Novel Generalized Predictive Iterative Learning Speed Controller for Ultrasonic Motors

Aiming at the needs of ultrasonic motor's motion control system, generalized predictive iterative learning control (GPILC) strategy is constructed by integrating iterative learning control and generalized predictive control. By designing 2D objective function with the information of the previous control process, it attempts to integrate the generalized predictive control methods such as multi-step predictive and rolling optimization into the iterative learning control law to improve the iterative learning control effect. An effective design method of the iterative learning control law is proposed. Based on 2D prediction model, the differential optimization of the objective function is carried out to derive the GPILC law. Then, based on the nonlinear Hammerstein model of ultrasonic motor, an inverse compensation method for the motor's nonlinearity is designed to realize the effective compensation for motor's nonlinearity. On this basis, a generalized predictive iterative learning speed controller for ultrasonic motors is designed. The results of simulation and experiment indicate that the proposed control strategy and its design method are effective. The iterative learning process of ultrasonic motor's speed response is gradually convergent, and the control performance is good.