自動控制原理2021雙語cha教學(xué)課件

ThePrincipleofAutomaticControl

自動控制原理Lecturers：Prof.JiangBinDr.LuNingyunCollegeofAutomationEngineeringNUAA，2021.Autumn1ThePrincipleofAutomaticConNUAA-ThePrincipleofAutomaticControl

Chapter1Introductiontocontrolsystems控制系統(tǒng)簡介2NUAA-ThePrincipleofAutomatiCourseDescriptionThiscourseisconcernedwiththeanalysisanddesignofcontrolsystemTime-domaintechniques(root-locusanalysis);Frequency-domaintechniques(Bodeplot,Nyquiststabilitytheory)Systemmodeling,sensitivityandstabilityAnalysisDesignSimulationAnalysisanddesignusingMATLAB3CourseDescriptionThiscourseReferences胡壽松主編，自動控制原理，科學(xué)出版社K.Ogata，Moderncontrolengineering(現(xiàn)代控制工程,第四版)，有原版翻印本和中譯本B.C.Kuo&F.Golnaraghi，Automaticcontrolsystems,8thedition,JohnWiley&Sons,2003〔有原版翻印〕://www-control.eng.cam.ac.uk/extras/Virtual_Library/Control_VL.html:///group/ctm/://.au/4References胡壽松主編，自動控制原理，科學(xué)出版社CourseEvaluation64hours,3credits:Homework:5%Classparticipation:5%Finalexam:90%5CourseEvaluation64hours,3cWelcometocontactusProf.JiangBinEmail:binjiang@Tel:84892301-6041(O)M)Office:A17-604(明故宮校區(qū)〕Dr.LuNingyunEmail:luningyun@Tel:84892301-6063(O)M)Office:A17-606(明故宮校區(qū)〕6WelcometocontactusProf.JiChapter1.IntroductiontocontrolsystemsWHATacontrolsystemis?WHYcontrolsystemsareimportant?WHATthebasiccomponentsofacontrolsystemare?ExamplesofcontrolsystemapplicationsWHYfeedbackisincorporatedintomostcontrolsystems?Typesofcontrolsystems7Chapter1.IntroductiontoconOutline1-1Basicconceptsofcontrolsystems1-2Controlsystemexamples1-3Classificationofcontrolsystems1-4Basicrequirementsofacontrolsystem1-5BriefintroductiontoMATLAB8Outline1-1Basicconceptsofc1-1Basicconcepts91-1Basicconcepts9Whatiscontrol?Control：使某些物理量按指定的規(guī)律變化〔e.g.keepconstant,ortrackareferencesignal〕，以保證生產(chǎn)平安，經(jīng)濟(jì)及產(chǎn)品質(zhì)量等要求的技術(shù)手段。Controlledvariable(被控量〕：指被測量(measured)并被控制(controlled)到期望值(expectedvalue)的變量Manipulatedvariable〔操縱量〕:按照指定規(guī)律變化使得被控量到達(dá)指定目標(biāo)的變量(variedbycontrollersoastoaffectthecontrolledvariable)AutomaticControl：就是應(yīng)用自動化儀表或控制裝置代替人，自動地對機器設(shè)備或生產(chǎn)過程進(jìn)展控制，使之到達(dá)預(yù)期的狀態(tài)或性能要求。e.g.Temperaturecontrolsystem(空調(diào)〕Speedcontrolsystem〔汽車〕10Whatiscontrol?Control：使某些物理Generallyspeaking,acontrolsystemisasystemthatisusedtorealizeadesiredoutputorobjectiveWhatiscontrolsystem?Plant(對象〕：Maybeapieceofequipment,perhapsjustasetofmachineparts,functioningtogether,toperformaparticularoperationProcess〔過程〕：Anaturalorartificial,progressivelycontinuingoperationordevelopmenttowardaparticularresultSystem〔系統(tǒng)〕：AcombinationofcomponentsthatacttogetherandperformacertainobjectiveDisturbance(擾動〕:Asignaltendstoaffecttheoutputofasystem11Generallyspeaking,acontrolcontrollerManipulatedvar.Open-loopcontrolsystemDefinition：thosesystemsinwhichtheoutputhasnoeffectonthecontrolaction.inputplantdisturbanceControlledvar.applications12controllerManipulatedOpen-loopOpen-loopDCMotorspeed-controlsystem電位器（產(chǎn)生給定電壓ur）假定0~10V轉(zhuǎn)速0~1000轉(zhuǎn)電位器電壓放大器可控硅功放直流電動機n擾動Purukua13Open-loopDCMotorspeed-contrCommentsonopen-loopcontrolsystemTheoutputisnotmeasuredandcomparedwiththeinput,nofeedbackEachinputcorrespondsafixedoperatingcondition

