Controller design and experimental validation of a robot joint with active compliance

Abstract

The design employs direct drive torque motor to achieve a robot single joint with active compliance based on the impedance model. In order to maximize the torque density, transmission transparency and backdrivability, the joint employs a quasi-direct actuator that a single-stage planetary gear is mounted on the motor's rotor. When robot interacts with environments, it's inevitable to change the stiffness and damping coefficient of the joint. In view of the situation, a simple and efficient method-fuzzy control is employed and the effectiveness of the controller is verified experimentally. Finally, according to the algorithm of the outer loop position and inner loop force control, the position control of single joint is realized, and the dynamic response of the joint to the given sine position is tested experimentally.