基于S7300的PLC模糊PID控制器调节因子英语论文及其翻译.docx
《基于S7300的PLC模糊PID控制器调节因子英语论文及其翻译.docx》由会员分享，可在线阅读，更多相关《基于S7300的PLC模糊PID控制器调节因子英语论文及其翻译.docx（24页珍藏版）》请在冰豆网上搜索。
基于S7300的PLC模糊PID控制器调节因子英语论文及其翻译
AFuzzy-PIDControllerwithadjustablefactorbasedonS7-300PLC
Abstract:
AFuzzy-PIDcontrollerwithadjustablefactorisdesignedinthispaper.Scalefactor’sself-adjustwillcometrue.FuzzycontrolalgorithmisfinishedinSTEP7software,andthendownloadedinS7-300PLC.WinCCsoftwarewillbeusedtocontrolthechange-trendinrealtime.DatacommunicationbetweenS7-300PLCandWinCCisachievedbyMPI.TheresearchshowsthatthisFuzzy-PIDcontrollerhasbetterrobustcapabilityandstability.It’saneffectivemethodincontrollingcomplexlongtime-varyingdelaysystems.
Keywords:
fuzzy-PID,adjustablefactor,temperaturecontrol,MPI.
1INTRODUCTION
Temperaturecontrolisveryimportantinindustrialproduction.Themostcommontemperaturecontrolobjectsinmodernindustryareboiler,electricfurnace,thecontrolsystemofsteamplantanddistillationcolumn（F.G.Hinskey,2004）.Temperaturecontrolsystemgenerallyhasthecharacteristicoflargeinertiaanddelay,soit’sdifficulttoestablishmathematicalmodelexactly.Inindustrialproductionprocess,somecontrolmethodshavebeenemployed,suchasPIDcontrol（Bolat,E.D.,Erkan,K.,Postalcioglu,S.,2005）,Smithpredictivecontrol（He,S.-Z.,Xu,F.-L.,Tan,S.,1992）,Modelpredictivecontrol,Fuzzycontrol（Chia-FengJuang,Jung-ShingChen,Hao-JungHuang,2004）,Robustcontrol（Ingram,J.E.,Hodel,A.S.,Kirkici,H.,1997）Neuralnetwork（Khalid,M.,Omatu,S.etc1992）.PIDcontrollerisstillwidelyusedinprocesscontrolfieldforitsmanyadvantages.Butforthetime-varyingprocesswithlargetime-delay,traditionalPIDalgorithmhasmanyshortcomings:
thecontrolaccuracyislow,thestructureisdifficulttostabilizeandthealgorithmismoresensitiveinthematchdegreeofthemodels.Therefore,industrialprocesscontrolwhichhaslargetime-delayisstillarecognizeddifficultproblematpresent.Andforlargelag,time-varyingprocesswhoseobjectparameterschangedasworkingconditionandenvironmentchanged,itismoredifficulttocontrolit.Andforlargelag,time-varyingprocesswhoseobjectparameterschangeasworkingconditionandenvironmentchange,itismoredifficulttocontrolit.
Fuzzycontrolhasthecharacteristicthatdoesn’tchargedwiththeobjectmodelandwithstrongrobust,butconventionalfuzzycontrolcannotovercomenegativeeffectscausedbylarge-lagverywell.Inthispagewe’llgiveadesignofahybridfuzzycontroller.
TheprojectisaidedbythekeyScientificandTechnologicalProject（IndustryPart）ofJiangsuProvince（BE2006090）,theScienceandTechnologyInnovationFundofJiangsuUniversity（1293000240）andtheNaturalFundforCollegesandUniversitiesinJiangsuProvince（05KDJ470048）.
2THESELECTANDIMPLEMENTOFCONTROLMETHOD
Commonlyusedtwo-dimensionalfuzzycontrolsystemalwaystakessystematicerroreandtheerrorrateecasinputvariables.Thiskindofcontrolsystemcanbedividedintotwocategories:
FuzzyPDcontrolandFuzzyPIcontrol.FuzzyPDcontroltakesuasoutputwhileFuzzyPIcontroltakesΔuasoutput（Han-XiongLi,Gatland.H.B.,1996）.Inthispage,wechoosefuzzyPIcontrollerasshowninFigure1（ChuJingetc.,1999）.