(電位器0-10v－－轉(zhuǎn)速0-1000轉(zhuǎn))TheaccuracyofthesystemdependsoncalibrationInthepresenceofdisturbance?14Commentsonopen-loopcontrolFeedbackcontrolsystemAsystemthatmaintainsaprescribedrelationshipbetweentheoutputandthereferenceinputbycomparingandusingthedifference(error)asameansofcontrol–feedbackcontrolsystemRefinputcontrollerManipulatedvar.plantdisturbanceOutputerrorsensor15FeedbackcontrolsystemAsysteBlockdiagramControllerActuatorPlantSensor-rExpectedvaluee

ErrorDisturbanceControlledvariablenycomparisoncomponent(comparisonpoint):itsoutputequalsthealgebraicsumofallinputsignals.“+〞:plus“-〞:minuslead-outpoint:Here,thesignalistransferredalongtwoseparateroutes.TheBlockrepresentsthefunctionandnameofitscorrespondingmode,wedon’tneedtodrawdetailedstructure,andthelineguidesforthetransferroute.u16BlockdiagramControllerActuatoFeedbackcontrolsystemsexisteverywhereE.g.thehumanbodyishighlyadvancedfeedbackcontrolsystem.Bodytemperatureandbloodpressurearekeptconstantbymeansofphysiologicalfeedback.Feedbackmakesthehumanbodyrelativelyinsensitivetoexternaldisturbance.Thuswecansurviveinachangingenvironment.17FeedbackcontrolsystemsexistInpractice,feedbackcontrolsystemandclosed-loopcontrolsystemareusedinterchangeablyClosed-loopcontrolalwaysimpliestheuseoffeedbackcontrolactioninordertoreducesystemerrorClosed-loopcontrolsystem18Inpractice,feedbackcontrolClosed-loopDCmotorspeedcontrolsystem19Closed-loopDCmotorspeedcon電位器電壓放大器可控硅放大器直流電動機測速機Purubuk-n擾動ua工作原理引入測速發(fā)電機，這時電壓放大器的輸入，如果外來的電網(wǎng)電壓波動使電機的轉(zhuǎn)速n，則由測速發(fā)電機確定的則則uk，ua則n，消除了偏差，控制轉(zhuǎn)速穩(wěn)定。——負(fù)反饋。同開環(huán)系統(tǒng)相比，該系統(tǒng)由于干擾引起的轉(zhuǎn)速誤差要小得多。20電位器電壓可控硅直流測速機Purubuk-n擾動ua工作原理電位器電壓放大器可控硅放大器直流電動機測速機Purubuk＋n擾動ua正反響不能用于控制系統(tǒng)用途——振蕩器〔正弦信號發(fā)生器〕如果極性接錯，這時電壓放大器的輸入，如果外來的電網(wǎng)電壓波動使電機的轉(zhuǎn)速n，則由測速發(fā)電機確定的則則uk，ua則n，則轉(zhuǎn)速越來越大，電動機損壞，失去控制?！答?。21電位器電壓可控硅直流測速機Purubuk＋n擾動ua正反響不Open-loopcontrolsystemsSimplestructure,lowcostEasytoregulateLowaccuracyandresistanceofdisturbanceClosed-loopcontrolsystemsAbilitytocorrecterrorHighaccuracyandresistanceofdisturbanceComplexstructure,highcostCriticalforselectingparameters(maycausestabilityproblem)Open-loop＋Closed-loop＝CompositecontrolsystemComparisonbetweenopen-loopandclosed-loopsystems22Open-loopcontrolsystemsCompa1-2Moreexamplesoffeedbackcontrolsystem231-2MoreexamplesoffeedbackFlushtoilet(沖水馬桶〕LevelWaterTankFloatPistonPlant:Input:Output:Expectedvalue:Sensor:Controller:Actuator:PlantControllerActuatorSensorwatertankwaterflowwaterlevelfloatleverpiston24Flushtoilet(沖水馬桶〕LevelWaterPlane-autopilot〔自動駕駛〕25Plane-autopilot〔自動駕駛〕25給定裝置放大器舵機飛機

