電氣工程及其自動(dòng)化優(yōu)秀畢業(yè)論文英文

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AcademicYear:(2012/2013)

Enrolmentnumber:12014664

Fullname:SijunWu

Course:BEngHonorsDegreeinElectricaland

ElectronicEngineering

ProjectTitle:Real-TimeComputerLevelControlofaWaterTank

1stSupervisor:GuopingLiu

2ndSupervisor:DrMikePrice

Date:April2013

Real-TimeComputerLevelControlofaWaterTank

Student:SijunWu

ID:12014664

Date:April2013

UniversityofGlamorgan

DissertationsubmittedinpartialfulfillmentfortheBEnginElectricalandElectronicEngineering.

FacultyofAdvancedTechnology

Declaration

Iunderstandthenatureofplagiarism,andIamawareoftheUniversity’spolicyonthis.

Ideclarethatthisdissertationistheresultofmyownindependentinvestigationandthatallsourceshavebeenappropriatelyacknowledgedinthebibliography.

Signature:Date:

Abstract

Withthedevelopmentofthetimes,Controlsystemisplayinganincreasinglyimportantroleinvariousfields.Watertankcontrolsystemisatypicalmodelofcontrolsystem.Controlofwatertankcanbeusedasthebasisofresearchintomorecomplexnonlinearsystem,Itnotonlyhasastrongtheoretical,belongstotheapplicationofbasicresearch,butalsoitwithstrongcomprehensive.Itcontainscontroltheory,intelligentcontrol,fluidmechanics,andotherdisciplines.

People'slifeandindustrialproduction,andmanyotherareasofteninvolveliquidlevelandflowcontrolproblem,forexampleinInhabitantdomesticwatersupply,beverages,foodprocessingandotherindustriestheproductionprocess,weusuallyneedtousethewatertank,itneedtomaintaintheappropriatelevel,neithertoooverflowcausewaste,alsocannottoolittleandcan'tmeetthedemand.Sotheliquidheightisanimportantparameteroftheindustrialprocesscontrol,especiallyinadynamicstate.Byusingsuitablemethodstodetecttheliquidlevelcancontrolitcanreceivegoodeffect.

Inthisfinalprojectdesign,Idutyistodesignawatertankliquidlevelcontrolsystem,whichinvolvesthedynamicliquidlevelcontrol,themodelingofthecontrolsystem,PIDparameterssetting.Iwilldiscussusingdifferentcontrolmethodstoachievecontrolrequire,forinstance,Proportionalcontroller,PIcontroller.Iwilldiscussbothdesignprocessesandtestresultsinthispaper.WhatmoreIwillintroducesomemainsoftwarewhichincludesMATLAB,SIMULINK,andNetConSystems.

Keywords:positioncontrol,PIcontroller,PIDparameterssetting,software

Acknowledgement

Firstofall,Iwantappreciatemyfirstsupervisorandsecondsupervisor.Icouldnotachievemyprojectwithouttheirhelp.EspeciallyprofessorGuopingLiu,hegivesmegreatsupport.Whensomequestionsreallyconfuseme,healwaysfillsofpatientandanswerforme.Heencouragesmeandteachesmehowtosolvetheproblems.Henotonlyteachesmeknowledgebutalsocreativemyabilityofresearchtheessentialoftheproblem.Nomatterinthetheoreticalknowledgeandpracticaltest.

SecondlyIwanttoappreciatetheUniversityofGlamorgan.Theygivemeopportunitytolearnthetheorywiththerealapplication.

ThirdlyIwanttosaythankstoBeijingUniversityofCivilEngineeringandArchitecturewhereIusedtostudy.TheygavemethechancetostudyintheUniversityofGlamorgannow.Iwanttoappreciatemyteacherinchina,especiallyprofessorZhijianJiang.

AtlastIwanttosaythanktoanypeoplewhosupportme.Especiallythankstomyparentsandmyfriends.

