Channel Assignment And Controller Design Of Networked Systems

All the existing results on networked control systems (NCSs) with limited channels are only limited to the scheduling and control co-design. However, in many NCSs, the protocol of channel assignment is often steered by a random event, namely, random event-driven systems. Such implementation action can be extensively found in vehicle formation control systems, sonar detection systems and environmental monitor systems. Under such circumstances, the existing control methods based on scheduling may be no longer feasible and there is a definite need for developing a methodolody of modeling, anslysis and control synthesis for this type of systems. This dissertation investigates the NCSs with limited channels, and the obtained results are as follows.By combining the advantages of static and dynamic scheduling strategies, a novel co-design method of controller and hybrid scheduling strategy is obtained for the NCSs, where the output and input communication sequences are schedulable. The co-design problem is solved as follows:determining scheduling sequences for both sides that can preserve controllability and observability; designing output feedback controller without considering the effect of limited communication channels; setting up a rule that governs the switching between obtained scheduling sequences under the conditions of closed-loop system.The NCSs, in which the channel assignments for sensors and actuators are steered by random events described as two independent Markov processes, are modeled as Markov jump linear systems (MJLSs) with known transition probabilities. Based on the random system theory and time delay system theory, a novel methodolody for stability anslysis and controller design is obtained. The obtained results are dependent on the states of Markov processes and transmission delays, and the results are extended to the case of partially unknown transition probabilities.The NCSs, where the output communication sequences are schedulable and the channel assignments for actuators are random, are built as hybrid systems with deterministic scheduling properties and random properties. The scheduling peoperties of communication sequence are described by the switching subsystems, and the random peoperties of channel assignment are described by the subsystems of MJLSs. The anslysis and control synthesis are studied in the context of almost sure stability. The necessary and sufficient conditions of mean-square stability for NCSs with limited channels are obtained by using a hold-input strategy. Based on the condition, a comparison between the hold-input strategy and the zero-input strategy is made. Then, the NCSs with packets loss are investigated by combining the advantages of the two strategies. The system is modeled as a random switching system with three subsyetems, and controllers are designed by using switching system theorem such that the closed-loop system is mean-square stable.