自控原理课件1(英文版)

Chapter1:

IntroductiontoAutomaticControl重点掌握:•控制系统的基本组成•基本的控制方式及反馈控制系统的特点•控制系统的性能要求Maincontents1-1Whatisacontrolsystem?1-2Whyarecontrolsystemsimportant?1-3Whatisanautomaticcontrolsystem?1-4Basiccomponentsandtypesofcontrolsystem.1-5Howtoevaluateaautomatic

controlsystem?1-6Thedevelopmentofautomatic

controltheory.1-1Whatisacontrolsystem?examplesControlofTrafficLightsPowerHeaterFurnaceSwitchFurnacetemperaturecontrolsystem1-1Whatisacontrolsystem?DesiredtemperaturefurnacethermometergasmixervalveairoperatorTemperaturecontrolsystem1-1Whatisacontrolsystem?waterlevelcontrolsystem1-1Whatisacontrolsystem?DefinitionofacontrolsystemAninterconnectionofcomponentsformingasystemconfigurationthatwillprovideadesiredsystemresponse.由相互关联的部件按一定的结构构成的系统，能够提供预期的系统响应。1-1Whatisacontrolsystem?1-2Whyarecontrolsystemsimportant?(1)控制系统无处不在.(2)提高产量，降低成本.(3)提高精度、可靠性.(4)能够在许多人不到达的场所发挥作用.furnacethermometergasmixervalveairDesiredtemperatureoperator1-3Whatisanautomaticcontrolsystem?Acontrolsystemwithoutpeopleinvolvediscalledautomaticcontrolsystem.Definitionofautomaticcontrolsystem1-3Whatisanautomaticcontrolsystem?TemperatureautomaticcontrolsystemGasMixerAirValveMotorAmplifierUTPotentiometerURAmplifierFurnaceThermocouple1-3Whatisanautomaticcontrolsystem?waterlevelautomatic

controlsystem1-3Whatisanautomaticcontrolsystem?1.Accordingtotheformofgivensignal

RegulatorSystemsversusServoSystems(恒值系统和随动系统）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被控对象FurnaceSwitch&HeaterCommandinputOutputControllerPlantFurnacetemperaturecontrolsystem1-4typesandBasiccomponentsofcontrolsystems.Example:TankValve1LeverDisturbance(valve2)Valve1Valve2TankWaterLevelcontrolsystem1-4typesandBasiccomponentsofcontrolsystems.Example:TemperaturecontrolsystemGasMixerAirValveMotorAmplifierUTPotentiometerURAmplifierFurnaceThermocoupleValveMixerAirAmplifierFurnaceCAmplifierThermocoupleMotorURUT1-4typesandBasiccomponentsofcontrolsystems.Example:AnOpen-loopcontrolsystemutilizesanactuatingdevicetocontroltheprocessdirectlywithoutusingfeedback.Openloopcontrol开环控制(Open-loopControl)——系统的输出端与输入端之间不存在反馈回路，输出量对系统的控制作用没有影响。1-4typesandBasiccomponentsofcontrolsystems.Open-loopControlSystemTheoutputoftheopen-loopsystemhasnoeffectupontheinputsignal.Thereistheneedtoknowanaccuratemodelofindividualcomponents.C被控对象ControllerPlantRUPlantControllerMeasurementnCU1-4typesandBasiccomponentsofcontrolsystems.优点：简单，相对来说成本低缺点：对可能出现的被控量偏离给定值的偏差没有任何修正能力，抗干扰能力差，控制精度不高。Featuresofopen-loopcontrol1-4typesandBasiccomponentsofcontrolsystems.Aclosed-loopcontrolsystemusesameasurementofoutputandfeedbackofthesignaltocompareitwiththedesiredoutput(referenceorcommand).Closed-loopcontrolsystemsReferenceinputComparisonControllerPlantOutputMeasurementFeedbacksignal)1-4typesandBasiccomponentsofcontrolsystems.优点：抗干扰能力强，控制精度高缺点：复杂，有时会产生不稳定。Featuresoffeedbackcontrolsystems1-4typesandBasiccomponentsofcontrolsystems.CompoundControlsystemsCombinationofopen-loopandclosed-loopControllerPlantCFeedbackelementR—CompensatorControllerPlantCFeedbackelementR—Compensatorn1-4typesandBasiccomponentsofcontrolsystems.ObjectivesofcontrolTheobjectivesofthecontrolsystemistocontroltheoutputsinsomeprescribedmannerbytheinputsthroughtheelementsofcontrolsystems.通常目标规定为系统的输入。Ingeneral,theobjectivescanbeidentifiedwithinputs.1-4typesandBasiccomponentsofcontrolsystems.Basiccomponentsofcontrolsystems被控对象(plant,process)测量元件（sensor）可以对被控量进行测量，并转换成能与输入信号进行比较的量纲和数值，也称为反馈元件；比较环节（comparison）实现误差检测；执行机构（actuator）实现对受控对象的操控，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

