robot gripper. All of details are extensively reported in the paper.

Keywords: Nuclear decommissioning, Manipulation
Abstract: This paper explores the problems of developing robotic systems for decommissioning legacy nuclear infrastructure, such as the many contaminated gloveboxes present in UK, USA and other countries. We begin with a discussion of these decomissioning challenges. We review the current manual methods for decommissioning alpha-contaminated plant, and review robotic approaches which might replace such direct human interventions. We then present our initial experiments with human test-subjects, exploring the ability of humans to control a remote robot to perform complex manipulation tasks. Our preliminary results reveal a number of interesting lessons: conventional tele-manipulation is very difficult and very slow without significant training; metrics for usability of such technology can be conflicting and hard to interpret; aptitude for tele-manipulation varies significantly between individuals; however such aptitude may be predicted by using spatial awareness tests to select prospective robot operators; additionally the abilities of people with different initial aptitudes appear to converge somewhat as learning progresses. An additional contribution of this paper is to show how rigorous scientific methodologies, drawn from the psychology and human-factors research fields, can be used to analyse the performance of humans using robots to perform practical tasks.

Keywords: Unmanned ground, aerial, and marine vehicles, Manipulation
Abstract: Lately there has been an increasing interest for subsea inspection and intervention tasks, and in particular on solutions which combine smaller size, increased flexibility and maneuverability, and decreased cost. Biologically inspired underwater snake robots (USRs) can provide both inspection and intervention capabilities and are thus interesting candidates for the next generation inspection and intervention vehicles. In this paper, we focus on a new type of USR equipped with thrusters, which combine the flexibility and maneuverability of conventional USRs with the locomotion capabilities of traditional marine vessels with thrusters. This vehicle configuration represents a promising solution for operations inside narrow and restricted parts of subsea structures. The paper considers the locomotion efficiency of this new type of USR with thrusters by experimentally investigating fundamental properties of the velocity and the power consumption of a USR with and without thrusters, both for lateral undulation and eel-like motion.

Keywords: Intelligent behaviors to improve robot performance and survivability, Structural assessment, Inspection of critical infrastructure
Abstract: This paper presents an algorithm to calculate mechanical stability margins of a Modular Snake Robot (MSR) during scouting poses. Scouting poses are defined as robot configurations in which one or two of the end modules of the robot are raised up to increase the range of perception of sensors that might be placed in its distal parts. The robot center of mass (CoM) and each of the module's contact pad positions are calculated by computing the robot kinematics. Then, this kinematic model is placed in an environment that consist of a height map (the terrain), built on a 2D grid base of defined size and resolution. Due the hyper-stability of the MSR structure, as it features many static contact points with the terrain, we approximate by weighting the distribution of forces to ensure an iso-static simplified problem. Using this information as input, the algorithm calculates a representation of the supporting surface (not necessarily horizontal), and then, it computes the minimum distance of the CoM projection into this surface to one of its edges to define a mechanical stability margin. The effectiveness and robustness of the method is demonstrated by comparisons of simulation and the real robot results. Moreover, a sequence of quasi-static motions bounded by a threshold in the stability margin, keeps the robot stable as it rises. Thus, demonstrating qualitatively the convenience of the method.

Keywords: Inspection of critical infrastructure, Intelligent behaviors to improve robot performance and survivability, Unmanned ground, aerial, and marine vehicles
Abstract: This paper presents a method for expressing the target form of a snake robot by connecting simple shapes. Because the characteristics of each combined shape are clear, we can intuitively design the target form and fit a snake robot to this form. In addition, we propose two novel gaits for the snake robot as a design example of the proposed method. The first gait is for pipe climbing to move over a flange on the pipe, while the other is the “Crawler-Gait” aimed at moving at high speed over uneven terrain. We demonstrate the effectiveness of each gait on a pipe, step, and set of stairs in a physical simulation.

Keywords: Sensing and sensor fusion, SLAM in complex and/or extreme environments, Unmanned ground, aerial, and marine vehicles
Abstract: Odometry-like localization solutions can be built upon Light Detection And Ranging (LIDAR) sensors, by sequentially registering the point clouds acquired along a robot trajectory. Yet such solutions inherently drift over time: we propose an approach that adds a graphical model layer on top of such LIDAR odometry layer, using the Iterative Closest Points (ICP) algorithm for registration. Reference frames called keyframes are defined along the robot trajectory, and ICP results are used to build a pose graph, that in turn is used to solve an optimization problem that provides updates for the keyframes upon loop closing, enabling the correction of the path of the robot and of the map of the environment. We present in details the configuration used to register data from the Velodyne High Definition LIDAR (HDL), and a strategy to build local maps upon which current frames are registered, either when discovering new areas or revisiting previously mapped areas. Experiments show that it is possible to build the graph using data from ICP and that the loop closings in the graph level reduces the overall drift of the system.

