Design of an adaptive feedforward/feedback combined control for piezoelectric actuated micro positioning stage

Abstract

This paper proposes a novel feedforward/feedback combined control applied to a piezoelectric （PZT） actuated micro positioning stage. Based on the rate-dependent P–I inverse hysteresis model, a feedforward controller is built to compensate the hysteresis characteristics of the piezoelectric actuators, and the relevant parameters of the model are obtained through system identification. An adaptive control algorithm is adopted in feedback controller to reduce the influence of external disturbance. By introducing error-related forgetting factors to adjust the weight of old data and new data in real time, the robustness and accuracy of the control system are improved. The simulations are carried out to estimate the performance of the time-varying forgetting factors based adaptive algorithm. Finally, experimental tests are conducted to investigate the performance of the proposed feedforward/feedback combined control. The experimental results indicates that the settling time is 53 ms corresponding to the square wave signal and the maximum tracking error of a sine trajectory with the frequency of 20 Hz is 1.63 μm.