Research On Key Technologies Of Ground Teleoperation For Space Robot

Space has the characteristics of microgravity, high vacuum, strong radiation and so on, and its harsh environment makes space activities extremely risky. The space robot becomes the main means of the deep space exploration. The complex space environment is usually partially or completely unknown, so we must rely on the ground operations personnel involved to give the control instruction. By means of telepresence(visual, haptic and tactile, etc.), people can be incorporated into the control loop to ensure the successful completion of the task. The ground teleoperation of space robot is the mainstream technology at present,which has great research significance as well as the application value. For the purpose of solving the key problem of space robot teleoperation, this paper has carried on the research of the system structure design,the master-slave motion matching, the predictive virtual environment and haptic/visual aids, the EMG control with the multi-event control structure and other aspects.Based on the actual task of space robot teleoperation, the structure and working mode of space robot, a space robot teleoperation system is designed and constructed, and the modeling analysis is carried on at the same time. The overall design and the design of functional modules, such as the main robot arm subsystem, the virtual environment subsystem, the human-machine interaction subsystem, the ground operation management subsystem and so on, are completed. The delay simulation system can be used to verify the typical space manipulator teleoperation task and function under the condition of large time delay.Aiming at the problem of the space mapping of the heterogeneous master-slave remote operating system,the kinematics of seven DOF hand controller with force feedback is analyzed, which provides the basis for calculating the position command from the human operator and generating the accurate force feedback. Then the kinematics of the Schunk redundant manipulator with seven degrees of freedom is analyzed, and the inverse kinematics problem of the redundant manipulator is solved. The singularity of the manipulator is analyzed by the method of screw suppression. In the end, the method of motion matching of master-slave heterogeneous teleoperation system is discussed.To solve the problem of large time delay in space teleoperation system, in view of the visual and force as the most important way for the human operator to perceive the environment, a visual/force aid teleoperation system based on 3D environment modeling and updating is built. The KINECT camera is used to collect the 3D point cloud information and rebuilt the virtual environment. Adaptive Window based Sliding Least Squares Method (AW-SLSM) is adopted to identify the model parameters in the unknown environment and update the parameters on-line. In addition, by using the artificial potential field method, the attractive force or repulsion force is provided, which improves the efficiency of obstacle avoidance and target approach.The EMG signals are adopted as one of the control signal sources of space robot teleoperation. Through the acquisition of EMG signal with the feature extraction, the operator's gripping force is adopted to control the clamping device. Based on the non-time reference event s, the delay information is excluded from the system, and the influence of time delay on the stability of teleoperation system is solved. The event generator and the event selector are also added. The passive stability of the system is proved by using the passive two-port theory.