On output sampling based sliding mode control for discrete time systems

This paper considers the problem of designing an output feedback sliding mode controller for discrete time systems. A minimal set of current and past outputs are identified to determine an extended output signal. This augmented system permits the design of a sliding manifold based upon output information only, which renders the sliding mode dynamics stable. It is shown that any transmission zeros of the augmented system will also be among the transmission zeros of the original plant. The class of discrete time systems which can be stabilised by output feedback sliding mode control is broadened by the proposed method. The theoretical results are constructive and are demonstrated via a motivational example which could not previously be solved by static output feedback.