Et
et
Ke
ΔUt
Fuzzy
Deduc-
tion
ut
Ku
ect
+
1-Z-1
Kc
ECt
Z-1
u（t-1）
Figure1FuzzyPIControl’sblockdiagram
Inthisfuzzycontroller,utiscontrolvariable,iscontrolledvariable,SVisreferenceinput,theinputoffuzzycontrolleriserrorEtanderrordifferenceECt,theoutputisΔut.KeandKcarethequantifyfactorsoferroranderrorraterespective.KuistheproportionfactoroffuzzyPIcontroller.ThefuzzycontrolalgorithmhasbeenbroughtintoeffectinStep7（LiaoChangchu,2005）anddownloadedinS7-300PLC,themonitorpictureandtendencycharthavebeenestablishedbymonitorsoftwareWinCC（KunZhe,2004）andusedtomonitorthechangetrendsofcontrolledplant,thedatacommunicationbetweenS7-300PLCandWinCCisbuiltbyMPInet.InthispagewechooseAE2000Aprocesscontrolequipment’sboilertemperatureascontrolledplant.
Thefuzzycontrolalgorithmwasrealizedbyinquiringatwo-dimensionaltableon-line.Theprocesscanbedividedintothefollowingthreesteps:
Step1:
Calculatesystem'serroranderrorrateaccordingtothesamplingsignalandthegivenvalueinthecontrolcircuit.Thenfuzzedtheerroranderrorrateaccordingtothesetwoequations:
Ke=n/emaxandKc=m/cmax
Step2:
Inquirethetwo-dimensionaltableaccordingtothefuzzifiederroranderrorrate.InStep7,there’snospecialinstructionforinquiringtwo-dimensionaltable.Asweknownthatthedatastructureinmicroprocessorislinear,sowewrittenatwo-dimensionalpollingroutinebasedonthischaracteristic.Inthetwo-dimensionarraywhichhasn×mfactors,thephysicaladdressofcelldataα[i][j]is:
（firstaddress+i×n+j）.AccordingtotheabsolutephysicaladdressandStep7STLinstructions’characteristic,wecangetthevalueofcelldataα[i][j].
Step3:
InordertocontrolthecontrolledplantweshoulddefuzzythefuzzycontrolvariableΔuwhichwegotfromstep2.Thedefuzzificationequationis:
Ku=Δumax/h.
3THEDESIGNOFSELF-ADJUSTINGFUZZYCONTROLLER
Thefuzzycontrolleriscomposedofthefollowingfourelements:
1.Arule-base（asetofIf-Thenrules）,whichcontainsafuzzylogicquantificationoftheexpert'slinguisticdescriptionofhowtoachievegoodcontrol.
2.Aninferencemechanism（alsocalledan"inferenceengine"or"fuzzyinference"module）,whichemulatestheexpert'sdecisionmakingininterpretingandapplyingknowledgeabouthowbesttocontroltheplant.
3.Afuzzificationinterface,whichconvertscontrollerinputsintoinformationthattheinferencemechanismcaneasilyusetoactivateandapplyrules.
4.Adefuzzificationinterface,whichconvertstheconclusionsoftheinferencemechanismintoactualinputsfortheprocess.
Thefuzzycontrolruleis:
IFE=AiTHENIFEC=BjTHENΔu=Cij,whichcanbedescribedbythefuzzyrelationshipR1,thatisR=∏ABC,whentheerroranderrorratearetakenfromthefuzzysubsetAandBseparately,wecangettheoutputvariableΔu=（A×B○R1）throughfuzzydeductionrules.The“centerofmass”defuzzification（SunZengqietc.,
ii
Z
2004）is:
WecangetaquerytablefromthefuzzycontrollerwhichwedesignedinMATLAB’sfuzzytoolbox（ZhangGuoliang,ZengJing，KeXizheng,2002）,asshowninTable1.