Keywords: SLAM in complex and/or extreme environments, Sensing and sensor fusion
Abstract: This paper presents a method for calibrating a camera for underwater use. We consider the case that the camera is encased in a housing and views the world through a flat port. The method is analogous to common air calibration methods except that it occurs underwater where refraction plays a significant role in imaging. The calibration approach is as follows. The camera intrinsics are first calibrated in air using standard tools. The housed camera then records a video sequence of a moving calibration target underwater. From this sequence, the housing parameters (refractive indices, relevant housing dimensions, glass thickness and inclination angles), as well as the camera poses, are determined through a non-linear optimization, which minimizes the reprojection errors of calibration target observations. In comparison to other methods, our method uses a moving, rather than static calibration target and we define our reprojection errors directly on the image plane of the camera, in order to accurately capture how noise affects the measurements. We show in a series of experiments that our approach significantly reduces the reprojection errors on an underwater evaluation sequence, when compared to an in air calibration and a model of underwater refraction with nominal parameters.

Keywords: Sensing and sensor fusion, Perception for navigation, hazard detection, and victim identification, Inspection of critical infrastructure
Abstract: This paper presents a sound-based online localization method for an in-pipe snake robot with an inertial measurement unit (IMU). In-pipe robots, in particular, snake robots need online localization for autonomous inspection and for remote operator supports. The GPS is denied in a pipeline, and conventional odometry-based localization may deteriorate due to slippage and sudden unintended movements. By putting a microphone on the robot and a loudspeaker at the entrance of the pipeline, their distance can be estimated by measuring the time of flight (ToF) of a reference sound emitted from the loudspeaker. Since the sound propagation path in the pipeline is necessary for estimating the robot location, the proposed sound-based online localization method simultaneously estimates the robot location and the pipeline map by combining the distance obtained by the ToF and orientation estimated by the IMU. The experimental results showed that the error of the distance estimation was less than 7% and the accuracy of the pipeline map was more than 68.0%.

Keywords: Robotics and Automation for safety and security, Unmanned ground, aerial, and marine vehicles, Sensing and sensor fusion
Abstract: This work presents a design and a field test result of a small USV system that has portability and wind tolerance for a lake bed depth mapping of volcanic crater lakes. The depth map of the crater lakes indicates an amount of water, crater wall caving and volcanic upthrust which is used for volcanic disaster prevention. However, today’s depth surveillance is achieved by using a manned canoe on the lake in high altitude, strong winded and restricted area. This research is aiming to realize the autonomous Unmanned Surface Vehicle (USV) for volcanic crater lake surveillance reducing risks to surveyors. In this research, the authors developed the lightweight semisubmersible USV system with a high draft that has portability and wind tolerance. The result of a field test at Mt. Zao Okama Crater Lake is shown. A depth map of the north half of the Okama Crater Lake was autonomously measured by using the USV system.

Keywords: Unmanned ground, aerial, and marine vehicles, Autonomous search and rescue, Robotics and Automation for safety and security
Abstract: This paper presents a new concept, the ”Directly Navigable Gap”, for reactive obstacle avoidance. A directly navigable gap DNG is defined as the gap that a robot can safely navigate through by executing only a single motion command. With this concept, it has been possible to achieve navigation in unknown cluttered environments, similar to the gap-based obstacle avoidance methods (e.g the Nearness-Diagram Navigation). Compared to these methods, however, our approach avoids the limitation of being prone to oscillatory and unstable motion, improving their navigation performance, especially in narrow spaces. Experimental results are presented to verify the outstanding performance of the proposed DNG approach. Moreover, a discussion and comparison with existing gap-based methods is reported where the DNG approach generates less-oscillatory, safer, and faster trajectories than its counterparts.

Keywords: Unmanned ground, aerial, and marine vehicles
Abstract: In case of volcanic eruption, a robotic volcano exploration for observing restricted areas is expected to judge the evacuation call for inhabitants. An unmanned ground vehicle (UGV) is one possibility to apply to such exploration missions. When a UGV traverses on volcanic fields, a slippage between the vehicle and the terrain occurs. This is because the volcanic environment is covered with loose soil and rocks, and there are many slopes. The slippage causes several problems for UGVs, particularly localization and traversability. Therefore, in this research, we propose a slip estimation method based on a slip model to apply to slip-compensated odometry for tracked vehicles. First, we propose a slip model for tracked vehicles based on the force acting on a robot on a slope. The proposed slip model has two parameters: a pitch angle dependence and a constant component, and these parameters were identified by indoor slope-traveling experiments. Next, we propose a slip parameter estimation method using a particle filter technique with a velocity measurement sensor, and report on the effectiveness of our method by slope-traveling experiments. The experimental result shows that the accuracy of our position estimation method based on the slip-compensated odometry is improved in comparison with conventional methods by using the slip parameters.

