Quasi-sliding mode networked controller for linear discrete time systems subject to disturbance

In this paper we consider the problem of network-based sliding mode control of linear plants operating in the presence of a priori unknown, bounded disturbances. We propose a discrete time, dead-beat sliding mode controller which explicitly takes into account network induced delays. The controller employs a model which represents the nominal dynamics of the plant without disturbance. Comparing the performance of the model and the actual plant we recover the delayed disturbance signal. Then, we estimate its effect on the current state of the plant and we propose a controller which nullifies the effect of the disturbance on the plant performance in the shortest possible time, i.e. after the network induced delay plus n control steps, where n represents the plant order.