Model-based Networked Control Systems – Necessary and Sufficient Conditions for Stability

In this paper the control of a continuous linear plant where the state sensor is connected to a linear controller/actuator via a network is addressed. The work focuses on reducing the network usage using knowledge of the plant dynamics. Specifically, the controller uses an explicit model of the plant that approximates the plant dynamics and makes possible the stabilization of the plant even under slow network conditions. Necessary and sufficient conditions for stability are derived in terms of the update time h and the parameters of the plant and of its model. The deterioration of behavior when either h or the modeling error increase is explicitly shown.