Joint driver and control design for large torque, long arm space remote manipulator

This paper presents an overview of the structure and requirements of a ground engineering model for a space remote manipulator system, with long arm and large torque driver capacity. The system consists of a 6 DOFs robot arm composed of six identical modular joints, and a large-error tolerated end effector. A FPGA based joint controller hardware structure is built to form a distributed control scheme of the robot arm, while a fourth-order hybrid controller based on the joint torque feedback is adopted to reduce the influence of joint flexibility, brought by the harmonic drivers and torque sensor, on the control precision. A single-joint control experiment, designed to lift up a load at the tip of a link, about two meters in length, is used to test the ability of trajectory tracking in the gravity field.