八足蜘蛛机器人文献翻译.docx

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八足蜘蛛机器人文献翻译

大型仿生机器人结构设计

英文翻译

分　院　理工学院　

专业11机械3班　　

届别11届

学号114174330

姓名刘圣斌

指导教师梁冬泰

20014年12月17日

<文献翻译一：

原文>学位论文

RoboticsandAutonomousSystems

Volume59,Issue2,February2011,Pages142–150

1Efficientforcedistributionandlegpostureforabio-inspiredspiderrobot

∙R.Vidoni, , , 

∙A.Gasparetto 

 Showmore

doi:

10.1016/j.robot.2010.10.001

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1.1Abstract

Leggedwalkingandclimbingrobotshaverecentlyachievedimportantresultsanddevelopments,buttheystillneedfurtherimprovementandstudy.Asdemonstratedbyrecentworks,bio-mimesiscanleadtoimportanttechnicalsolutionsinordertoachieveefficientsystemsabletoclimb,walk,flyorswim（Saunderset al.,2006[36],Ayers,2001 [25],SafakandAdams,2002 [26]）.Inthispaper,takingintoaccounttheanatomyandtheadhesiveandlocomotioncapabilitiesofthespider（i.e.,aneight-leggedsystem）,wepresentontheonehandastudyofthefootforceandtorquedistributionindifferentoperativeandslopeconditionsand,ontheotherhand,apostureevaluationbycomparingdifferentlegconfigurationsinordertominimizethetorqueeffortrequirements.

1.1.1.1Researchhighlights

►Weaddressedtheforceandtorquedistributionforaneight-leggedspiderrobot.►Weconsideredtheanatomyandtheadhesiveandlocomotioncapabilitiesofthespider.►Thestaticproblemissolvedinalltheworkingconditions.►Weevaluateddifferentbio-mimeticposturesfromaminimumeffortpointofview.►TheC-shapepostureallowsaloweffortandatorquediminutionalongthelegjoints.

1.2Keywords

∙Climbingspiderrobot; 

∙Leggedmechanism; 

∙Bio-mimesis; 

∙Forcedistribution; 

∙Adhesion

1.31.Introduction

Mostofthevehiclesthatwearefamiliarwithusewheelsfortheirlocomotion.Theycanachievehighspeedandrelativelysmallcontrolcomplexitybut,evenwithcomplexsuspensionsystems,theypresentalotoflimitationsinirregularandroughterrains（e.g.,hazardousenvironmentsandunevenground）.Withleggedsystems,mostofthedifficultiescanbeovercomethankstotheflexibilityandgroundadaptation.Indeed,theopportunitytochoosebetweendifferentavailablesolutionsandtoadaptandcontrolthepositionofthecenterofmassofthesystemallowsavoidingslippageandoverturnsduetoterrainirregularities.Thecoststhathavetobepaidarelowerspeedoflocomotionandhighercomplexityofthecontrolwithrespecttowheeledsystems.However,bio-inspiredlocomotioncontrollersbasedoncentralpatterngenerators（CPGs;see [1]）,i.e.,neuralcircuitscapableofproducingcoordinatedpatternsofhigh-dimensionalrhythmicoutputsignalswhilereceivingonlysimpleinputsignals,andonreflexivecontrollers,i.e.,Crusecontrolforthecoordinationofthelegs [2] and [3],arelookingtofillthegap.

Moreover,duetothefactthatthelegsareindependentlycontrolled,leggedsystemshavealargenumberofdegreesoffreedom（DOFs）tobecoordinatedinordertocontroltheposition,balancetheforces（e.g.,load,externalforces）andconsumeaslittleenergyaspossible.Sincethetaskoffindinganoptimalforceallocationshouldbedoneinrealtime,fastalgorithmsandcontrolfunctionshavetobeused,asalsowhenabodyforcecommandsolutionisnotachievableandanewplanhastobeformulated.

Leggedrobotshaveabodyandanumberofarticulatedlegsthatstartfromit.Eachofthesekinematicchainscanbeviewedasamanipulatorthatactslikealimbandcontributestotheoverallpositionandequilibriumofthestructure.

Inordertoevaluateandcreateaneffectiveleggedrobot,theideaistodrawinspirationfromnature.Innature,differentleggedsystemsabletowalkandclimbdifferentsurfaceswithalowenergeticconsumptionandhighautonomycanbefound.Indeed,safeattachmenttoandeasydetachmentfromsmoothsubstratesisamajorfeatureofadiverserangeofanimalspecies.Attachmentwithoutusingfluids,so-calleddryadhesion,isexploitedbygeckosand Evarchaarcuata spidersbymeansoffibrillarelements  [4], [5], [6] and [7].

Theadhesionforceseemstoberelatedtotheapproachinganglebetweentheattachingelementsandthesurface:

themaximumadhesionconditionisreachedwhentheangleisaround30°;aslidingconditionoccurswhentheangleissmaller,anddetachmentoccurswhentheangleisbigger [8] and [9].

Inthisworkourattentionisfocusedonabio-mimeticspiderrobot.

Startingfromthekinematicmodelandsimulator（Fig. 1）,whicharetheresultofapreviousbiologicalandkinematicstudy [10] and [11],thestaticandquasi-staticproblemsappliedtothespidereight-leggedsystemindifferentslopeconditionsaresolved.