Keywords: Autonomous search and rescue, Human-robot interaction and interfaces, Unmanned ground, aerial, and marine vehicles
Abstract: An architecture suitable for the control of multiple unmanned aerial vehicles deployed in Search & Rescue missions is presented in this paper. In the proposed system, a single co-located human operator is able to coordinate the actions of a set of robots in order to retrieve relevant information of the environment. This work is framed in the context of the SHERPA project whose goal is to develop a mixed ground and aerial robotic platform to support search and rescue activities in alpine scenario. Differently from typical human-drone interaction settings, here the operator is not fully dedicated to the drones, but involved in search and rescue tasks, hence only able to provide sparse and incomplete instructions to the robots. In this work, the domain, the interaction framework and the executive system for the autonomous action execution are discussed. The overall system has been tested in a real world mission with two drones equipped with on-board cameras.

Keywords: Human-robot interaction and interfaces
Abstract: A complete prototype for multi-modal interaction between humans and multi-robot systems is described. The application focus is on search and rescue missions. From the human-side, speech and arm and hand gestures are combined to select, localize, and communicate task requests and spatial information to one or more robots in the field. From the robot side, LEDs and vocal messages are used to provide feedback to the human. The robots also employ coordinated autonomy to implement group behaviors for mixed initiative interaction. The system has been tested with different robotic platforms based on a number of different useful interaction patterns.

Keywords: Human-robot interaction and interfaces, Autonomous search and rescue, Multi-agent coordination
Abstract: This paper describes a monitoring and reporting system for robot-assisted long-term USAR missions. It is able to monitor robot activities and human verbal communication persistently and to make the information available to users in a structured multimodal interface integrating textual event descriptions, visualizations and audio playback as reports for briefing and debriefing activities as well as for creating situation awareness for new or outside participants. It is realized as a web application allowing it to be used anytime anywhere on any web enabled device. We also present results from an end-user evaluation of the system.

Keywords: Human-robot interaction and interfaces, Autonomous search and rescue, Robotics and Automation for safety and security
Abstract: We present a study on sketch-map interpretation and sketch to robot map matching, where maps have nonuniform scale, different shapes or can be incomplete. For humans, sketch-maps are an intuitive way to communicate navigation information, which makes it interesting to use sketch-maps for human robot interaction; e.g., in emergency scenarios.

To interpret the sketch-map, we propose to use a Voronoi diagram that is obtained from the distance image on which a thinning parameter is used to remove spurious branches. The diagram is extracted as a graph and an efficient error-tolerant graph matching algorithm is used to find correspondences, while keeping time and memory complexity low.

A comparison against common algorithms for graph extraction shows that our method leads to twice as many good matches. For simple maps, our method gives 95% good matches even for heavily distorted sketches, and for a more complex real-world map, up to 58%. This paper is a first step toward using unconstrained sketch-maps in robot navigation.

Keywords: Intelligent behaviors to improve robot performance and survivability, Human-robot interaction and interfaces
Abstract: Emergency response in hostile environments often involves remotely operated vehicles (ROVs) that are teleoperated as interaction with the environment is typically required. Many ROV tasks are common to such scenarios and are often recurrent. We show how a probabilistic approach can be used to learn a task behavior model from data. Such a model can then be used to assist an operator performing the same task in future missions. We show how this approach can capture behaviors (constraints) that are present in the training data, and how this model can be combined with the operator's input online. We present an illustrative planar example and elaborate with a non-Destructive testing (NDT) scanning task on a teleoperation mock-up using a two-armed Baxter robot. We demonstrate how our approach can learn from examples task specific behaviors and automatically control the overall system, combining the operator's input and the learned model online, in an assistive teleoperation manner. This can potentially reduce the time and effort required to perform teleoperation tasks that are commonplace to ROV missions in the context of security, maintenance and rescue robotics.

Keywords: Human-robot interaction and interfaces, Robotics and Automation for safety and security, Casualty assessment, care and extraction
Abstract: Beyond robot hardware and control, one major element for an efficient, constructive and safe mission of teleoperated robots in disaster scenarios such as Fukushima is the quality of the interface between operator and robot. In this contribution, we present the concept of utilizing 3D simulation as a central interface component for the operator to intuitively collaborate with teleoperated robots. Thus, means of 3D simulation are not only used during the development but also in the deployment of the final field system. Based on this notion, we will discuss operator interfaces with regards a) to direct interaction with the robot, b) communication between control station and real robot and c) the integration of already acquired knowledge and existing libraries in the robotics community.