A Generalized Input-output-based Digital Sliding-mode Control for Piezoelectric Actuators with Non-minimum Phase Property

In this paper, a generalized input-output-based digital sliding-mode control (GIODSMC) is developed for piezoelectric actuators (PEA) with non-minimum phase (NMP) property. First, the instability mechanism of the traditional input-output-based digital sliding-mode control (IODSMC) for NMP systems is analyzed. Then, a generalized approximate input-output model is established to cancel the effect of unstable zeros in NMP systems. The generalized model can be transformed into different forms, which represents a class of approximate models suitable for this situation. Based on this model, a controller, called the GIODSMC, is presented. Unlike existing works, the developed controller ensures precision motion control for PEA with NMP property. Moreover, additional control parameters are not required to stabilize the NMP systems, and neither a hysteresis model nor a state observer is needed for the developed method. Stability of the closed-loop system is theoretically analyzed. At last, the presented method is tested through numerical simulations and experimental investigations on a piezoelectric actuator device.