3.1Themodificationoftemperaturefuzzycontroller’squerytable
Becauseoftheparticularityofexperimentinstallation,weneedtoadjustthetemperaturefuzzycontroller’squerytable.Theboiler’selectricheatingsilkisthree-phaseresistancewireandthethree-phaseelectricheatingtube'scurrentiscontrolledbySCR’sconductiveangle.ThroughexperimentweknewthatwhenthemaxvalueofPLC’sanalogoutputmodulewas27648,thevalueofelectricheatingtube’sammeterwas4.2A.There’snocurrentdisplayuntilthevalueofPLC’sanalogoutputmodulewasabout12500andthentheresistancewirestartedheating.Atthebeginningofthetest,thetemperaturevaluewasrisingandthefuzzycontroller’squeryvaluewasfloatingbetween[6,-6]and[6,6],that’sjustthedatainthelastlineofTable1.Iftheinquiredvalueistoosmall,thequantifiedoutputvaluewillbeverylittleandthetransferredanalogoutputvaluewillbetoolittletoreachtheSCR’sconductivevalue,sotheSCRcan’tbeconductedandtheresistancewirecan’twork.Accordingtoanalysisbasedoncontroltheory,weknowthatlargercontroleffectisneededintherisingstagesoastomakeactualvaluereachsetvaluerapidly.So,wejustmodifiedthelastlineofTable1,thenewmodifiedquerytableasshowninTable2.
StorethisquerytableinthememoryofS7-CPU315-2DP.Inreal-timecontrolprocess,theprogramsearchesthisquerytabledirectlyandgetsthecontrolvalueΔuijaccordingtothevalueoffuzzfiederroranderrorrate,thenmultiplyitbytheproportionalfactorKu,thisresultcanbeusedtocontrolthecontrolledplantasoutputvalue.
Δu
Errorrateec
-6
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
Err
or
e
-6
-5.8
-5.5
-5.45
-5.5
-5.48
-5.09
-4.22
-3.73
-2.8
-2.33
-19.
-1.00
0.35
-5
-5.5
-5.59
-5.46
-5.59
-5.5
-5.09
-4.2
-3.6
-2.67
-2.29
-1.61
0.12
0.61
-4
-5.45
-5.46
-5.22
-5.19
-5.17
-4.26
-4.25
-3.02
-2.33
-1.1
0.15
1.06
1.19
-3
-5.5
-5.59
-5.19
-5.09
-4.88
-3.68
-3.11
-2.26
-1.39
0.30
1.1
2.15
2.33
-2
-5.48
-5.5
-5.17
-4.88
-4.72
-3.47
-2.7
-1.96
0.18
0.15
1.19
2.32
2.8
-1
-5.09
-5.09
-4.43
-3.68
-3.47
-2.28
-1.09
0.30
0.97
1.29
2.79
3.52
3.73
0
-4.33
-4.14
-2.83
-2.24
-2.00
-1.13
0
1.13
1.89
2.24
3.43
4.14
4.33
1
-3.73
-3.52
-1.57
-2.09
-0.93
0.3
1.16
3.03
4.00
4.11
4.15
5.09
5.09
2
-2.8
-2.33
-1.18
-0.30
0.56
1.53
2.23
3.05
4.20
4.22
5.17
5.5
5.48
3
-2.33
-2.1
-0.8
0.3
1.39
2.34
3.11
3.11
4.22
4.84
5.19
5.59
5.5
4
-1.19
-0.80
0.3
1.56
1.74
3.02
3.25
4.26
4.47
5.15
5.22
5.46
5.45
5
-0.78
0.12
1.1
2.19
2.70
3.48
4.14
4.92
4.92
5.5
5.46
5.59
5.5
6
0.45
0.78
1.9
2.37
2.8
3.73
4.22
5.09
5.48
5.5
5.45
5.5
5.8
Table1ThequerytableoffuzzyPIDcontroller’scontrolvariableΔu
Error
e
ErrorRateec
3.0
3.0
3.5
3.5
4.0
4.5
4.5
5.09
5.48
5.5
5.45
5.5
5.8
Table2ThemodifiedquerytableofΔu
3.2Thedesignofadjustablefactor
Theproportionalfactoron-lineself-adjustmentmethodwasemployedinthisfuzzycontroller.Asconventionalcontrol,fuzzycontrolisstillhascontradictionbetweenitsstaticanddynamiccharac
升级会员 