Robot joint module equipped with joint torque sensor with disk-type coupling for torque error reduction

Abstract

Force control and collision detection of a robot were usually conducted using a 6 axis force/torque sensor mounted at the end-effector. This scheme, however, suffers from its high cost and inability to detect collisions at the robot body. As an alternative, joint torque sensors embedded in each joint were used, but they also suffered from various errors in torque measurement. To solve this problem, a robot joint module with an improved joint torque sensor is proposed in this study. In the proposed torque sensor, a cross-roller bearing and disk-type coupling are added to prevent the moment load from adversely affecting the measurement of the joint torque and to reduce the stress induced in the assembly process of the sensor. The performance of the proposed joint torque sensor was verified through various experiments.