AllofyouareveryimportantformeandIreallyappreciatethehelpthatyougavemeinthiswholeyear.

content

Abstract

4

Acknowledgement

5

content

6

Figurelist

9

Chapter1.ProjectOverview

11

1.1 AimandObjectives:

11

1.2GeneralBackground:

11

1.2.1Singlewater-tanksystem

11

1.2.2Couplewater-tanksystem

12

Chapter2.SoftwareIntroduction

14

2.1MATLABIntroduction

14

2.2Simulinkintroduction

16

2.3NetConSystem

17

2.3.2NetConLink

18

2.3.3NetConTop

19

Chapter3.HardwareIntroduction

20

3.1Coupled-tanksystemdescription

20

3.2Componentnomenclature

21

3.3componentdescription

22

3.3.1Overallframeandwatertanks

22

3.3.2Pump

22

3.3.3Pressuresensor

22

3.4Coupled-tankmodelparameters

22

Chapter4.Theoryandmathematicalmodel

25

4.1Mathematicalmodel

25

4.2Mathematicalmodeloftheupperwatertank

25

4.2.1Upperwatertanklevelmodelingnonlinearequationofmotion

25

4.2.2Upperwatertanklevelmodelinglinearizationandsystemtransferfunction

28

4.3Mathematicalmodelofthecouplewatertank

31

4.3.1Couplewatertanklevelmodelingnonlinearequationofmotion

31

4.3.2Couplewatertanklevelmodelinglinearizationandsystemtransferfunction

33

Chapter5.IntroductionofcontrolsystemsandControllerDesign

37

5.1Introductionofcontrolsystems

37

5.2Upperwatertankwaterlevelcontrollerdesign

38

5.2.1UpperwatertankwaterlevelP-plus-feedforwardcontroller

38

5.2.2UpperwatertankwaterlevelPI-plus-feedforwardcontroller

42

5.2.3UpperwatertankwaterlevelCascadeandfeedbackcontroller

46

5.3Couplewatertankwaterlevelcontrollerdesign

48

5.3.1TheInstructionsforthecascadesystem.