反饋電位器

垂直陀螺儀θ0θc擾動俯仰角控制系統(tǒng)方塊圖26給定裝置放大器舵機飛機反饋電位器垂直O(jiān)therexamples胡壽松教材pages7-9Ogata教材pages3-6Kuo教材pages2-627Otherexamples胡壽松教材pages7-927Whycontrolsystemsareimportant?Inotherwords,whywe(engineer)shouldknowcontrol?ControlisanessentialelementofalmostallengineeringsystemsIthappensveryoftenthatsystemsperformpoorlybecausetheyaredesignedfrompurelystaticanalysis,withnoconsiderationofdynamicsandcontrolControlcangivedesignersextradegreesoffreedomControlhasbeautifultheoreticalresultsandreallyneatdevices28Whycontrolsystemsareimport1-3Classificationof

controlsystems291-3ClassificationofcontrolAccordingtostructureOpen-loopcontrolsystemsClosed-loopcontrolsystemsCompositecontrolsystems30AccordingtostructureOpen-looAccordingtotypeofreferenceinputConstant-valuecontrolsystem〔常值控制系統(tǒng)〕輸入量是恒定的常值，在各種擾動作用下都能使輸出量保持在恒定希望值附近，如恒溫、水位、恒壓控制系統(tǒng)Servo/tracking(侍服/跟蹤〕controlsystem〔隨動控制系統(tǒng)〕輸入量是事先不知道的任意時間函數(shù)，使輸出量迅速而準(zhǔn)確地跟隨輸入量的變化而變化，比方：飛機和艦船的操舵系統(tǒng)，雷達(dá)自動跟蹤系統(tǒng)。Programmingcontrolsystem〔程序控制系統(tǒng)〕輸入量按照給定的程序變化，使輸出量按預(yù)先給定的程序指令而動作，最典型的就是數(shù)控車床和機器人控制系統(tǒng)。31AccordingtotypeofreferenceAccordingtosystemcharacterLinearsystemprincipleofsuperpositionapplies〔齊次疊加原理〕describedbylineardifferentialequation〔線性微分方程〕Nonlinearsystemdescribedbynonlineardifferentialequation〔非線性微分方程〕32AccordingtosystemcharacterLAccordingtosystemcharacterwithrespecttotimeTime-invariantsystemTheparametersofacontrolsystemarestationarywithrespecttotimeTime-varyingsystemSystemcontainelementsthatdriftorvarywithtimeE.g.Guided-missilecontrolsystem,time-varyingmassresultsintime-varyingparametersofthecontrolsystem33AccordingtosystemcharacterAccordingtoformofthesignalsContinuous-datacontrolsystem〔連續(xù)控制系統(tǒng)〕Thesignalsareallfunctionsofcontinuoustimevariablet〔信號是時間的連續(xù)值〕Discrete-datacontrolsystemThesignalsareintheformofeitherapulsetrainoradigitalcode〔信號是脈沖序列或數(shù)字編碼〕sample-dataanddigitalcontrolsystem34Accordingtoformofthesigna1-4Basicrequirementsforcontrolsystems胡壽松教材，p13351-4BasicrequirementsforconTwo-foldtasks:howthesystemresponsestotheexternalinput?howthesystemresistsdisturbances?Thesystemisexpectedtobeaffected

ONLYbycontrolinput,NOTbydisturbance.36Two-foldtasks:ThesystemiseTypicalexternalsignals為了能對不同的控制系統(tǒng)的性能用統(tǒng)一的標(biāo)準(zhǔn)來恒量，通常需要選擇幾種典型的外作用Rulesofselection〔1〕Easytogenerate〔2〕Frequentlyencountered〔3〕Simplemathematicalexpression。37Typicalexternalsignals為了能對不同Step-functioninput〔階躍輸入〕在t=0時刻出現(xiàn)幅值為R的跳變，R=1時的階躍函數(shù)叫unitstepfunction〔單位階躍函數(shù)〕，denotedby1(t)。最不利的外作用,常用階躍函數(shù)作為評價系統(tǒng)動態(tài)性能的典型外作用,所以階躍函數(shù)在自動控制系統(tǒng)的分析中起著特別重要的作用。例如飛機飛行中遇到的常值陣風(fēng)擾動。38Step-functioninput〔階躍輸入〕在t=0例如雷達(dá)-高射炮防空系統(tǒng)，當(dāng)雷達(dá)跟蹤的目標(biāo)以恒定速率飛行時，便可視為該系統(tǒng)工作于斜坡函數(shù)作用之下。Ramp-functioninput〔斜坡輸入〕在t=0時刻開場，以恒定速率R隨時間變化0

