工厂模型生成PLC仿真外文翻译.docx
- 文档编号:24652574
- 上传时间:2023-05-29
- 格式:DOCX
- 页数:23
- 大小:1.94MB
工厂模型生成PLC仿真外文翻译.docx
《工厂模型生成PLC仿真外文翻译.docx》由会员分享,可在线阅读,更多相关《工厂模型生成PLC仿真外文翻译.docx(23页珍藏版)》请在冰豆网上搜索。
工厂模型生成PLC仿真外文翻译
PlantModelGenerationforPLCSimulation
Hyeong-TaePark
Abstract:
ThispaperreportsanautomatedprocedureforconstructingaplantmodelforPLCsimulation.SincePLCprogramscontainonlythecontrollogicwithoutinformationontheplantmodel,itisnecessarytobuildthecorrespondingplantmodeltoperformthesimulation.Conventionally,aplantmodelforPLCsimulationhasbeenconstructedmanually,whichrequiresmucheffortandindepthknowledgeofthesimulation.Asaremedyforthisproblem,weproposeanautomatedprocedureforgeneratingaplantmodelfromthesymboltableofaPLCprogram.Todoso,weproposeanamingruleforPLCsymbolssothatthesymbolnamesincludesufficientinformationontheplantmodel.Byanalysingsuchsymbolnames,weextractaplantmodelautomatically.Theproposedmethodologyhasbeenimplementedandtestrunsperformed.
Keywords:
agilemanufacturing;CAD/CAM;CAPP;simulation
1.Introduction
Tosurviveandprosperinthemodernmanufacturingera,manufacturersneedtocontinuouslyimprovetheirproducts,aswellastheirproductionsystems.Amodernmanufacturinglineisahighlyintegratedsystemcomposedofautomatedworkstations,suchasrobotswithtool-changingcapabilities,ahardwarehandlingsystemandstoragesystem,andacomputercontrolsystemthatcontrolstheoperationsoftheentiresystem.
Sincetheimplementationofamanufacturinglinerequiresheavyinvestment,properverificationofaline’soperationalstatusshouldbeperformedtoensurethatthehighlyautomatedmanufacturingsystemwillsuccessfullyachievetheintendedbenefits.Simulationtechnologyisconsideredtobeanessentialtoolinthedesignandanalysisofcomplexsystemsthatcannotbeeasilydescribedbyanalyticalormathematicalmodels.Simulationisusefulforcalculatingutilisationstatistics,findingbottlenecks,pointingoutschedulingerrors,andevenforcreatingmanufacturingschedules.Traditionally,varioussimulationlanguages,includingARENAandAutoMod,havebeenusedforthesimulationofmanufacturingsystems.Thesesimulationlanguageshavebeenwidelyacceptedbothbyindustryandbyacademia;however,theyremainasanalysistoolsfortheroughdesignstageofaproductionline,becausetheirsimulationmodelsarenotsufficientlyrealistictobeutilisedforadetaileddesignorforimplementationpurposes.Forexample,realproductionlinesareusuallycontrolledbyPLC(ProgrammableLogicController)programs(Rullan1997),butconventionalsimulationlanguagesroughlydescribethecontrollogicwithindependententityflows(jobflows)betweenprocesses.
Productionsystemstypicallyconsistofsimultaneouslyoperatingmachines,whicharecontrolledbyPLCs,currentlythemostsuitableandwidelyemployedindustrialcontroltechnology.APLCemulatesthebehaviourofanelectricladderdiagram.Astheyaresequentialmachines,toemulatetheworkingsofparallelcircuitsthatrespondinstantaneously,PLCsuseaninput/outputsymboltableandascanningcycle.WhenaprogramisbeingruninaPLCitiscontinuouslyexecutingascanningcycle.TheprogramscansolvestheBooleanlogicrelatedtotheinformationintheinputtablewiththatintheoutputandinternalrelaytables.Inaddition,theinformationintheoutputandinternalrelaytablesisupdatedduringtheprogramscan.InaPLC,thisBooleanlogicistypicallyrepresentedusingagraphicallanguageknownasaladderdiagram(IEC2003).
SincetheabstractionlevelsofconventionalsimulatorsandPLCprogramsarequitedifferent,thecontrollogicofconventionalsimulatorscannotbereusedforthegenerationofPLCprograms.Usually,electricalengineersmanuallywritePLCprogramsbyreferringtotheroughcontrollogicofconventionalsimulators,asshowninFigure1.SincePLCprogrammingisaverytediousanderror-pronejob,itisessentialtoverifythePLCprogramsofflinetoreducethestabilisationtimeofaproductionsystem.
PreviousapproachestoaPLCprogramcanbecategorisedintotwogroups:
(1)verificationofagivenPLCprogramand
(2)generationofadependablePLCprogram.Inthefirstgroup,varioussoftwaretoolshavebeendevelopedfortheverificationofPLCbasedsystemsviatheuseoftimedautomata,suchasUPPAAL2k,KRONOS,SupremicaandHyTech,mainlyforprogramswritteninastatementlistlanguage,alsotermedBoolean(ManesisandAkantziotis2005).SuchsoftwaretoolsverifyPLCprogramstoacertainextent;however,theyremainlimited.Sincetheymainlyfocusonthecheckingoftheoreticalattributes(safety,liveness,andreachability),itisnoteasyforuserstodeterminewhetherthePLCprogramsactuallyachievetheintendedcontrolobjectives.Inthesecondgroup,manyresearchershavefocusedontheautomaticgenerationofPLCprogramsfromvariousformalismsincludingstatediagrams,Petrinets,andIDEF0.Theseformalismscanhelpthedesignprocessofcontrollogics;however,itisstilldifficulttofindhiddenerrors,whichisthemostdifficultpartofverifyingacontrolprogram.
