Keywords: Human -Machine Interfaces, Novel Industry Applications of Mechatroinics, Mobile Robots
Abstract: In this study, we propose a low-cost power-assisted cart that distributes the torque of a motor using a differential gear and brakes. Carts are designed to help transport heavy payloads and have multiple applications. As the cart size and payload weight increase, cart operation becomes difficult. This led to the development of power-assisted carts, which employ actuators to support the workload. Adding several actuators and high-performance sensors actually increases cart maneuverability; however it increases the cart cost. Commercialization of power-assisted carts warrants that their cost should be decreased without compromising their maneuverability. To this end, we created a power-assisted cart using a motor and a few simple inexpensive sensors. The motor torque is distributed using a differential gear and brakes. However, the characteristics of the differential gear cause an increase in the speed of the cart when turning; hence, we implemented a control algorithm that regulates cart speed during turning. Through experiments, we confirmed that the speed of the cart during turning was kept constant, thereby validating the effectiveness of the developed algorithm.

Keywords: Human -Machine Interfaces, Artificial Intelligence in Mechatronics, Fault Detection and diagnosis in Manufacturing
Abstract: Robots working with humans are expected to be more adaptive to failures of tasks and to have easier communication channels with those co-working humans. With this goal in mind, this paper presents a motion recognition framework for robots including a success/failure classification of tasks based on natural language representation. The proposed method consists of three parts: motion language model, natural language model and hierarchical task description. It realizes motion recognition by natural language using motion information of task execution including success and failures. When a sentence is given to the system, a state in the task description is evoked. Through the process, hierarchical relation between states is considered. The proposed framework was implemented and experiments confirmed that the proposed method identifies various motion types and provides natural language expressions. It was also confirmed that hierarchical relations among task representations are reflected to language recognition results.

Keywords: Human -Machine Interfaces, Medical Robotics/Mechatronics, Actuators in Mechatronic Systems
Abstract: Tactile sensing is an important biological function. Additionally, not only humans, robotic manipulators also require tactile sensing ability to improve quality of grasping and environment perception. Regarding tele-operated robotics, object manipulation, and surface texture recognition is an important function. These sensor data should be transmitted to the operator correctly so that the operator can evaluate the griping forces, object surface conditions, and edges of an object which are governing factors for manipulation and environment exploration. Force and vibration are the key modalities which required to recognize incipient slip and surface textures correctly. For this purpose, several researches have been carried out to implement tactile feedback actuator systems. In our study, a novel method is introduced for artificial tactile feedback. The device is designed so that it can be worn on the user’s finger. The experimental setup consists of three pairs of micro gear motors with a belt attached to each pair. When motors in one pair are rotating in the opposite directions, user can sense the feeling of force due to tension of the belt, whilst rotation of the motors in same direction and oscillating the direction frequently gives the sensation of vibration. Having three pairs of motors, which is the specialty in this device, gives the ability to identify the correct contact location of the applied force or vibration, and also it helps for edge detection as well. According to the experimental results, this device can successfully provide combination of force and vibration sensations as well.

Keywords: Human -Machine Interfaces, Machine Learning, Sensor Integration, Data Fusion
Abstract: This paper exploited the single trial decoding of cortical-muscular activities (CMAs). The activities were measured by acquiring Electromyographic (EMG) signals, and Electroencephalographic (EEG) signals. We focused on CMAs related to sustained muscular contractions (SMC), and investigated on the classification performance of four types of CMAs with different combinations of three types of features. The four types of CMAs were relaxing, conducting precise hand operation without distractive mental task, conducting precise hand operation with distractive mental task, and conducting rough hand operation. The three types of features were combined root mean square (RMS) and wavelet packet decomposition (WPD) feature of EMG signals, common pattern spatial (CSP) filtered WPD feature of EEG signals, and cortical-muscular coherence (CMC) feature of EMG-EEG signals, which were noted as EMG features, EEG features, and CMC features respectively. In total of 5 subjects participated in the experiments. According to the experiments, we concluded that the classification performance of myoelectric controller can be significantly improved by the combination of EEG and EMG features and the combination of CMC and EMG features, compared with sole EMG features. The improvements were 9.83% and 6.06% respectively.

Keywords: Human -Machine Interfaces, Tele-operation, Parallel Mechanisms
Abstract: In this paper, a cable-driven haptic interface able to move in the six-dimensional space, suitable for applications in various robotic scenarios is presented. The device takes advantage of four force-controlled twisted string actuators to generate a linear force along the three Cartesian space dimensions while providing a considerable force-weight ratio and low inertia. The system consists of a frame fixed to the ground, where the twisted string actuation modules are arranged, and by a mechanical interface devoted to the physical connection of the actuators with the forearm of the human operator. This mechanical interface allows to secure the forearm of the user while leaving to her/him the freedom to use the hand to accomplish other tasks, such as teleoperating a robotic gripper. The four twisted string actuators allow to control the three linear DoF of the haptic interface, allowing both Cartesian position and a force regulation. Both the design, the simulation and the preliminary implementation of the haptic interface are presented in this work.

Keywords: Human -Machine Interfaces, Virtual Reality and Human Interface
Abstract: This paper proposes a new relative-motion-based force bounding approach (dynamic FBA) for stably interacting with dynamic virtual objects. The new approach can overcome some limitations of the previous static approach (static FBA) [8] that cannot display the interaction force with moving virtual objects because the previous controller considered only the motion of the operator. A new passivity condition is derived considering the relative motion between a virtual object and a human operator. In order to show effectiveness of the proposed approach, three typical dynamic scenarios are tested. Experimental results demonstrate that the proposed approach can ensure stability of the haptic interaction with any (even active) dynamic systems.

Keywords: Service Robots, Modeling and Design of Mechatonic Systems, Flexible Manipulators and Structures
Abstract: This paper describes a principle, a design and an evaluation of a light-weight safe arm equipped with 3-dimensional gravity compensation mechanism for a collaborating robot. This arm realizes the gravity compensation for 3-dimensional arm posture by the addition of a rotary joint to the base of a pantograph mechanism and arranging links and counterweights to balance the center of gravity. It is possible to reduce the weight of the arm by using joint driving motors as counterweights. Moreover, this arm is equipped with a compensation force adjustment mechanism using wires to make the mechanism compact. Since application of this mechanism makes it is possible to adjust the compensation force according to the payload, joint driving motors can be made smaller. Based on the simulation result and the experimental result of the developed arm, it was confirmed that the arm is able to reduce the joint torque by 75% - 85% by the effect of this gravity compensation mechanism.

Keywords: Biomechatronics, Flexible Manipulators and Structures, Rehabilitation Robots
Abstract: This paper shows a prosthetic wrist joint that has 3 rotary axes controlled in antagonistic actuation similar to a human musculo-skeletal system. Some dexterous actions of human arm toward external entities are much attributed to adjustability of its joint stiffness. The joint stiffness of human articulations or of those of any other vertebrate animals is adjustable due to an antagonistic structure of their musculo-skeletal system and non-linear elasticity of individual muscle. In our previous studies we have developed a mechanical system that mimics the human musculo-skeletal system, in which muscle-like actuators: ANLES (actuator with non-elasticity system) was developed and deployed in antagonistic configuration to control rotation angles and rotary stiffness of a multi-DOF robotic joint. This paper shows a subsequent development of the 3 DOF wrist joint. Main points of refinement are as follows. First is a downsizing to serve it as a forearm prosthesis having an active wrist joint, second is an extension of stiffness adjustable range especially that of inner/outer rotation.

Keywords: Micro-Electro-Mechanical Systems, Flexible Manipulators and Structures, Modeling and Design of Mechatonic Systems
Abstract: As the rapid progress of science and technology, the freeform surface optical component has played an important role in spaceflight, aviation, national defense, and other areas of the technology. While the technology of fast tool servo (FTS) is the most promising methods for the machining of free-form surface optical component. However, the shortcomings of short-stroke of fast tool servo device has constrained the development of free-form surface optical component. To address the problem, a new large-stroke flexible FTS device is proposed in this paper. A series of mechanism modeling and optimal designs are carried out via compliance matrix theory, pseudo-rigid body theory, and Particle Swarm Optimization (PSO) algorithm, respectively. The mechanism performance of the large-stroke FTS device is verified by the Finite Element Analysis (FEA) method. For this study, a piezoelectric (PZT) actuator P-840.60 that can travel to 90 µm under open-loop control is employed, the results of experiment indicate that the maximum of output displacement can achieve 258.3μm, and the bandwidth can achieve around 316.84 Hz. Both theoretical analysis and the test results of prototype uniformly verify that the presented FTS device can meet the demand of the actual microstructure processing.

Keywords: Sensors and Sensing Systems
Abstract: For humans, the sense of touch is essential for interactions with the environment. With robots slowly starting to emerge as a human-centric technology, tactile information becomes increasingly important. Tactile sensors enable robots to gain information about contacts with the environment, which is required for safe interaction with humans or tactile exploration. Many sensor designs for the application on robots have been presented in literature so far. However, most of them are complex in their design and require high-tech tools for their manufacturing. In this paper, we present a novel design for a tactile sensor that can be built with low-cost, widely available materials, and low effort. The sensor is flexible, may be cut to arbitrary shapes and may have a customized spatial resolution. Both pressure distribution and absolute pressure on the sensor are detected. An experimental evaluation of our design shows low detection thresholds as well as high sensor accuracy. We seek to accelerate research on tactile feedback methods with this easy to replicate design. We consider our design a starting point for the integration of multiple sensor units to a large-scale tactile skin for robots.

Keywords: Flexible Manipulators and Structures, Modeling and Design of Mechatonic Systems, Mechatronics in Manufacturing Processes
Abstract: Selecting transmission components for tendon driven actuation systems can be challenging because of the variety of available solutions. Synthetic fiber ropes have great potential for these systems, but the typically provided characteristics are not always suitable to decide whether a rope should be used in the specific system or not. In this paper, a comparative evaluation of the elongation characteristic regarding different rope materials, manufacturers and temperatures is presented. Further, the influence of guiding pulleys is investigated concerning the application at ultra lightweight tendon driven series elastic robots. The knowledge gained from the performed new rope analysis supports the design process of tendon driven robots. Since tendon elongation influences the control performance and joint torque estimation of the regarded class of robots, a novel observer-based approach for tendon elongation detection is presented and evaluated, which enables to monitor wear for quality assurance and to avoid failures.

Keywords: Humanoid Robots, Actuators in Mechatronic Systems, Modeling and Design of Mechatonic Systems
Abstract: This paper presents the design and control of a biomimetic knee joint for biped robots. The robotic knee joint driven by pneumatic artificial muscles is designed by imitating the structure of the human knee. It has desirable characteristics similar with human knee joint including joint compliance, changeable instantaneous center of rotation, as well as large range of joint motion. In order to model and compensate the length/pressure hysteresis of pneumatic artificial muscles in the position control, a novel method termed as direct inverse hysteresis modeling approach is introduced. Other than deriving from the forward hysteresis model, the inversion of the length/pressure hysteresis is directly modeled by a modified Prandtl-Ishlinskii model which has two newly-designed play operators. Then a cascade position controller with forward hysteresis compensation is proposed for the knee joint. The mechanical structure and control scheme of the knee joint are validated by experiments.

