Adaptive sliding mode control for discrete-time systems

In this paper, robust adaptive sliding mode tracking control for discrete-time multi-input multi-output (MIMO) systems with unknown parameters and disturbances is considered. The robust tracking controller is comprised of adaptive control and sliding mode control design. Bounded motion of the system around the sliding surface and stability of the global system in the sense that all signals remain bounded are guaranteed. The adaptive algorithms of estimating the parameters (including the parameters in the interactor matrix) are formulated even though the upper and lower bounds of the disturbances are unknown. An example and its simulation results are presented to illustrate the proposed approach.