48

5.3.2CouplewatertankwaterlevelPI-plus-feedforwardcontroller

49

Chapter6.Thesimulationofthesystemcontroller

52

6.1Thesimulationofupperwatercontroller

52

6.1.1SimulationofProportionalcontroller

52

6.1.2Simulationofproportionalintegralcontroller

54

6.1.3Simulationofcascadeandfeedbackcontroller

55

6.2Thesimulationofcouplewatertankcontroller

57

Chapter7.Actualexperimentaloperationandtestresults

61

7.1TheInstructionsforactualexperimental

61

7.1.1TheInstructionsforthedigitaltoanalogandanalogtodigitalconversion

61

7.1.2TheInstructionsforusingNetConSystemNetConLinkandNetConTop

62

7.1.3Waterlevelsensorcalibration

64

7.14look-uptable

65

7.1.5Limitvoltageprotectionsystem

66

7.2Experimentalresultsandanalysisoftheupperwatertank

67

7.2.1ExperimentalresultsofP-plus-feedforwardcontroller

67

7.2.2ExperimentalresultsofPI-plus-feedforwardcontroller

69

7.2.3Experimentalresultsofcascadeandfeedbackcontroller

71

7.3Experimentalresultsandanalysisofthecouplewatertank

73

Chapter8.Mistakeanalysis

76

Chapter9.Conclusions

77

Chapter10.FutureWork

78

Reference

79

Appendix1

80

Appendix2

97

Figurelist

Figure1.IllustratingtheAnalogy

Figure2.SchematicoftheCoupled-Tankplant

Figure3TheoverallNetConsystem

Figure4NetController

Figure5InterfaceofNetConLink

Figure6UserInterfaceofNetConTopsoftware

Figure7Coupled-tankModel

Figure8Coupled-tankComponent

Figure9Upperwatertanklevelmodel

Figure10Theopen-looptransferfunctionoftheupperwatertank

Figure11couplewatertanklevelmodel

Figure12Theopen-looptransferfunctionofcouplewatertank

Figure13Open-loopcontrolsystem

Figure14Close-loopcontrolsystem

Figure15P-plus-feedforwardclose-loopcontrolsystem

Figure16Stepresponseofafirstordersystem-timeconstant

Figure17PI-plus-feedforwardclose-loopcontrolsystem

Figure18Cascadeandfeedbackcontrolsystem

Figure19Theblockofwholesystem

Figure20Cascadesystem

Figure21TheblockdiagramofCouplewatertankwaterlevelPI-plus-feedforward

Controlsystem

Figure22TheblockdiagramofProportionalcontroller

Figure23TheblockdiagramofProportionalintegralcontroller

Figure24TheblockdiagramofProportionalcontroller

Figure25TheblockdiagramofcouplewatertankPIcontroller

Figure26Thesystemamplitudeoscillationcurve

Figure27couplewatertankPIcontrollersimulationresults

Figure28Digital-to-analogandanalog-to-digitalconverter

Figure29NetConset

Figure30NetConset

Figure31NetConset

Figure32NetConset

Figure33NetConTopset

Figure34NetConTopset

Figure35Calibrationmodel

Figure36Calibrationcircuitboard

Figure37Saturationblock

Figure38Saturationset

Figure39Proportionalcontrolsystemblockdiagram

Figure40P-plus-feedforwardcontrollerexperimentresult1

Figure41P-plus-feedforwardcontrollerexperimentresult2

Figure42PI-plus-feedforwardcontrolsystemblockdiagram

Figure43PI-plus-feedforwardcontrollerexperimentresult1

Figure44PI-plus-feedforwardcontrollerexperimentresult2

Figure45PI-plus-feedforwardcontrollerexperimentresult3

Figure46Cascadeandfeedbackcontrolsystemblockdiagram

Figure47Cascadeandfeedbackcontrollerexperimentresult1

Figure48Cascadeandfeedbackcontrollerexperimentresult2

Figure49Cascadeandfeedbackcontrollerexperimentresult3

Figure50CouplewatertankPI-plus-feedforwardcontrolsystemblockdiagram.

Figure51CouplewatertankPI-plus-feedforwardcontrollerexperimentresult1

Figure52CouplewatertankPI-plus-feedforwardcontrollerexperimentresult2

Figure53CouplewatertankPI-plus-feedforwardcontrollerexperimentresult3

Figure54CouplewatertankPI-plus-feedforwardcontrollerexperimentresult4

Chapter1.ProjectOverview

AimandObjectives:

Theaimoftheproject:

Thekeyaimoftheprojectistoapplyvariouscontrolstrategiestoreal-timelevelcontrolofawatertankusingcomputers.

Theobjectivesoftheprojectinclude:

Understandthelevelcontrolproblemofawatertank;

Studyclassandadvancecontrolmethods,e.g.,PIDcontrol,optimalcontrol,adaptivecontrol,fuzzycontrol,etc.

Befamiliarwiththefollowingsoftware:Matlab,Simulink,Real-TimeWorkship,NetConSystem;

Simulatevariouscontrolstrategies(e.g.,PI,PIDcontrol,optimalcontrol,adaptivecontrol,fuzzycontrol)inSimulinkforclosed-looplevelcontrolbasedonthemodelofawatertank;

Simulatevariouscontrolstrategies(e.g.,PI,PIDcontrol,optimalcontrol,adaptivecontrol,fuzzycontrol)ontheNetConSystemforreal-timeclose-looplevelcontrol,basedonthemodelofawatertank;

Applythesimulatedcontrolstrategiestoapracticallevelcontroltestrig.

1.2GeneralBackground:

1.2.1Singlewater-tanksystem

NowdayinInhabitantdomesticwatersupply,beverages,foodprocessingandotherindustriestheproductionprocess,weusuallyneedtousethewatertank,itneedtomaintaintheappropriatelevel,neithertoooverflowcausewaste,alsocannottoolittleandcan'tmeetthedemand.

Amodelofsinglewater-tankisshowasthefigureonebelow.V1iswaterdrainvalve.V2istheinletvalve.Theliquidlevelofthecontrolrequirementish0.Thewaterflow,whichdrainintothetankiscontrolledbyV2valve,waterflow,whichdrainsoutofthetank,iscontrolledbyV1valve.TheV1openlibraryischangewiththeneedsofusers.Asaconsequencetocontrolthevariablevalueofthewaterlevelh0itistransfertocontroltheWaterinflow.Inisexperimenttoachievecontroltheinletflowbyusingchangethevoltagewhichisdriventhepump.

