Chapter1:

IntroductiontoAutomaticControl重點掌握:?控制系統的基本組成?基本的控制方式及反饋控制系統的特點?控制系統的性能要求Maincontents1-1Whatisacontrolsystem?1-2Whyarecontrolsystemsimportant?1-3Whatisanautomaticcontrolsystem?1-4Basiccomponentsandtypesofcontrolsystem.1-5Howtoevaluateaautomatic

controlsystem?1-6Thedevelopmentofautomatic

controltheory.1-1Whatisacontrolsystem?examplesControlofTrafficLightsPowerHeaterFurnaceSwitchFurnacetemperaturecontrolsystem1-1Whatisacontrolsystem?DesiredtemperaturefurnacethermometergasmixervalveairoperatorTemperaturecontrolsystem1-1Whatisacontrolsystem?waterlevelcontrolsystem1-1Whatisacontrolsystem?DefinitionofacontrolsystemAninterconnectionofcomponentsformingasystemconfigurationthatwillprovideadesiredsystemresponse.由相互關聯的部件按一定的結構構成的系統，能夠提供預期的系統響應。1-1Whatisacontrolsystem?1-2Whyarecontrolsystemsimportant?(1)控制系統無處不在.(2)提高產量，降低成本.(3)提高精度、可靠性.(4)能夠在許多人不到達的場所發揮作用.furnacethermometergasmixervalveairDesiredtemperatureoperator1-3Whatisanautomaticcontrolsystem?Acontrolsystemwithoutpeopleinvolvediscalledautomaticcontrolsystem.Definitionofautomaticcontrolsystem1-3Whatisanautomaticcontrolsystem?TemperatureautomaticcontrolsystemGasMixerAirValveMotorAmplifierUTPotentiometerURAmplifierFurnaceThermocouple1-3Whatisanautomaticcontrolsystem?waterlevelautomatic

controlsystem1-3Whatisanautomaticcontrolsystem?1.Accordingtotheformofgivensignal

RegulatorSystemsversusServoSystems(恒值系統和隨動系統）2.AccordingtowhetherthesystemissatisfiedthesuperpositionprincipleLinearSystemsversusNonlinearSystemAlinearsystemsatisfiesthepropertiesofsuperpositionandHomogeneity:(PrincipleofSuperposition).1-4typesandBasiccomponentsofcontrolsystems.SuperpositionPropertysystemsystemsystemHomogeneityPropertysystemsystemPrincipleofsuperposition1-4typesandBasiccomponentsofcontrolsystems.3.Accordingtowhetherthesystem’sparametersare

changedwithtime

Time-InvariantSystemsversusTime-varyingSystem4.Accordingtotheformofthesignal

ContinuousSystemsversusDiscreteSystems

5.AccordingtothenumberofI/O

SISOSystemsversusMIMOSystems6.AccordingtothestructureofthesystemOpen-loopsystem,closed-loopsystem(feedbackcontrolsystems),CompoundControlsystems1-4typesandBasiccomponentsofcontrolsystems.Example:nextpagesTheblockdiagramdescriptionforacontrolsystem:ConvenienceBlockdiagramofcontrolsystems1-4typesandBasiccomponentsofcontrolsystems.1-4typesandBasiccomponentsofcontrolsystems.Desiredoutputresponse(Commandinput)ActuatingdeviceprocessOutputControllerplantExample:PowerHeaterFurnaceSwitch被控對象FurnaceSwitch&HeaterCommandinputOutputControllerPlantFurnacetemperaturecontrolsystem1-4typesandBasiccomponentsofcontrolsystems.Example:TankValve1LeverDisturbance(valve2)Valve1Valve2TankWaterLevelcontrolsystem1-4typesandBasiccomponentsofcontrolsystems.Example:TemperaturecontrolsystemGasMixerAirValveMotorAmplifierUTPotentiometerURAmplifierFurnaceThermocoupleValveMixerAirAmplifierFurnaceCAmplifierThermocoupleMotorURUT1-4typesandBasiccomponentsofcontrolsystems.Example:AnOpen-loopcontrolsystemutilizesanactuatingdevicetocontroltheprocessdirectlywithoutusingfeedback.Openloopcontrol開環控制(Open-loopControl)——系統的輸出端與輸入端之間不存在反饋回路，輸出量對系統的控制作用沒有影響。1-4typesandBasiccomponentsofcontrolsystems.Open-loopControlSystemTheoutputoftheopen-loopsystemhasnoeffectupontheinputsignal.Thereistheneedtoknowanaccuratemodelofindividualcomponents.C被控對象ControllerPlantRUPlantControllerMeasurementnCU1-4typesandBasiccomponentsofcontrolsystems.優點：簡單，相對來說成本低缺點：對可能出現的被控量偏離給定值的偏差沒有任何修正能力，抗干擾能力差，控制精度不高。Featuresofopen-loopcontrol1-4typesandBasiccomponentsofcontrolsystems.Aclosed-loopcontrolsystemusesameasurementofoutputandfeedbackofthesignaltocompareitwiththedesiredoutput(referenceorcommand).Closed-loopcontrolsystemsReferenceinputComparisonControllerPlantOutputMeasurementFeedbacksignal)1-4typesandBasiccomponentsofcontrolsystems.優點：抗干擾能力強，控制精度高缺點：復雜，有時會產生不穩定。Featuresoffeedbackcontrolsystems1-4typesandBasiccomponentsofcontrolsystems.CompoundControlsystemsCombinationofopen-loopandclosed-loopControllerPlantCFeedbackelementR—CompensatorControllerPlantCFeedbackelementR—Compensatorn1-4typesandBasiccomponentsofcontrolsystems.ObjectivesofcontrolTheobjectivesofthecontrolsystemistocontroltheoutputsinsomeprescribedmannerbytheinputsthroughtheelementsofcontrolsystems.通常目標規定為系統的輸入。Ingeneral,theobjectivescanbeidentifiedwithinputs.1-4typesandBasiccomponentsofcontrolsystems.Basiccomponentsofcontrolsystems被控對象(plant,process)測量元件（sensor）可以對被控量進行測量，并轉換成能與輸入信號進行比較的量綱和數值，也稱為反饋元件；比較環節（comparison）實現誤差檢測；執行機構（actuator）實現對受控對象的操控，起到功率放大的作用。控制律或控制算法（algorithm):控制器的核心。1-4typesandBasiccomponentsofcontrolsystems.AnalysisofautomaticcontrolsystemStep1

