Research on Impedance Control of Flexible Joint Space Manipulator OnOrbit Servicing In this paper, the positional accuracy and contact force index requirements of the manipulator are analyzed according to the tolerance index of the space manipulator screwing. An positionbased in Cartesian space impedance control strategy based on friction identification and compensation is proposed. By using joint friction torque compensation to improve the system control precision and setting the desired Cartesian position of the manipulator end point to control the contact force, this strategy solves the contradiction between the positional accuracy index and the contact force index requirement of manipulator during contact operating. The control algorithm is designed based on the system dynamics model, and the stability analysis of the control algorithm is given. The correctness of the control strategy is verified by simulation and onorbit implementation. Chinau0027s space manipulator has successfully completed the actual onorbit servicing mission based on impedance control for the first time.

Impedance Control Strategy and Experimental Analysis of Collaborative Robots Based on Torque Feedback In this paper, through the modeling and analysis of flexible joints, an impedance controller based on torque feedback is proposed, which is used to realize the active compliance of collaborative robots. The controller includes two parts: torque controller and impedance controller. The torque controller is used to compensate the robot dynamics, and the impedance controller is used to adjust the joint stiffness and damping. The theoretical analysis of the control strategy shows that the significance of torque feedback is that it can reshape the inertia of the motor, reduce friction torque and suppress unknown disturbances. In order to ensure tracking accuracy, a task errorbased disturbance observer is designed. Experiments with a 7DOF collaborative robot show that the proposed controller in this paper can realize the body compliance and obtain better compliance performance than the traditional compliance control method.