Keywords: Biomechatronics
Abstract: 　In this study, we developed a 4-degrees of freedom (DOF) force feedback device independent of its operational component comprising pneumatic artificial muscles and magnetorheological clutches. Research and development of force feedback devices is becoming popular in fields such as entertainment, remote operation, and rehabilitation. These areas of research are related to virtual reality and augmented reality. People are focusing their research efforts on force feedback devices that display three-dimensional virtual objects or can provide realistic force sensing as that of stroking the surface of a virtual object. Many of these devices comprise motors; hence, they are likely to be hazardous in the event of delayed response to an unexpected external force. In addition, their back drivability decreases when the motor output is increased via reduction gears. To solve these problems, we previously developed a 3-DOF force feedback device using pneumatic artificial muscles, which are structurally flexible and have a wide range of stiffness, and magnetorheological clutches. As the next step toward developing a 6-DOF device, we have developed a 4-DOF feedback device.

Keywords: Rehabilitation Robots, Human -Machine Interfaces, Actuators in Mechatronic Systems
Abstract: Pneumatic muscles (PMs)-driven robots become more and more popular in medical and rehabilitation field as the actuators are intrinsically complaint and thus are safer for patients than traditional rigid robots. This paper proposes a new compliance adaptation method of a soft ankle rehabilitation robot that is driven by four pneumatic muscles enabling three rotational movement degrees of freedom (DoFs). The stiffness of a PM is dominated by the nominal pressure. It is possible to control the robot joint compliance independently of the robot movement in task space. The controller is designed in joint space to regulate the compliance property of the soft robot by tuning the stiffness of each active link. Experiments in actual environment were conducted to verify the control scheme and results show that the robot compliance can be adjusted when provided changing nominal pressures and the robot assistance output can be regulated, which provides a feasible solution to implement the patient-cooperative training strategy.

Keywords: Actuators in Mechatronic Systems, Actuators, Flexible Manipulators and Structures
Abstract: Inflatable manipulators open new trends in robotic applications. In this paper, a new inflatable actuator to articulate a long-range inflatable robotic arm, is presented. Completely made of high strength fabric, its low mass leads to large force-weight ratios and a stroke almost equal to twice its overall length. The operation principle, as well as the relations among the displacement, the pressure and force, are described in this paper. The analysis is under validation through a finite elements simulation and a test on a prototype.

Keywords: Control Application in Mechatronics, Modeling and Design of Mechatonic Systems, Actuators in Mechatronic Systems
Abstract: This paper discusses modeling and nonlinear control of a joint antagonistically actuated by two pneumatic, artificial muscles. The model of the joint, the muscles and the proportional valves is obtained by a combined physical and phenomenological approach resulting in a nonlinear, affine-in-control system description. The model is used to derive control laws for an input/output linearization approach to linearize the plant. Modeling and parametrization errors are covered via an outer control loop consisting either of a state-feedback which is extended to a state-feedback with additional feedback of error integral. Extensive experimental results show the quality of the model and the performance of the respective control laws.

Keywords: Control Application in Mechatronics, Mechatronics in Manufacturing Processes, Modeling and Design of Mechatonic Systems
Abstract: In this paper, to simultaneously meet the challenge of complex high-speed large-curvature contouring tasks and high-performance motion control accuracy, a generalized global task coordinate frame (GTCF) based learning adaptive robust control (LARC) strategy is synthesized for biaxial mechatronic motion systems. The generalized GTCF is globally defined based on a constructed equivalent shape function of the desired contour, and can guarantee the multi-axes coordination to deal with high-speed large-curvature contouring tasks even under complex contours. After transforming the system dynamics of an industrial biaxial mechatronic motion system into the generalized GTCF, a LARC contouring controller is constructed for the strongly coupled nonlinear dynamics in each coordinate to achieve excellent contouring motion performance. In LARC, adaptive model compensation term and robust term are utilized to deal with parametric variation and uncertain disturbances respectively. With reasonable weight allocation of contouring error and distance error, iterative learning term is designed to address the unmodelled repetitive contouring error. Comparative experiments are carried out to demonstrate that the generalized GTCF-LARC can successfully implement various complex contouring tasks. Furthermore, comparing with conventional CCC and ARC control algorithm, the proposed generalized GTCF-LARC possesses strong coordination mechanism and excellent transient/steady-state contouring control performance.

Keywords: Control Application in Mechatronics, Actuators, Space Robotics
Abstract: Comparing with the indirect drive gimbal servo system of single gimbal control moment gyroscope (SGCMG), direct drive gimbal servo system based on permanent magnet synchronous motor (PMSM) can achieve higher precision and faster response. However, the difficulty of PMSM controller design increases, because PMSM has to endure larger multi-source and multi-band disturbances due to the lack of a decelerator. In this paper, PMSM direct drive system is described, importantly, based on SVPWM control strategy, a novel composite control strategy is proposed: an adaptive nonsingular terminal sliding mode controller (ANTSMC) with a disturbance sliding mode observer (SMO) is designed to achieve high precision speed closed-loop control and compensate uncertain large low frequency disturbances; a repetitive controller (RC) is designed to compensate high frequency disturbances. Simulation results show that the proposed controller has strong robustness and disturbance tolerance, and can achieve high precision and fast response control performances.

Keywords: Space Robotics, Design Optimization in Mechatronics, Modeling and Design of Mechatonic Systems
Abstract: According to the characteristic of large space manipulator, an on-board real-time singularity detection design is proposed. On the basis of forward and inverse kinematics calculation, the forward and inverse power method is applied to obtain the singularity by iterative computation. Firstly, the 7-DOF manipulator kinematics model is described and analyzed, and the main computational process is presented; then, the pseudo inverse of Jacob matrix is obtained, and condition number is deduced by power method; at last, the real-time singularity detection module is designed based on FPGA, and multi-processing unit is used to accelerate the calculating speed, which costs milliseconds. The on-board real-time singularity detection, eliminates the delay of interaction between spacecraft and ground, and reduces the risk of damnification in movement process. Compared with the previous methods, the proposed can guarantee the autonomous operation of space manipulator.

Keywords: Control Application in Mechatronics, Robot Dynamics and Control, Novel Industry Applications of Mechatroinics
Abstract: Adaptive gain dynamics for time-delay control (TDC) of robot manipulators is proposed. TDC is a well-known controller for robot manipulators: it is model-free, efficient, and robust. The gain of conventional TDC is a constant matrix, which could pose two drawbacks. First, because the gain is tuned manually by a trial-and-error method, one cannot be convinced whether the gain is well-tuned. Second, when the system dynamics varies rapidly, and the posture of the robot manipulator has changed significantly, the performance of the conventional TDC degrades with a constant gain. To cope with these problems, we propose an adaptive gain dynamics for the TDC by using sliding variables and acceptance layer concept. The time-varying acceptance layer automatically adjusts the gain to minimize the sliding mode error. As a result, the TDC with the proposed adaptive gain dynamics becomes adaptive and robust. The effectiveness of the proposed gain dynamics has been verified experimentally using a whole arm manipulator.

Keywords: Mobile Robots, Vehicle Control, Robot Dynamics and Control
Abstract: Feedback control of mobile robots guaranteeing preservation of state constraints resulting from obstacles in the environment and input constraints imposed by robot mechanical construction is essential in practical applications of robotic systems. The safety of motion execution is often ensured by a strategy of driving the robot through a sequence of funnels representing safe, positively invariant subsets of robot configuration space for utilized feedback control laws. In this paper, the VFO (Vector Field Orientation) control law is leveraged to develop such a feedback control strategy for a unicycle robot with bounded curvature of motion. The proposed definition of funnels arises naturally from analysis of the VFO control law under curvature constraints. Obstacles in the environment are handled by shrinking the funnels using additional artificial curvature constraints. An exact analytic method for computation of funnels is presented. To make the funnels positively-invariant and guarantee motion safety, the original VFO control law has been modified. In contrast to numerous methods available in the literature, proposed feedback control strategy ensures at least C¹ continuity of the control signals during transitions between funnels. Effectiveness of our approach has been verified by simulations, during which the robot was driven through a sequence of funnels planned in the cluttered environment using the RRT* algorithm.

Keywords: Control Application in Mechatronics, Robot Dynamics and Control
Abstract: This paper addresses the problem of global asymptotic regulation for robot manipulators subject to actuator constraints and a single saturation function for every joint. A saturated proportional-derivative (PD) plus gravity compensation (PD+) control is designed. The proposed saturated PD+ (SPD+) controller is conceived within only a single saturation function for every joint. The benefit of such design is that it does not need to elaborately discriminate the terms that shall be bounded, and thus it is ready for implementation with an improved performance. Lyapunov theory is employed to show global asymptotic stability. Simulations are performed to verify the improved performance of the proposed approach.

Keywords: Sensor Integration, Data Fusion, Sensors and Sensing Systems
Abstract: In order to realize leakage detection and leakage localization by ultrasonic waves leak generated, ultrasonic gas leak location method based on sensor array is proposed, and it achieves accurate positioning of the leak point only by time difference of arrival between leak point and sensors. Use envelopes of ultrasonic signals received by sensors to obtain whole cycle numbers of time difference of arrival, combined with remaining time difference (i.e. the part of time difference of arrival less than one signal cycle) calculated by the traditional cross-correlation algorithm, then the time difference of arrival is obtained. According to the TDOA positioning algorithm, equation group to solve the leak location is written. Finally, use combination of least square method and Newton iteration method to estimate leak location. The experimental results show that this method can accurately estimate the leak location, verifying the correctness and feasibility of the method.

Keywords: Hybrid intelligent systems, Intelligent Sensors, Mechatronics in Manufacturing Processes
Abstract: A typical intelligent factory, a smart home or a smart city consists of several nodes or machines. In a typical Machine to Machine Communication mode (M2M), each machine senses some information (pressure, temperature, presence of person, etc.) and then communicates this information to other machines. This communication could be unicast or multicast depending on the application. Further, the destination node of the M2M communication is many-a-times not in the direct communication range. In the presence of tens and hundreds of machines forming a network, it is essential to have an efficient communication mechanism for multihop multicast transmission between different machines. This paper proposes a network coding (NC) based multihop multicast communication for different topologies - butterfly, flattened butterfly, hypercube and folded-clos model. It is observed that random linear network coding (RLNC) technique outperforms the best routing protocol for different topologies, by requiring less time for data transmission, reducing the time required by upto 50%, depending on the model. Further, in order to improve the performance of network coding for M2M in a disconnected network; an integrated network coding and routing approach is proposed and evaluated. It is observed that such an integrated mechanism requires upto 25% time less than pure routing and upto 10% time less than time required by RLNC.