確定系統任務；Step2

明確：被控對象、被控量、給定值、測量元件、執行機構和比較元件；Step3敘述系統工作原理；Step4

系統原理方框圖。1-4typesandBasiccomponentsofcontrolsystems.terms1.被控對象（plant）

指被控制的設備或過程2.控制器（控制裝置controller） 除了被控制對象之外的各部分的組合；3.控制系統(controlsystem) 受控對象與控制裝置構成控制系統。4.給定值（期望值、輸入量reference/input） 被控制量要求的變化規律(Excitationappliedtoacontrolsystemfromanexternalsource).1-4typesandBasiccomponentsofcontrolsystems.terms5.被控量(controlledvariable) 被控制的物理量；6.輸出（Output）Theresponseobtainedfromasystem（通常與被控量一致。）7.干擾(disturbance) 所有使被控量偏離期望值的因素8.反饋（Feedback）-Theoutputofasystemthatisreturnedtomodifytheinput.1-4typesandBasiccomponentsofcontrolsystems.TurntablespeedcontrolTachometerdcamplifierTurntabledcmotorbatterySpeedsettingAmplifierdcmotorTurntableActualspeedDesiredSpeed(voltage)Tachometer1-4typesandBasiccomponentsofcontrolsystems.amplifierMotorGearingValveActuatorWatercontainerProcesscontrollerFloatmeasurement(Sensor)ErrorFeedbacksignalresistancecomparatorDesiredwaterlevelInputActualwaterlevelOutputThewaterlevelcontrolsystem:Figure1.11-4typesandBasiccomponentsofcontrolsystems.1-5Howtoevaluateacontrolsystem?Specifications(RequirementsonControlSystem)(1)Stability:

Stable

（穩）（Basicrequirement）,Thesystemmustbestable(3)Swiftness:Swift,peaktime,settlingtime（快）（Requirementoftransientresponse）Transientprocessofsystem’sstepresponsemustbestableandquick(2)Accuracy:Accurate,

steady-sateerror（準）（Requirementofsteady-state）Outputandtrackingprecisionmustsatisfytherequirementwhentheresponsereachedthesteady-state1-5Howtoevaluateacontrolsystem?1-6HistoryofAutomaticControl1769:JamesWatt’ssteamengineandflyballgovernor.一種憑借直覺的實證性發明。1-6HistoryofAutomaticControl1868:J.C.Maxwellformulatesamathematicalmodelforagovernorcontrolofsteamengine.A.M.Lyapunov（李雅普諾夫，1892年）,thefirstandsecondmethodJ.C.Maxwell（麥克斯韋爾），1868年發表《論調節器》Hurwitz（霍爾維茨，1895年）andE.J.Routh（勞斯，1884年）stabilitycriterion1-6HistoryofAutomaticControlBode(波德，1927年）developedamethodofLogarithmicfrequencycharacteristic1932:H.Nyquist(奈奎斯特）developedamethodforanalyzingthestabilityofsystems.W.R.Evans（伊萬斯，1948年)developedroot-locusmethod1-6HistoryofAutomaticControl1948,N.Wienerpublished《Cybernetics》(控制論）Classicalcontroltheoryforsingleinputsingleoutputsystems二次世界大戰中火炮，雷達，飛機以及通訊系統的控制研究直接推動了經典控制的發展。1-6HistoryofAutomaticControl空間軍備競賽催生了現代控制理論蘇聯L.S.Pontryagin(龐特里亞金）提出極大值原理(MaximumPrinciple)(1956)美國R.Bellman發表著名的DynamicProgramming（動態規劃）（1957）L.S.Pontryagin1-6HistoryofAutomaticControl美籍匈牙利人R.E.Kalman發表“OntheGeneralTheoryofControlSystems”等論文，引入狀態空間法分析系統，提出能控性，能觀測性，最佳調節器和kalman濾波等概念，奠定了現代控制理論的基礎(1960)1963年,美國的LoftiZadeh與C.Desoer發表LinearSystems-AStateSpaceApproach。1965年，Zadeh提出模糊集合和模糊控制概念R.E.KalmanC.Desoer1-6HistoryofAutomaticControl1980:Robustcontrolsystemdesignwidelystudied.