Variable Structure Controller Design for Output Tracking of a Class of Discrete-time Nonlinear Systems

In this paper, a robust controller based on the variable structure control technique for the output tracking of a class of discrete-time uncertain nonlinear systems is developed. An upper bound on the uncertainties is derived to ensure the existence of a quasi-sliding mode in these uncertain systems. Analysis results indicate that the output of the closed-loop system tracks a desired output trajectory and, simultaneously, all signals inside the loop are bounded. Furthermore, the tracking error depends on the proposed controller's parameters. Two examples are given to demonstrate the effectiveness of the proposed control scheme.