Discrete-time output integral sliding mode control for a piezo-motor driven linear motion stage

In this work a discrete-time output integral sliding mode control (DOISMC) is developed for precision control of a piezo-motor driven linear motion stage. A new integral type sliding surface is first designed for arbitrary output reference tracking control. To estimate unknown state and disturbance, two observers based on the integral type sliding surface are designed. It is shown in this work 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 with respect to the sampling interval T. The superior performance of DOISMC achieved in the control of piezo-motor driven linear motion stage indicates that it is a suitable control method for precision control applications.