Figure1.IllustratingtheAnalogy

1.2.2Couplewater-tanksystem

Coupletankwaterisatypicalmodelofnonlineardelayobjects,muchofthecontrolledobjectinindustrialwholeorpartialcanbeabstractedasmathematicsmodelofdoublewatertank.Ithasstrongrepresentationandstrongindustrialbackground.Inindustrialproductionthemathematicalmodelingandcontrolstrategyofcouplewatertankhastheguidingsignificanceinresearchofliquidlevelcontrolsystem.Suchasindustrialboilers,moldlevelcontrol.

Asisshowedbelowthefigure2isthecouplewatertank.Theexperimentsrequireiscontrolthebottomtankwaterlevelfromthewaterflowcomingoutofthetoptank.

Figure2.SchematicoftheCoupled-Tankplant[1]

Tobemorespecific,thesetabovetwoexperimentalsequencesareaimedat:

HowtomathematicallymodeltheCoupled-Tankfromfirstprinciplesinordertoobtainthetwoopen-looptransferfunctionscharacterizingthesystem,intheLaplacedomain.

Howtolinearizetheobtainednon-linearequationofmotionaboutthequiescentpointofoperation.

Howtodesign,thoughpoleplacement,aproportional-plus-integral-plus-feedforward-basedcontrollerfortheCoupled-Tanksysteminorderforittomeettherequireddesignspecificationsforeachconfiguration.

Howtoimplementeachconfigurationcontrollerinreal-timeandevaluatetheiractualperformance.

Chapter2.SoftwareIntroduction

2.1MATLABIntroduction

MATLABisaprogrammingenvironmentforalgorithmdevelopment,dataanalysis,visualization,andnumericalcomputation.UsingMATLAB,youcansolvetechnicalcomputingproblemsfasterthanwithtraditionalprogramminglanguages,suchasC,C++,andFORTRAN.

YoucanuseMATLABinawiderangeofapplications,includingsignalandimageprocessing,communications,controldesign,testandmeasurement,financialmodelingandanalysis,andcomputationalbiology.Foramillionengineersandscientistsinindustryandacademia,MATLABisthelanguageoftechnicalcomputing[2].

KeyFeatures:

High-levellanguagefortechnicalcomputing

Developmentenvironmentformanagingcode,files,anddata

Interactivetoolsforiterativeexploration,design,andproblemsolving

Mathematicalfunctionsforlinearalgebra,statistics,Fourieranalysis,filtering,optimization,andnumericalintegration

2-Dand3-Dgraphicsfunctionsforvisualizingdata

Toolsforbuildingcustomgraphicaluserinterfaces

FunctionsforintegratingMATLABbasedalgorithmswithexternalapplicationsandlanguages,suchasC,C++,Fortran,Java?,COM,andMicrosoftExcel

MATLABcanbeusedinfollowingworks:

(1).Creatingtransferfunctions

Atransferfunctioncanbeexpressedasanumeratorpolynomialdividedbyadenominatorpolynomial,thatis,F(s)=N(s)/D(s).Thenumerator,N(s),isrepresentedbyarowvector,numf,thecontainsthecoefficientsofN(s).Similarly,thedenominator,D(s),isrepresentedbyarowvector,denf,thatcontainsthecoefficientsofD(s).WeformF(s)withthecommand,F=tf(numf,denf).Fiscalledalineartime-invariant(LTI)object,ortransferfunction,canbeusedasanentityinotheroperations,suchasadditionormultiplication.

(2)Timeresponse

WecanuseMATLABtocalculatecharacteristicsofasecondordersystem,suchasdampingratio,;naturalfrequency;percentovershoot,%OS;settlingtime,Ts;andpeaktime,Tp.

(3)Stability

MATLABcansolveforthepolesofatransferfunctioninordertodeterminestability.Also,wecanuseMATLABtofindtherangeofgainforstabilitybygeneratingaloop,changinggain,andfindingatwhatgainweobtainright-half-planepoles.

(4)Steady-stateerror

Staticerrorconstantsarefoundusingas.Oncethestaticerrorconstantisfound,wecanevaluatethesteady-stateerror.

(5)Rootlocustechniques

MATLABallowsrootlocitobeplottedwiththerlocus(GH)command.Pointsontherootlocuscanbeselectedinteractivelyusingthe‘rlocfind’command.MATLABthenyieldsthegain(K)atthatpointaswellasallotherpoles(p)thathavethatgain.Wecanzoominandoutoftherootlocusbychangingtherangeofaxisvalues.Therootlocuscanbedrawnoveragridthatshowsconstantdampingratio()andconstantnaturalfrequency()

(6)FrequencyResponseTechniques

WecanuseMATLABtomakeBodeplotsusingbode(G),whereG/(s)=numg/dengandGisanLTItransferfunctionobject.Also,wecanuseMATLABtomakeNyquistdiagramsusingNyquist(G)[2].

