Parameter identification of a direct-drive robot by a disturbance observer

This paper presents a dynamics identification algorithm based on a disturbance observer for a multi-degrees-of-freedom robot. In the conventional approach, the disturbance observer is used to increase the robustness of the robot. In this case, the estimated disturbance torque is directly fed back to cancel out the disturbance torque imposed on the robot. In this paper, the estimated disturbance torque is analysed from the physical point of view and the robot dynamics are identified by resolving the estimated disturbance torque. First, the basic structure of the disturbance observer is simply introduced from the motion equation of the robot. Second, the parameter identification algorithm based on the disturbance observer is explained. Finally, we show the numerical and experimental results to confirm the validity of the proposed parameter identification algorithm.