




已閱讀5頁,還剩19頁未讀, 繼續(xù)免費閱讀
版權(quán)說明:本文檔由用戶提供并上傳,收益歸屬內(nèi)容提供方,若內(nèi)容存在侵權(quán),請進行舉報或認領(lǐng)
文檔簡介
OntheMechanicalDesignoftheBerkeleyLowerExtremityExoskeleton(BLEEX)AdamZoss,H.Kazerooni,AndrewChuDepartmentofMechanicalEngineeringUniversityofCalifornia,Berkeley,CA,94720,USA,Abstract-ThefirstenergeticallyautonomouslowerextremityexoskeletoncapableofcarryingapayloadhasbeendemonstratedatU.C.Berkeley.ThispapersummarizesthemechanicaldesignoftheBerkeleyLowerExtremityExoskeleton(BLEEX).Theanthropomorphically-basedBLEEXhassevendegreesoffreedomperleg,fourofwhicharepoweredbylinearhydraulicactuators.Theselectionofthedegreesoffreedomandtheirrangesofmotionaredescribed.Additionally,thesignificantdesignaspectsofthemajorBLEEXcomponentsarecovered.IndexTermsBLEEX,exoskeleton,wearablerobotics,mechanicaldesign,leggedlocomotionI.INTRODUCTIONHeavyobjectsaretypicallytransportedusingwheeledvehicles.However,manyenvironments,suchasrockyterrainsandstaircases,posesignificantchallengestowheeledvehicles.Thusleggedlocomotionbecomesanattractivemethodoftransportationwithinthesesettings,sincelegscanadapttoawiderangeofextremeterrains.TheBerkeleyLowerExtremityExoskeleton(commonlyreferredtoasBLEEX)isthefirstfield-operationalroboticsystemwhichiswornbyitsoperatorandprovidesitswearertheabilitytocarrysignificantloadsonhis/herbackwithminimaleffortoveranytypeofterrain.BLEEXiscomprisedoftwopoweredanthropomorphiclegs,apowersupply,andabackpack-likeframeonwhichavarietyofheavypayloadscanbemounted(Fig.1).BLEEXprovidesloadcarryingcapabilitythroughleggedlocomotionguidedbyhumaninteraction,butinsteadofactively“driving”thevehicle,BLEEXshadowstheoperatorsmovementashe/she“wears”itlikeapairofartificiallegs.Bycombiningthestrengthcapabilitiesofroboticswiththenavigationintelligenceandadaptabilityofhumans,BLEEXallowsheavyloadstobecarriedoverrough,unstructured,anduncertainterrains.Exoskeletonsareusuallyconceivedassystemsincludingupperextremities,lowerextremities,orboth;theBLEEXprojectfocusessolelyonlowerextremityexoskeletons.Upperextremityexoskeletonsaregenerallyformanipulatingheavyobjectsandareusuallyusedinwarehouses,manufacturingfacilities,anddistributioncenters(e.g.14).Lowerextremityexoskeletonsaregenerallyforcarryingheavyobjectslongdistances(usuallyoutdoors)andonpathsthatarenotpassablebywheeledvehicles.ThereisnoThisworkispartiallyfundedbyDARPAgrantDAAD19-01-1-0509.practicalreasonforusingalowerextremityexoskeletoninasettingwherewheeledvehiclescanbeusedorwheredistancesaresoshortthatoverheadcranesarepractical.Lowerextremityexoskeletonsaremostsuitedforcarryingheavyobjectsalongunstructured,outdoorpaths.PayloadKneeAnkleHipExoskeletonFootExoskeletonShankExoskeletonThighHarnessPowerSupply&ComputerFig.1Conceptualsketchofalowerextremityexoskeleton.Properactuationoftheroboticlegsremovesthepayloadweightfromthewearer,whileallowingthewearertoeffortlesslycontrolandbalancethemachine.BLEEXhasnumerousapplications;itcanprovidesoldiers,disasterreliefworkers,wildfirefighters,andotheremergencypersonneltheabilitytocarrymajorloads,suchasfood,rescueequipment,first-aidsupplies,communicationsgear,andweaponry,withoutthestraintypicallyassociatedwithdemandinglabor.ItisourvisionthatBLEEXwillprovideaversatiletransportplatformformission-criticalequipment.II.BACKGROUNDThefirstactiveexoskeletonsappearedinthelate1960sandearly70satGeneralElectric(GE)andtheMihajloPupinInstituteinBelgrade.TheHardimanprojectatGE5wasalarge,full-bodyexoskeletonweighing680kgandcontrolledusingamaster-slavesystem.Safetyconcernsandcomplexityissuespreventeditfromeverwalking,orevenstablymovingthelegs.TheBelgradeexoskeletonwasahuman-sizedlowerextremityrobotdesignedtohelprehabilitateparaplegics6.SimilartotheHardimanproject,itcouldnevercarryitsownpowersource.TheBelgradeexoskeletononlyfollowedpre-programmedwalkingmotions,whichgreatlylimiteditsusefulness.However,thisprojectdidproduceZeroMomentPointcontrol,whichisstillusedinhumanoidrobots.Followingthe1970attempts,relativelyfewpeopleinvestigatedlowerextremityexoskeletons.Oneprojectin1993wastheElectricPowerExtenderattheUniversityofCaliforniaatBerkeley1.Thisfull-bodyexoskeletonusedelectricactuationtoamplifyhumancapabilitiessimilartotheHardiman.TheBerkeleyprojectusedforcesensorstodetectandamplifythehumansforces,butstillhadlimitedsuccessinwalking.The21stcenturyhasseenresurgenceinexoskeletoninvestigation.InJapan,theKanagawaInstituteofTechnologyhasdevelopedafullbody“wearablepowersuit”,poweredbyuniquepneumaticactuators7.Theforcesattheirthreeactuators(knee,waist,andelbow)arecontrolledbymeasuringthehardnessofthecorrespondinghumanmuscles.Limitedactuationandlackofaportablepowersupplyrestrictsthisexoskeletonsapplications.TsukubaUniversityinJapandevelopedthelightweightpowerassistdevice,HAL8.UsingEMGsensorsonthehumanslegmusclesandgroundreactionforcesensors,HALcontrolsitselectricactuatorsatthekneeandhip.Thisexoskeletonhasaportablepowersupply,butonlyassiststheoperatorslegmuscles;itcannotcarryanexternalload.Stillindevelopmentareseveralotherlowerextremityexoskeletonsdesignedtoaiddisabledpersons(911).Besidesexoskeletons,someotheractivelowerextremitydevicesareworthmentioning.Amodernrehabilitationdeviceisthelowerlimblocomotiontrainer,Lokomat(12and13).Insteadofcarryingaload,therobotstorsoismountedtoastandandmovestheoperatorsfeetinapredeterminedpath.Whilenotanexoskeleton,theLokomatisasuccessfulproductthatfacessimilarchallenges.TheRoboKnee,developedbyYobotics,isapoweredkneeorthoticdesignedtoenhancetheoperatorsstrengthandenduranceduringwalking14.RoboKneeusesgroundreactionforcestoestimatethedesiredkneetorques.Alternatively,researchersatHokkaidoUniversityinJapanarecreatingapowerassistdeviceforthelowerback15.Attachedatthethighandtorso,thedeviceusesEMGsensorstocontrolitselectricmotors.Avarietyofotheractiveorthosesarealsobeingdeveloped,suchasapneumaticmusclepoweredankleorthotic16.TheBerkeleyLowerExtremityExoskeleton(BLEEX)projecthasdevelopedanenergeticallyautonomousexoskeletoncapableofcarryingitsownweightplusanexternalpayload.Allpreviousexoskeletonsareeithertetheredtoafixedpowersupplyornotstrongenoughtocarryanexternalload.Also,BLEEXtransfersthepayloadforcestothegroundinsteadofwearer,unlikeorthosesandbraces.Tocombatthecomplexitiesinherentwithcreatingawalkingexoskeleton,theBLEEXprojectdevelopedanovelcontrolscheme,whicheliminatesmeasurementsofthehumanorhumaninteractionwiththerobot.III.EXOSKELETONCONTROLTheBLEEXcontrolalgorithmensuresthattheexoskeletonshadowstheoperatorwithminimalinteractionforcesbetweenthetwo.Additionally,thecontrolschemeneedsnodirectmeasurementsfromtheoperatororwheretheoperatorcontactstheexoskeleton(e.g.noforcesensorsbetweenthetwo);instead,thecontrollerestimates,basedonmeasurementsfromtheexoskeletononly,howtomovesuchthatthepilotfeelsverylittleforce17.Thecontrolmethodeliminatestheproblemsassociatedwithmeasuringinteractionforcesorhumanmuscleactivity.ThebasicprincipleforthecontrolofBLEEXrestsonthenotionthattheexoskeletonneedstoshadowthewearersvoluntaryandinvoluntarymovementsquickly,andwithoutdelay.Thisrequiresahighlevelofsensitivityinresponsetoallforcesandtorquesthepilotimposesontheexoskeleton.TheBLEEXcontrolincreasestheclosedloopsystemsensitivitytotheoperatorsforcesandtorquesbymeasuringvariablesonlyfromBLEEX17.TheBLEEXcontrolschemedoeshavetworealisticconcerns.First,anexoskeletonwithhighsensitivitytoexternalforcesrespondstoexternalforceswhetherornottheyarefromtheoperator.Forexample,ifsomeonepushedagainstanexoskeletonthathadhighsensitivity,itwouldmoveasiftheforceswerefromitsoperator.Thekeytostabilizingtheexoskeletonandpreventingitfromfallinginresponsetoexternalforcesdependsontheoperatorsabilitytomovequickly(e.g.stepbackorsideways)tocreateastablesituationforherself/himselfandtheexoskeleton.Forthis,averywidecontrolbandwidthisneededsotheexoskeletoncanrespondtoboththeoperatorsvoluntaryandinvoluntarymovements(i.e.reflexes).Thesecondconcernisthatthiscontrolmethodhaslittlerobustnesstoparametervariationsandthereforerequiresarelativelygooddynamicmodelofthesystem17.IV.DESIGNARCHITECTUREFundamentaltodesigningalowerextremityexoskeletonisselectingtheoverallstructuralarchitectureofthelegs.Manydifferentlayoutsofjointsandlimbscancombinetoformafunctioningleg,butanyarchitecturegenerallyfallsintooneofafewcategories:A.AnthropomorphicArchitectureAnthropomorphicarchitecturesattempttoexactlymatchthehumanleg(Fig.2).Bykinematicallymatchingthehumandegreesoffreedomandlimblengths,theexoskeletonslegpositionexactlyfollowsthehumanlegsposition.Thisgreatlysimplifiesmanydesignissues.Forexample,onedoesnothavetobeconcernedwithhuman/exoskeletoncollisions.However,onemajordifficultyisthatthejointsinhumanlegscannotbeduplicatedusingthecommonstateoftechnologyindesigningjoints.Forinstance,thehumankneedoesnotexhibitapurerotationandduplicatingallitskinematicswillresultinacomplicated(andperhapsnon-robust)mechanicalsystem.Anothermajorpointofconcerninthisarchitectureisthattheexoskeletonlimblengthsmustbeequaltothehumanlimblengths.Thismeansthatfordifferentoperatorstoweartheexoskeleton,almostalltheexoskeletonlimbsmustbehighlyadjustable.Ingeneral,theanthropomorphicarchitectureiserroneouslyregardedtobethepreferredchoicebecauseitallowstheexoskeletontoattachtotheoperatorwhereverdesired.Fig.2ExamplesofAnthropomorphicArchitecture(Left)andNon-AnthropomorphicArchitecture(Right)B.Non-anthropomorphicArchitectureWhilenotascommoninexoskeletondesigns,manynon-anthropomorphicdevicesarehighlysuccessful,suchasbicycles.Non-anthropomorphicarchitecturesopenupawiderangeofpossibilitiesforthelegdesignaslongastheexoskeletonneverinterferesorlimitstheoperator(Fig.2).Oftenitisdifficulttodeveloparchitecturesignificantlydifferentfromahumanlegthatcanstillmovethefootthroughallthenecessarymaneuvers(e.g.turningtightcornersanddeepsquats).Safetyissuesbecomemoreprominentwithnon-anthropomorphicdesignssincetheexoskeletonmustbepreventedfromforcingtheoperatorintoaconfigurationtheycannotreach.Anotherproblemwiththisarchitectureisthattheexoskeletonlegsmaycollidewiththehumanlegsorexternalobjectsmoreoftenbecausetheexoskeletonjointsarenotlocatedinthesameplaceasthehumanjoints.C.Pseudo-anthropomorphicFormaximumsafetyandminimumcollisionswiththeenvironment,theBLEEXprojectchoseanarchitecturethatisalmostanthropomorphic.ThismeanstheBLEEXlegiskinematicallysimilartoahumans,butdoesnotincludeallofthedegreesoffreedomofhumanlegs.Additionally,theBLEEXdegreesoffreedomareallpurelyrotaryjoints.Sincethehumanandexoskeletonlegkinematicsarenotexactlythesame(merelysimilar),thehumanandexoskeletonareonlyrigidlyconnectedattheextremities(feetandtorso).Anyotherrigidconnectionswouldleadtolargeforcesimposedontheoperatorduetothekinematicdifferences.However,compliantconnections,allowingrelativemotionbetweenthehumanandexoskeleton,aretolerable.AnotherbenefitofnotexactlymatchingthehumankinematicsisthatBLEEXiseasiertosizeforvariousoperators.V.DEGREESOFFREEDOMSinceBLEEXispseudo-anthropomorphic,ithaship,knee,andanklejointslikeahuman,butthedetailsofthesejointsdifferfromahuman.Overall,BLEEXhassevendistinctdegreesoffreedomperleg:3degreesoffreedomatthehip1degreeoffreedomattheknee(purerotationinthesagittalplane)3degreesoffreedomattheankleThehumanhipisaballandsocketjointwiththreedegreesoffreedom18.Itisnaturaltodesignathreedegree-of-freedomexoskeletonhipjointsuchthatallthreeaxesofrotationpassthroughthehumanballandsockethipjoint.However,throughthedesignofseveralmockupsandexperiments,welearnedthatthesedesignshavelimitedrangesofmotionandresultinsingularitiesatsomehumanhippostures.Therefore,thehiprotationjointforbothlegswaschosentobeasingleaxisofrotationbehindtheperson,asshowninFig.3;thusitnolongerpassesthroughthehumanshipjoint.Additionally,analternativerotationjointwasaddeddirectlyaboveeachexoskeletonlegfortestingpurposes.Bothhipabduction/adductionandflexion/extensionaxespassthroughthehumanhipjoint.Fig.3BLEEXHipDegreesofFreedom(viewedfromback).Althoughboththeabduction/adductionandflexion/extensionaxespassthroughthecenterofthehumanhipjoint,therotationaxisdoesnot.Theadjustmentbracket,betweenthetwoabduction/adductionaxes,isreplaceabletoaccommodatewearersofvariouswidths.Thehumankneejointisacomplexcombinationofrollingandslidingbetweenthefemurandtibiawhichallowsthejointscenterofrotationtomoveasthekneeflexes18.ChoosingapurerotaryjointfortheBLEEXkneeleadstosimplicityandrobustness,inadditiontomorestraightforwarddynamicmodeling,butcausestheexoskeletonkneetovaryfromthehumansknee.Also,theBLEEXkneelacksthehumankneesabilityto“l(fā)ockout”thelegbecauseitdoesnothavethemovingcenterofrotation.Likethehumansankle,theBLEEXanklehasthreedegreesoffreedom.Theflexion/extensionaxiscoincideswiththehumanankleflexion/extensionaxis.Fordesignsimplification,theabduction/adductionandrotationaxesontheBLEEXankledonotpassthroughthehumansfootandformaplaneoutsideofthehumansfoot(Fig.4).AnadditionaldegreeoffreedomisaddedtotheBLEEXfoot.Thefrontoftheexoskeletonfoot,undertheoperatorstoes,iscomplianttoallowtheexoskeletonfoottoflexwiththehumansfoot(seeSectionIX.B).Fig.4BLEEXAnkleDegreesofFreedom.Onlytheflexion/extensionaxispassesthroughthehumansanklejoint.Abduction/adductionandrotationaxesarenotpowered,butareequippedwithappropriateimpedances.VI.RANGEOFMOTIONTheBLEEXkinematicsareclosetohumankinematics,sotheBLEEXjointrangesofmotionaredeterminedbyexamininghumanjointrangesofmotion.Attheveryleast,theBLEEXjointrangeofmotionshouldbeequaltothehumanrangeofmotionduringwalking(shownincolumn1inTable1),whichcanbefoundbyexaminingClinicalGaitAnalysis(CGA)data(1921).SafetydictatesthattheBLEEXrangeofmotionshouldnotbemorethantheoperatorsrangeofmotion(showninColumn3ofTable1)22.Foreachdegreeoffreedom,thesecondcolumnofTable1liststheBLEEXrangeofmotionwhichis,ingeneral,largerthanthehumanrangeofmotionduringwalkingandlessthanthemaximumrangeofhumanmotion.TABLE1BLEEXJOINTRANGESOFMOTIONHumanWalkingMaximumBLEEXMaximumAverageMilitaryMaleMaximumAnkleFlexion14.14535AnkleExtension20.64538AnkleAbductionnotavailable2023AnkleAdductionnotavailable2024KneeFlexion73.5121159HipFlexion32.2121125HipExtension22.510notavailableHipAbduction7.91653HipAdduction6.41631TotalRotationExternal13.23573TotalRotationInternal1.63566Ideally,toarriveatthemostmaneuverableexoskeleton,onedesirestohaveasystemwithrangesofmotionslightlylessthanthehumansmaximumrangeofmotion.However,BLEEXuseslinearactuators(seeSectionVIII),sosomeofthejointrangesofmotionarereducedtopreventtheactuatorsaxesofmotionfrompassingthroughthejointcenter.Ifthiswasnotprevented,thejointcouldreachaconfigurationweretheactuatorwouldbeunabletoproduceatorqueaboutitsjoint.Additionally,allthejointrangesofmotionweretestedandrevisedduringprototypetesting(Fig.5).Forexample,mock-uptestingdeterminedthattheBLEEXankleflexion/extensionrangeofmotionneedstobegreaterthanthehumananklerangeofmotiontoaccommodatethehumanfootssmallerdegreesoffreedomnotmodeledintheBLEEXfoot.Fig.5BLEEXMock-upusedtotestandrevisetheBLEEXdegreesoffreedom,rangesofmotion,andergonomics.TheseprototypeswerebuiltonaFusedDepositio
溫馨提示
- 1. 本站所有資源如無特殊說明,都需要本地電腦安裝OFFICE2007和PDF閱讀器。圖紙軟件為CAD,CAXA,PROE,UG,SolidWorks等.壓縮文件請下載最新的WinRAR軟件解壓。
- 2. 本站的文檔不包含任何第三方提供的附件圖紙等,如果需要附件,請聯(lián)系上傳者。文件的所有權(quán)益歸上傳用戶所有。
- 3. 本站RAR壓縮包中若帶圖紙,網(wǎng)頁內(nèi)容里面會有圖紙預(yù)覽,若沒有圖紙預(yù)覽就沒有圖紙。
- 4. 未經(jīng)權(quán)益所有人同意不得將文件中的內(nèi)容挪作商業(yè)或盈利用途。
- 5. 人人文庫網(wǎng)僅提供信息存儲空間,僅對用戶上傳內(nèi)容的表現(xiàn)方式做保護處理,對用戶上傳分享的文檔內(nèi)容本身不做任何修改或編輯,并不能對任何下載內(nèi)容負責(zé)。
- 6. 下載文件中如有侵權(quán)或不適當(dāng)內(nèi)容,請與我們聯(lián)系,我們立即糾正。
- 7. 本站不保證下載資源的準確性、安全性和完整性, 同時也不承擔(dān)用戶因使用這些下載資源對自己和他人造成任何形式的傷害或損失。
最新文檔
- 新生兒簡易胎齡評估法
- Cephaibol-D-生命科學(xué)試劑-MCE
- 動保行業(yè)4月跟蹤報告:4月圓環(huán)、偽狂、腹瀉等疫苗批簽發(fā)增速突出大環(huán)內(nèi)酯類原料藥延續(xù)強勢表現(xiàn)
- A股市場2025年6月投資策略報告:震蕩行情靜待增量催化
- 2025年綠色建筑示范項目資金申請與綠色建筑產(chǎn)業(yè)政策優(yōu)化報告
- 2025年工業(yè)互聯(lián)網(wǎng)平臺安全多方計算在智能工廠生產(chǎn)設(shè)備狀態(tài)實時監(jiān)控與報警中的應(yīng)用報告
- 2025年高端醫(yī)療器械國產(chǎn)化替代下的產(chǎn)業(yè)政策與環(huán)境適應(yīng)性研究報告
- 2025年文化與科技融合趨勢下的數(shù)字文創(chuàng)產(chǎn)業(yè)政策研究報告
- 數(shù)字化轉(zhuǎn)型背景下的商業(yè)地產(chǎn)項目運營策略與客戶體驗優(yōu)化報告
- 2025年潮玩產(chǎn)業(yè)分析:收藏價值與文化推廣策略研究報告
- 2025年山東省煙臺市中考真題數(shù)學(xué)試題【含答案解析】
- 2025年山東將軍煙草新材料科技有限公司招聘筆試沖刺題(帶答案解析)
- 2025年高考真題-語文(全國一卷) 無答案
- 兵團開放大學(xué)2025年春季《公共關(guān)系學(xué)》終結(jié)考試答案
- 2025年中考語文押題作文范文10篇
- 拆遷名額轉(zhuǎn)讓協(xié)議書
- 2025年初中學(xué)業(yè)水平考試地理試卷(地理學(xué)科核心素養(yǎng))含答案解析
- 《重大電力安全隱患判定標準(試行)》解讀與培訓(xùn)
- 《人工智能基礎(chǔ)與應(yīng)用》課件-實訓(xùn)任務(wù)18 構(gòu)建智能體
- 人工智能筆試題及答案
- 打造重點??茀f(xié)議書
評論
0/150
提交評論