t

r(t)39例如雷達(dá)-高射炮防空系統(tǒng)，當(dāng)雷達(dá)跟蹤的目標(biāo)以恒定速率飛行時，t0Pulse/Impulsefunctioninput〔脈沖輸入〕r(t)0tPulsefunction脈動函數(shù)impulsefunction沖激函數(shù)？Note:〔1〕Theaboveimpulsefunctiondoesnotexistinreality,itisjustmathematicaldefinition.WhenA=1時，itiscalledunitimpulsefunction，denotedbyδ(t);(2)脈沖函數(shù)很重要，任意一個外作用的輸出響應(yīng)可分解為不同時刻系列脈沖輸入之和40t0Pulse/ImpulsefunctioninputSinusoidfunctioninput〔正弦輸入〕A－Amplitudew=2πf－angularfrequencyIftheinitialphaseφisnon-zero，thenr(t)canbedescribedby例如海浪對艦船的顛簸，電源及機械振動的噪聲可視為正弦擾動。系統(tǒng)在正弦函數(shù)作用下的響應(yīng)，即frequencycharacteristic，是自動控制理論中研究系統(tǒng)性能的重要依據(jù)。41Sinusoidfunctioninput〔正弦輸入〕BasicrequirementsforsystemperformanceSincestepinputfunctionjumpsfromzerotoaconstantvalue,itisalwayschosenasatypicalinputsignaltoinvestigatesystemperformance.Systemperformanceaboutstepinputresponsecanbesummarizedas:1.Stability－－－穩(wěn)定性2.Accuracy－－－準(zhǔn)確性3.Quickness－－－快速性42Basicrequirementsforsystem控制器執(zhí)行機構(gòu)被控對象輸入信號給定值偏差-測量傳感元件輸出量Acontrolsystemwithoutdisturbance當(dāng)輸入信號突然發(fā)生跳變時，這時輸出量還處在原有的平衡狀態(tài)，這樣就出現(xiàn)了偏差，這個偏差控制輸出量到達(dá)新的平衡，這就是一個regulationprocess〔調(diào)節(jié)過程〕。43控制器執(zhí)行機構(gòu)被控對象輸入信號偏差-測量傳感元件輸出量Act01Inputr(t)t01Outputc(t)Responsecurve1Responsecurve2理想的調(diào)節(jié)過程是：出現(xiàn)偏差后，執(zhí)行機構(gòu)突然動作，使輸出量立即到達(dá)新的平衡狀態(tài)，調(diào)節(jié)過程瞬時完成，實際上這是不可能的，為什么呢？系統(tǒng)從原平衡狀態(tài)到達(dá)新的平衡狀態(tài)都要經(jīng)歷一個過渡過程，過渡過程的曲線形狀隨系統(tǒng)的不同而有所差異.物理系統(tǒng)均是慣性系統(tǒng)Curve1monotonouslyincreasestothesteady-statevalue.Curve2(decaying)oscillatestothesteady-statevalue.stable44t01Inputt01OutputResponsecurt01Outputc(t)Thewholeregulationprocesscanbedividedintotwostages:Steady-stateprocess〔穩(wěn)態(tài)過程〕reflectssteady-statecharacter，即輸出量穩(wěn)定在新的平衡狀態(tài)，并保持不變。Transientprocess(瞬態(tài)過程〕reflectsdynamiccharacter〔動態(tài)特性〕，即輸出量處于劇烈變化之中。Quickness〔快速性〕Stability〔穩(wěn)定性〕Accuracy(準(zhǔn)確性〕45t01OutputThewholeregulationDefinitionsStability：referstoabilityofasystemtorecoverequilibrium,i.e.,convergenceoftransientprocess(converge)Quickness:referstodurationoftransientprocess(quick)Accuracy：referstothesizeofsteady-stateerrorwhenthetransientprocessends.〔small)(Steady-stateerror=desiredoutput–actualoutput)46DefinitionsStability：referstoNoteForacontrolsystem,theabovethreeperformanceindices(stability,quickness,accuracy)aresometimescontradictory.Indesignofapracticalcontrolsystem,wealwaysneedtomakecompromise.47NoteForacontrolsystem,the1-5MATLAB481-5MATLAB48MATLABMATLAB是具有很強數(shù)值計算、符號運算、仿真和圖形顯示功能的計算分析軟件。它具有編程方便、簡單易學(xué)等諸多優(yōu)點，同時提供了大量的內(nèi)置函數(shù)和外置工具箱，被廣泛應(yīng)用于數(shù)學(xué)計算、工程應(yīng)用和社會科學(xué)研究的諸多領(lǐng)域。49MATLABMATLAB是具有很強數(shù)值計算、符號運算、仿真和SimulationusingMATLAB1請同學(xué)們自學(xué)MATLAB根底知識2.本課程局部章節(jié)中將給出MATLAB常用函數(shù)以及程序?qū)嵗?，輔助學(xué)習(xí)課程相關(guān)內(nèi)容50SimulationusingMATLAB1請同學(xué)們自1-6Additionalreadingmaterials——shorthistoryofcontrol511-6AdditionalreadingmateriaKeepingaccuratetrackoftime–Waterclock(Ktesibios,270BC)Shorthistoryofcontrol52KeepingaccuratetrackoftimeShorthistoryofcontrolIndustrialrevolution Temperatureregulatorforfurnace(Drebbel,1624)Floatregulatorforsteamboiler(Brindley,1758)Pressureregulatorforsteamengine(Papin,1707)53ShorthistoryofcontrolIndustShorthistoryofcontrolBirthofmathematicalcontroltheoryDifferentialequationsfortelescopepointing(Airy,1840)StabilitytheoryforWatt’sflyballgovernor(Maxwell,1868)Systemtheoryoforganicmechanism(Whitehead,1925)54ShorthistoryofcontrolBirthShorthistoryofcontrolMasscommunicationFrequencydomainanalysisforcommunicationsystems(1920’s,BellTelephoneLaboratory)55ShorthistoryofcontrolMasscShorthistoryofcontrolWorldWarsandclassicalcontrolShipcontrol(Minorsky,1922)Weaponsdevelopmentandgunpointing(Hazen,1934)MITradiationlaboratory(1940’s)Stochasticanalysis(Wiener,1942)56ShorthistoryofcontrolWorldShorthistoryofcontrolSpace/computerageandmoderncontrolTime-domaindesignfornonlinearsystemsOptimalcontrolandestimationtheoryNonlinearcontroltheoryComputersincontrolsdesignandimplementation57ShorthistoryofcontrolSpace/ShorthistoryofcontrolUnionofmodernandclassicalcontrolAdvancedcontroltheories58ShorthistoryofcontrolUnionSuggestionsonthecoursestudyPayenoughattentioncontroltheoryisveryinteresting,veryuseful,butsometimes,verydifficultPractice,practice,andpractice59SuggestionsonthecoursestudEndofChapter1Thankyouall!60EndofChapter1Thankyouall!ThePrincipleofAutomaticControl