Keywords: Sensors and Sensing Systems, Intelligent Sensors, Opto-Mechatronic Sensors
Abstract: Recent developments of a novel electromagnetic tactile sensors have prompted requirements to investigate the mutual inductance between a micro planar coil and a non-coaxial planar coil. To realize miniaturization design for robot applications, the ratio of pitch to radius for planar spiral coil is over 20%. In this paper, an extended formula is proposed for mutual inductance calculation of energy-transferring component which consists of two micro planar spiral coils sandwiched between two substrates for tactile sensor. The calculated results have higher accuracy than previous methods and it can quickly determine the mutual coupling of two planar coils that have different relative positions and distance between them. This new calculation method provides a convenient and useful tool for determining the mutual inductance of micro planar spiral coil with high ratio of pitch to radius. The theory has been favorably tested by finite-element analysis and compared with predecessors' research.

Keywords: Sensors and Sensing Systems, Applications of nano technology
Abstract: In this contribution, we present a physically motivated dynamic model for a plasmonic hydrogen sensor based on a multilayer sample design with palladium nanodisks, which exhibits near-perfect absorption at visible wavelengths. This plasmonic gas sensor enables detection of low hydrogen concentrations providing the advantages of optical measurement principles and may be produced cost-effectively as a miniaturizable system. However, the response is highly temperature-dependent and exhibits a nonlinear relationship between the external hydrogen pressure and the output. Furthermore, the response time depends on the hydrogen concentration and it can take up to several minutes until the steady state is reached and the sensor response can be evaluated. By deriving a dynamic model of the sensor behavior, it is possible to compensate these unfavorable properties of the sensing system. The model derived in this paper consists of a model for the pressure-composition isotherms, which describes the relationship between the external hydrogen pressure and the stationary atomic ratio H/Pd in the palladium crystal using thermodynamic relations, a diffusion model with a concentration-dependent diffusion coefficient and a linear model for the optical response. The parameters of the dynamic model are identified based on literature research and measured data. Finally the dynamic model is validated using experimental data at 30°C, 50°C and 90°C.

Keywords: Tele-operation, Network Robotics, Vehicle Technology
Abstract: The most important factor in the remote control environment of the unmanned system is the reliability of wireless communication. As a method for improving the reliability and performance of communication, there is a system improvement method such as using an advanced antenna and a repeater, and a method using an algorithm such as automatic traffic control. In this paper, system design and control algorithms are proposed by adding redundancy concepts to these methods. The reliability and performance of the proposed system which has the redundant structure providing seamless video are compared with those of the existing system.

Keywords: Sensors and Sensing Systems, Mobile Robots, Sensor Integration, Data Fusion
Abstract: Mobile sensors deployment over a target area is an important problem for autonomous operations in applications such as surveillance and environmental monitoring. The problem of optimal deployment of heterogeneous anisotropic field sensor network, having different sensing range, is addressed in this paper. A sensor coverage model for a planar field sensor is developed through introducing a performance measure which reveals the sensor’s coverage strength. In addition, a gradient based control law was introduced using a modified Voronoi partitioning. This control law regulates the sensors toward the direction that represents the gradient direction of the performance function, subject to the speed constraint of the sensor. A circular sector is selected as a simulation example of the planar field sensor coverage model to demonstrate the effectiveness of the developed idea for task optimization.

Keywords: Sensors and Sensing Systems, Design Optimization in Mechatronics
Abstract: This paper proposes a calibration method for a 3D laser scanning system built with a rotating 2D laser rangefinder (LRF) in unprepared environments. Although the combination of a 2D LRF with a rotating unit yields a low-cost and compact 3D scanner, construction misalignments must be calibrated to reduce measurement error. Existing calibration techniques are generally used either with a special target object or in prepared environments with flat surfaces, and this imposes a limitation on the applicable domain of the system. To solve this problem, we propose a novel calibration method using redundant measurements of 3D point clouds. The main idea of the proposed method is to focus on the fact that rotating LRF systems observe the same object twice during a single rotation at different times. Therefore, by minimizing the extent of misalignment of these redundant measurements, we can estimate the calibration parameters without using any special target object. We formulate this calibration by redundant measurements as a non-linear cost minimization problem. The results of the simulation and real-world experiments in challenging, real environments show that the proposed method works well in unprepared and even cluttered environments

Keywords: Machine Vision, Image Processing, Fault Detection and diagnosis in Manufacturing
Abstract: Electric rail vehicles are driven by the current collected from the electrical lines of the railway catenary system. For this purpose, trains are equipped with a current collector (the pantograph) that comes in contact with the wires by means of a pair of carbon strips. The sliding movement along the wires subjects the carbon strips to wear and damage so that frequent inspection is essential to ensure the train and catenary safety. In this paper we describe an automatic visual inspection system, made of a 3D laser scanner and a 2D high resolution camera, which is able to automatically determine the health state of the railway contact strips thanks to a sophisticated data processing tool. The system collects color and geometrics information on the carbon strips and performs several automated assessments both on the 3D and 2D data. For each test, the system provides an index and decides between three different levels of wear (low, medium, high) to support the human operator in inspection and maintenance decisions. Experimental results reveal the effectiveness of the system, comparing the human judgment with the automated analysis.

Keywords: Sensor Integration, Data Fusion, Image Processing, Machine Vision
Abstract: Reconstructing a 3D model of an unknown object via incremental registration of multiple appearance models is a challenging task. With availability of low cost sensors and robust algorithms, the field of visual scene reconstruction has advanced considerably. While these advances has enabled robust reconstructions of cluttered and unstructured scenes, an active 3D reconstruction of a generic handheld object through registration of multiple appearance models from a single RGB–D viewpoint remains a difficult problem. The difficulty is maintaining the physical boundaries of an unknown object subjected to non-linear and unknown hand motion and appearance changes. As a consequence of these abrupt changes the registration fails either due to motion drifting or boundary overflow. In this paper, we present a novel algorithm for active tracking and simultaneous registration of handheld objects subjected to abrupt changes in motion model. To reduce the effects of drifting in registration, a tracking algorithm with robust updating scheme is used to track the motion of the objects in real time. The updating algorithm is based on the idea of Gestalt principles formulated into Bayesian filter framework. The tracker predicted motion is used for object region segmentation and structured registration i.e., pre- registration using the motion of tracker for initial alignment, fast feature based alignment and ICP based dense alignment. In this pipeline, we are able to compensate the effects of motion drifting and reject outliers from non-object regions while maintaining the boundary of the object.

Keywords: Image Processing, Planning and Navigation, Mobile Robots
Abstract: This paper proposes a novel velocity estimation approach for single image points, while both the camera and the observed object may be in motion. In order to obtain absolute velocities, a flow-stereo setup is utilized, but no explicit depth reconstruction is carried out. Omitting the calculation in the Cartesian space increases the robustness of the estimation, which is shown in a comparison between the error propagation of the proposed method and a disparity-based approach. An important factor is the maximum distance in which the velocity could be estimated. Simulations and tests using real images demonstrate that the estimation range could be increased by the proposed method. Possible applications are motion-planning or obstacle avoidance for ground-based mobile robots in dynamic environments.

Keywords: Service Robots
Abstract: To keep up with the boom in e-commerce, fulfilment companies need to leverage robotics and automation to speed up delivery of orders to clients. In this paper, we present a mobile robot with suction grippers designed for item picking in an e-commerce fulfilment warehouse. The robot uses a novel visual marker that we have developed called VITag, to navigate towards the location of the items to be picked, identify them, and generate plans how to approach them. Through the marker, the robot finds the optimum path to the items and the most efficient way to pick them. To improve picking efficiency, the robot derives a picking list (order of how to pick the items) from the order list (items to pick) and its knowledge of the shelf content. The SMACH library for ROS is also used to enable the robot to do high level planning more quickly. Simulation and initial tests show the feasibility of the system.

Keywords: Human -Machine Interfaces, Flexible Manipulators and Structures, Modeling and Design of Mechatonic Systems
Abstract: This paper presents a novel tongue-operated joystick device for severely disabled persons. The human tongue can generate varied movements and has superior tactile sensations. The utilization of tactile sensation enables humans to interactively communicate with life support equipment, such as powered wheel chair and robotic manipulators and to control them skillfully and safely. In this study, the ability and characteristics of the human tongue as both a motile and tactile organ were analyzed. Based on these analyses, a new joystick device with a simple mechanism that utilizes feedback reaction force was designed. In this device, an elastic plate was used as a contact tip of the joystick to provide a reaction force to the user through tactile sensation. The reaction force was controlled by adjusting the effective length of the plate with a slider-crank mechanism. In this paper, functionalities of the tongue, as well as the proposed joystick device, are described in detail.

Keywords: Human -Machine Interfaces, Compuational Models and Methods, Software Design for System Integration
Abstract: Energy efficiency of buildings and districts is a core element in facing the climate change and scarcity of energy resources. A major domain for improving energy efficiency is building automation and control. Especially the application of advanced control methodologies requires special attention during the engineering process in order to guarantee for a meaningful, reasonable and comprehensible system behavior. In this paper, we present the concept of operating modes for increasing both, the operability and the applicability of advanced control methods in building energy systems. Referring to process automation methods, we introduce Petri-Nets as a powerful description method for mode-based building control development.

Keywords: Human -Machine Interfaces, Control Application in Mechatronics, Mechatronics in Manufacturing Processes
Abstract: In human-robot comanipulation, virtual guides are an important tool used to assist the human worker by reducing physical effort and cognitive overload during tasks accomplishment. However, virtual guide's construction often requires expert knowledge and modeling of the task which restricts the usefulness of virtual guides to scenarios with unchanging constraints. To overcome these challenges and enhance the flexibility of virtual guide's programming, we present a novel approach that allows the worker to create virtual guides by demonstration through an iterative method based on kinesthetic teaching and Akima splines. Thanks to this approach, the worker is able to locally modify the guides while being assisted by them, increasing the intuitiveness and naturalness of the process. Finally, we evaluate our approach in a simulated sanding task with a collaborative robot.

Keywords: Human -Machine Interfaces, Mechatronics in Manufacturing Processes, Tele-operation
Abstract: Control trading between fully automated robot control and teleoperated robot control can take advantage of both machine precision and speed and human adaptability and reasoning to improve overall performance. In mixed initiative interactions, both the human and machine can take control and execute the next action. However, when both the human and the machine are allowed to propose control trades, there is potential for conflict if there is no consensus on whether the trade should occur. The main contribution of this article is to integrate an explicit consensus development process that only completes a control trade with the consent of the agent that did not propose the trade and includes an explicit contingency procedure if consent is not given. This contingency-based mixed-initiative control trading is demonstrated with a robotic peg-in-hole insertion task that captures end-effector positioning challenges associated with confined-space manufacturing tasks such as drilling. Experimental results show that limit cycling (the rapid switching of control initiative), when the agents disagree on a control trade, can be removed by using a comprehensive set of task-specific contingency procedures. For the demonstration task, the proposed consensus-based approach facilitates the traded controller to i) substantially reduce baseline operation time by 50% when compared to the pure teleoperation case; and ii) increase success rate in the presence of sensing errors from 3% with fully automated operation to 97%.

