




已阅读5页,还剩19页未读, 继续免费阅读
版权说明:本文档由用户提供并上传,收益归属内容提供方,若内容存在侵权,请进行举报或认领
文档简介
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“lockout”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
温馨提示
- 1. 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
- 2. 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
- 3. 本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
- 4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
- 5. 人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对用户上传分享的文档内容本身不做任何修改或编辑,并不能对任何下载内容负责。
- 6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
- 7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。
最新文档
- 土地综合整治投标方案
- 沉井施工期质量检验与评定合同
- 婚姻解除后财产分割与经济补偿协议范本
- 防汛围栏井安装方案
- 拦污栅项目规划方案
- 乡村网络面试题及答案
- 内外踝骨折护理常规
- 天花玻璃安装方案
- 金融创新:厂房股权转让与融资租赁一体化合同
- 2026版《全品高考》选考复习方案生物0420 课时作业(十九) 细胞的分化、衰老、死亡 含答案
- 战术搜索教学课件
- 2025年福建厦门港务控股集团有限公司招聘考试笔试试题(含答案)
- 2025年陕西省行政执法资格考试模拟卷及答案(题型)
- 2025年长三角湖州产业招聘笔试备考题库(带答案详解)
- 办公室副主任考试试题及答案详解
- 《电火花检漏仪校准规范试验报告》
- 2025至2030中国高端英语培训行业市场发展分析及发展趋势与投资机会报告
- 地质灾害治理工程施工安全管理制度
- 克拉玛依市公安局招聘警务辅助人员考试真题2024
- 2025年茶艺师职业技能鉴定考试试卷(含答案)
- 公司电子发票管理制度
评论
0/150
提交评论