Robust H∞ state feedback control of networked control systems with congestion control

This paper examines the problem of robust state feedback control of networked control systems with a simple congestion control scheme. This simple congestion control scheme is based on comparing current measurements with last transmitted measurements. If their difference is less than a prescribed percentage of the current measurements then no measurement is transmitted to the controller. The controller always uses the last transmitted measurements to control the system. With this simple congestion control scheme, a robust H_∞ state feedback controller design methodology is developed based on the Lyapunov-krasovskii functional approach. Sufficient conditions for the existence of delay mode dependent controllers are given in terms of bilinear matrix inequalities (BMIs). These BMIs are converted into quasi convex linear matrix inequalities (LMIs) and solved by using the cone complementarity linearization algorithm. The effectiveness of the simple congestion control in terms of reducing the network´s bandwidth is elaborated using simulation examples.