北航自控原理教学教案5(外文翻译版).ppt

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1、Chapter5Theperformanceoffeedbackcontrolsystems重点掌握：1、一、二阶系统时域性能指标的定义和计算。2、系统稳态误差的计算。Typicaltestsignalsforthetimeresponseofcontrolsystems.Theunit-stepresponseandtime-domainspecifications.Timeresponseoffirst-orderandsecond-ordersystems.4.Improvementperformanceof

2、secondsystems.5.Thesteady-stateerroroffeedbackcontrolsystem.Maincontents1.Unitimpulsefunction00tTypicaltestsignalsforthetimeresponseofcontrolsystems.2.Unitstepfunction10t103.Unitrampfunctiont004.Unitparabolicfunction0t0Theunit-stepresponseandtime-domainspecifi

3、cationsUnit-stepresponse:Theresponseofacontrolsystemwhentheinputisaunit-stepfunction.Time-domainspecifications1.超调量（Percentovershoot）：指响应超出稳态值的最大偏离量与稳态值之比。6.稳态误差(steady-stateerror），期望值与稳态值之差，2.上升时间（risetime）：指单位阶跃响应曲线，从稳态值得10%上升到90%所需要的时间（也有指丛零上升到稳态之所需要的时间）。3.

4、调节时间（settlingtime）：在单位阶跃响应曲线的稳态值附近，取（或）作为误差带，响应曲线达到并不在超出该误差带的最小时间。4.延迟时间(delaytime)td：指响应曲线第一次达到其终值一半所需的时间。5.峰值时间(Peaktime)tp：指响应超过其终值到达第一个峰值所需的时间。Timeresponseofafirst-ordersystemAssumethetransferfunctionofafirst-ordersystemisTheunitstepresponseforthissystemwh

5、enResponseduetounitstepsignalTimeresponseofasecond-ordersystemTheunitstepresponseforthissystemjwherewhenunderdampedNaturalundampedfrequencyDampingratioDampedfrequencycriticallydampedundampedoverdampednegativelydampedThesystemisunstable.Improvementperformanceof

6、asecondsystem(1).VelocityfeedbackcontrolofoutputwhereR(s)E(s)k1sC(s)--(2).Theproportion-differentialcontroloferrorsignalR(s)E(s)1TdsC(s)-whereEffectsofthirdpoleandazeroonthesecond-ordersystemresponseTheresponseofathird-ordersystemcanbeapproximatedbythesecond-o

7、rdersystem.Theresponseforthesecond-ordertransferfunctionwithazeroforvaluesoftheratioA=0.5,B=1,C=2andD=5whenThesteady-stateerroroffeedbackcontrolsystemDefinitionoferrorThesteady-stateerrorisdefinedassetwhereOpenloopgainType1systemThenumberofintegrationsiscalled

8、typenumberofsystemType0systemType2systemSteady-stateerrorduetoinputsignal(1).SteadyStateErrorintheStepinput(2).SteadyStateErrorintheslopinput(3).SteadyStateErrorintheacceleratorinp