A control scheme based on discrete time-varying sliding surface for position control systems

A sliding mode control scheme for second-order discrete system is proposed using the time-varying sliding surface instead of the fixed sliding surface. The time-varying sliding surface is designed first to pass arbitrary initial states, and subsequently move towards a final sliding surface by rotating. The sliding surface rotating procedures are presented in detail. The proposed control scheme is applied to a position control system. Simulation results show that the scheme provides high performance dynamic characteristics, and is insensitive to uncertainties including parameter variations and external disturbance in the whole control process.