Output sliding-mode control of discrete-time nonminimum phase systems

Aiming to tracking problem of the nonminimum phase system, this paper proposes an output feedback sliding-mode method for a discrete-time input-output plant model. Using the solutions accomplished from two Diophantine equations associated with the sliding function, the proposed design algorithm can force the system trajectory to enter the sliding layer and ensure robust stability such that the tracking error is bounded in a small region. In addition, combining with a parameter adaptive algorithm is to maintain the operation of the proposed method in a system with unknown parameters. A numerical simulation result is presented to demonstrate the validity of the developed method.