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Follow the Gap Method (FGM) is a safety-focused geometric obstacle avoidance algorithm for local navigation. In this method, the largest gap around the robot is selected and the robot moves towards a goal point considering the largest gap and minimum distance to obstacle. One of the drawbacks of the method is the extension of the path which sometimes happens unnecessarily. Another drawback comes from...
Trajectory tracking is one of the most control tasks for robotic manipulators. To take the advantages of nonlinear PD (NPD) control and sliding mode control (SMC), a NPD-SMC law is proposed for tracking control of a 3-DOF planar robotic manipulator. The NPD-SMC is a nonlinear feedback control without the requirement of system dynamic modeling. The proposed NPD-SMC is applied for linear and nonlinear...
Traditional joint space admittance controller for N-DOF robotic systems is complexity and easily leads to incongruous movement among all joints. Our study introduces a central pattern generator (CPG) network into one-dimension joint space admittance control for the custom-made lower limb robotic exoskeleton with four DOFs, to guarantee the coordinated movement and security of users. The predefined...
The aim of the study is to design a novel protocol to characterize the ankle movements during dorsal and plantar flexion reaching tasks using the pediAnklebot. Five healthy children were instructed to control a pointer and hit targets appearing on the monitor, by moving their ankle alternatively up and down. The protocol consisted of 60 targets, 30 up and 30 down, reachable via dorsiflexion and plantarflexion...
We shall study non-holonomic robotic systems represented by either a driftless or a control affine control system with outputs. Two types of singularities are considered: the posture singularities around which the growth vector of the system's distribution is non-constant, and the configuration singularities at which the system's Jacobian is not surjective, related with the singular optimal controls...
The Cooperative Multi-Area Coverage (CMAC) refers to a class of complex tasks in which multiple robots are required to jointly cover multiple areas by performing specific operations while moving across them. Practical operations may be garbage clearance, demining, area scanning for information acquisition, and so on. This paper proposes a distributed motion planning method for multiple robots to cooperatively...
This paper addresses the safe and legible navigation of mobile robots in multi-agent encounters. A novel motion model provides the basis to predict, plan and coordinate agent trajectories in intersection scenarios. The approach establishes an implicit, non-overt cooperation between the robot and humans by linking the prediction and planning of agent trajectories within a unified representation in...
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 golf-courses, which require structured and precise cutting patterns. The geographical polygon is recorded...
This paper presents a real time hybrid 2D position and orientation tracking system developed for an upper limb rehabilitation robot. Designed to work on a table-top, the robot is to enable home-based upper-limb rehabilitative exercise for stroke patients. Estimates of the robot's position are computed by fusing data from two tracking systems, each utilizing a different sensor type: laser optical sensors...
This paper presents a cascaded methodology for enhancing the path accuracy of industrial robots by using advanced control schemes. It includes kinematic calibration as well as dynamic modeling and identification. This is followed by a centralized model-based compensation of robot dynamics. The implemented feed-forward torque control shows the expected improvements of control accuracy. However, external...
Trajectory planning has been a common and important topic in robotics since its generation. As a powerful tool, it can enhance the performance of the robots in manufacturing industry. In this paper, a trajectory planning method based on unit quaternion was proposed. Unit quaternions were used to represent the orientations of the target as there are no more singularities. The trajectory was planning...
The number of people with physical disabilities and impaired motion control is increasing. Consequently, there is a growing demand for intelligent assistive robotic systems to cooperate with people with disability and help them carry out different tasks. To this end, our group has pioneered the use of robot learning from demonstration (RLfD) techniques, which eliminate the need for task-specific robot...
This paper is addressed to a problem of humanoid robot locomotion with the use of computer vision. The robot is 20 DoF Darwin OP equipped with video camera in its head and has built-in PC. To determine the desired path we use the algorithm of video processing based on image filtration within threshold values in HSV color model. Developed control system includes tracking system for the head with camera...
Recently, there has been a growing interest in biomimetic underwater vehicles. Although a lot of research has been conducted in the area of dynamics and kinematics of robotic fish, most of the approaches solve the inverse problem by finding the required force the caudal fin should produce, in order for the robotic fish to follow a trajectory. Others use predefined undulatory body motions which usually...
Distributed mobile robotics (DMR) involves teams of networked robots navigating in a physical space to achieve tasks in a coordinated fashion. A major challenge in DMR is to program the ensemble of robots with formal guarantees and high assurance of correct operation. To this end, we introduce DRONA, a framework for building reliable DMR applications. This paper makes three central contributions:...
A distributed target search and predictive approach that uses wireless sensor network topology map is presented in this paper. The decision-making and information gathering is distributed, and the target prediction is based on the weighted least square method. The knowledge of target location and moving direction is obtained by time sets recorded by each sensor node. Time set is a collection of time...
This paper presents a distributed area coverage optimization algorithm for a group of heterogeneous robots operating on a planar area. Distributed control algorithms for solving such area coverage problems are well-established in the literature. However, the real-time implementation of these algorithms requires significant computational resources, especially when the robots operating in the environment...
This paper studies the formation tracking problem for a multi-agent system composed by a set of quadrotor UAVs. Parrot AR.Drone 2.0 quadrotors are used as the agents of the system. The proposed control strategy is designed using a time- varying version of the backstepping technique for each agent. For the implementation of the control law, it is assumed that each agent only measures the leader and...
The technology of lower limb rehabilitation robot is a hot research topic in recent years, while the exoskeleton robot is a typical representative. Accurate trajectory tracking ability is the base of the exoskeleton mechanical leg to coordinately drive trainers to do rehabilitation training on the treadmill. In this paper, aiming at the existing exoskeleton body, taking into account the uncertain...
The purpose of this paper is design a stable walking gait for robot UXA-90. We applied Zero Moment Point (ZMP) based preview control to generate Center of Mass (CoM) trajectory. The ankle trajectories were created by spline interpolation method. Experiment results show that our method can make robot walking stable.
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