Uncertain discrete sliding mode variable structure control systems by gray model estimation method

The design of sliding mode variable structure control (SMVSC) for discrete time systems with uncertainties is discussed by discrete reaching law in this paper. The reason of causing chattering is given and a discrete reaching law with border lay is developed. Gray model estimation is built for the uncertainty items and the values of parameters are obtained. The reaching time is reduced by the proposed method and it can drive the system to reach the switching belt in finite time and remain on the switching surface. The system will not be passed through the switching surface and the chattering is eliminated effectively.