Sliding Mode Control for Time-delay Discrete Systems with Unmatched Uncertainty

According to a class of uncertain time-delay discrete systems,the sliding mode control problem is discussed.The delay of the system is time varying and the uncertainty is unmatched.The uncertainty is transferred into the matched part and the unmatched part by a nonsingular matrix transformation,the unmatched uncertainty is needed to satisfy the norm bounded condition.The sliding mode controller satisfied the hitting condition is designed by variable structure control method which make the state of the system hit the sliding mode surface in finite time and stay on it subsequently,so the system can derive stable sliding mode.The conservative feature is overcome in the traditional sliding mode control approach which needs matched uncertainty.