Non-Uniformly Sampled-Data Control For Networked Control Systerms With Communication Constraints

A Networked Control System (NCS) is a feedback control system in which the sensors controllers and actuators are connected through a share real-time network. It is also a fully spatially distributed system based on the network. A great deal of attention has been focused on this class of control systems in the recent years. Compared with the conventional point to point control systems, NCS has advantages of less wiring, low cost, good flexibility, share of information resources and remote operation, etc. Because of these distinctive benefits, application of these systems ranges over various fields. However, intervention of the shared communication network brought many new problems to networked control system, such as network-induced time delay, packets loss, communication constraints, network scheduling and so on. These problems make the analysis of NCS complex.For the multiple inputs and multiple outputs NCS with limited communication channels, the modeling of systems, the scheduling of network and the design of controller are studied. The main work lies in the following items:Firstly, for NCS with limited channels which are permitted some of sensors and actuators can access to networks at any time, the notion of sampling sequence and update sequence are introduced to describe the system scheduling strategy. The augmented state space model of the NCS is established by using lifting technique. The controllability and observability of the system are analyzed, and the output feedback controller is designed based on the model. Simulation results verify the feasibility and validity of this analysis.Secondly, a model integrated with control and scheduling is derived. The schedulability conditons and asymptotic stability results of this closed loop system are discussed. The solution of output feedback controller is given out by the means of linear matrix inequalities approach. It turns out that the performance of networked control system is not only related with the control design, but also the scheduling strategy.Finally, for the networked control system with communication constraints and noise, a new model integrated with control and scheduling is established. The optimal state estimator based on the output value is designed by using the idea of kalman filtering. According to the optimal estimate state, and using the method of linear matrix inequality, optimal guaranteed cost controller is designed. Through the simulation of several cases, the feasibility of the algorithm is verified.