Control And Filtering Of Time-delay Switched Systems In Network Environment

With the rapid development of network technology, more and more complicatedsystems have applied network communication. Compared with the traditional controlsystems, Networked Control Systems have many advantages, such as the more simplestructure and better flexibility, which are also easier to expand, upgrade and maintain.However, the introduction of the network has brought a series of problems andconstraints including network induced delay, packet loss, signal quantization and etc. Sothe study on systems in network environment is of great necessity and importance. Onthe other hand, switched systems consisting of several subsystems and the switchingrule governing the switch between the subsystems are applied in various fields. Thisthesis aims to explore the control and filtering of switched systems in networkenvironment, especially for the case caused by network induced delay and packet loss.Firstly, this thesis is concerned with the analysis of continuous-time systems withtime-varying delays. Under the frame of input-output method and small gain theorem,we model the time-varying delay as two parts: approximation part as time-invariantdelay and the error part. Here we introduce one-term approximation and two-termapproximation and provide the sufficient conditions for system stability andperformance analysis.Secondly, based on switched system theory, stabilization problems of NetworkedControl Systems with network induced delays in communication channels is focused.We combine the two delays from sensor to controller and from controller to actuator asa whole and assume the delay satisfy the Markovian jump process with partly unknowntransition probabilities. This is a more general form which covers the systems withcompletely known and completely unknown transition probabilities as two special cases.It provides the design of the state feedback controller. Moreover, linear matrixinequality-based sufficient conditions for stochastic stabilization of the underlyingsystems are investigated. Numerical example is given to illustrate the usefulness andflexibility of the results developed.Finally, T-S fuzzy filtering for time-delay switched systems in networkenvironment is addressed. According to T-S fuzzy modeling theory, we design themode-independent filter to guarantee input-output stability and stochastic stability forthe filtering error system through small gain theorem. Packet loss under Bernoullidistribution and network induced time-varying delays are taken into consideration.Numerical example is given to illustrate the given results.