机电 自动化控制类 外文翻译英文文献 为柔性制造系统设计的可编程控制器平台.docx

机电 自动化控制类 外文翻译英文文献 为柔性制造系统设计的可编程控制器平台.docx

《机电 自动化控制类 外文翻译英文文献 为柔性制造系统设计的可编程控制器平台.docx》由会员分享，可在线阅读，更多相关《机电 自动化控制类 外文翻译英文文献 为柔性制造系统设计的可编程控制器平台.docx（11页珍藏版）》请在冰豆网上搜索。

机电自动化控制类外文翻译英文文献为柔性制造系统设计的可编程控制器平台

TheoreticalComputerScience253（2001）61{93

DevelopingaHybridProgrammableLogicControllerPlatformforaFlexibleManufacturingSystem

HenningDierks1

UniversityofOldenburg,FachbereichInformatik,Postfach2503,2900Oldenburg,Germany

Abstract:

Inthisarticle,wepresentthedesignandimplementationofaflexiblemanufacturingsystem（FMS）controlplatformbasedonaprogrammablelogiccontroller（PLC）andapersonalcomputer（PC）-basedvisualman-machineinterface（MMI）anddataacquisition（DAS）unit.ThekeyaspectofanFMSisitsflexibilitytoadapttochangesinademandingprocessoperation.ThePLCprovidesfeasiblesolutionstoFMSapplications,usingPC-basedMMI/DAS,wherebyPLCsareoptimizedforexecutingrapidsequentialcontrolstrategies.PCsrunningMMI/DASfront-endsmakeintuitiveoperationinterfaces,fullofpowerfulgraphicsandreportingtools.InformationfromthePCcanbedistributedthroughacompany’slocalareanetworkorwebusingclient-servertechnologies.Currently,withtheconvergenceofunderlyingmicroprocessortechnologyandsoftwareprogram-mingtechniques,manyusersfindthatPLCsprovideacost-effectivesolutiontoreal-timecontrolinsmall-tomedium-sizedprocessplants,especiallywhencombinedwithsupervisoryPCsusinghybridsystems.ThemajorworkofthisarticledemonstratesthatPLCsareresponsivetorapidandrepetitiouscontroltasks,usingPCsthatpresenttheflowofinformationautomationandacceptoperatorinstructions,therebyprovidingtheuseratooltomodifyandmonitortheprocessastherequirementschange.

KeyWords:

PLC、FMS、PC.

1．Introduction

Inavarietyofproductmanufacturingindustries,themostautomatedformofproductionisaFlexiblemanufacturingsystem（FMS）,firstintroducedin1970s.SincetheFMSscanprovideahighpotentialforproductivityimprovementinbatchmanufacturing,thenumberofFMSsisgrowingsubstantially（GrooverandZimmers,1984）.Theaccelerationthroughouttheworldisduetoincreasedglobalcompetition,reducedmanufacturingcycletimes,andcutsinproductioncosts.

Generally,anFMSconsistsofagroupofmachinesorotherautomatedworkstations,whichformintomodularsubsystems,suchasCNCmachines,robots,visionsystems,andaprocessstation.Theseareinterconnectedbyamaterialshandlingsystemandusuallydrivenbyacomputer（Maleki,1991）.Eachmodularsystemrequiresanindividualmodularcontrolsystem,withdifferentcomponentsbeingcontrolledbyindividualcontrollerunits.Allofthemodularsubsystemsarecontrolledbycomputersasusual.Thesecontrollersperformtheirintendedtasksundersupervisionofahigherlevelcontroller.Tothesystem,boththecontroldevicesaswellastheflowofinformationneedtobeautomated.ThekeyaspectofanFMSisitsabilitytoadapttochangesinthecontroltasks.Thisflexibilityincludesthequantitiesandvarietiesofparttypeswhichitcanproduce,theorderinwhichoperationsmaybeperformed,anditsabilitytoreroutepartsbackintoflowpaths.Intheend,thecontrolplatformshouldhavethecapabilitytoautomatetheflowofinformation.

Typically,therearethreetypesofcontrolplatformsusedinFMSs:

minicomputers,microcomputers,andPLCs（Maleki,1991）.Theminicomputersarebestsuitedforcomplexlarge-scale,continuous,regulatorycontrolapplications.ThePLCsareusedforrapidandrepetitiouslogiccontrol.Personalcomputers（PCs）aresuitedforoperatorinterfacefunctions.Primarily,PLCsaredesignedtoreplacehardwiringrelays,tooperateinanindustrialenvironment,tobeeasilymodifiedbyplantengineersandmaintenancepersonnel,andtobemaintainedbyplantelectricians.Currently,withtheconvergenceofunderlyingmicroprocessortechnologyandsoftwareprogramming,manyusersfindthatPLCsprovideacost-effectivesolutiontoreal-timecontrolinsmall-tomedium-sizedprocessplants,especiallywhencombinedwithsupervisoryPCsusinghybridsystems.

Thepurposeofthisarticleistoaddressthestate-of-the-arttechnologyofFMSs.ThedesignandconstructionofanFMSusingPLC-controlledandPC-basedvisualman-machineinterface（MMI）anddataacquisitionsystem（DAS）arepresented.Itisorganizedasfollows.Section2beginswiththedescriptionoftheFMSonthefactoryflooroftheCenterforManufacturingSystemsattheNewJerseyInstituteofTechnology（NJIT）.Section3showstheoperationaldescriptionoftheFMS.Sections4and5presenttheapplicationsofPLC-controlledandPC-basedMMI/DASfortheFMSatNJIT.Section6containsasummaryoftheadvantagesofthisPLC-controlledandPC-basedMMI/DASforFMSapplication.

