High Backdrivability Control Based on Estimation of Shaft Torsion Using Load Side Angle Sensor

Abstract

This paper proposes high backdrivability control which can be applied to R/C servo motors. This control method is constituted by shaft torsion control and admittance control. In shaft torsion control, the motion of the robot is derived from shaft torsion. Shaft torsion is estimated by using Shaft Torsion Observer (STOB). On the other hand, in admittance control, the motion of the robot is derived from reaction force. The reaction force is estimated by using Reaction Force Observer (RFOB). These control methods are selectively used depending on the movement of the motor. By using the proposed method, back-drivability of the R/C servo motor was improved in comparison with conventional admittance control.