Output-based discrete-time sliding mode control for a piezoelectrically actuated system

This paper presents a new scheme of discrete-time sliding mode control (DSMC) dedicated to precision positioning control of a piezoelectrically actuated system. Traditionally, a hysteresis model is required to compensate for the piezoelectric nonlinearity and a state observer is needed to implement the DSMC, which renders a time-consuming procedure. The proposed output-based DSMC scheme allows the relief of these computational burdens. Specifically, the piezoelectric nonlinearity is considered as a lumped perturbation term which is predicted by a perturbation estimation technique. The elimination of state observer is realized by establishing a control scheme based on the system output only. In addition, the stability of the control system is proved in theory. The effectiveness of the reported scheme is validated on a prototype piezoelectric actuation system by carrying out several experimental investigations.