搜索
附件一：ARapidlyDeployableManipulatorSystemAuthor:ChristiaanJ.J.Paredis,H.BenjaminBrown,PradeepK.KhoslaAbstract:Arapidlydeployablemanipulatorsystemcombinestheflexibilityofreconfigurablemodularhardwarewithmodularprogrammingtools,allowingtheusertorapidlycreateamanipulatorwhichiscustom-tailoredforagiventask.Thisarticledescribestwomainaspectsofsuchasystem,namely,theReconfigurableModularManipulatorSystem(RMMS)hardwareandthecorrespondingcontrolsoftware.1IntroductionRobotmanipulatorscanbeeasilyreprogrammedtoperformdifferenttasks,yettherangeoftasksthatcanbeperformedbyamanipulatorislimitedbymechanicalstructure.Forexample,amanipulatorwell-suitedforprecisemovementacrossthetopofatablewouldprobablynobecapableofliftingheavyobjectsintheverticaldirection.Therefore,toperformagiventask,oneneedstochooseamanipulatorwithanappropriatemechanicalstructure.Weproposetheconceptofarapidlydeployablemanipulatorsystemtoaddresstheabovementionedshortcomingsoffixedconfigurationmanipulators.AsisillustratedinFigure1,arapidlydeployablemanipulatorsystemconsistsofsoftwareandhardwarethatallowtheusertorapidlybuildandprogramamanipulatorwhichiscustomtailoredforagiventask.ThecentralbuildingblockofarapidlydeployablesystemisaReconfigurableModularManipulatorSystem(RMMS).TheRMMSutilizesastockofinterchangeablelinkandjointmodulesofvarioussizesandperformancespecifications.OnesuchmoduleisshowninFigure2.Bycombiningthesegeneralpurposemodules,awiderangeofspecialpurposemanipulatorscanbeassembled.Recently,therehasbeenconsiderableinterestintheideaofmodularmanipulators,forresearchapplicationsaswellasforindustrialapplications.However,mostofthesesystemslackthepropertyofreconfigurability,whichiskeytotheconceptofrapidlydeployablesystems.TheRMMSisparticularlyeasytoreconfigurethankstoitsintegratedquick-couplingconnectorsdescribedinSection3.EffectiveuseoftheRMMSrequires,TaskBasedDesignsoftware.Thissoftwaretakesasinputdescriptionsofthetaskandoftheavailablemanipulatormodules;itgeneratesasoutputamodularassemblyconfigurationoptimallysuitedtoperformthegiventask.Severaldifferentapproacheshavebeenusedsuccessfullytosolvesimpli-fiedinstancesofthisAthirdimportantbuildingblockofarapidlydeployablemanipulatorsystemisaframeworkforthegenerationofcontrolsoftware.Toreducethecomplexityofsoftwaregenerationforreal-timesensor-basedcontrolsystems,asoftwareparadigmcalledsoftwareassemblyhasbeenproposedintheAdvancedManipulatorsLaboratoryatCMU.Thisparadigmcombinestheconceptofreusableandreconfigurablesoftwarecomponents,asissupportedbytheChimerareal-timeoperatingsystem,withagraphicaluserinterfaceandavisualprogramminglanguage,inplementedinOnika.Althoughthesoftwareassemblyparadigmprovidesthesoftwareinfrastructureforrapidlyprogrammingmanipulatorsystems,itdoesnotsolvetheprogrammingproblemitself.Explicitprogrammingofsensor-basedmanipulatorsystemsiscumbersomeduetotheextensiveamountofdetailwhichmustbespecifiedfortherobottoperformthetask.Thesoftwaresynthesisproblemforsensor-basedrobotscanbesimplifieddramatically,byprovidingrobustroboticskills,thatis,encapsulatedstrategiesforaccomplishingcommontasksintherobotstaskdomain.Suchroboticskillscanthenbeusedatthetasklevelplanningstagewithouthavingtoconsideranyofthelow-leveldetailsAsanexampleoftheuseofarapidlydeployablesystem,consideramanipulatorinanuclearenvironmentwhereitmustinspectmaterialandspaceforradioactivecontamination,orassembleandrepairequipment.Insuchanenvironment,widelyvariedkinematic(e.g.,workspace)anddynamic(e.g.,speed,payload)performanceisrequired,andtheserequirementsmaynotbeknownapriori.Insteadofpreparingalargesetofdifferentmanipulatorstoaccomplishthesetasks—anexpensivesolution—onecanusearapidlydeployablemanipulatorsystem.Considerthefollowingscenario:assoonasaspecifictaskisidentified,thetaskbaseddesignsoftwaredeterminesthetask.ThisoptimalconfigurationisthenassembledfromtheRMMSmodulesbyahumanor,inmanipulator.Theresultingmanipulatorisrapidlyprogrammedbyusingthesoftwareassemblyparadigmandourlibraryofroboticskills.Finally,themanipulatorisdeployedtoperformitstask.Althoughsuchascenarioisstillfuturistic,thedevelopmentofthereconfigurablemodularmanipulatorsystem,describedinthispaper,isamajorstepforwardtowardsourgoalofarapidlydeployablemanipulatorsystem.Ourapproachcouldformthebasisforthenextgenerationofautonomousmanipulators,inwhichthetraditionalnotionofsensor-basedautonomyisextendedtoconfiguration-basedautonomy.Indeed,althoughadeployedsystemcanhaveallthesensoryandplanninginformationitneeds,itmaystillnotbeabletoaccomplishitstaskbecausethetaskisbeyondthesystem’sphysicalcapabilities.Arapidlydeployablesystem,ontheotherhand,couldadaptitsphysicalcapabilitiesbasedontaskspecificationsand,withadvancedsensing,control,andplanningstrategies,accomplishthetaskautonomously.2Designofself-containedhardwaremodulesInmostindustrialmanipulators,thecontrollerisaseparateunithousingthesensorinterfaces,poweramplifiers,andcontrolprocessorsforallthejointsofthemanipulator.Alargenumberofwiresisnecessarytoconnectthiscontrolunitwiththesensors,actuatorsandbrakeslocatedineachofthejointsofthemanip