自控原理課件1(英文版)

Chapter1:

IntroductiontoAutomaticControl重點(diǎn)掌握:?控制系統(tǒng)的基本組成?基本的控制方式及反饋控制系統(tǒng)的特點(diǎn)?控制系統(tǒng)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(guān)聯(lián)的部件按一定的結(jié)構(gòu)構(gòu)成的系統(tǒng)，能夠提供預(yù)期的系統(tǒng)響應(yīng)。1-1Whatisacontrolsystem?1-2Whyarecontrolsystemsimportant?(1)控制系統(tǒng)無處不在.(2)提高產(chǎn)量，降低成本.(3)提高精度、可靠性.(4)能夠在許多人不到達(dá)的場(chǎng)所發(fā)揮作用.furnacethermometergasmixervalveairDesiredtemperatureoperator1-3Whatisanautomaticcontrolsystem?Acontrolsystemwithoutpeopleinvolvediscalledautomaticcontrolsystem.Definitionofautomaticcontrolsystem1-3Whatisanautomaticcontrolsystem?TemperatureautomaticcontrolsystemGasMixerAirValveMotorAmplifierUTPotentiometerURAmplifierFurnaceThermocouple1-3Whatisanautomaticcontrolsystem?waterlevelautomatic

controlsystem1-3Whatisanautomaticcontrolsystem?1.Accordingtotheformofgivensignal

RegulatorSystemsversusServoSystems(恒值系統(tǒng)和隨動(dòng)系統(tǒng)）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(duì)象FurnaceSwitch&HeaterCommandinputOutputControllerPlantFurnacetemperaturecontrolsystem1-4typesandBasiccomponentsofcontrolsystems.Example:TankValve1LeverDisturbance(valve2)Valve1Valve2TankWaterLevelcontrolsystem1-4typesandBasiccomponentsofcontrolsystems.Example:TemperaturecontrolsystemGasMixerAirValveMotorAmplifierUTPotentiometerURAmplifierFurnaceThermocoupleValveMixerAirAmplifierFurnaceCAmplifierThermocoupleMotorURUT1-4typesandBasiccomponentsofcontrolsystems.Example:AnOpen-loopcontrolsystemutilizesanactuatingdevicetocontroltheprocessdirectlywithoutusingfeedback.Openloopcontrol開環(huán)控制(Open-loopControl)——系統(tǒng)的輸出端與輸入端之間不存在反饋回路，輸出量對(duì)系統(tǒng)的控制作用沒有影響。1-4typesandBasiccomponentsofcontrolsystems.Open-loopControlSystemTheoutputoftheopen-loopsystemhasnoeffectupontheinputsignal.Thereistheneedtoknowanaccuratemodelofindividualcomponents.C被控對(duì)象ControllerPlantRUPlantControllerMeasurementnCU1-4typesandBasiccomponentsofcontrolsystems.優(yōu)點(diǎn)：簡(jiǎn)單，相對(duì)來說成本低缺點(diǎn)：對(duì)可能出現(xiàn)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(yōu)點(diǎn)：抗干擾能力強(qiáng)，控制精度高缺點(diǎn)：復(fù)雜，有時(shí)會(huì)產(chǎn)生不穩(wěn)定。Featuresoffeedbackcontrolsystems1-4typesandBasiccomponentsofcontrolsystems.CompoundControlsystemsCombinationofopen-loopandclosed-loopControllerPlantCFeedbackelementR—CompensatorControllerPlantCFeedbackelementR—Compensatorn1-4typesandBasiccomponentsofcontrolsystems.ObjectivesofcontrolTheobjectivesofthecontrolsystemistocontroltheoutputsinsomeprescribedmannerbytheinputsthroughtheelementsofcontrolsystems.通常目標(biāo)規(guī)定為系統(tǒng)的輸入。Ingeneral,theobjectivescanbeidentifiedwithinputs.1-4typesandBasiccomponentsofcontrolsystems.Basiccomponentsofcontrolsystems被控對(duì)象(plant,process)測(cè)量元件（sensor）可以對(duì)被控量進(jìn)行測(cè)量，并轉(zhuǎn)換成能與輸入信號(hào)進(jìn)行比較的量綱和數(shù)值，也稱為反饋元件；比較環(huán)節(jié)（comparison）實(shí)現(xiàn)誤差檢測(cè)；執(zhí)行機(jī)構(gòu)（actuator）實(shí)現(xiàn)對(duì)受控對(duì)象的操控，起到功率放大的作用?？刂坡苫蚩刂扑惴ǎ╝lgorithm):控制器的核心。1-4typesandBasiccomponentsofcontrolsystems.AnalysisofautomaticcontrolsystemStep1

確定系統(tǒng)任務(wù)；Step2

明確：被控對(duì)象、被控量、給定值、測(cè)量元件、執(zhí)行機(jī)構(gòu)和比較元件；Step3敘述系統(tǒng)工作原理；Step4

系統(tǒng)原理方框圖。1-4typesandBasiccomponentsofcontrolsystems.terms1.被控對(duì)象（plant）

指被控制的設(shè)備或過程2.控制器（控制裝置controller） 除了被控制對(duì)象之外的各部分的組合；3.控制系統(tǒng)(controlsystem) 受控對(duì)象與控制裝置構(gòu)成控制系統(tǒng)。4.給定值（期望值、輸入量reference/input） 被控制量要求的變化規(guī)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(wěn)）（Basicrequirement）,Thesystemmustbestable(3)Swiftness:Swift,peaktime,settlingtime（快）（Requirementoftransientresponse）Transientprocessofsystem’sstepresponsemustbestableandquick(2)Accuracy:Accurate,

steady-sateerror（準(zhǔn)）（Requirementofsteady-state）Outputandtrackingprecisionmustsatisfytherequirementwhentheresponsereachedthesteady-state1-5Howtoevaluateacontrolsystem?1-6HistoryofAutomaticControl1769:JamesWatt’ssteamengineandflyballgovernor.一種憑借直覺的實(shí)證性發(fā)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(fā)表《論調(diào)節(jié)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(wàn)斯，1948年)developedroot-locusmethod1-6HistoryofAutomaticControl1948,N.Wienerpublished《Cybernetics》(控制論）Classicalcontroltheoryforsingleinputsingleoutputsystems二次世界大戰(zhàn)中火炮，雷達(dá)，飛機(jī)以及通訊系統(tǒng)的控制研究直接推動(dòng)了經(jīng)典控制的發(fā)展。1-6HistoryofAutomaticControl空間軍備競(jìng)賽催生了現(xiàn)代控制理論蘇聯(lián)L.S.Pontryagin(龐特里亞金）提出極大值原理(MaximumPrinciple)(1956)美國(guó)R.Bellman發(fā)表著名的DynamicProgramming（動(dòng)態(tài)規(guī)劃）（1957）L.S.Pontryagin1-6HistoryofAutomaticControl美籍匈牙利人R.E.Kalman發(fā)表“OntheGeneralTheoryofControlSystems”等論文，引入狀態(tài)空間法分析系統(tǒng)，提出能控性，能觀測(cè)性，最佳調(diào)節(jié)器和kalman濾波等概念，奠定了現(xiàn)代控制理論的基礎(chǔ)(1960)1963年,美國(guó)的LoftiZadeh與C.Desoer發(fā)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.