A Cartesian impedance control for a 7-DOF space robotic arm (SRA) based on the feedback from a 6-dimensional force/torque sensor on its end effecter is presented in this paper. The unavoidable position error of SRA would generate large contact forces during the connection between SRA’s end effecter (EE) and grapple fixture (GF). To control the contact force we used 6D force feedback to modify the desired trajectory controlling a PID position inner loop to make the manipulator exert desired impedance dynamic properties on its end-effecter. After optimization of impedance parameters in Simulink, this control strategy has significantly improved the force control effect in EE/GF connection experiment. Kinematic solution of the 7-DOF redundant manipulator is also provided.
Robust Impedance Control of Kinematically Redundant Manipulator Based on Disturbance Observer