Unified external torque-sensing algorithm for flexible-joint robot based on Kalman filter

The external torque estimation problem in a flexible-joint robot system with joint torque sensors is revisited. A flexible-joint robot has two dynamics, motor dynamics and manipulator dynamics, resulting undesirable sensor torques reflecting neither the external link torques nor the actuating motor torques. A unified external torque-sensing algorithm for a flexible-joint robot is proposed, which estimates all the external torques by full utilizing the flexible-joint robot dynamics, regardless of the flexible-joint robot system condition. The basic structure of the proposed algorithm is illustrated, and the performance verification is briefly discussed.