2.2Simulinkintroduction

SIMULINKisanenvironmentformultidomainsimulationandModel-BasedDesignfordynamicandembeddedsystems.Itprovidesaninteractivegraphicalenvironmentandacustomizablesetofblocklibrariesthatletyoudesign,simulate,implement,andtestavarietyoftime-varyingsystems,includingcommunications,controls,signalprocessing,videoprocessing,andimageprocessing.

Add-onproductsextendSIMULINKsoftware

tomultiplemodelingdomains,aswellasprovidetoolsfordesign,implementation,andverificationandvalidationtasks.

SIMULINKisintegratedwithMATLAB,providingimmediateaccesstoanextensiverangeoftoolsthatletyoudevelopalgorithms,analyzeandvisualizesimulations,createbatchprocessingscripts,customizethemodelingenvironment,anddefinesignal,parameter,andtestdata[3].

KeyFeatures

Extensiveandexpandablelibrariesofpredefinedblocks

Interactivegraphicaleditorforassemblingandmanagingintuitiveblockdiagrams

Abilitytomanagecomplexdesignsbysegmentingmodelsintohierarchiesofdesigncomponents

ModelExplorertonavigate,create,configure,andsearchallsignals,parameters,properties,andgeneratedcodeassociatedwithyourmodel

Applicationprogramminginterfaces(APIs)thatletyouconnectwithothersimulationprogramsandincorporatehand-writtencode

MATLAB

FunctionblocksforbringingMATLABalgorithmsintoSIMULINKandembeddedsystemimplementations

Simulationmodes(Normal,Accelerator,andRapidAccelerator)forrunningsimulationsinterpretivelyoratcompiledC-codespeedsusingfixed-orvariable-stepsolvers

Graphicaldebuggerandprofilertoexaminesimulationresultsandthendiagnoseperformanceandunexpectedbehaviorinyourdesign

FullaccesstoMATLABforanalyzingandvisualizingresults,customizingthemodelingenvironment,anddefiningsignal,parameter,andtestdata

Modelanalysisanddiagnosticstoolstoensuremodelconsistencyandidentifymodelingerrors

2.3NetConSystem

TheNetCon(NetworkedControl)systemisaplatformforteachingandresearchofreal-timecontrolsystemsthroughIntranet/Internet.Itconsistsofthreehardwareandsoftwareparts:NetController,NetConLinkandNetConTop.Classic,modernandadvancedcontrolmethodscaneasilybeimplementedforreal-timecontrolusingtheNetConsystem,whichisbasedonthevisualconfigurationtechnology.[4]

Figure3.TheoverallNetConsystem[4]

2.3.1NetController

NetControlleristhefront-endexecutionunitsofNetConsystem,runningspecificcontrolalgorithms.NetControllerthroughthenetworkinterfacereceivesthemonitoringandcontrolparametersandcontrolcommandfromconfigurationplatform,andcontrolthereal-timerunningstateanduploadedtothemonitoringobjectconfigurationplatform.Itisbasedon32-bitARMmicroprocessor,whichishighperformance,lowpowerconsumption.Itrunningembeddedreal-timeoperatingsystemanduseindustry-specificmodulardesign,providemoreroadinput/outputinterfacestandards,suchasA/DandD/A,PWM,digitalI/O,etc,andalsoprovidesLCDdisplayoutput.Comparedwiththetraditionalfront-endcontroller,networkcontrollerhashigherspeedandlargeraddressingcapability,coupledwithmulti-taskingandreal-timeembeddedoperatingsystemitcancompletelyguaranteethesmoothrunningofcomplexcontrolalgorithms.