Keywords: Human -Machine Interfaces, Rehabilitation Robots, Sensor Integration, Data Fusion
Abstract: In this study, we proposed a method which could be used for mapping people’s emotion state on the two- dimensional arousal-valence model of effect. The final target of our research is to apply this kind of emotional recognition system to robots or some assistant apparatus which service activities of daily living (ADL). Since in our previous studies, we have finished the work of recognizing people’s emotion state on the dimension of arousal by evaluating subjects’ heartbeat and LF/HF, which is calculated from the frequency domain analysis of HRV, as the second step’s work, we focused on how to recognize people’s emotion state on valence dimension. To be specific, we used some kinds of normative affective stimuluses to elicit subjects’ emotional change, then collected multiple physiological data during this emotional stimulation process. Finally, as for data analyzing, we didn’t use the supervised learning method, like SVM, but made a new attempt to apply the unsupervised clustering method to sample data, dividing the data set into several natural clusters by analyzing the physiological features we abstracted. The calculated results of our experiment have verified the feasibility of mapping human’s emotion state on the two-dimensional arousal-valence model of effect at a quadrant level.

Keywords: Tele-operation, Human -Machine Interfaces, Robot Dynamics and Control
Abstract: Tele-operation systems have been developed to perform tasks in extreme environments that cannot be accessed easily by humans. However, non-intuitive control interfaces, low immersive feeling, and wireless communication issues have prevented the wide application of such tele-operation systems. In this study, an intuitive and interactive control interface using inertial measurement units (IMUs), a wearable sensing glove, and a head-mounted display (HMD) is proposed to control a tele-operated robot in a remote place. Using user information measured from the wearable interface, the desired joint angles of the robot are derived by a kinematic analysis of the robot. Also, the measured visual information and the torque of the robot hand are transmitted to the user as visual feedback on the HMD and vibrational feedback to the user’s fingertips, respectively. A semi-autonomous control strategy, referred to as shared control, was developed to overcome dimensional differences between the user and the robot, and to reduce the user’s workload. As telecommunication methods, a long-term evolution (LTE) and a virtual private network (VPN) are used. The performance of the proposed system was verified by experiments.

Keywords: Legged Robots, Mobile Robots, Flexible Manipulators and Structures
Abstract: This paper presents the design, development, and basic operation of MinIAQ, an origami-inspired, foldable, untethered, miniature quadruped robot. Instead of employing multilayer composite structures similar to most microrobotic fabrication techniques, MinIAQ is fabricated from a single sheet of thin A4-sized PET film. Its legs are designed based on a simple four-bar locomotion mechanism that is embedded within its planar design. Each leg is actuated and controlled individually by separate DC motors enabling gait modification and higher degree of freedom on controlling the motion. The origami-inspired fabrication technique is a fast and inexpensive method to make complex 3D robotic structures through successive-folding of laser-machined sheets. However, there is still a need for improvement in modulating and extending the design standards of origami robots. In an effort to addressing this need, the primitive foldable design patterns of MinIAQ for higher structural integrity and rigidity are presented in detail. The current robot takes less than two hours to be cut and assembled and weighs about 23 grams where 3.5 grams is the weight of its body, 7.5 grams is its motors and encoders, 5 grams is its battery, and about 7 grams is its current on-board electronics and sensors. The robot is capable of running about 30 minutes on a single fully charged 150mAh single cell LiPo battery. Using the feedback signals from the custom encoders, MinIAQ can perform a trot gait with a speed of approximately 0.65 Bodylengths/sec, or equivalently 7.5 cm/s.

Keywords: Control Application in Mechatronics, Identification and Estimation in Mechatronics
Abstract: Galvanometer laser scanners are high-performance rotary motors for optical applications and are often utilized in production engineering. The dynamic properties of current scanner systems do not always fulfill the desired requirements. The controler-based solutions that have been presented in the past years primarily concentrate on changes in operation points or simple trajectories and neglect to address general trajectory tracking. This becomes a crucial issue in many production processes. In this article, a modification of adaptive inverse control applied to scanner systems to improve the dynamics and simultaneously address parameter and environmental changes is presented. An online identification of the system via an LMS-algorithm delivers an adaptive model of the PID-stabilized galvanometer drives. An inversion based feed-forward controller is designed, to improve dynamics and suppress eigenmovements, e.g. overshooting. The performance is verified by an experimental setup in which the error is reduced by almost 90% for the chosen example, compared to a state of the art scanner system.

Keywords: Sensors and Sensing Systems, Flexible Manipulators and Structures, Novel Industry Applications of Mechatroinics
Abstract: This paper presents the design, fabrication and calibration of a stretchable strain sensor array based on carbon nanocomposite. The sensor array is used to be integrated into a soft bodied gripper for deformation control. The gripper can move the fragile object in planer motion and rotation by pressuring its inflation chambers. The sensor has a sandwiched structure: both the protection layer and substrate are made of Ecoflex, and the strain sensitive layer is made of carbon nanotubes filled Ecoflex composite. There are four sensor pads in the array for strain sensing of four inflation chambers. Each of the sensor pads is used to sense the deformation of one chamber through sensor’s resistance changes. An OptiTrack system with Flex3 small volume motion capture cameras is used to record the inflation chambers’ surface deformation. The measurements of the soft strain sensor array agree with those of the motion capture system, indicating the developed sensor can deliver repeatable and reliable results. Further experiments will be carried out after the developed sensor array integrated into the soft bodied gripper for objects manipulation.

Keywords: Part Feeding and Object Handling , Modeling and Design of Mechatonic Systems, Mechatronics in Manufacturing Processes
Abstract: Ultra-thin wafer (thickness <100 um) gripper is a challenging component to design since the wafer is one of the thinnest and fragile materials. In this paper, a soft acting non-contact gripper based on the distributed Bernoulli principle for ultra-thin wafer is developed and evaluated. The theoretical analysis and experimental studies of the designed gripper are carried out. The effects of the two key operation parameters: air flow rate and gap height (between the gripper and the wafer) on the gripper performance are investigated. From the experimental results, the appropriate parameters can be recommended. Finally, a performance comparison among the designed gripper and two existing grippers is studied, which shows that the designed gripper can provide a more gentle lifting force.

Keywords: Modeling and Design of Mechatonic Systems, Design Optimization in Mechatronics, Sensors and Sensing Systems
Abstract: Low stiffness elements have a number of applications in Soft Robotics, from Series Elastic Actuators (SEA) to torque sensors for compliant systems.

In its general formulation, the design problem of elastic components is complex and depends on several variables: material properties, load range, shape factor and size constraints.

Consequently, most of the spring designs presented in literature are based on heuristics or are optimized for specific working conditions.

This work presents the design study and characterization of a scalable spoked elastic element with hinge tip constraints.

We compared the proposed design with three existing spring principles, showing that the spoked solution is the convenient option for low-stiffness and low shape factor elastic elements.

Therefore, a design analysis on the main scaling parameters of the spoked spring, namely number of spokes and type of constraints, is presented. Finally, an experimental characterization has been conducted on physical prototypes. The agreement among simulations and experimental results demonstrates the effectiveness of the proposed concept.

Keywords: Modeling and Design of Mechatonic Systems, Mechatronics in Manufacturing Processes, Control Application in Mechatronics
Abstract: Abstract—The high-accuracy trajectory tracking pneumatic position servo system proposed in this paper mainly consists of a cylinder which is controlled by a proportional directional control value. Due to there exist large extent of parametric uncertainties and severe uncertain nonlinearities in the pneumatic system, an adaptive robust control strategy was constructed, which employs on-line recursive least squares estimation to reduce the extent of parametric uncertainties, and utilizes the sliding mode control method to attenuate the effects of parameter estimation errors, unmodeled dynamics and disturbances. Since the system model uncertainties are unmatched, the recursive backstepping design technology was applied. After the control strategy validated on dSPACE control system, was transplanted into DSP controller. Experimental results were presented to illustrate the excellent achievable performance of the controller.

Keywords: Compuational Models and Methods
Abstract: The paper is devoted to the stiffness modeling of heavy industrial robots with pneumatic gravity compensators. The main attention is paid to the identification of elastostatic parameters and calibration accuracy. To identify the desired set of parameters two-step identification procedure is developed. To reduce impact of the measurement errors, the set of manipulator configurations for calibration experiments is optimized with respect to the proposed performance measure related to the end-effector position accuracy. Advantages of the developed technique are illustrated by dedicated experimental study.

Keywords: Biomechatronics, Mobile Robots
Abstract: In this study, we developed a wall-climbing robot for airplane body inspection. To move on airplane body, the robot needs to move on walls and curved surfaces. A traveling-wave-type, omnidirectional wall-climbing robot that uses magnetic force to adhere could move on such a wall and curved surface. However, magnetic force cannot be used to adhere to airplane body. Therefore, we developed a wall-climbing robot that uses negative pressure suction to adhere and move on airplane body. We performed basic experiments on the robot and designed the robot based on the experimental results.

Keywords: Control Application in Mechatronics, Modeling and Design of Mechatonic Systems, Identification and Estimation in Mechatronics
Abstract: In this paper, a cascaded nonlinear control design for the position of a hydraulic servo cylinder is presented that is based on a control-oriented mathematical model of the test rig. The difference pressure is controlled in the inner loop, whereas the position control is addressed in the outer control loop. Additionally, the outer positioin control loop is extended by a combination of feedforward friction compensation and an observer-based disturbance compensation to improve the position tracking behaviour. Thereby, the benefits of both measures can be exploited: fast reaction and robustness w.r.t. remaining parameter uncertainties and inaccuracies in the friction model. As the system states are measurable, a reduced-order disturbance observer is designed. The efficiency of the overall control structure and the impact of the individual control actions are pointed out by experimental results obtained at a test rig at the Chair of Mechatronics, University of Rostock.

Keywords: Medical Robotics/Mechatronics, Actuators in Mechatronic Systems, Modeling and Design of Mechatonic Systems
Abstract: In this paper, backstepping control techniques are presented for a mechanism dedicated to accurately reproduce the breathing-induced motion of a human lung tumour. A lung tumour mimic model should perform the same smooth motion as a real one in a human body during inhalation and exhalation. Therefore, a three-dimensional mechanism with three pneumatically driven axes has been developed and built up. For each axis, the proposed design involves a cascaded tracking control structure: fast inner control loops are responsible for the chamber pressures of the corresponding pneumatic cylinder, whereas the outer control loop is related to the cylinder position. Moreover, a lumped disturbance force is addressed properly either within an adaptive backstepping scheme or by the combination of backstepping control with a sliding mode observer. These alternative control approaches have been implemented, compared to each other and successfully validated on an innovative test rig.

