Hao Yang

This book provides its reader with a good understanding of the stabilization of switched nonlinear systems (SNS), systems that are of practical use in diverse situations: design of fault-tolerant systems in space- and aircraft; traffic control; and heat propagation control of semiconductor power chips. The practical background is emphasized throughout the book; interesting practical examples frequently illustrate the theoretical results with aircraft and spacecraft given particular prominence. Stabilization of Switched Nonlinear Systems with Unstable Modes treats several different subclasses of SNS according to the characteristics of the individual system (time-varying and distributed parameters, for example), the state composition of individual modes and the degree and distribution of instability in its various modes. Achievement and maintenance of stability across the system as a whole is bolstered by trading off between individual modes which may be either stable or unstable or by exploiting areas of partial stability within all the unstable modes. The book can be used as a reference for academic research on switched systems or used by graduate students of control theory and engineering. Readers should have studied linear and nonlinear system theory and have some knowledge of switched and hybrid systems to get the most from this monograph.

This book provides its reader with a good understanding of the stabilization of switched nonlinear systems (SNS), systems that are of practical use in diverse situations: design of fault-tolerant systems in space- and aircraft; traffic control; and heat propagation control of semiconductor power chips. The practical background is emphasized throughout the book; interesting practical examples frequently illustrate the theoretical results with aircraft and spacecraft given particular prominence. Stabilization of Switched Nonlinear Systems with Unstable Modes treats several different subclasses of SNS according to the characteristics of the individual system (time-varying and distributed parameters, for example), the state composition of individual modes and the degree and distribution of instability in its various modes. Achievement and maintenance of stability across the system as a whole is bolstered by trading off between individual modes which may be either stable or unstable or by exploiting areas of partial stability within all the unstable modes. The book can be used as a reference for academic research on switched systems or used by graduate students of control theory and engineering. Readers should have studied linear and nonlinear system theory and have some knowledge of switched and hybrid systems to get the most from this monograph.

Hybridsystems(HS)aredynamicalsystemsthatinvolvetheinteractionofconti- ousanddiscretedynamics. ThestudyofHSismotivatedbythefundamentally- bridnatureofmanyreallifeapplications. Overthelastdecade,signi?cantprogress has taken place in modeling and simulation, veri?cation, stability and controller synthesisforHS. Faultsinautomatedprocessesoftencauseundesiredreactionsandshut-downof a controlledplant,andtheconsequencescouldbedamagetotechnicalpartsofthe plant or to its environment. Fault diagnosis (FD) and fault tolerant control (FTC) arehighlyrequiredforsafetypurpose,andaimatguaranteeingcertainsystemp- formances and/or properties to be maintained in spite of faults. In the past more than30years,fruitfultheoreticalresultsonFDandFTChavebeenreportedforv- iouslinearandnonlinearsystemswithmanysuccessfulengineeringapplicationsin practicalsystems. FD problem for HS has attracted some attentions. However, to the best of the authors' knowledge, until now, the FTC issue for HS has not yet been intensively studied. FTC method for HS deserves further investigations due to its academic meaningaswellaspracticalone. 1. Motivationfromacademicresearch Itiswellknownthatthestabilityandsomespeci?cationsofHScanbeachieved underquite rigorousconditions. Most of existing results are devotedto off-line analysisanddesign,suchthattheHSworkswellaswhatitisexpected. However, faultsmayabruptlychangesystembehavior,FTCstrategiesmustbeapplied- line,notonlytokeepthestabilitybutalsotomaintainsomespeci?cationsofthe HSinpresenceoffaults. Thisresultsinagreattheoreticalchallenge,sincemany classicalFTCmethodsfornon-hybridsystemscannotbeeasilyextendedtoHS. FTCtheoryforHSneedstobedeveloped. VIII Preface 2. Motivationfrompracticalapplications Manypracticalsystemshavetobemodeledbyhybridmodels,e.g.chemicalp- cesses,switchedRLCcircuits,intelligenttransportationsystems,etc. Thesafety andreliabilityofthesesystemsareneeded,andFTCtechniquesforHSarehighly required. The HS considered in this book consists of a series of continuous modes and a switching logic. Switching from one mode to another is due to a switching law generated from the switching logic. Faulty behaviors of HS are investigated s- tematically. Two main kindsof faults are considered:Continuous faults that affect continuous modes; Discrete faults that affect the desired switching. In these two faultycases,theFTCdesignhastwomainobjectivesasfollows: 1) maintainthecontinuousperformancesincludingvariousstabilities (e.g. L- punovstability,asymptoticalstability andinput-to-statestability)oftheoriginand theoutputtracking/regulationbehaviorsalongthetrajectoriesofHS. 2) maintain the discrete speci?cations that have to be followed by HS, e.g. a desiredswitchingsequence.