自動控制原理Lecturers：Prof.JiangBinDr.LuNingyunCollegeofAutomationEngineeringNUAA，2021.Autumn61ThePrincipleofAutomaticConNUAA-ThePrincipleofAutomaticControl

Chapter1Introductiontocontrolsystems控制系統(tǒng)簡介62NUAA-ThePrincipleofAutomatiCourseDescriptionThiscourseisconcernedwiththeanalysisanddesignofcontrolsystemTime-domaintechniques(root-locusanalysis);Frequency-domaintechniques(Bodeplot,Nyquiststabilitytheory)Systemmodeling,sensitivityandstabilityAnalysisDesignSimulationAnalysisanddesignusingMATLAB63CourseDescriptionThiscourseReferences胡壽松主編，自動控制原理，科學(xué)出版社K.Ogata，Moderncontrolengineering(現(xiàn)代控制工程,第四版)，有原版翻印本和中譯本B.C.Kuo&F.Golnaraghi，Automaticcontrolsystems,8thedition,JohnWiley&Sons,2003〔有原版翻印〕://www-control.eng.cam.ac.uk/extras/Virtual_Library/Control_VL.html:///group/ctm/://.au/64References胡壽松主編，自動控制原理，科學(xué)出版社CourseEvaluation64hours,3credits:Homework:5%Classparticipation:5%Finalexam:90%65CourseEvaluation64hours,3cWelcometocontactusProf.JiangBinEmail:binjiang@Tel:84892301-6041(O)M)Office:A17-604(明故宮校區(qū)〕Dr.LuNingyunEmail:luningyun@Tel:84892301-6063(O)M)Office:A17-606(明故宮校區(qū)〕66WelcometocontactusProf.JiChapter1.IntroductiontocontrolsystemsWHATacontrolsystemis?WHYcontrolsystemsareimportant?WHATthebasiccomponentsofacontrolsystemare?ExamplesofcontrolsystemapplicationsWHYfeedbackisincorporatedintomostcontrolsystems?Typesofcontrolsystems67Chapter1.IntroductiontoconOutline1-1Basicconceptsofcontrolsystems1-2Controlsystemexamples1-3Classificationofcontrolsystems1-4Basicrequirementsofacontrolsystem1-5BriefintroductiontoMATLAB68Outline1-1Basicconceptsofc1-1Basicconcepts691-1Basicconcepts9Whatiscontrol?Control：使某些物理量按指定的規(guī)律變化〔e.g.keepconstant,ortrackareferencesignal〕，以保證生產(chǎn)平安，經(jīng)濟(jì)及產(chǎn)品質(zhì)量等要求的技術(shù)手段。Controlledvariable(被控量〕：指被測量(measured)并被控制(controlled)到期望值(expectedvalue)的變量Manipulatedvariable〔操縱量〕:按照指定規(guī)律變化使得被控量到達(dá)指定目標(biāo)的變量(variedbycontrollersoastoaffectthecontrolledvariable)AutomaticControl：就是應(yīng)用自動化儀表或控制裝置代替人，自動地對機器設(shè)備或生產(chǎn)過程進(jìn)展控制，使之到達(dá)預(yù)期的狀態(tài)或性能要求。e.g.Temperaturecontrolsystem(空調(diào)〕Speedcontrolsystem〔汽車〕70Whatiscontrol?Control：使某些物理Generallyspeaking,acontrolsystemisasystemthatisusedtorealizeadesiredoutputorobjectiveWhatiscontrolsystem?Plant(對象〕：Maybeapieceofequipment,perhapsjustasetofmachineparts,functioningtogether,toperformaparticularoperationProcess〔過程〕：Anaturalorartificial,progressivelycontinuingoperationordevelopmenttowardaparticularresultSystem〔系統(tǒng)〕：AcombinationofcomponentsthatacttogetherandperformacertainobjectiveDisturbance(擾動〕:Asignaltendstoaffecttheoutputofasystem71Generallyspeaking,acontrolcontrollerManipulatedvar.Open-loopcontrolsystemDefinition：thosesystemsinwhichtheoutputhasnoeffectonthecontrolaction.inputplantdisturbanceControlledvar.applications72controllerManipulatedOpen-loopOpen-loopDCMotorspeed-controlsystem電位器（產(chǎn)生給定電壓ur）假定0~10V轉(zhuǎn)速0~1000轉(zhuǎn)電位器電壓放大器可控硅功放直流電動機n擾動Purukua73Open-loopDCMotorspeed-contrCommentsonopen-loopcontrolsystemTheoutputisnotmeasuredandcomparedwiththeinput,nofeedbackEachinputcorrespondsafixedoperatingcondition

