Error feedback sliding mode controllers in output regulation of nonlinear systems

The output tracking control problem of MIMO systems, both minimum and nonminimum phase, is here discussed in sliding mode terms. The first goal of the paper is to address the problem of designing an error feedback controller able to achieve the asymptotic tracking of an exosystem-generated reference trajectory. To this end two design techniques are illustrated. A second goal is to address the robustness of the proposed control scheme against parameter uncertainties and external disturbances