Prandtl-Ishlinskii model-based adaptive feedforward control for piezoelectric-stack-actuator-driven systems

In this paper, a Prandtl-Ishlinskii (PI) model-based adaptive feedforward controller is proposed to overcome hysteretic behaviors of a piezoelectric-stack-actuator (PSA)-driven system. The feedforward control design is centered on the PI inverse hysteresis model. In addition, in order to capture the rate-dependent characteristics of the PSA-driven system, a normalized least mean-squares (NLMS) algorithm is adopted to online identify optimal weight vectors of the PI hysteresis models. The identified PI hysteresis model is then utilized to compute the inverse PI model. The feedforward controller can be designed accordingly. Tracking experiments focusing on sinusoidal and random-like signals were performed on a high-stiffness flexible micro-positioning system driven by a PSA. The experimental results show that the tracking accuracy is significantly improved using solely open-loop feedforward control in comparison with traditional open-loop control without compensation.