外文翻译--并联机器人及其远程操作.doc

AparallelroboticattachmentanditsremotemanipulationLihuiWanga,FengfengXib,DanZhangcaIntegratedManufacturingTechnologiesInstitute,NationalResearchCouncilofCanada,800CollipCircle,London,OntarioN6G4X8,CanadabDepartmentofAerospaceEngineering,RyersonUniversity,Toronto,OntarioM5B2K3,CanadacFacultyofEngineeringandAppliedScience,UniversityofOntarioInstituteofTechnology,Oshawa,OntarioL1H7K4,CanadaReceived7October2005；accepted25November2005-AbstractThispaperdiscussesa3-dof(degreeoffreedom)parallelroboticattachmentanditsremotemanipulation.Thisattachmentisdesignedasatripodthatprovidestworotarymotionsandonelinearmotion.Theattachmentcanbemountedontoavarietyofmachinesfordifferentapplications,includingCNCmillingmachines,industrialrobots,andCMM.Javatechnologiesareusedtodeveloparemotemanipulationsystemfortheparallelroboticattachment,includingremotemonitoringandcontrol.Themaindifferenceofthissystemfromtheexistingweb-basedorinternet-basedremotesystemsisthewaytocontrolthemotionofthemachinefromaremotesite.Insteadofusingacameraformonitoring,thetripodismodeledusing3Dcomputergraphicswithbehavioralcontrolnodesembedded.Comparedwithcamera-basedsolutions,networktrafficislargelyreduced,therebymakingreal-timeremotedevicemanipulationpracticalontheweb.Ourparallelroboticattachmentisonetypeofparallelkinematicmechanisms(PKM).WithPKMemergingasanewwayofbuildingflexiblesystemsoragilemachines,itsadvantageoverserialmechanismisalsopresented.2006ElsevierLtd.Allrightsreserved.Keywords:Parallelkinematicmachines；Stiffnessmapping；Inversekinematics；Remotereal-timemanipulation-1.IntroductionParallelkinematicmechanismshavesignificantadvantagesoverserialmechanisms.Inparticular,theypossessreducedmovingmassandhigherstiffness.Thus,parallelmechanismscanworkathighervelocities,andyetmaintainsufficientrigiditytodeliverhighlevelsofaccuracy.ThisresearchrepresentsourcontinuouseffortsofPKMdesign,analysisandcontrol.Parallelmechanismsgenerallycomprisetwoplatformsthatareconnectedbyjointsorlegsactinginparallel1.Overthepastdecades,parallelmechanismshavereceivedmuchattentionfromresearchersandindustrialpractitioners.Theycanbefoundinseveralpracticalapplications,includingaircraftsimulators2,positiontracker3,telescopes4,andmicro-motiondevice5.Morerecently,theyhavebeenusedinthedevelopmentofhighprecisionmachinetools6-8bymanycompaniessuchasGiddings&Lewis,Ingersoll,Hexel,GeodeticandToyoda.Amongothers,hexapodmachinetoolsareonetypeofthesuccessfulapplications.Withthegrowingmanufacturingdecentralization,designandfabricationfunctionsofmostoriginalequipmentmanufacturers(OEM)havebeendistributedgeographically.Followingthetrend,manufacturingoperationshavebeenshiftedrapidlyfromintra-corporationtoglobalnetworks.Howtokeepallactivitiesundercontrolisachallengingissue.Insuchadistributedenvironment,controllabilityandpredictabilityoffactoryoperationsaretwoessentialrequirementsforweb-basedcollaborativemanufacturing.Inthispaper,thischallengeisaddressedthroughaparallelroboticattachmentbyapplyingthelatestWebandJavatechnologies.Since1993shortlyafteritsdebut,theWebhasgainedawideacceptancefordevelopingbusinessapplications.Ithasbeenwidelyusedbymanyasamediumtoshareinformation,knowledgeandbusinessdecisions9-11.Duetothedecentralizationoftodaysmanufacturing,web-basedsolutionshavebecomethenormfordistributedcollaborativemanufacturingbecauseoftheirplatform,networknormfordistributedcollaborativemanufacturingbecauseoftheirplatform,networkandoperatingsystemtransparency,andtheireasy-to-useuserinterfacethewebbrowser.InadditiontotheWeb,Javatechnologyhasbroughtaboutafundamentalchangeinthewaythatapplicationsaredesignedanddeployed.WithJava,thebrowserparadigmhasemergedasacompellingwaytoproducemanufacturingapplicationsovertheInternet.Inthispaper,weintroduceaJava-basedmonitoringandcontrolapproachthatdemonstratesagreatpotentialtosupportdispersedengineersinacollaborativeenvironment.PoweredbyJavaswriteonce,runanywhereconcept,ourJava-basedapproachcanlargelyreducethecomplexityandcosttraditionallyassociatedwithsoftwaredevelopmentonmultipledistincthardwareplatforms.Aparallelroboticattachmentisintroducedasatestingdeviceforsystemvalidation.This3-dof(degreesoffreedom)attachmentcanbecombinedwithmillingmachines,industrialrobots,orcoordinatemeasuringmachines(CMM)toprovidefinetuningforCorrespondingauthor.Tel.:+15194307084；