Frequency-shaped sliding mode control of piezoelectric nano-stages with hysteresis estimation.

Due to the emerging applications of ultra-high precision scanning in many engineering fields, dynamical tracking of desired reference trajectories for nano-stages has attracted a lot of significant research. An adaptive integral sliding mode control (AISMC) framework in combination with frequency-shaped optimization and hysteresis observer is proposed to improve tracking performance of piezoelectric nano-stages in this article, where hysteresis nonlinearities, undesired high-frequency dynamics and model uncertainties are the major issues that limit high-precision dynamic tracking. The convergence regarding both the observation error of the hysteresis state and the tracking error of the considered system is analyzed. By comparison with representative results in the literature, the experimental studies conducted on an multi-axis nano-stage are used to verify the proposed approach has a substantial improvement in terms of robustness and tracking performance.