New discrete-time sliding mode control for a piezoelectric actuation system

This paper presents a new discrete-time sliding mode control (DSMC) scheme dedicated to precision positioning control of a piezoelectric actuation system. Traditionally, hysteresis modeling is required to compensate for the piezoelectric nonlinearity and state observer design is needed to implement the DSMC control, which renders a time-consuming procedure. The proposed DSMC control scheme releases these computational burdens by a new approach. Specifically, the elimination of state observer is realized by developing a discrete-time dynamics model of the whole system. In addition, the piezoelectric nonlinearity is considered as a perturbation term and predicted by perturbation estimation technique. The stability of the control system is proved in theory and demonstrated through experimental studies on a prototype system. Experimental results reveal the efficiency of the presented control scheme for the precision positioning control.