2.DescriptionoftheFMS

SIhandlingconveyorsystem

Thisconsistsoffourcarts,A,B,C,andD,withfixturesmountedoneach,twotransfertables,TT1andTT2,anddualconveyorswhichtransportmaterialstoeachworkstation.

Figure1.Flexiblemanufacturingsystem.

NASAIICNCmillingmachine

Themillingmachineacceptsrectangularsolidblanksandmachineseachpartofdifferenttypesaccordingtoitscomputercontroller.

GEP50robot

AsharedrobotisusedtoloadandunloadthematerialbetweentheCNCmillingmachineandtheconveyorsystem,andbetweenthepartspresentationstationandconveyorsystem.ItcontainsfivecomputerprogramsassignablebythePLC.ThecomputerprogramsdirecttherobottoloadthematerialbetweenthepartspresentationstationandthecartsandbetweentheCNCmachineandthecarts.Thelasttwoprogramsplacethecompletedpartsintheacceptorrejectarea.

Partspresentationstation

Thisstationincludesagravity-chute,whichsuppliesrectangularsolidblanksasrawmaterials.Thisstationalsocontainstwobintypes,oneeachforacceptedpartsandrejectedparts.

Computervisionsystem

Thevisionsystemprovidesforthevisualautomatedinspectionoftheparts.Itisamenu-driven,64-levelgrayscale,edgedetectionsystem.

Drillingmachine

AnIBM7535industrialrobotwithanautomateddrillasanend-effectordrillsvariousholesinthepartsasdirected.

Insummary,theFMShastworobots,oneCNCmill,amaterialtransferconveyorsystemincludingtransportationcartsandpositioninglimitswitches,andavisionsystem,whicharesupervisedbyaGE-SeriesSixPLCandmonitoredbyaPC-basedvisualMMI/DAS.

3.Operationaldescription

TheworkingcycleforthisFMSproceedsinthefollowingmanner:

1.Initially,allfourcartsontheconveyorsystemareemptyandavailablefortherawmaterialstobeloadedontothemfromthepartspresentationstation.

2.TheGErobotloadsfourparts,onebyone,ontothefourcartsontheconveyorsystem.Thecartsmoveclockwiseastheyarebeingloaded.

3.Figure2showsthepositionsacquiredbythefourcartsoncethefourpartsofdifferenttypeshavebeenloaded.

4.TheIBMrobotdrillsvariousholesoneachblankpartasthecartstopsatthedrillingmachine.

5.TheGErobotmovestotheconveyor,removesthepartfromthecartatpositionX1,andloadsitintothefixturelocatedontheCNCmachinetable.

6.OncethepartisloadedontheCNCmillingmachine,therobotretracts,andthemillingmachinemillstherectangularpartasrequired.

7.Afterthemillingoperation,therobotarmmovestothemillingmachinetoremovethepartthatwasmachinedfromtheholdingfixture.

Figure2.Loadingstateoftheconveyorsystem.

8.Therobotreturnsthefinishedparttothesamecartontheconveyor.

9.Asignalissenttothevisioncameratoinspectthepart.

10.Thevisionsystemanalyzesthepartandoutputsasignalthatdirectstherobottoacceptorrejectthepart.

11.Therobotrunseitheranacceptprogramtoplacethepartintheacceptbinorrunsarejectprogramtoplacethepartintherejectbin.

12.TheGErobotgoestothepartspresentationstationandloadsanewblankpartintothecart.

13.Thecartisreleasedtothesystemandthenextcycleisstarted.

4.ControlofanFMSwithaPLC

ThesignificantfeaturesoftheFMScontrolsystemareasfollows:

1.Thesystemiseasytoconfigureandtomodifytoaccommodatechangesandupdates,becauseoftheladderlogiccapabilityofthesystem.

2.Inasimilarmanner,thesystemiseasytoprogramanddocument.

3.Thesystemcanbeeasilymaintained,andtroubleshootingisdecreasedbecauseon-linediagnosticsareprovidedtopinpointproblemsanddecreasemaintenance.

4.Naturally,thesystemisreadilyinterfacedwiththecomputer.

ThePLCisageneralpurposeindustrialcomputerwhichiswidelyusedinindustrialprocesscontrol.Itiscapableofstoringinstructionstoimplementcontrolfunctionssuchassequencing,timing,counting,arithmetic,datamanipulation,andcommunicationtocontrolindustrialmachinesandprocesses.ThePLCischosentoperformanFMScontroltaskbasedonthefollowingfeatures:

1）goodreliability;

2）lessspacerequiredandoperatesinanindustrialenvironment;

3）easiertomaintainbyplantengineerortechnician;

4）canbereprogrammedifcontrolrequirementschange;

5）cancommunicateandnetworkwithothercomputers.

Inthisapplication,aGE-SeriesSixPLCisequippedwithamemorybank,andtheI/Oracksareloadedwiththefollowinginputandoutputinterfaces:

120VACinputmoduleswith8ports/module,24VDCinputmoduleswith8ports/module,and120VACoutputmoduleswith8ports/module.

5.PC-basedvisualoperatorinterfaceunit

Withtheconvergenceofmicroprocessortechnologyandsoftwaretechniques,thePChasbecomeveryusefulinoperatorinterfaceapplications.PCsrunningMMI/DASfront-endsmakepowerful,intuitiveoperationinterfaces,fullofusefulgraphicsandreportingtools.InformationfromthesePCscanbedistributedt