| Switching control as an intersection of computer science and control science has attracted considerable attention of scientific community due to its extensive applicability.As a typical hybrid system,the switched system is mostly used to describe the complex system formed by the coupling of continuous dynamic systems and discrete event systems that exist widely in reality.The stability analysis and stabilization problems of switched systems have received considerable attention since they were proposed.In recent years,with the increasing requirements of system security,the fault detection problem of switched systems has also attracted extensive research by the scientific community.However,in time-driven switched dynamic systems,most of the current research mainly focuses on the field of synchronous switching where all subsystems are stable,while the research on control and fault detection problems for asynchronous switched systems and switched systems with all subsystems unstable is still not well-established.In the event-driven switched dynamic system,on the other hand,the research of the switched discrete event systems is in its infancy,and it is an urgent problem to be solved.This thesis mainly studies the control and fault detection problem of switched systems composed of different kinds of subsystems.The switched system composed of different types of subsystems refers that switched systems with partially unstable subsystems,which formed as asynchronous switched systems in this dissertation,switched systems with all subsystems unstable,and switched systems whose subsystems are discrete event systems which are represented as asynchronous sequential machines in this thesis.The first two are time-driven dynamic systems,and the stabilization and fault detection of these two kinds of switched systems are studied in this dissertation.The latter is an event-driven dynamic system.The model matching and fault tolerance of switched asynchronous sequential machines are investigated in this dissertation.The main contents of this thesis are as follows:Firstly,the stability analysis and stabilization problems of continuous-time and discrete-time asynchronous switched linear systems with model-dependent average dwell time are addressed.In the actual situation,the switching of the designed controller often lags behind its corresponding subsystem,which makes the operating time of each subsystem can be divided into two parts:the controller-matched part and the controller-mismatched part.By controlling the proportion of these two parts and utilizing the multi-Lyapunov function technology,sufficient conditions to guarantee the globally uniformly exponentially stability and weighted L2（l2）performance of asynchronous switched systems are obtained.Furthermore,the concept of the switching instant set is first proposed in this thesis,which makes the proof process clearer when using the model-dependent average dwell time to research the asynchronous switching problems.Secondly,the state filtering and fault detection problems of asynchronous switched systems with model-dependent average dwell time are studied.In this part of the research,it is assumed that all subsystems are stable,a set of mode-dependent fault detection filters are designed with respect to each subsystem and combined with the switched system into an augmented switched system.Under the asynchronous mechanism,the obtained augmented system is transformed into an asynchronous augmented system.Utilizing theμ-dependent discontinuous multi-Lyapunov function and the model-dependent average dwell time,the globally uniformly exponentially stability and weighted l2 or H-/weighted l2 performance of the asynchronous augmented system are guaranteed.Then,the design parameters of the required filter are obtained.The main idea of this part is to transform the filter design problem into the stability analysis problem of the asynchronous augmented system.Thirdly,the stabilization and fault detection problems of discrete-time switched systems with all subsystems unstable are investigated.For the situation where the energy of the switched system cannot be attenuated due to all the subsystems being unstable,we suppose that there is aμ-dependent discretized multi-Lyapunov function such that the energy of the switched system can be attenuated by the switching behavior.Sufficient conditions for guaranteeing globally uniformly asymptotically stable of the switched system with all subsystems unstable are derived by utilizing the discretized Lyapunov function technique and bounded dwell time switching strategy.On the other hand,a set of mode-dependent fault detection filters are also designed with respect to each subsystem and combined with the switched system into an augmented switched system.The globally uniformly asymptotically stability and H-/non-weighted l2 performance of the asynchronous augmented system are guaranteed.Then,the required fault detection filter can be obtained.In addition,a novel pair of the residual evaluation function and threshold function is also provided for improving the sensitivity and practicability of fault detection logic.Finally,the concept of switched asynchronous sequential machines driven by external switching signals is first proposed in this thesis,and the model matching and fault tolerance problems under this model are studied.The additional control burden imposed by the arbitrary switching signals and fault input has been discussed in detail and quantified by defining novel skeleton matrices.The necessary and sufficient conditions to guarantee the existence of a proper model matching and fault tolerance controller are obtained as well as a solid procedure for such a controller is designed in the framework of corrective control theory.And the design process of the correction controller is explained in detail by use of an illustrative example. |
