Sensing the torque in a robot's joints

Abstract

As direct-drive robots become increasingly popular, there is a need for high-performance motion controllers that can achieve dynamic accuracy in practice. A direct approach to control is possible if joint torque sensors are used to measure the external loads on all joints. Positive feedback of the torque signal can then compensate for the dynamics of the robot manipulator. A joint torque sensor which can accurately measure the torsion moment in a direct-drive robot, even in the presence of strong overhang, thrust forces, and bending moments, is presented.