Process_Control_2009_05_18A__重庆大学自动化过控试卷.docx

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1、Byradiotransmissions.InacentralizedfaciIityWiIhdisplayedmeasurements.Throughpsychicpower.3.Thetransferfunctionderivedinthisexamplesecondorder.Why?(2points)fortheCSTR,sinseriesis(T)ThechemicalreactionrateissecondorderThegainissecondorderThemodelinvolvestwodynamicbalances命题人组题人审题人4.Selecttheoutputresp

2、onsewhichwouldresultfromasinglestepinputtoafirstordersystem.(2points)命题时间：教务处制5. Completethisstatement:Self-regulationis.(2points) Thetendencyofasystemtoattainsteady-statewithoutexternalcontrolbeingapplied. Thetendencyofanoutputvariabletoreturntoitsinitialvalueafteradisturbance.重庆大学ProcessControl课程试

3、卷B卷20082009学年第二学期中都一、BasicConcepts(30points)1Foreachcommonhouseholditem,decidewhetheritusesautomaticfeedbacktoachieveitsperformancegoals(2points) Themicrowaveiswonderfulfo,tnakingpopcornorreheatingf()d(Yes,orNo) Thehotwaterheaterisaconveniencethatprovideshotwaterwithoutwaiting(Yes,orNo) Thetoilettan

4、kstoreswater,whichcanbeusedtoflushthetoiletbowl;wearegladthatthetoilettankstoresthecorrectamountofwater.(Yes,orNo)2.Achemicalplantcanbeverylargeandinvolvemanyhundredstothousandsofsensorsandvalves.Howdotheplantpersonnelmonitorprocessbehaviorandadjustvalveopenings?(2points)Bywalkingaroundtheplant. Ate

5、rmappliedonlyto1iquidintanks. Apropertyofallsystemswithinherentpositivefeedback.6. Toderive(i.e.,obtain)thetransferfunctionsofaprocess,wecaneitheruse,or.(4points)7. WhenusingZiegler-Nicholsultimate-cyclemethod,youcansettheintegraltimeto,andthederivativetimetoifitisnotpossibletodisabletheintegralandd

6、erivativecontrolmodes.(4points)8. Statetheperformancecriteriaforaclosed-loopcontrolsystem:(4points)9. Describeyourconsiderationsforimprovingthecontrolperformanceofthegasfurnaceshowninthisexample,andshowallyourconsiderationontotheFigure(hints:cascadecontrol,andsoonandsoforth)(4points)Fuelgas10. Expla

7、intherelativegainarray(RGA)(4points)二、BasicTheory(30points)1. Thereisacontinuousflowstirred-tankreactor(CSTR)withafirst-orderchemicalreaction,asshownbelow,q,CoWhereCaisthemolarconcentrationofA,Visthereactorvolume,qisthevolumetricflowrate,CQistheinletconcentrationofA.Supposethatthechemicalreactionint

8、hetankisofthefirstorderwiththereactionrateconstantk,Derivethemodelforthischemicalreaction(4points)Observethedifferenceofthetimeconstant,andspacetime(3points)Inwhatconditioncanthemodelequationbeofalinearone?(3points)2. DescribeyourconsiderationsforthechoiceofcontrolIerunderthecircumstanceofPT-Dcombin

9、ation.forflowcontrol(5points)(2) forlevelcontrol(5points)3. Belowisthefeedforward-feedbackcontrolsystemforagasfurnace Simplifytheblockdiagram(5points) Findthetransferfunctionofyoursimplifieddiagram(5points)三、BasicApplication(40points)1. Weknowthatphysicalsystemsthatareunstablerequirecontrol.(10point

10、s)Discussatleast2physicalsystemsthatareunstable(withoutcontrol)Foreachitemin（八）above,discusswhetherautomaticcontrolisrequiredorwhethercorrectionsbyapersonareadequate.2. Givenastirred-tankheatersystemshownasfollow,Q，Tin72/Steam,且/ SketchtheblockdiagramofthisSISOcIosed-100psystemwithphysicalunits(5poi

11、nts) DerivethetransferfunctionofthesystemwhileyourblockdiagramhastransferfunctionsKm,Ge,Ga,Gp,G.,Gm(5points)3. Thereisablendingprocesswhichmixestwostreamswithmassflowratemlandm2.HerethecontrolledvariablesaretotalflowrateFandthecompositionxofasoluteA.Theprocessisshownasfollow: GiventhatGclandGc2aretwocontrollersusedfortheprocess,sketchtheblockdiagramforthisMIMOsystem(5points) Findtheprocessgainmatrix(5points)4. GivenaPIcontrollerGC(三)=KC1+1/SS)foraprocess,Deriveitsmagnitudeandphaselag(5points)(2)MakeaMatlabprogramfortheBodeandNyquistplots(5points)