Figure4.NetController[4]

2.3.2NetConLink

Networkvisualcontrolconfigurationsoftware(NetConLink)isbasedonMatlab/SimulinkanditcanachieveseamlessandSIMULINKcombined.FirstlyUserscanusevariousmodulesandcustomizationoftheS-functionsystemfunction,whichisprovidingbySimulink.Secondlyusinggraphicalwaytocreatemodelofcontrollerandcontrolledobject.Thencontrolstrategyistestedmanytimesforthewholecontrolsystemoftheofflineandonlineinordertoverifythefeasibility.AfterthatcodeisgeneratedandautomaticallycanbedownloadedintoNetControllerbyNetConLinkinafewseconds.NetConLinkprovideshardwaredrivermoduleandnetworkcontroltoolbox,andprovidetheinterfaceforNetConTop.

Figure5.InterfaceofNetConLink[4]

2.3.3NetConTop

Networkvisualmonitoringconfigurationsoftware(NetConTop)isbasedonWindowsoperatingsystemanditisusedtogeneratecomputinggraphicalmonitoringprogramconfigurationsoftwaredevelopmentplatform.Itprovidesacompleteprogramofsolvingengineeringmonitoringproblems.Userscaneasilydesignvisualmonitorinterface.Itoffersavarietyofstandardconfigurationcontrol,suchasthegraph,instrument,theinputbox,andsupporttheclient/serverarchitecture.Itsmainfunctionsinclude:NetConcontrollerreal-timedataacquisitionandmanagement,real-timemonitoring,commissioningandmanagement.

Figure6.UserInterfaceofNetConTopsoftware[4]

Chapter3.HardwareIntroduction

3.1Coupled-tanksystemdescription

Figure7.Coupled-tankModel[1]

TheCoupled-tankplantmoduleisconsistingbyapumpwithawaterbasinandtwotanks.AsshowninFigure7.Thetwotanksarefixedonthepanel.Agearpumpisinstalledatthebottomofthepanel.Thepumpcanthruststhewaterfromthewaterreservoir,whichisundertheCouple-tanks,throughthehoseaffluxintotheuppertank,suchthatflowfromtheuppertankcandrainthroughanoutletorifice,whichislocatedatthebottomoftheuppertank,intothelowertank.Flowfromthelowertankflowsintothemainwaterreservoir.Ineachoneofthetwotanks,liquidiswithdrawnfromthebottomthroughanoutfloworifice.Theoutletpressureisatmospheric.Inordertointroduceadisturbanceflowtheuppertankisalsoequippedwithadraintapsothatwhenopen,flowcanbedraindirectlyintothewaterreservoir.Foreachwaterstankwecanseeastaffgaugeattachbesidethetanktodisplaytherealtimewaterlevel.TwopressuresensorsareinstalledonthebottomofeachwatertanksinordertomonitorReal-timewaterlevelandgivefeedbacksignal.

3.2Componentnomenclature

Coupled-TankOverFrame

UpperTank

LowerTank

MainWaterBasin

Pump

FlexibleTubing

Quick-ConnectInletOrificeOut1

Quick-ConnectInletOrificeOut2

Quick-ConnectOut1CouplingAndHose

Quick-ConnectOut2CouplingAndHose

SmallOutletInsert

MediumOutletInsert

LargeOutletInsert

PlainOutletInsert

DisturbanceTap

FlowSplitter

PressureSensor

Figure8.Coupled-tankComponent[1]

CalibrationAndSignalConditioningCircuitBoard

PumpMotor4-PinDINConnector

PressureSensorCable6-Pin-MiniDINConnector

TankLevelScale

3.3componentdescription

3.3.1Overallframeandwatertanks

Thecoupled-tankoverallframeandwatertanksaremadeofPlexiglas.Thewatertankshaveuniformcrosssection.[1]

Description

Value

Unit

Overallframeheight

0.915

m

Overallframewidth

0.305

m

Overallframedepth

0.305

m

Form1

3.3.2Pump

TheCoupled-tankpumpisagearpumpcomposedofa12VoltDCmotorwithheatradiatingfins.[1]

3.3.3Pressuresensor

TwopressuresensorsareinstalledonthebottomofeachwatertanksinordertomonitorReal-timewaterlevel.Thesensoroutputvoltageincreasesproportionallytotheappliedpressure.ItsoutmeasurementisprocessedthroughaSignalConditioningBoardandmadeavailableas0to5VDCsignal.

3.4Coupled-tankmodelparameters

Symbol

Description

Value

Unit

Kp

PumpFlowConstant

3.3

cm3/S/V

Vp_max

P