Dynamic output feedback controllers for mismatched uncertain variable structure systems

This paper proposes a dynamic output feedback controllers for variable structure systems. It is based on the concept of output feedback controllers, introduced by Zak and Hui and Kwan for matched uncertain variable structure systems in which the state is unavailable and no estimated state is required. In this paper, we extend this idea to a class of mismatched uncertain variable structure systems. A modified variable structure controllers is derived to guarantee the existence of the sliding mode by using output feedback only. The stability of the equivalent reduced-order system in the sliding mode is assured under certain conditions.