自动化专业毕业论文外文文献翻译Word格式.docx

自动化专业毕业论文外文文献翻译Word格式.docx

《自动化专业毕业论文外文文献翻译Word格式.docx》由会员分享，可在线阅读，更多相关《自动化专业毕业论文外文文献翻译Word格式.docx（22页珍藏版）》请在冰豆网上搜索。

Abstract:

Theauthorsofthispapertrytoanalyzethedynamicbehavioroftheproduct-sumcrisptypefuzzycontroller,revealingthatthistypeoffuzzycontrollerbehavesapproximatelylikeaPDcontrollerthatmayyieldsteady-stateerrorforthecontrolsystem.ByrelatingtotheconventionalPIDcontroltheory,weproposeanewfuzzycontrollerstructure,namelyPIDtypefuzzycontrollerwhichretainsthecharacteristicssimilartotheconventionalPIDcontroller.Inordertoimprovefurthertheperformanceofthefuzzycontroller,weworkoutamethodtotunetheparametersofthePIDtypefuzzycontrolleronline,producingaparameteradaptivefuzzycontroller.Simulationexperimentsaremadetodemonstratethefineperformanceofthesenovelfuzzycontrollerstructures.

Keywords:

Fuzzycontroller;

PIDcontrol;

Adaptivecontrol

1.Introduction

Amongvariousinferencemethodsusedinthefuzzycontrollerfoundinliteratures,themostwidelyusedonesinpracticearetheMamdanimethodproposedbyMamdaniandhisassociateswhoadoptedtheMin-maxcompositionalruleofinferencebasedonaninterpretationofacontrolruleasaconjunctionoftheantecedentandconsequent,andtheproduct-summethodproposedbyMizumotowhosuggestedtointroducetheproductandarithmeticmeanaggregationoperatorstoreplacethelogicalAND（minimum）andOR（maximum）calculationsintheMin-maxcompositionalruleofinference.

Inthealgorithmofafuzzycontroller,thefuzzyfunctioncalculationisalsoacomplicatedandtimeconsumingtask.TagagiandSugenoproposedacrisptypemodelinwhichtheconsequentpartsofthefuzzycontrolrulesarecrispfunctionalrepresentationorcrisprealnumbersinthesimplifiedcaseinsteadoffuzzysets.Withthismodelofcrisprealnumberoutput,thefuzzysetoftheinferenceconsequencewillbeadiscretefuzzysetwithafinitenumberofpoints,thiscangreatlysimplifythefuzzyfunctionalgorithm.

BoththeMin-maxmethodandtheproduct-summethodareoftenappliedwiththecrispoutputmodelinamixedmanner.Especiallythemixedproduct-sumcrispmodelhasafineperformanceandthesimplestalgorithmthatisveryeasytobeimplementedinhardwaresystemandconvertedintoafuzzyneuralnetworkmodel.Inthispaper,wewilltakeaccountoftheproduct-sumcrisptypefuzzycontroller.

2.PIDtypefuzzycontrollerstructure

Asillustratedinprevioussections,thePDfunctionapproximatelybehaveslikeaparametertime-varyingPDcontroller.Sincethemathematicalmodelsofmostindustrialprocesssystemsareoftype,obviouslytherewouldexistansteady-stateerroriftheyarecontrolledbythiskindoffuzzycontroller.ThischaracteristichasbeenstatedinthebriefreviewofthePIDcontrollerintheprevioussection.

Ifwewanttoeliminatethesteady-stateerrorofthecontrolsystem,wecanimaginetosubstitutetheinput（thechangerateoferrororthederivativeoferror）ofthefuzzycontrollerwiththeintegrationoferror.Thiswillresultthefuzzycontrollerbehavinglikeaparametertime-varyingPIcontroller,thusthesteady-stateerrorisexpelledbytheintegrationaction.However,aPItypefuzzycontrollerwillhaveaslowrisetimeifthePparametersarechosensmall,andhavealargeovershootifthePorIparametersarechosenlarge.Sotheremaybethetimewhenonewantstointroducenotonlytheintegrationcontrolbutthederivativecontroltothefuzzycontrolsystem,becausethederivativecontrolcanreducetheovershootofthesystem'

sresponsesoastoimprovethecontrolperformance.Ofcoursethiscanberealizedbydesigningafuzzycontrollerwiththreeinputs,error,thechangerateoferrorandtheintegrationoferror.However,thesemethodswillbehardtoimplementinpracticebecauseofthedifficultyinconstructingfuzzycontrolrules.Usuallyfuzzycontrolrulesareconstructedbysummarizingthemanualcontrolexperienceofanoperatorwhohasbeencontrollingtheindustrialprocessskillfullyandsuccessfully.Theoperatorintuitivelyregulatestheexecutortocontroltheprocessbywatchingtheerrorandthechangerateoftheerrorbetweenthesystem'

soutputandtheset-pointvalue.Itisnotthepracticefortheoperatortoobservetheintegrationoferror.Moreover,addingoneinputvariablewillgreatlyincreasethenumberofcontrolrules,theconstructingoffuzzycontrolrulesareevenmoredifficulttaskanditneedsmorecomputationefforts.HencewemaywanttodesignafuzzycontrollerthatpossessesthefinecharacteristicsofthePIDcontrollerbyusingonlytheerrorandthechangerateoferrorasitsinputs.

