Ultra-precision positioning system using robust sliding mode observer and control

In this paper, the robust sliding mode control based on reduced order observer is proposed to overcome the model imperfections in ultra-precision positioning system. The reduced order sliding mode observer enables the states and the estimated outputs to be available for controller design. The manifold of the sliding mode control is composed of the estimated output only instead of system states. Using the reduced order observer, the sliding mode control is designed in output feedback form. The effectiveness of the proposed control algorithm has been proved from the application of an ultra-precision stage.