Improving Tracking Precision of Piezoceramic Actuators Using Feedforward-Feedback Control

Abstract

This paper presents a feedforward-feedback controller to improve tracking precision of piezoceramic actuators with hysteresis and creep nonlinearities. Rather than the commonly used approach to construct an inverse of the hysteresis model in the feedforward path, a direct inverse hysteresis compensation method is used to linearize the asymmetric hysteresis nonlinearity with a modified Prandtl-Ishlinskii model. Considering the limitation of the robustness of the feedforward controller, a proportional integral derivative controller is integrated in the feedback loop to mitigate the modeling uncertainty and creep nonlinearity. To demonstrate the performance improvement of the feedforward-feedback control strategy, a piezoceramic actuated platform is built, and comparative tests are conducted on the experimental platform. In comparison with the open-loop operation, the maximum tracking error of the feedforward-feedback controller is reduced from 6.47 μm to 30 nm, and the maximum hysteresis caused error is reduced from 13.19% to less than 0.1% with respect to the desired displacement range. The experimental results clearly demonstrate the feasibility and effectiveness of the developed feedforward-feedback controller using the modified Prandtl-Ishlinskii model.