(電位器0-10v－－轉(zhuǎn)速0-1000轉(zhuǎn))TheaccuracyofthesystemdependsoncalibrationInthepresenceofdisturbance?74Commentsonopen-loopcontrolFeedbackcontrolsystemAsystemthatmaintainsaprescribedrelationshipbetweentheoutputandthereferenceinputbycomparingandusingthedifference(error)asameansofcontrol–feedbackcontrolsystemRefinputcontrollerManipulatedvar.plantdisturbanceOutputerrorsensor75FeedbackcontrolsystemAsysteBlockdiagramControllerActuatorPlantSensor-rExpectedvaluee

ErrorDisturbanceControlledvariablenycomparisoncomponent(comparisonpoint):itsoutputequalsthealgebraicsumofallinputsignals.“+〞:plus“-〞:minuslead-outpoint:Here,thesignalistransferredalongtwoseparateroutes.TheBlockrepresentsthefunctionandnameofitscorrespondingmode,wedon’tneedtodrawdetailedstructure,andthelineguidesforthetransferroute.u76BlockdiagramControllerActuatoFeedbackcontrolsystemsexisteverywhereE.g.thehumanbodyishighlyadvancedfeedbackcontrolsystem.Bodytemperatureandbloodpressurearekeptconstantbymeansofphysiologicalfeedback.Feedbackmakesthehumanbodyrelativelyinsensitivetoexternaldisturbance.Thuswecansurviveinachangingenvironment.77FeedbackcontrolsystemsexistInpractice,feedbackcontrolsystemandclosed-loopcontrolsystemareusedinterchangeablyClosed-loopcontrolalwaysimpliestheuseoffeedbackcontrolactioninordertoreducesystemerrorClosed-loopcontrolsystem78Inpractice,feedbackcontrolClosed-loopDCmotorspeedcontrolsystem79Closed-loopDCmotorspeedcon電位器電壓放大器可控硅放大器直流電動機測速機Purubuk-n擾動ua工作原理引入測速發(fā)電機，這時電壓放大器的輸入，如果外來的電網(wǎng)電壓波動使電機的轉(zhuǎn)速n，則由測速發(fā)電機確定的則則uk，ua則n，消除了偏差，控制轉(zhuǎn)速穩(wěn)定?！?fù)反饋。同開環(huán)系統(tǒng)相比，該系統(tǒng)由于干擾引起的轉(zhuǎn)速誤差要小得多。80電位器電壓可控硅直流測速機Purubuk-n擾動ua工作原理電位器電壓放大器可控硅放大器直流電動機測速機Purubuk＋n擾動ua正反響不能用于控制系統(tǒng)用途——振蕩器〔正弦信號發(fā)生器〕如果極性接錯，這時電壓放大器的輸入，如果外來的電網(wǎng)電壓波動使電機的轉(zhuǎn)速n，則由測速發(fā)電機確定的則則uk，ua則n，則轉(zhuǎn)速越來越大，電動機損壞，失去控制?！答仭?1電位器電壓可控硅直流測速機Purubuk＋n擾動ua正反響不Open-loopcontrolsystemsSimplestructure,lowcostEasytoregulateLowaccuracyandresistanceofdisturbanceClosed-loopcontrolsystemsAbilitytocorrecterrorHighaccuracyandresistanceofdisturbanceComplexstructure,highcostCriticalforselectingparameters(maycausestabilityproblem)Open-loop＋Closed-loop＝CompositecontrolsystemComparisonbetweenopen-loopandclosed-loopsystems82Open-loopcontrolsystemsCompa1-2Moreexamplesoffeedbackcontrolsystem831-2MoreexamplesoffeedbackFlushtoilet(沖水馬桶〕LevelWaterTankFloatPistonPlant:Input:Output:Expectedvalue:Sensor:Controller:Actuator:PlantControllerActuatorSensorwatertankwaterflowwaterlevelfloatleverpiston84Flushtoilet(沖水馬桶〕LevelWaterPlane-autopilot〔自動駕駛〕85Plane-autopilot〔自動駕駛〕25給定裝置放大器舵機飛機

