Robust Discrete-Time Sliding Mode Controller for a Class of Nonlinear Perturbed Systems

The output tracking problem for a class of nonlinear systems presented in Nonlinear Block Controllable (NBC) form is addressed. Both matched and unmatched perturbations are considered. First, the Block Control iterative feedback linearization technique combined with a perturbation estimation are employed to design a sliding manifold. With the perturbation estimation, the effect of unmatched perturbation is mitigated. Then, a discrete-time sliding mode controller is synthesized such that the system state is driven toward a vicinity of the designed sliding manifold and stays there for all sampled time instants, avoiding chattering and reducing the matched perturbation effect. The effectiveness of the proposed methodology is confirmed by simulation.