Fig. 1. 

Kinematicmodelofthespiderrobot.Eachlegiscomposedofthreelinksandthreejoints（oneuniversalandtworevolutepairs;see [10] and [11]）.

Figureoptions

InSection 2,theanalysisofthedifferenttheoriesandapproachesrelatedtotheforceandtorquefootdistributionthatcanbefoundinliterature [12], [13], [14], [15], [16], [17], [18], [19], [20], [21], [22],[23] and [24] arereviewed.

InSection 3,thetheoryoftheoptimalforcedistributionispresentedandextendedinordertosearchforaneffectiveresultforthespidersysteminallworkingconditions（i.e.,flat,verticalandinvertedsurfaces）.

InSection 4 ananalysisoftheoverallamountoftorquethathastobeappliedformaintainingdifferentconfigurationsandacomparisonbetweendifferentbio-mimeticposturesandconditionsforthelegsismade.

Finally,concludingremarksandfutureworkdirectionsarepresentedinSection 5.

2.Leggedrobots:

theforcedistributionproblem（FDP）

Thecomplexityoflightleggedrobots,suchassix-leggedandfour-leggedrobots,isduetothedifferentkinematicchains（i.e.,legs）thatduringthelocomotionhavetodeveloptwodifferentactions:

thosethatareinarestedconditionhavetosupportandshiftthebodywhilebalancingtheforces;thelegsinflighthavetoreachthefuturesupportposition.

Moreover,duetotheexistenceoffouractuatedjointsineachleg,asin [10] and [11],theoctopodmodelhasaredundantactuationleadingtomoreactivejointsthanthenumberofrobotdegreesoffreedom.Therefore,therearefewerforcemomentbalanceequationsthanunknowndesignvariables,andthemathematicalsolutionoftheseequationsisnotunique,duetothepresenceofanon-squaredmatrix.Lookingattherealworld,therearesomephysicalconstraintsthathavetobetakenintoaccount（i.e.,thecontactnature,friction,adhesion,torquelimits）andthatcanberepresentedonlythroughinequalitiesduetothenatureofthecontact.

Aneffectiveapproachistheonebasedonthedistributionofforcesthattrytosolvetheso-called forcedistributionproblem  （FDP;see,e.g., [13]）.Eachlegthattouchesandsupportsthebodyappliesacertainforce（fd）onthesupportpointthatisbalancedbymeansofan（equalandopposite）reactionforce（fr）ofthesubstrate. fd isthedistributedforcebecauseitrepresentsthedistributedcomponentoftheexternalforcesandmomentsappliedonthatleg.Hence,eachlegcanbeconsideredasamanipulatoranchoredtothebodythathastobeabletogenerateonthetipofthelastlimboftheleg（i.e.,theend-effector）an fd forceinordertocreateastaticequilibrium.Thegeometryofthestructureandthepositionofthelegsproducethedistributionofforcesandmomentsonthelegs.Sincethemathematicalsolutionisnotuniqueandthephysicalconstraintsareonlyinequalities,theFDPinvolvestheoptimizationoftheforceforthelegs.Then,theFDPcanbeformulatedasanonlinearconstrainedprogrammingproblemundernonlinearequalityandinequalityconstraints.

Intheliterature,severalapproachesandalgorithmshavebeenproposedforsolvingandfindingtheoptimalsolutionoftheFDPforleggedrobots.Therearefourmainmethodsthatcanbestudiedandevaluatedforarealimplementationofthecontrol.

1.

Linear-programming（LP）method [14].

2.

Compact-dualLP（CDLP）method [16].

3.

Quadraticprogramming（QP）method [21].

4.

Analyticalmethod [22].

Incomparisonwiththeexistingliterature,severaloriginalfeaturesofthisworkcanberemarkedupon.

Thespiderisaneight-leggedsystem,whereasusuallysix-leggedandfour-leggedrobotsarestudied.NoapplicationsoftheFDPproblemforaneight-leggedsystemhavebeenfoundintheliterature.Asaconsequence,atleastfourlegsareincontactwiththesubstrateinthesupportphasecondition（i.e.,fourlegsincontactandfourlegsinflight）andthehypothesisadoptedforsix-leggedrobotsinordertoreducethecomplexityofthesystem [22] cannotbeapplied.

Moreover,thespiderroboticsystemmustbeabletowalkandclimbondifferentslopeconditionsuptotheinvertedcondition;hence,theadhesivecapabilitieshavetobetakenintoaccount.

Finally,inthemodelpresentedinthiswork,eachspiderleghasfourDOFswhileintheliteraturethenumberofDOFsoftheeight-leggedrobotsisusuallythreeorless [25], [26] and [27].

Thus,thepresentstudyismoregeneralwithrespecttoalltheotherstudiesdealingwithleggedsystems.Inparticular,notonlythefrictionforcebutalsotheadhesionforceshavetobetakenintoaccountinordertosimulateandcontrolthesystemintheclimbingphases.

Theartificialattachingsystemsdevelopeduntilnow [28], [29], [30] and [31] donotreachtheadhesivecapabilitiesoftherealones,andusuallydegradethemselveswithuse;asaconsequence,inordertoevaluateandsimulateanefficientmodel,thebiologicalcharacteristicsandadhesivecapabilitiesofthespiderE.arcuata  [6] and [7] willbeu