Figure2.TheconceptofPLCsimulation.
Toovercometheaforementionedproblems,itisnecessarytoutilisesimulation
techniquesforPLCprogramverification.BysimulatingPLCprograms,itispossibletoanalysethecontrollogicinvariouswaysandrecognisehiddenerrorsmoreintuitively(David1998).AlthoughPLCsimulationcanbeaverypowerfultoolforthedetailedverificationofaproductionsystem,theaccompanyingconstructionofaplantmodelisamajorobstacle(thecounterpartmodelofacontrolprogram).SincePLCprogramsonlycontainthecontrolinformation,withoutdevicemodels,itisnecessarytobuildacorrespondingplantmodeltoperformsimulation,asshowninFigure2.However,constructingaplantmodelrequiresanexcessiveamountoftimeandeffort.Sometimes,theplantmodelconstructionrequiresmuchmoretimethanthePLCprogramming.ThisservesasthemotivationforexploringthepossibilityoffindinganautomaticprocedureforgeneratingaplantmodelfromagivenPLCprogram.
Figure3.SymboltableofaPLCprogram.
AlthoughtheobjectiveofaPLCprogramisnottodescribeaplantmodel(devicemodels),thesymboltableofaPLCprogramcanprovideaglimpseoftheplantmodel.AsshowninFigure3,symbolsinaPLCprogramusuallycontainsomeinformationrelatedtotheplant.Forexample,‘EXLINE_MB_AGV_P1’meansthatthesymbolisasignalthatisrelatedtothecontrolofan‘AGV’(AutoGuidedVehicle)belongingtothe‘MB’stationof‘EXLINE’line.Theabovescenariorevealsthekeyideaofthepresentstudy.IfwecandevelopapropernamingruleforPLCsymbols,thenitmightbepossibletoextractaplantmodelbyanalysingthesymbolnames.
Thispaperhastwomajorobjectives:
(1)toproposeapropernamingruleforPLCsymbolsand
(2)todevelopaprocedureforgeneratingaplantmodelbyanalysingthesymbolnames.TheapplicationareaoftheproposedmethodologyincludesalltypesofautomatedmanufacturingsystemscontrolledbyPLCprograms,suchasautomotiveproductionlines,FMSs(flexiblemanufacturingsystems),andASRSs(automaticstorageandretrievalsystems).Theoverallstructureofthepaperisasfollows.Section2addressesthespecificationsofaplantmodelforPLCsimulation.Section3describesanamingruleforPLCsymbols,whichenablestheautomaticgenerationofaplantmodel.Finally,concludingremarksaregiveninSection4.
2.PlantmodelforPLCsimulation
BeforeexplainingthespecificationofaplantmodelenablingPLCsimulation,wewanttoaddresstheimportanceofthePLCsimulation.Chuangetal.(1999)proposedaprocedureforthedevelopmentofanindustrialautomatedproductionsystemthatconsistsofninesteps,asfollows:
(1)definetheprocesstobecontrolled;
(2)makeasketchoftheprocessoperation;(3)createawrittensequenceoftheprocess;(4)onthesketch,addthesensorsneededtocarryoutthecontrolsequence;(5)addthemanualcontrolsneededfortheprocesssetuporforoperationalchecks;(6)considerthesafetyoftheoperatingpersonnelandmakeadditionsandadjustmentsasneeded;(7)addthemasterstopswitchesrequiredforasafeshutdown;(8)createaladderlogicdiagramthatwillbeusedasabasisforthePLCprogram;and(9)considerthepossiblepointswheretheprocesssequencemaygoastray.Themosttime-consumingtaskforthecontrollogicdesignersistheeighthstep,whichisusuallydonebytherepetitivemethodofcodewriting,testing,anddebugginguntilthecontrolobjectivesareachieved(ManesisandAkantziotis2005).ThisisthereasonwhyconventionalPLCprogrammingisofteninefficientandpronetohumanerror.Astheconfigurationsofproductionlinesandtheircontrolprogramsbecomemorecomplicated,thereisastrongneedforamoreefficientPLCsimulationenvironment.Itishopedthatthispaperwilltakepositivestepsinthisdirection.
APLCcanbeconsideredasadedicatedcomputersystemhavinginputandoutput
signals.TorunaPLC,thecorrespondingplantmodel(thecounterpartsystem)isrequiredtointeractwiththeinputandoutputofthePLC.ThebehaviouroftheplantmodelshouldbethesameasthatoftheactualsystemtoachievePLCverification.Sinceaproductionlineconsistsofvariousdevices,includingrobots,transporters,jigs,solenoids,proximitysensors,andlightsensors(Groover2006),wecanconsideraplantmodelasasetofdevicemodels.Tobuildsuchadevicemodel,thispaperemploysZeigler’sDEVS(DiscreteEventSystemsSpecifications)formalism(Zeigler1984,Kim1994),whichsupportsthespecificationofdiscreteeventmodelsinahierarchical,modularmanner.Thesemanticsoftheformalismarehighlycompatiblewithobject-orientedspecificatio
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- 工厂 模型 生成 PLC 仿真 外文 翻译