确定系统任务；Step2

明确：被控对象、被控量、给定值、测量元件、执行机构和比较元件；Step3叙述系统工作原理；Step4

系统原理方框图。1-4typesandBasiccomponentsofcontrolsystems.terms1.被控对象（plant）

指被控制的设备或过程2.控制器（控制装置controller） 除了被控制对象之外的各部分的组合；3.控制系统(controlsystem) 受控对象与控制装置构成控制系统。4.给定值（期望值、输入量reference/input） 被控制量要求的变化规律(Excitationappliedtoacontrolsystemfromanexternalsource).1-4typesandBasiccomponentsofcontrolsystems.terms5.被控量(controlledvariable) 被控制的物理量；6.输出（Output）Theresponseobtainedfromasystem（通常与被控量一致。）7.干扰(disturbance) 所有使被控量偏离期望值的因素8.反馈（Feedback）-Theoutputofasystemthatisreturnedtomodifytheinput.1-4typesandBasiccomponentsofcontrolsystems.TurntablespeedcontrolTachometerdcamplifierTurntabledcmotorbatterySpeedsettingAmplifierdcmotorTurntableActualspeedDesiredSpeed(voltage)Tachometer1-4typesandBasiccomponentsofcontrolsystems.amplifierMotorGearingValveActuatorWatercontainerProcesscontrollerFloatmeasurement(Sensor)ErrorFeedbacksignalresistancecomparatorDesiredwaterlevelInputActualwaterlevelOutputThewaterlevelcontrolsystem:Figure1.11-4typesandBasiccomponentsofcontrolsystems.1-5Howtoevaluateacontrolsystem?Specifications(RequirementsonControlSystem)(1)Stability:

Stable

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

steady-sateerror（准）（Requirementofsteady-state）Outputandtrackingprecisionmustsatisfytherequirementwhentheresponsereachedthesteady-state1-5Howtoevaluateacontrolsystem?1-6HistoryofAutomaticControl1769:JamesWatt’ssteamengineandflyballgovernor.一种凭借直觉的实证性发明。1-6HistoryofAutomaticControl1868:J.C.Maxwellformulatesamathematicalmodelforagovernorcontrolofsteamengine.A.M.Lyapunov（李雅普诺夫，1892年）,thefirstandsecondmethodJ.C.Maxwell（麦克斯韦尔），1868年发表《论调节器》Hurwitz（霍尔维茨，1895年）andE.J.Routh（劳斯，1884年）stabilitycriterion1-6HistoryofAutomaticControlBode(波德，1927年）developedamethodofLogarithmicfrequencycharacteristic1932:H.Nyquist(奈奎斯特）developedamethodforanalyzingthestabilityofsystems.W.R.Evans（伊万斯，1948年)developedroot-locusmethod1-6HistoryofAutomaticControl1948,N.Wienerpublished《Cybernetics》(控制论）Classicalcontroltheoryforsingleinputsingleoutputsystems二次世界大战中火炮，雷达，飞机以及通讯系统的控制研究直接推动了经典控制的发展。1-6HistoryofAutomaticControl空间军备竞赛催生了现代控制理论苏联L.S.Pontryagin(庞特里亚金）提出极大值原理(MaximumPrinciple)(1956)美国R.Bellman发表著名的DynamicProgramming（动态规划）（1957）L.S.Pontryagin1-6HistoryofAutomaticControl美籍匈牙利人R.E.Kalman发表“OntheGeneralTheoryofControlSystems”等论文，引入状态空间法分析系统，提出能控性，能观测性，最佳调节器和kalman滤波等概念，奠定了现代控制理论的基础(1960)1963年,美国的LoftiZadeh与C.Desoer发表LinearSystems-AStateSpaceApproach。1965年，Zadeh提出模糊集合和模糊控制概念R.E.KalmanC.Desoer1-6HistoryofAutomaticControl1980:Robustcontrolsystemdesignwidelystudied.