Robust control of high-speed precise positioning of robot arm with flexible drive system (The case of utilizing both information of joint and motor angles)

摘要

Generally, for the position control of industrial robots, the semi-closed-loop control which only utilizes information of the motor angle is adopted, since it contributes to the stability of the control system and does not require a high-resolution encoder. In this method, however, precise positioning cannot be attained because of uncertainty and flexibility of the driving system. Since the cost of a high-resolution encoder has become less prohibitive, direct measurement of joint angle is now possible. In this paper, in order to realize high performance, precision, speed, and robust stability, we propose a control method which utilizes both information of motor and joint angles. The controller is derived from the loop shaping procedure which is based on the H{sub}∞ control theory. Moreover, we introduce 2DOF control to improve tracking performance of the joint angle. Experimental results show that the proposed controller is useful to achieve the desired performance.