Robust H∞ output feedback control of networked control systems with multiple quantizers

This paper is concerned with the stability and stabilizability problems of networked control systems (NCSs) with multiple quantizers. More precisely, sensors and controllers' outputs are quantized at different quantization levels and experiencing different network-induced delays. This consideration is much more natural in NCSs due to the distributive nature of sensors and controllers. Multiple quantizers can be used to mitigate network congestions, that is, by having different quantization levels for each of the sensors and controllers. Network-induced delays are modeled by a Markov chain and quantization errors are represented as convex poly-topic uncertainties. Based on the Lyapunov-Krasovskii (L-K) functional approach, sufficient conditions for the existence of a quantized robust H∞ output feedback controller for NCSs with multiple quantizers is given in terms of bilinear matrix inequalities (BMIs). Furthermore, an iterative cone complementarity algorithm is used to convert these BMIs into a quasi-convex optimization problem which can be solved easily. A simulation example is provided to demonstrate the effectiveness of proposed theorems.