Discrete-Time Output Integral Sliding-Mode Control for a Piezomotor-Driven Linear Motion Stage

In this paper, a discrete-time output integral sliding-mode control (DOISMC) is developed for the precision control of a piezomotor-driven linear motion stage. A new integral-type sliding surface is first designed for arbitrary output reference tracking control. To estimate the unknown state and disturbance, two observers based on the integral-type sliding surface are designed. It is shown in this paper, through both theoretical analysis and experiments, that the discrete-time output integral sliding mode controller, together with the state and disturbance estimation, achieves an O(T2) tracking precision w.r.t. the sampling period T. The superior performance of DOISMC achieved in the control of piezomotor-driven linear stage indicates that it is a suitable control method for precision control or servo applications.