反饋電位器

垂直陀螺儀θ0θc擾動俯仰角控制系統(tǒng)方塊圖86給定裝置放大器舵機飛機反饋電位器垂直O(jiān)therexamples胡壽松教材pages7-9Ogata教材pages3-6Kuo教材pages2-687Otherexamples胡壽松教材pages7-927Whycontrolsystemsareimportant?Inotherwords,whywe(engineer)shouldknowcontrol?ControlisanessentialelementofalmostallengineeringsystemsIthappensveryoftenthatsystemsperformpoorlybecausetheyaredesignedfrompurelystaticanalysis,withnoconsiderationofdynamicsandcontrolControlcangivedesignersextradegreesoffreedomControlhasbeautifultheoreticalresultsandreallyneatdevices88Whycontrolsystemsareimport1-3Classificationof

controlsystems891-3ClassificationofcontrolAccordingtostructureOpen-loopcontrolsystemsClosed-loopcontrolsystemsCompositecontrolsystems90AccordingtostructureOpen-looAccordingtotypeofreferenceinputConstant-valuecontrolsystem〔常值控制系統(tǒng)〕輸入量是恒定的常值，在各種擾動作用下都能使輸出量保持在恒定希望值附近，如恒溫、水位、恒壓控制系統(tǒng)Servo/tracking(侍服/跟蹤〕controlsystem〔隨動控制系統(tǒng)〕輸入量是事先不知道的任意時間函數(shù)，使輸出量迅速而準(zhǔn)確地跟隨輸入量的變化而變化，比方：飛機和艦船的操舵系統(tǒng)，雷達(dá)自動跟蹤系統(tǒng)。Programmingcontrolsystem〔程序控制系統(tǒng)〕輸入量按照給定的程序變化，使輸出量按預(yù)先給定的程序指令而動作，最典型的就是數(shù)控車床和機器人控制系統(tǒng)。91AccordingtotypeofreferenceAccordingtosystemcharacterLinearsystemprincipleofsuperpositionapplies〔齊次疊加原理〕describedbylineardifferentialequation〔線性微分方程〕Nonlinearsystemdescribedbynonlineardifferentialequation〔非線性微分方程〕92AccordingtosystemcharacterLAccordingtosystemcharacterwithrespecttotimeTime-invariantsystemTheparametersofacontrolsystemarestationarywithrespecttotimeTime-varyingsystemSystemcontainelementsthatdriftorvarywithtimeE.g.Guided-missilecontrolsystem,time-varyingmassresultsintime-varyingparametersofthecontrolsystem93AccordingtosystemcharacterAccordingtoformofthesignalsContinuous-datacontrolsystem〔連續(xù)控制系統(tǒng)〕Thesignalsareallfunctionsofcontinuoustimevariablet〔信號是時間的連續(xù)值〕Discrete-datacontrolsystemThesignalsareintheformofeitherapulsetrainoradigitalcode〔信號是脈沖序列或數(shù)字編碼〕sample-dataanddigitalcontrolsystem94Accordingtoformofthesigna1-4Basicrequirementsforcontrolsystems胡壽松教材，p13951-4BasicrequirementsforconTwo-foldtasks:howthesystemresponsestotheexternalinput?howthesystemresistsdisturbances?Thesystemisexpectedtobeaffected

