An Adaptive Force Control Method for 7-Dof Space Manipulator Repairing Malfunctioning Satellite

This paper presents an adaptive force control method for 7-Dof space manipulator repairing malfunctioning satellite. The whole control scheme contains two loops: outer force control and inner motion control. There are two parts in the force controller, position-based impedance control and direct force control. In the impedance controller, translational impedance and rotational impedance based on Euler angles are both achieved, successfully avoiding destructive contact force and adjusting the orientation of the end-effector. And the direct force controller can tracking the desired force. In the inner loop, the robustness to dynamics uncertainty is achieved by an adaptive motion control method. The global stability and the convergence of trajectory tracking error are strictly proved. During the operation, the collision between the manipulator and the chaser is easily arisen due to the wide-range motion of the second joint. An acceleration-level redundancy resolution method of the 7-Dof manipulator is proposed avoiding the ill condition. A set of numerical experiments by MSC ADAMS (R)/SIMULINK (R) co-simulation verify the validity and feasibility of the proposed approach.