Keywords: Biomechatronics, Actuators
Abstract: If pipes with narrow diameters are not well inspected, preventing accidents become difficult. Therefore, we developed a pneumatically powered earthworm-type robot for Half-inch pipes (each having an inner diameter of approximately 16 mm); these pipes are extremely difficult to inspect. When the robot travels for a long distance, its speed significantly decreases. When the movement distance of one cycle is small and the interoperation period is short, the influence of the response delay of the pneumatic actuator increases and the speed decreases. Therefore, we developed a robot whose response delay is less likely to influence the driving speed and that has a large amount of movement per cycle. To create the proposed robot, we developed an extension unit and a grip unit as pneumatic actuators and experimented on pneumatic response characteristics. Also, the driving speed was measured using running tests. This confirmed that the robot’s speed increased, and the speed decay owing to the long air tube decreased. The proposed robot will help reduce accidents arising from the corrosion of pipelines.

Keywords: Mobile Robots, Legged Robots, Modeling and Design of Mechatonic Systems
Abstract: This paper presents a novel wheel-track-Leg hybrid Locomotion Mechanism that has a compact structure. Compared to most robot wheels that have a rigid round rim, the transformable wheel with a flexible rim can switch to track mode for higher efficiency locomotion on swampy terrain or leg mode for better over-obstacle capability on rugged road. In detail, the wheel rim of this robot is cut into four end-to-end circles to make it capable of transforming between a round circle with a flat ring (just like "O" and "∞") to change the contact type between transformable wheels with the ground. The transformation principle and constraint conditions between different locomotion modes are explained. The driving methods and locomotion strategies on various terrains of the robot are analyzed. Meanwhile, an initial experiment is conducted to verify the design.

Keywords: Compuational Models and Methods, Modeling and Design of Mechatonic Systems
Abstract: On the basis of introducing the working principle of the electric-controlled pressure amplifier for ultra high pressure common rail system, the three dimension flow field characteristics model of it was built by FIRE software, and the accuracy of this model was verified by the pressure curve in pressurization chamber which obtained via the ultra high pressure common rail system injection characteristic experiment, then the numerical simulation analysis on the three dimensional flow field characteristics of electric-controlled pressure amplifier was conducted based on the model, and the flow field pressure and velocity change and distribution during the pressurization process were obtained. The results show that when the flow field of pressurization oil circuit is at the end of compression stroke, the highest pressure mainly distributed around the outlet of electric-controlled pressure amplifier, and the maximum velocity mainly distributed around the oil inlet passage of one-way valve chamber and pumping chamber. When the flow field of control oil circuit is at the end of compression stroke, the pressure in control volume reduced greatly, and the pressure of control volume outlet orifice was less than critical pressure during pressurization process, which may lead to the occurrence of gasification phenomenon. This research provides a basis for analysis the design rationality and specify the structural optimization direction of electric-controlled pressure amplifier, at the same time, combined with the choice of fuel injection pump and injector, it is helpful to speed up the design of ultra high pressure common rail system and optimize the combustion system matching of diesel engine.

Keywords: Automotive Systems, Transportation Systems, Vehicle Control
Abstract: The Hybrid Electric Vehicles (HVEs) are reaching a wide diffusion both because the energy density and life of batteries increased in the last years with a decrease of their costs and because the reduction of air pollution is a very important issue, especially in big cities. This latter is one, or probably the main, reason that pushes the development of HEVs and electric vehicles (EVs). A secondary advantage of HEVs could be to protect the clutch components from overheating problems. For this reason, the electric motor (EM) contribution to reduce overheating of clutch material during the slipping phase has been investigated in this paper. As well known, thermal issue is one of the most important aspects which affect automotive dry clutch systems. In fact, if the clutch material reaches a temperature of 250-300 Celsius degree it could suffer permanent damage as well as to produce a burnt smell perceived by car passengers. Thus, in this paper vehicle launch simulations have been carried out to highlight how the intervention of the electric motor can effectively reduce thermal field during the slipping phase by avoiding to reach critical values.

Keywords: Planning and Navigation, Vehicle Control, Mobile Robots
Abstract: This paper presents a multi stage technique for dealing with path planning problem on poorly traversable and partially unknown rough terrains. Traditionally, this problem is solved using D*– like algorithms, but by including a vehicle model, along with its constraints and the dynamics of the environment, this problem becomes very challenging. Another problem that requires a close attention is that the data measurements of the environment are usually discrete in nature, while current frameworks deal with mostly continuous data and systems. We propose solution based on fast D* lite algorithm for global path cost-to-go computation while employing MPC planning paradigm for solving constrained optimal control problem for the purpose of local planning. With this paradigm in use, both global, stationary, state of the environment, and local dynamics of the environment are taken into account in the near–optimal path planning.

Keywords: Mobile Robots, Robot Dynamics and Control, Control Application in Mechatronics
Abstract: Skid-steered mobile robot has been widely used in different fields. In most of existing controllers for skid-steered mobile robots, the wheel velocities are controlled independently to track the desired velocities from the remote manipulation or high level computer. However, this kind of control method may lead to chattering phenomenon of skid steer mobile robots in practice. In this paper, the cause of chattering phenomenon is analyzed. And to solve this problem, a two level adaptive robust control law integrated with torque allocation technique is proposed. In the high level, an adaptive robust control law is developed such that the minimum velocity on the same side track the desired velocity. In the low level, a torque allocation technique is developed for regulating driving torque of each motor. Moreover, a novel control law with consideration of the error of each wheel on the same side is proposed to avoid the spin of wheels when the wheel is lifted from ground. Comparative experiments are carried out to verify the excellent performance of the proposed scheme. The results show that the proposed controller will achieve a good performance and adapt well with the ground condition.

Keywords: Planning and Navigation, Mobile Robots, Vehicle Control
Abstract: A covering path generation algorithm is developed to generate a lengthwise pattern based on a polygon describing the outer boundary and obstacles (polygon holes) of a geographical area. The algorithm is applied to an autonomous lawn-care robot for application to large grass turfs, for example golfcourses, which require structured and precise cutting patterns. The geographical polygon is recorded by manually driving the vehicle around the contour, resulting in a polygon given as geographical (latitude, longitude) coordinates of the vertices, which together with machine parameters are used to generate a suitable toolpath. The algorithm has been tested on a recorded polygon from a local park turf which is non-convex and has holes, illustrating the algorithm functionality and limitations wrt. optimality. In particular, the algorithm is able to generate a tool-path for any polygon orientation.

Keywords: Identification and Estimation in Mechatronics, Actuators, Control Application in Mechatronics
Abstract: This paper presents a novel angular velocity estimation strategy of a Reaction Sphere (RS) for satellite attitude control based on a Linear Parameter-Varying (LPV) Kalman Filter. The reaction sphere is a permanent magnet synchronous spherical actuator whose rotor is magnetically levitated and can be accelerated about any desired axis. The spherical actuator is composed of an 8-pole permanent magnet spherical rotor and of a 20-coil stator. The proposed technique relies on the implementation of a Kalman Filter observer over a LPV state-space model based on the rotor dynamics and the spherical harmonic decomposition of the magnetic flux density generated by the rotor. First, a theoretical development of the aforementioned estimator will be exposed, followed by a description of simulation and experimental set-ups for the tests. Finally, the proposed estimator is compared with the previous method used for angular velocity estimation based on the estimation of the back-EMF voltages induced in the coils, obtaining a significant reduction in amplitude and frequency of oscillations in the angular velocity control loop.

Keywords: Identification and Estimation in Mechatronics, Modeling and Design of Mechatonic Systems, Compuational Models and Methods
Abstract: Robotic manipulators are sold with reference to repeatability, but the manufacturers rarely quote figures for accuracy. The repeatability figures for many small/medium sized industrial 5 degree or 6 degree of freedom (5/6DoF) arms are on the scale of 20um, which is certainly impressive. But, this is not a measure of accuracy it is a measure of whether the arm will return to the same requested position again. As the paper will reveal, we encountered accuracy nearly two orders of magnitude worse than the repeatability metric. Our work on integrating 2D and 3D imaging systems with robotic manipulators for high precision interaction with 3D objects identified the requirement to determine the level of intrinsic/out of the box errors. This is in order to prevent potential collisions when automatically interacting at close proximity with any object in an unknown orientation where typical teach pendent or other prior correction is not applicable. In addition, understanding how to derive accurate calibration data allowed us to develop an approach for precise kinematic re-calibration of the manipulator.

Keywords: Identification and Estimation in Mechatronics, Modeling and Design of Mechatonic Systems, Micro/Nano Manipulation
Abstract: Micro/nano-manipulation systems have been developed and utilized for decades due to their irreplaceable roles in fields such as MEMS/NEMS fabrication and biological studies. Generally, the motion precision of a micro/nano-manipulator highly depends on its actuator, whose performance can be enhanced by proper control strategies. To design satisfactory controllers, an accurate plant model is ideal. For micro/nano-manipulators, the implemented actuators are mostly Smart Materials (SMs), which exhibit strong hysteretic and dynamic coupling characteristics. The construction of linear dynamics preceded by hysteresis is a prevalent representation for describing SM actuators' behaviors. To effectively and accurately model SM actuators, this paper employs the Extended Unparallel Prandtl-Ishlinskii (EUPI) model to describe complicated hysteretic behaviors. For modeling dynamics of SM actuators, firstly, the EUPI inverse is implemented to compensate the hysteretic effect of the plant; subsequently, the Weighted Complex Least-Squares (WCLS) identification method is proposed to estimate parameters of the dynamic part in the form of complex number function. To guarantee stability of the identified model, the Particle Swarm Optimization based WCLS (PSO-WCLS) optimization approach is proposed. The advantage of the proposed modeling scheme is that, it is capable of accurately describing complicated hysteresis of SM actuators and does not require the drive signal to be small while modeling its dynamics; besides this scheme contains frequency domain identification merits, such as easy noise reduction and easy combination of data from different experiments. The modeling and identification scheme is verified through comparison tests conducted on a piezoelectric actuator platform.

Keywords: Control Application in Mechatronics, Identification and Estimation in Mechatronics
Abstract: Servo drives comprise a high dynamic and smooth motion control which is typically based on a cascaded control structure with position measurement or estimation. By including an additional acceleration feedback, the command and disturbance behavior can be improved significantly. Based on the proven cascaded control structure, this contribution analyzes an extended control concept with additional acceleration feedback for elastic mechanical systems with high stiffness. In order to reduce the measurement effort, a Kalman filter is used to estimate the acceleration. Based on an experimentally identified two-mass model of the system, the proposed concept is compared with the proven cascaded control by simulations and experimental results. For the experimental validation, a stiff mechanical system coupling two electrical synchronous motors, for the intended driving and emulated loading is utilized.

Keywords: Flexible Manipulators and Structures, Identification and Estimation in Mechatronics, Fault Detection and diagnosis in Manufacturing
Abstract: In this paper an Extended Kalman Filter (EKF) is used as an observer for temperature monitoring, like a virtual sensor, of a metal-polymer fibre based heater structure. Metal-coated polymers are relevant for the realisation of smart systems (capable of both sensing and actuating). A real-time implementation of the temperature estimator is important to guarantee a gentle, fault-free operation of the heater and to reject disturbances. It can be used to control the resulting temperature without a direct measurement or to guarantee the users' safety by reacting to overheating. An estimation strategy is necessary because for normal operation in the real world, measurements of the temperature are usually not available, but it is important to know it in order to implement health monitoring algorithms or to do a safe shutdown if necessary. Simulations justify the observation strategy while measurements validate the utilized model.