ONLYbycontrolinput,NOTbydisturbance.96Two-foldtasks:ThesystemiseTypicalexternalsignals為了能對不同的控制系統(tǒng)的性能用統(tǒng)一的標(biāo)準(zhǔn)來恒量，通常需要選擇幾種典型的外作用Rulesofselection〔1〕Easytogenerate〔2〕Frequentlyencountered〔3〕Simplemathematicalexpression。97Typicalexternalsignals為了能對不同Step-functioninput〔階躍輸入〕在t=0時刻出現(xiàn)幅值為R的跳變，R=1時的階躍函數(shù)叫unitstepfunction〔單位階躍函數(shù)〕，denotedby1(t)。最不利的外作用,常用階躍函數(shù)作為評價系統(tǒng)動態(tài)性能的典型外作用,所以階躍函數(shù)在自動控制系統(tǒng)的分析中起著特別重要的作用。例如飛機飛行中遇到的常值陣風(fēng)擾動。98Step-functioninput〔階躍輸入〕在t=0例如雷達(dá)-高射炮防空系統(tǒng)，當(dāng)雷達(dá)跟蹤的目標(biāo)以恒定速率飛行時，便可視為該系統(tǒng)工作于斜坡函數(shù)作用之下。Ramp-functioninput〔斜坡輸入〕在t=0時刻開場，以恒定速率R隨時間變化0

t

r(t)99例如雷達(dá)-高射炮防空系統(tǒng)，當(dāng)雷達(dá)跟蹤的目標(biāo)以恒定速率飛行時，t0Pulse/Impulsefunctioninput〔脈沖輸入〕r(t)0tPulsefunction脈動函數(shù)impulsefunction沖激函數(shù)？Note:〔1〕Theaboveimpulsefunctiondoesnotexistinreality,itisjustmathematicaldefinition.WhenA=1時，itiscalledunitimpulsefunction，denotedbyδ(t);(2)脈沖函數(shù)很重要，任意一個外作用的輸出響應(yīng)可分解為不同時刻系列脈沖輸入之和100t0Pulse/ImpulsefunctioninputSinusoidfunctioninput〔正弦輸入〕A－Amplitudew=2πf－angularfrequencyIftheinitialphaseφisnon-zero，thenr(t)canbedescribedby例如海浪對艦船的顛簸，電源及機械振動的噪聲可視為正弦擾動。系統(tǒng)在正弦函數(shù)作用下的響應(yīng)，即frequencycharacteristic，是自動控制理論中研究系統(tǒng)性能的重要依據(jù)。101Sinusoidfunctioninput〔正弦輸入〕BasicrequirementsforsystemperformanceSincestepinputfunctionjumpsfromzerotoaconstantvalue,itisalwayschosenasatypicalinputsignaltoinvestigatesystemperformance.Systemperformanceaboutstepinputresponsecanbesummarizedas:1.Stability－－－穩(wěn)定性2.Accuracy－－－準(zhǔn)確性3.Quickness－－－快速性102Basicrequirementsforsystem控制器執(zhí)行機構(gòu)被控對象輸入信號給定值偏差-測量傳感元件輸出量Acontrolsystemwithoutdisturbance當(dāng)輸入信號突然發(fā)生跳變時，這時輸出量還處在原有的平衡狀態(tài)，這樣就出現(xiàn)了偏差，這個偏差控制輸出量到達(dá)新的平衡，這就是一個regulationprocess〔調(diào)節(jié)過程〕。103控制器執(zhí)行機構(gòu)被控對象輸入信號偏差-測量傳感元件輸出量Act01Inputr(t)t01Outputc(t)Responsecurve1Responsecurve2理想的調(diào)節(jié)過程是：出現(xiàn)偏差后，執(zhí)行機構(gòu)突然動作，使輸出量立即到達(dá)新的平衡狀態(tài)，調(diào)節(jié)過程瞬時完成，實際上這是不可能的，為什么呢？系統(tǒng)從原平衡狀態(tài)到達(dá)新的平衡狀態(tài)都要經(jīng)歷一個過渡過程，過渡過程的曲線形狀隨系統(tǒng)的不同而有所差異.物理系統(tǒng)均是慣性系統(tǒng)Curve1monotonouslyincreasestothesteady-statevalue.Curve2(decaying)oscillatestothesteady-statevalue.stable104t01Inputt01OutputResponsecurt01Outputc(t)Thewholeregulationprocesscanbedividedintotwostages:Steady-stateprocess〔穩(wěn)態(tài)過程〕reflectssteady-statecharacter，即輸出量穩(wěn)定在新的平衡狀態(tài)，并保持不變。Transi