Guaranteed Cost Control over Quality-of-Service Networks

The communication quality has a strong effect on the stability and control performance of a networked control system (NCS). To achieve superior control performance, better communication quality is desired. However, high network cost is induced. This paper aims at finding an optimal trade-off between control performance and network cost. A Quality-ofService (QoS) communication network is introduced, where the statistical properties of the transmission delay can be controlled by adjusting its transition generator. The QoS concept enables a conjoint control of communication network and control system itself, which results in a Markovian jump linear system (MJLS) with mode-dependent delays. A delay-dependent stability condition ensuring stochastic mean-square stability is derived by using the Lyapunov-Krasovskii functional. A guaranteed cost of state evolutions is determined and the perturbation upper bound on Markov process transition generator is obtained. A performance-cost trade-off is achieved by optimizing the Markov process transition generator within the perturbation upper bound. The performance benefit of the proposed control concept is demonstrated in a numerical example.