Keywords: Compuational Models and Methods, Flexible Manipulators and Structures, Identification and Estimation in Mechatronics
Abstract: In this paper, a new kinematic parameter calibration method is proposed for robot manipulators having elastic joints. Kinematic screw and compliance parameters are identified through the proposed calibration procedure, so that an enhanced kinematic accuracy is achieved. Traditional circular point analysis is modified to cope with new product-of-exponential (POE) kinematic model that accounts for joint deflection. Simulation result is provided to validate the proposed kinematic calibration method.

Keywords: Machine Vision, Intelligent Process Automation, Service Robots
Abstract: In order to enable robot systems to solve challenging tasks autonomously, it is sufficient to provide visual perception systems, which can solve different recognition tasks. The work presented here is designed for maintenance applications which are very similar to (dis-)assembly tasks. Therefore, we describe a novel perception strategy using RGBD data to get the required information for manipulation planning, like object class, position and geometric appearance. To handle this problem, well-known segmentation and recognition algorithms are used and task-specifically allocated. The system works with different levels of detail. On the one hand, it is possible to fit geometric primitives related to the different components. On the other hand, classifiers are used to assign the corresponding object semantic. Combining this information in a scene analysis allows the creation of a relational graph, which is further used for manipulation planning. All methods are explained and experimental validated.

Keywords: Machine Vision, Machine Learning, Neural Networks
Abstract: Object recognition from depth sensors has recently emerged as a renowned and challenging research topic. The current systems often require large amounts of time to train the models and to classify new data. In this work, we present a novel fast approach for object recognition from 3D data acquired from depth sensors such as Structure or Kinect sensors. We first extract simple but effective frame-level features from the raw depth data and build a recognition system based on extreme learning machine with a local receptive field. We test the presented method on two datasets: A self-collected dataset and the benchmark RGB-D object dataset. Experiments on both datasets show the effectiveness of our presented approach compared with the state-of-the-art methods. Fast computational time and high recognition accuracy make the presented method readily applicable for online recognition applications.

Keywords: Sensors and Sensing Systems, Machine Vision, Image Processing
Abstract: This study proposes a concept for multithread active vision sensing that can measure dynamically changing displacement and vibration at multiple points on civil engineering structures. In multithread active vision sensing, a high-speed camera can function virtually as multiple tracking cameras by accelerating its measurement, computation, and actuation with ultrafast viewpoint switching at millisecond level. We developed a galvano-mirror-based high-speed multithread active vision system that can switch 500 different views in a second; it functioned as 15 virtual cameras each operating at 33.3~fps to observe multiple scenes in completely different views. The experimental results for a 4-m-long truss-structure bridge model to which 15 markers were attached show that a single active vision system can observe the deformation of the bridge structure and estimate modal parameters, such as resonant frequencies and mode shapes, at a frequency on the order of dozens of Hertz.

Keywords: Sensors and Sensing Systems, Image Processing, Vehicle Technology
Abstract: In this paper, we introduce a new sensor system to measure the vehicle body velocity using a CMOS camera and it’s motion blur. When the camera faced on the ground and mounted on the vehicle body is shaken by a specific path to artificially form a motion blur, a Modulated Motion Blur is recorded on the image sensor. This Modulated Motion Blur implies the relative motion between the camera and the ground. The relative velocity of the vehicle and the ground can be estimated by measuring the slopes of the motion blur. In this paper, the invariance of the proposed system against the rolling shutter effect is demonstrated. Then, the performance of the proposed method through various experiments is presented. The proposed method has a small amount of calculation and high accuracy. Therefore, in addition to the dynamic control of the ground vehicle, it can be applied to various fields such as precise position estimation and autonomous driving of a field robot.

Keywords: Machine Vision, Image Processing, Control Application in Mechatronics
Abstract: This paper addresses the analysis of an experimental setup designed with the aim of calibrating important parameters involved in visual servoing. More precisely, the effects of parameters related to image processing, camera calibration and noise reduction are investigated. Great attention is given to the algorithms used for improving the pose accuracy of a moving target while reducing their computational burden for an online implementation. A simple test case of visual servoing on an electric linear axis is shown in order to prove the effectiveness of the study. However, the obtained results are also valid for general motion of typical robotic systems. Actually, the present work is preliminary to the visual servoing of minor and full mobility parallel kinematic machines.

Keywords: Rapid Prototyping, Sensors and Sensing Systems, Service Robots
Abstract: This paper proposes a novel soft robotic design that possesses variable stiffness and position feedback. A gripper adopting this design is presented. Each finger in the gripper is based on a 3D printed substrate (driven by an air actuated soft actuator) composed of two smart materials: shape memory polymer (SMP) and conductive thermoplastic polyurethane (TPU). SMP’s dramatic change of elastic modulus around its glass transition temperature (Tg) enables the finger to have variable stiffness. The conductive TPU acts as a heater to provide Joule heating for the SMP when a weakening of stiffness is needed. Furthermore, the deflection of the substrate can be estimated due to the conductive TPU’s inherent piezo-resistive effect. Experiments regarding the finger’s position estimation capability and variable stiffness property are conducted. A gripper is fabricated to perform grasping demonstration. The proposed robotic design has other potential applications such as metamorphic legged robots.

Keywords: Micro-Electro-Mechanical Systems, Machine Vision, Flexible Manipulators and Structures
Abstract: Working at micro-scale efficiently requires accurate and integrated force feedback implemented with a sensor adapted to the scale. This paper presents a 3D-printed vision-based micro-force sensor intended to be used inside the chamber of a Scanning Electron Microscope (SEM). The combination of 3D printed elastic structures with a highly effective vision based measurement method allows to design integrated sensors at the cutting edge of the state of the art. Moreover the presented design respects the Abbe's alignment principle. The paper presents the general design, manufacturing and experimental characterization in SEM environment of the proposed sensor. Images of periodical patterns are used to measure the differential displacement between the two parts of the compliant structure. By the knowledge of its stiffness, the force applied on it is measured. The stiffness of the elastic structure has been measured to be 15.3 N/m, leading to a force range of 25 uN.

Keywords: Modeling and Design of Mechatonic Systems, Rapid Prototyping, Mechatronics in Manufacturing Processes
Abstract: The term 'Conformal Printing' refers to 3D printing onto uneven surfaces. Whilst some very high priced solutions exist for known uneven surfaces, where the toolpath is generated in advance, based on CAD data of the object to be printed onto, there is nothing available yet for conformal printing onto unknown uneven surfaces that are scanned on-the-fly. A low-cost prototype named ‘InSPIREd’ was recently developed to achieve this, made possible with a combination of multi- disciplinary expertise, ingenuity and problem tackling know-how, and the latest improvements are presented in this paper. The prototype now includes more capable scanning technology and a simplified calibration procedure.

Keywords: Mechatronics in Manufacturing Processes, Rapid Prototyping, Control Application in Mechatronics
Abstract: This paper develops a closed-loop approach for ink-jet 3D printing. The control design is based on a distributed model predictive control scheme, which can handle constraints (such as droplet volume) as well as the large-scale nature of the problem. The high resolution of ink-jet 3D printing make centralized methods extremely time-consuming, thus a distributed implementation of the controller is developed. First a graph-based height evolution model that can capture the liquid flow dynamics is proposed. Then, a scalable closed-loop control algorithm is designed based on the model using Distributed MPC, that reduces computation time significantly. The performance and efficiency of the algorithm are shown to outperform open-loop printing and closed-loop printing with existing Centralized MPC methods through simulation results.

Keywords: Rapid Prototyping, Actuators in Mechatronic Systems, Flexible Manipulators and Structures
Abstract: Soft materials have been incorporated in the design of robotic systems particularly as a damper, cover or contact pads. With the emergence of soft robotics, which focuses on robotic devices partially or entirely made of soft materials, robotic systems with high deformability, conformability and biomimicry can be realized. By pushing the limits of low cost 3D printing, this study focuses on designing and fabricating low cost, thin-wall, airtight, soft and monolithic fingers and a fully compliant gripper as a one-piece robotic device. Fused filament fabrication method was used to 3D print the soft monolithic fingers and gripper. Their bending and blocking force capabilities were experimentally evaluated. The proposed method can be used not only to 3D print fully compliant inflatable soft robots using a low cost additive fabrication method but also all-in-one piece soft robots ready to operate out of one-step fabrication such as soft grippers and mobile assistive devices with major advantages of low cost, underactuated, and more importantly compliant and highly conformable.

Keywords: Control Application in Mechatronics, Motion Vibration and Noise Control, Robot Dynamics and Control
Abstract: Low-cost, indirect-drive actuators, like timing belts are widely used in many industrial applications requiring linear translational motion. However, the timing belt faces greater control challenges as newer technological processes necessitate an increased tracking accuracy, precision and a need for minimal vibration all in the presence of rapid payload changes. Firstly, it is widely known that belt dynamics contribute higher order modes to the system. This causes a non-collocated control problem where the encoder position on the motor side does not provide a good estimate of the end-effector position. Second, these higher order modes coupled with Coulomb friction associated with the end-effector makes system identification tedious and inviable. In addition, this makes control tricky as standard discontinuous robust techniques have a tendency to excite those higher frequency dynamics. Furthermore, they are used to carry payloads of varying mass and are loaded and unloaded in quick succession adding to model uncertainty. In order to achieve higher position tracking accuracy, the authors propose a continuous robust controller that compensates for higher order disturbance while having a DOB that handles lower frequency, friction-related dynamics of the timing belt. In this paper, the details of this control scheme, simulation results justifying our approach and relevant stability proofs are presented.

Keywords: Biomechatronics, Compuational Models and Methods, Flexible Manipulators and Structures
Abstract: A modular cable-driven manipulator that consists of cable-driven joint modules can produce intrinsically-safe motions because of its light-weight structure and variablestiffness property. In this paper, we focus on the issue of stiffness-oriented cable tension distribution for a 3-DOF 6-cable Cable-driven Spherical Joint Module (CSJM), which is modeled as a convex optimization problem. An algorithm based on Lagrange multiplier method and Karush-Kuhn-Tucker (KKT) Condition is employed to find the optimal cable tension solution. To validate the proposed algorithm, a simulation example with four cases is carried out. The result shows that the required stiffness can be successfully achieved through cable tension regulation.

Keywords: Control Application in Mechatronics, Humanoid Robots
Abstract: Research on the control using a load-side encoder for two-mass system is getting more active due to the widespread use of the load-side encoder. We previously proposed Self Resonance Cancellation, which is a position control method for two-mass system. SRC has steady-state error and the vibration suppression performance is not improved. In the industry, Proportional-Proportional Integral control is commonly used, however, P-PI has problems such that poles can’t be arranged arbitrarily and bad performance in the disturbance suppression performance. In this paper, SRC and P-PI combined and complement each other’s faults and control performance is improved. In other words, poles can be arranged arbitrarily, the vibration suppression performance and the disturbance suppression performance is improved and the control bandwidth become higher. Simulation and experimental results show the effectiveness of the proposed method.