OnewayistohaveanintegratorseriallyconnectedtotheoutputofthefuzzycontrollerasshowninFig.1.InFig.1,

and

arescalingfactorsforeand~respectively,andflistheintegralconstant.Intheproceedingtext,forconvenience,wedidnotconsiderthescalingfactors.HereinFig.2,whenwelookattheneighborhoodofNODEpointinthee-~plane,itfollowsfrom

（1）thatthecontrolinputtotheplantcanbeapproximatedby

（1）

Hencethefuzzycontrollerbecomesaparametertime-varyingPIcontroller,itsequivalentproportionalcontrolandintegralcontrolcomponentsareBK2DandilK1Prespectively.WecallthisfuzzycontrollerasthePItypefuzzycontroller（PIfc）.WecanhopethatinaPItypefuzzycontrolsystem,thesteady-stateerrorbecomeszero.ToverifythepropertyofthePItypefuzzycontroller,wecarryoutsomesimulationexperiments.Beforepresentingthesimulation,wegiveadescriptionofthesimulationmodel.InthefuzzycontrolsystemshowninFig.3,theplantmodelisasecond-orderandtypesystemwiththefollowingtransferfunction:

（2）

WhereK=16,

=1,and

=0.5.Inoursimulationexperiments,weusethediscretesimulationmethod,theresultswouldbeslightlydifferentfromthatofacontinuoussystem,thesamplingtimeofthesystemissettobe0.1s.Forthefuzzycontroller,thefuzzysubsetsofeanddaredefinedasshowninFig.4.Theircores

ThefuzzycontrolrulesarerepresentedasTable1.Fig.5demonstratesthesimulationresultofstepresponseofthefuzzycontrolsystemwithaPlfc.Wecanseethatthesteady-stateerrorofthecontrolsystembecomeszero,butwhentheintegrationfactorflissmall,thesystem'

sresponseisslow,andwhenitistoolarge,thereisahighovershootandseriousoscillation.Therefore,wemaywanttointroducethederivativecontrollawintothefuzzycontrollertoovercometheovershootandinstability.WeproposeacontrollerstructurethatsimplyconnectsthePDtypeandthePItypefuzzycontrollertogetherinparallel.WehavetheequivalentstructureofthatbyconnectingaPIdevicewiththebasicfuzzycontrollerseriallyasshowninFig.6.Where~istheweightonPDtypefuzzycontrollerandfiisthatonPItypefuzzycontroller,thelargera/fimeansmoreemphasisonthederivativecontrolandlessemphasisontheintegrationcontrol,andviceversa.Itfollowsfrom（7）thattheoutputofthefuzzycontrolleris

（3）

3.Theparameteradaptivemethod

Thusthefuzzycontrollerbehaveslikeatime-varyingPIDcontroller,itsequivalentproportionalcontrol,integralcontrolandderivativecontrolcomponentsarerespectively.WecallthisnewcontrollerstructureaPIDtypefuzzycontroller（PIDfc）.Figs.7and8arethesimulationresultsofthesystem'

sstepresponseofsuchcontrolsystem.Theinfluenceof~andfltothesystemperformanceisillustrated.When~>

0and/3=0,meaningthatthefuzzycontrollerbehaveslikePDfc,thereexistasteady-stateerror.When~=0andfl>

0,meaningthatthefuzzycontrollerbehaveslikeaPIfc,thesteady-stateerrorofthesystemiseliminatedbutthereisalargeovershootandseriousoscillation.

When~>

0and13>

0thefuzzycontrollerbecomesaPIDfc,theovershootissubstantiallyreduced.Itispossibletogetacomparativelygoodperformancebycarefullychoosingthevalueof

.

4.Conclusions

Wehavestudiedtheinput-outputbehavioroftheproduct-sumcrisptypefuzzycontroller,revealingthatthistypeoffuzzycontrollerbehavesapproximatelylikeaparametertime-varyingPDcontroller.Therefore,theanalysisanddesigningofafuzzycontrolsystemcantakeadvantageoftheconventionalPIDcontroltheory.AccordingtothecoventionalPIDcontroltheory,wehavebeenabletoproposesomeimprovementmethodsforthecrisptypefuzzycontroller.

IthasbeenillustratedthatthePDtypefuzzycontrolleryieldsasteady-stateerrorforthetypesystem,thePItypefuzzycontrollercaneliminatethesteady-stateerror.Weproposedacontrollerstructure,thatcombinesthefeaturesofbothPDtypeandPItypefuzzycontroller,obtainingaPIDtypefuzzycontrollerwhichallowsthecontrolsystemtohaveafastriseandasmallovershootaswellasashortsettlingtime.

ToimprovefurthertheperformanceoftheproposedPIDtypefuzzycontroller,theauthorsdesignedaparameteradaptivefuzzycontroller.ThePIDtypefuzzycontrollercanbedecomposedintotheequivalentproportionalcontrol,integralcontrolandthederivativecontrolcomponents.Theproposedparameteradaptivefuzzycontrollerdecreasestheequivalentintegralcontrolcomponentofthefuzzycontrollergraduallywiththesystemresponseprocesstime,soastoincreasethedampingofthesystemwhenthesystemisabouttosettledown,meanwhilekeepstheproportionalcontrolcomponentunchangedsoastoguaranteequickreactionagainstthesystem'

serror.Wit