fax:+15194307090.E-mailaddress:lihui.wangnrc.gc.ca(L.Wang).0736-5845/$-seefrontmatter2006ElsevierLtd.Allrightsreserved.doi:10.1016/j.rcim.2005.11.012motioncontrol.ThispaperreportsonnewR&Dfindingsandisarrangedasfollows.TheprinciplesoftheJava-basedmonitoringandcontrolapproacharepresentedinSection2.Themechanismandkinematicsofaparallelroboticattachment(atripod)arerevealedinSection3.Forthepurposeofsystemvalidation,theparalleltripodisattachedtoagantrysystemforlightpolishing.ItisusedasacasestudyinSection4todemonstratetheJava-basedmonitoringandcontrol.Finally,conclusionsandfutureworkaresummarizedinSection5.2.Java-basedmonitoringandcontrol2.1.ConceptandapproachTraditionally,remotemonitoringandcontrolsolutionshavebeenfollowingtwoapproaches:signalsonlyorbundledwithcamerasforvisualization.WiththeemergenceoftheInternetandWeb,moreandmorecompaniesareseekingcompellingwaysforweb-basedsolutions.Althoughacamera-basedmonitoringandcontrolsystemcanbeportedtotheInternetasaweb-basedapplication,thebandwidthconservationofanetworkpreventsitfrombeingpracticalasareal-timesolution.Targetingtheproblem,weproposeaJava-basedapproachtocombiningsensordatawithcomputergraphics.ItutilizesthelatestJavatechnologiesincludingJava3DandJavaServletforsystemimplementation,andallowsclientstomonitorandcontroladistantdevicewithvisualhelpsenabledbyaJava3Dmodel.The3Dmodelisareplicaofthephysicaldevicebeingrenderedoff-siteforvisualization,anditsbehaviorisdrivendirectlybyreal-timesensorsignalsofitsphysicalcounterpart.Oncedownloadedfromanapplicationserver,the3Dmodelworksonbehalfofitscounterpartataclientside,butremainsalivebyconnectingwiththephysicaldevicethroughlow-volumesensordatapassing.Inotherwords,thehybridsolutionsformeetinguserrequirementsdemandingrichdatasharingandthereal-timeconstraintsovertheInternetare:(1)usinginteractivescene-graphbasedJava3Dmodelsinsteadofbandwidth-consumingcameraimagesforboff-sitevisualization；(2)transmittingonlythesensordataandcontrolcommandsbetweenmodelsanddeviceControllersformonitoringandcontrol；(3)providingclientswithaplatform-transparentgraphicaluserinterfacefornavigation；and(4)deployingmajorcontrollogicsinasecureapplicationserverforpropertyprotection.Thegoalistosignificantlyreducenetworktraffic,whilestillprovidingenduserswithanintuitiveenvironment.Ithencemakesreal-timemonitoringandcontrolpracticalovertheInternetforusersonrelativelyslowhook-ups.ThisJava-basedmonitoringandcontrolapproachissupportedbyaWise-ShopFloorframework12,andshownasmodulesinthegreyboxesinFig.1.Withintheframework,themid-tierapplicationserverhandlesmajorsecurityconcerns,suchassessioncontrol,userregistration,sensordatacollection/distribution,andrealdevicemanipulation.AcentralSessionManagerisdesignedtolookaftertheissuesofuserauthentication,sessioncontrol,sessionsynchronization,andsensitivedatalogging.AllinitialtransactionsneedtopassthroughtheSessionManagerforaccessauthorization.Asaserver-sidemodule,theSignalCollectorisresponsibleforsensordatacollectionfromnetworkedphysicaldevices.Thecollecteddataarethenpassedtoanotherserver-sidemoduleSignalPublisherwhointurnmulticaststhesensordatatotheregisteredsubscribers(clients)throughapplet-servletcommunication.ARegistrarisdesignedtomaintainalistofsubscriberswiththerequestedsensordata.AphysicaldeviceiscontrollableonlybytheControlCommanderthatresidesinthesameapplicationserver.TheconceptoftheJava-basedmonitoringandcontrolisdesignedtousethepopularclient-serverarchitectureandVCM(view-control-model)designpattern.Thecontrol-tierisanapplicationserverthathostsmajormanufacturingcontrollogics.Themodel-tierisadatabasethatstoresneededdata,knowledgeand3Dmodelsformonitoringandcontrol.Atclientside,aJavaappletuserinterface(fittingintheview-tier)providesclientswithamodel-basedandsensor-drivenenvironment.Inamulti-clientenvironment,differentclientsmayrequiredifferentsetsofsensordatafordevicemanipulation.Itisnotefficienttohavemultipleclientswhosharethesamemodeltalkwiththesamedeviceatthesametime.Instead,apublish-subscribedesignpatternisadopted,basedonwhichtwoserver-sidemodules(SignalCollectorandSignalPublisher)areresponsibleforsensordatacollectionanddistributiontotherightclients,efficiently.HTTPStreamingischosenasthecommunicationprotocolbetweenappletsandservlets.Fig.2illustrateshowatripodismonitoredandcontrolremotelyaccordingtoourJava3Denabledconcept.