Keywords: Actuators in Mechatronic Systems, Actuators, Modeling and Design of Mechatonic Systems
Abstract: In this work, we present a thermally-controlled coiled polymeric wire as a novel variable stiffness element for robotics applications. We characterized the stiffness behavior of a single twisted nylon wire with 1 mm diameter at different operating temperatures between 25 °C to 50 °C. We observed a linear relationship between the temperature and the stiffness of the nylon wire. This is promising since it would facilitate straightforward adjustment of spring behavior in variable stiffness actuated systems. In order to see the stiffness modulation through temperature change, we conducted dynamic tests on a single joint mechanism with two nylon springs connected in an antagonistic configuration. Specifically, the nylon springs were immersed in water and the temperature was controlled using a Peltier cell. Experimental results indicate that the natural frequency and the damping ratio of the second order system are proportional and inversely proportional to the temperature, respectively.

Keywords: Control Application in Mechatronics
Abstract: In modeling and simulation of large-scale systems, Model Order Reduction (MOR), and specifically parametric MOR (pMOR), has grown in importance recently. In this paper, a concept based on distance between subspaces has been automated and combined with the efficient parametric reduction approach Matrix Interpolation to give an automatic adaptive sampling strategy in pMOR. An algorithm is developed and its efficacy established with the help of numerical results for a parametric Timoshenko beam model.

Keywords: Human -Machine Interfaces, Tele-operation, Virtual Reality and Human Interface
Abstract: This paper presents a lightweight haptic interface (200 g) suitable for tele-robotics and virtual reality applications. The kinematics architecture of the interface consists of a total of 3DOFs that are measured by endless-rotation potentiometers. As main novelty the end-effector includes three vibrating motors displaced with an angle of 120° one from another and capable to generate vibrations with a maximum frequency of 150 Hz. Due to a weak mechanical coupling between the motors, vibrations can be rendered in different directions, allowing the implementation of a 2-dimensional haptic feedback. Tests conducted on five subjects show the effectiveness of the interface in displaying the touch sensation and demonstrate how a combined haptic and visual feedback can enhance the execution of a simulated teleoperation task reducing the number of collisions.

Keywords: Fixture and Grasping
Abstract: Ice-clamping devices are of great advantage in deformation-free and sustainable workpiece clamping by using frozen water to fix pieces during machining operations. The adhesive bonding of ice generates high forces, encapsulating the piece form-fitted around and underneath its surface. The freezing is generated by thermoelectric coolers (TECs), placed under a clamping plate. The colder the plate is chilled, the higher the total forces of ice bonding are, guaranteeing a secure grip during machining. However, process heat generated by machining tools pose the risk of thawing the ice, illustrating an external disturbance which is needed to be controlled. Traditional control strategies for TECs use PID algorithm due to its simplicity. To attenuate disadvantages of a PID controller, such as oscillations, overshoots and settling time as well as to attain a better performance and robustness in the presence of parameter uncertainties and disturbances, a model based feedforward regulator including Anti-windup method is proposed additionally to a PI controller for the nonlinear thermal system. Furthermore, a technical requirement is formulated mathematically proving the existence of a structural stability of the thermal system. Simulation results, performed in MATLAB Simulink, are shown and are validated with experimental data.

Keywords: Fixture and Grasping, Opto-Mechatronic Sensors, Sensors and Sensing Systems
Abstract: This work presents the design of the tactile sensor within the WIRES project, aimed at automating the cabling process of switchgears. The design objective is the development of a sensor able to estimate both position and orientation of the grasped wire, with respect to a known reference frame. To this aim, an extensive Finite Element analysis has been performed to optimize the number of taxels, by simulating the contact between the sensor and wires with various diameters and grasping conditions. A specific algorithm for the reconstruction of the grasped wire shape has been developed and used for defining suitable metrics adopted in the design phase. Based on simulation results, a first prototype of the sensor has been realized and the proposed reconstruction algorithm has been experimentally tested.

Keywords: Fixture and Grasping, Novel Industry Applications of Mechatroinics
Abstract: We report on a novel low-computation object grasping method that can classify complex objects into primitive shapes and then select the object grasping posture based on predefined grasping postures associated with the approximated primitive shapes. In this approach, the object is not precisely modeled, and the grasping posture is selected from a small number of candidates without massive search; thus, the grasping posture for the object can be quickly derived. Because the object and primitive shape have geometrical discrepancy, the gripper is compliant and implemented with an infrared proximity sensor on the fingers to compensate the geometrical uncertainties and provide adequate contact between the object and the grippers. The methodology is experimentally evaluated with several types of objects in different postures.

Keywords: Fixture and Grasping, Mechatronics in Manufacturing Processes, Novel Industry Applications of Mechatroinics
Abstract: In industrial production is Zero Defect Management a current topic towards high requirements in manufacturing quality. An important industry application is the clamping system, which is essential in machining operation. The workpiece clamping system is the point of contact between workpiece and tool and due to that a crucial element for ensuring process reliability of the manufacturing process. The main difficulty in clamping process is to apply an appropriate force on a fragile workpiece, which has to be as much as necessary and as little as possible. This paper presents a novel actuator approach for a workpiece clamping system with the use of a solenoid considering pulse width modulated (PWM) voltage feed. The common usage for energization a solenoid is to apply alternating (AC) or direct current (DC). This common technique has just two switching states powered on and turned off. Therefore, this paper is proposing a special treated PWM signal, such that it is possible to control the magnetic field, and consequently the clamping forces, over an adjustable range of different power states. This approach allows to control the clamping force for holding the workpiece without physical displacement of the workpiece material. In this context the generated forces, with respect to the electromagnetic fields, powered by PWM signals, are evaluated with numerical simulations. The validation of the model is carried out through measurements to prove its accuracy.

Keywords: Fixture and Grasping, Planning and Navigation, Service Robots
Abstract: Grasping of unknown objects with neither appearance data nor object models given in advance is very important for robots that work in an unfamiliar environment. In this paper, we propose an original fast grasping algorithm for unknown objects. The geometry of the under-actuated gripper is approximated as a C-shape, which is used to fit the point cloud of the target object to find a suitable grasp. In order to make the robot arm quickly execute the grasp found by the grasping algorithm, we made a comparison of the popular online motion planners. The motion planner with the highest solved runs, lowest computing time and the shortest path length is chosen to execute the grasp action. Simulations and experiments on a UR5 robot arm and an under-actuated gripper are used to examine the performance of the grasping algorithm, and successful results are obtained.

Keywords: Vehicle Control, Vehicle Technology, Motion Vibration and Noise Control
Abstract: In vehicle motion control, it is important to improve both motion performance and ride comfort by vibration suppression. Vehicles with combustion engines or on-board motors can suppress resonant modes only in low frequency band such as the heave, pitch, and roll mode due to the limitation of torque responsiveness. However, in the case of the vehicles with in-wheel motors, it is possible to suppress vibration in higher frequency range. In order to improve motion performance and ride comfort, we propose two degrees of freedom control using an experimentally identified plant model of a geared in-wheel motor vehicle. Application of the proposed method improves the vehicle body longitudinal response characteristics while suppressing the vibration. In order to further improve the performance, a state observer that takes the delay of CAN communication into consideration is applied while securing stability margin. The effectiveness of the proposed method is evaluated by simulations and experiments.

Keywords: Vehicles and Space Exploration, Mobile Robots, Modeling and Design of Mechatonic Systems
Abstract: This work presents theoretical and experimental investigations on an untethered rolling tensegrity robot. Previous research has shown, that rolling locomotion of compliant tensegrity robots can be realized without change of their shape, by using only internal mass shifting. The use of simple tensegrity structures, based on curved compressed members enables pure rolling locomotion in contrast to the most known prototypes of this kind. Therefore, theoretical and experimental investigations of an untethered locomotion system based on a simple tensegrity structure, consisting of two disconnected compressed curved members connected to a continuous net of twelve prestressed tensioned members with pronounced elasticity, are considered. Planar locomotion is induced by the movement of only two drive units as internal masses along the curved compressed members. Theoretical considerations show the influence of the geometrical system parameters on the movement behavior of the system. With the help of experimental investigations, by using motion-capturing technique, main properties of the locomotion performance of a prototype are discussed.

Keywords: Vehicle Control, Wed-based Control of Robotic and Automation Systems, Control Application in Mechatronics
Abstract: Control methods for adaptive vehicle suspension systems have been in the focus of automotive research for several years, hence some car companies already apply these suspension systems to enhance stability and comfort of their luxury models. Generally these suspension systems are only capable to react to instantaneous impacts induced by road bumps, while only few of them are able to adapt to oncoming road conditions. However, as camera-based road monitoring systems become more and more widespread, automotive companies recently focus on adaptive suspension systems with oncoming road adaptation. This paper introduces a novel method based on the emerging cloud computing technology, where the look-ahead adaptation is based on historic road information gathered and preprocessed in the cloud database. The proposed adaptive suspension control based on Vehicle-to-Cloud-to-Vehicle (V2C2V) technology is validated in a real data simulation in TruckSim simulation environment.

Keywords: Vehicle Control, Automotive Systems
Abstract: The paper proposes the analysis and control of a steering system which is linked to the requirements of autonomous vehicles. The steering system of an autonomous vehicle must guarantee reliable and highly efficient intervention even in extreme conditions. Therefore, the determination of the reachability domain of the steering system is important. Both simulations and frequency domain methods are applied to the calculation. The paper shows that the reachability domain significantly depends on both the steering angle and the steering speed, which is utilized in the steering control design. Two results are incorporated in the robust control design of the steering. First, the analysis results of the steering system are built into the robust H∞ control design through frequency-dependent weighting functions. Second, experimental vehicle tests have been performed to examine the steering style of the driver. This information is also incorporated in the steering control through preview information. Finally, high-fidelity simulation scenarios show that the proposed method has several advantages compared to the conventional steering control solution.

Keywords: Automotive Systems, Vehicle Control, Identification and Estimation in Mechatronics
Abstract: Electric Vehicles (EV) equipped with independent drives are capable of controlling the car body motion in multiple degrees-of-freedom with driving force distribution through the suspension reaction force. These electric powertrains could thus suppress primary (1-3Hz) and secondary (4-10Hz) resonant modes improving ride comfort, road holding and safety of passenger cars. On-Board-Motor (OBM) drivetrains can subdue primary vibrations including the heave, pitch and roll modes, but are limited by the torsional resonance of the halfshaft. In-Wheel-Motor (IWM) drivetrains alleviate the torsional restriction potentially reaching higher bandwidths and thereby improving road holding and passenger comfort. However, the additional unsprung mass aggravates the secondary vibration urging for an appropriate motion control design. This research proposes a dynamic model in multiple degrees-of-freedom for vibration suppression control and an experimental validation of both primary and secondary dynamics in EVs. In this work, the vibration performance of both powertrains are compared on a test vehicle in experimental and operational conditions. Moreover, the modal coupling between the torsional, longitudinal and vertical motions are analysed and the slip-ratio dependency assessed. The deterioration in dynamic behaviour using IWMs is demonstrated and a precise parametric model identified for vibration suppression control of geared In-Wheel-Motor drivetrains.

Keywords: Control Application in Mechatronics, Identification and Estimation in Mechatronics, Vehicle Control
Abstract: The design of a disturbance observer (DOB) for a nonlinear half-car hydraulic active suspension system is presented. The system is controlled by the flatness-based controller (FBC) which is capable to provide efficient control under deterministic road disturbances and model uncertainties. The main objective is to design the mutually coupled general-proportional-integral (GPI) disturbance observers which estimate the disturbances in on-line mode during the car driving. It is assumed that the nonlinear effects, parameter variations, road profiles and possibly input unmodeled dynamics are lumped into an unknown time-varying and stochastic disturbance input signal. The quality and effectiveness of the proposed GPI-based DOB are shown by simulation results.

Keywords: Identification and Estimation in Mechatronics, Control Application in Mechatronics, Fault Detection and diagnosis in Manufacturing
Abstract: Physical human-robot interaction is one of the hottest topic in robotics and safety issues are its fundamental aspect. The present paper contributes to this aspect in that collision detections can be completed on the servo level in an intuitive way. The principle of the proposed collision detection strategy is based on the relative difference of the feedback commanded torque, which is able to identify the abrupt change in the feedback commanded torque’s slope during collisions. Under the assumptions that the planned motion is smooth enough and that the gravity with respect to the joint variable is continuous, the detection strategy presented here can work fast and efficiently. A prototype with one degree of freedom (DOF) has been built to verify the given approach. Experiment results reveal that the proposed method is valid in different situations. In addition, since no external force/torque sensors (F/T sensors) are needed in this process, the proposed method is also economical.

Keywords: Identification and Estimation in Mechatronics
Abstract: Identification of industrial robots is a prolific topic that has been deeply investigated over the last three decades. The standard method is based on the use of the inverse dynamic model and the least-squares estimation (IDIM-LS method) while robots are operating in closed loop by tracking exciting trajectories. Recently, in order to secure the consistency of the parameters estimates, an instrumental variable (IV) approach, called IDIM-IV method, has been designed and experimentally validated. However, the statistical analysis of estimates was not treated. Surprisingly, this topic is rarely addressed in mechatronics whereas it has been deeply investigated in automatic control. This paper aims at bridging the gap between these two communities by presenting a pragmatic statistical analysis of the IDIM-IV estimates. This analysis consists of a two-step procedure: first, the consistency of the IDIM-IV estimates is validated by the Revised Durbin- Wu-Hausman test, and then the statistical analysis of the IDIM-IV residuals is treated. This two-step approach is experimentally validated on the TX40 robot.

Keywords: Control Application in Mechatronics, Identification and Estimation in Mechatronics, Mechatronics-Enabled Teaching and/or Training
Abstract: The controlled operation of hydraulic machines with multiple degrees of freedom is challenging due to complex nonlinear dynamics of cylinder actuators, in addition to multi-body dynamics like in the case of hydraulic manipulators. This paper addresses the system identification and control design for path tracking of a standard hydraulic loader crane. The kinematics of the crane is solved for operation in the vertical plane and generation of trajectories for the tool tip to be followed. A frequency response measurements and analysis have been done for dynamics modeling of both hydraulic cylinders actuating main boom and jib. The static dead-zone type input non-linearity has been identified and compensated through the inverse. A suitable control structure combining the proportional feedback regulator with model-based feed-forward control part has been derived and implemented. The experimental evaluation is shown for the Cartesian path tracking with a constant tangential velocity. The results demonstrate a way of application-related identification and control design for hydraulic manipulators with limited access into internal actuator and control structure.

Keywords: Identification and Estimation in Mechatronics
Abstract: This paper deals with two robot identification methods recently introduced. The first one is based on the use of the Inverse Dynamic Identification Model (IDIM) and the Instrumental Variable (IV). The second one is the Direct and Inverse Dynamic Identification Models (DIDIM) method, which is a closed-loop output error method minimizing the quadratic error between the actual and simulated joint torques. Both methods rely on the simulation of the Direct Dynamic Model (DDM). They are compared with a six degrees of freedom industrial robot. The experimental results show that the DIDIM method has the advantage of requiring less data preprocessing. Nevertheless, the IDIM-IV method appears to be more robust to modelling errors in the simulation which are not located in the identified dynamic model.

Keywords: Identification and Estimation in Mechatronics, Actuators
Abstract: Many applications of induction machines require a model and its electrical and mechanical parameters. The parameters can be estimated during the machine’s operation in closed-loop by recursive algorithms. On-line estimation algorithms can yield suitable results when parameter identifiability is guaranteed. This work analyzes the identifiability of the induction machine by the condition of sufficient excitation. The result is a reduced model order and a condition on the machine operation to yield useful parameter estimates. The practicality of the presented method is shown on data from a real test bed. Additional emphasis is put on signal processing to compute the necessary first and second derivative of noisy measurements.

Keywords: Actuators in Mechatronic Systems, Modeling and Design of Mechatonic Systems, Actuators
Abstract: Control moment gyroscope(CMG) is an indirect actuator used for the attitude control tasks where actuators cannot be directly applied. Control of the gimbal position becomes important to maximize the induced torque. As a torque amplifier, the gimbal axis of CMG should be controlled to produce fine and regulated torque. Since the torque performance is dependent upon the return performance of the gimbal axis, both the magnitude and direction of gyroscopic torque should be controlled to achieve agility and regulation. In this paper, a robust current controller is designed with an angle restriction property by the current compensation designed through the model identification by real-time recursive least square(RLS) algorithm. Firstly, the configuration and mechanism of designed CMG is presented and the angle restriction problem is stated. Secondly, RLS algorithm is designed for online identification, implemented, and validated. Thirdly, the proposed current control scheme of gimbal axis is verified by experiments.

Keywords: Service Robots, Machine Learning, Neural Networks
Abstract: Abstract—Robotic graspable object recognition is a crucial ingredient in many exciting autonomous manipulation applications. However, identifying complex image features from limited data remains largely unsolved. In this paper, we leverage the advantages of two kinds of feature representation approaches, kernel descriptors and deep neural networks, to present a novel hierarchical feature learning framework for robotic graspable object recognition. This work enables the recovery of sparse and compressible features from limited data examples. Firstly, we design multiple kernel descriptors from the raw RGB-D images to adequately capture the discriminative structure of the object. Then, the extracted abstract representations are transferred to a four-layer deep neural network to generate more representative features for final graspable discrimination. Our network obtains impressive generalization capability with limited training data. Extensive experiments are carried out to validate the proposed method and the results show the state-of-the-art performance in discriminating graspable object task under limited-data.

Keywords: Artificial Intelligence in Mechatronics, Machine Learning, Learning and Neural Control in Mechatronics
Abstract: In the operation of robots in regular human lives, the capability of object handling is of fundamental importance. Robotic manipulation has gone from handling single rigid body objects with firm grasping to handling soft objects and dealing with slip and contact. Meanwhile, technologies such as robot learning from demonstration has enabled intuitive human-to-robot teaching. This paper discusses a new level of robotic learning-based manipulation. Instead of the single form of learning from demonstration, we propose a polymorphic learning scheme that integrates additional types of robot skill acquiring, including adaptive definition and evaluation. In addition, compared to the current studies of handling pure rigid or soft objects in a pseudo-static manner, our work aims to allow robots to learn to manipulate objects that are partly soft partly rigid, require time-critical dynamic skills and subtle contact control, such as handling tethered tools and even using martial arts instruments. This type of tasks, once successfully robotized, open a variety of new possibilities in robot-human coexistence.

Keywords: Service Robots, Part Feeding and Object Handling 
Abstract: This paper describes a system that can find and lift a specific object in a bin containing piled objects. Such a task is ubiquitous in our daily life, for example, in finding a small toy in a toy box or in finding a stationary in a drawer. To efficiently achieve this task, it is necessary to recognize the object placements with consideration of occlusions and to plan a proper hand motions for lifting or searching for the target object. We developed methods for such two necessary functions, with introducing a sweep motion for removing many non-target objects at once. We implemented the methods on a dual-arm humanoid robot with an RGB-D camera and a suction mechanism. The experimental results show the effectiveness of the proposed approach.

Keywords: Modeling and Design of Mechatonic Systems
Abstract: Previous dual arm manipulators have been developed to follow dual arm tasks of human and to be a substitute for human in the indoor field. Nowadays, it is necessary for a robot to perform various tasks such as search and rescue in the battle field and disaster field. In the paper, a dual arm manipulator which is mounted on the mobile robot is proposed for rescue activity. The kinematic configuration is determined to satisfy the representative poses for rescue activity in the battle field. Kinematic parameters and dynamic parameters of the dual arm manipulator are investigated through the dynamic simulation on the various conditions. The performance of the manufactured dual-arm manipulator is proved through the experiments.

Keywords: Robot Dynamics and Control, Control Application in Mechatronics
Abstract: Dexterous manipulation has broad applications in assembly lines, warehouses and agriculture. To perform broad-scale manipulation tasks, it is desired that a multi-fingered robotic hand can robustly manipulate objects without knowing the exact objects dynamics (i.e. mass and inertia) in advance. However, realizing robust manipulation is challenging due to the complex contact dynamics, the nonlinearities of the system, and the potential sliding during manipulation. In this paper, a dual-stage grasp controller is proposed to handle these challenges. In the first stage, feedback linearization is utilized to linearize the nonlinear uncertain system. Considering the structures of uncertainties, a robust controller is designed for such a linearized system to obtain the desired Cartesian force on the object. In the second stage, a manipulation controller regulates the contact force based on the Cartesian force from the first stage. The dual-stage grasp controller is able to realize robust manipulation without contact modeling, prevent the slippage, and withstand 40% mass and 50% inertia uncertainties. Moreover, it does not require velocity measurement or 3D/6D tactile sensor. Simulation results on Mujoco verify the efficacy of the proposed method.

Keywords: Modeling and Design of Mechatonic Systems, Novel Industry Applications of Mechatroinics, Fixture and Grasping
Abstract: We describe the concept and first prototype of a novel mechatronic design of a robotic gripper, which aims at being mounted on a humanoid robot to achieve firm (i.e. locked) and robust grasps. Such grasps could ideally support complex multi-contact motions, such as ladder climbing, or manipulation of complex tools, with energy efficiency. For this purpose, we propose a solution by designing a smart self-locking underactuated mechanism mounted in parallel to actuators to be triggered automatically when the desired grasp is achieved. This design leverages adjustable power distribution between the gripper and the brake through a differential gear. The advantages of adaptive, firm grasping, and energy-saving capabilities of our gripper are experimentally demonstrated by a prototype gripper.