基于慧魚組件的通訊排障機(jī)器人的擴(kuò)展模塊【履帶式災(zāi)害救援機(jī)器人】

基于慧魚組件的通訊排障機(jī)器人的擴(kuò)展模塊【履帶式災(zāi)害救援機(jī)器人】,履帶式災(zāi)害救援機(jī)器人,基于慧魚組件的通訊排障機(jī)器人的擴(kuò)展模塊【履帶式災(zāi)害救援機(jī)器人】,基于,組件,通訊,通信,機(jī)器人,擴(kuò)展,擴(kuò)大,模塊,履帶式,災(zāi)害,災(zāi)難,救援,救濟(jì),營救 AdvancedRobotics ,Vol.17,No.4,pp.339358(2003) VSPandRoboticsSocietyofJapan2003.Alsoavailableonline- FulpaperTheconceptandresearchofapipecrawlingrescuerobot ZHELONGWANG andERNESTAPPLETONSchoolofEngineering,UniversityofDurham,DurhamDH13LE,UK Received19June2002;accepted31July2002AbstractThispaperpresentsthecontrolalgorithmanddesignofapipecrawlingrobotwhichcan beusedforthepurposeofearthquakerescueandpipelinemaintenance.Therobotisdesignedtobeabletointelligentlyalteritsbodyshapetobullet5tthepipeortunnel-likevoidswithinrubble.Thepaperintroducesasimulationtotesthowtherobotaltersitsbodyshapetobullet5tvoids.Thecontrolalgorithmusesalook-uptablemethodcombinedwiththemethodofleastsquarestopredicttheshape oftherobotundertheinbullet6uenceofactuators.Thepaperalsopresentsthedesignofboththehardwareandsoftwaresystemsoftherobot,andlaboratoryexperimentsontherobotbodymodule.ComputersimulationresultsbyusingMATLABandtheexperimentalresultsindicatethefeasibilityoftherobotbodyshapechangecontrolalgorithmproposal. Keywords:Piperobot;controlalgorithm;methodofleastsquares;deformablebody;rescuerobot. 1.INTRODUCTION1.1.Apipecrawlingrobot Internationalpipelinesystemsusedforthetransmissionofoil,gasandwateraregrowinginage,andsomeinstallationshavealreadybeeninoperationbeyondtheservicelifetheyhadoriginallybeendesignedfor.Inspectionofshortpipesisanimportanttaskfacedbymanyindustries.Thedeteriorationoftheinnersurface ofpipesisespeciallycommoninrebullet5neriesandsteamplants.Itisthereforeofever-increasingimportancethatpipelineoperatorsareprovidedwiththemeanstoaccuratelyandreliablyinspecttheirpipelines,andobtaintheinformationneededfordecisionmakingregardingsafeoperation,rehabilitationandrepair1.Theuse ofautomaticpipeinspectioncouldreducethedowntimeandmanpowerrequiredforthepipeinspectionprocess.Thishighlydemandingrequirementhasresultedinthedevelopmentofvariouskindsofpiperobots. Towhomcorrespondenceshouldbeaddressed.E-mail:zhelong.wangdurham.ac.uk 340 Z.WangandE.Appleton1.2.Earthquakerescuerobots Earthquakesareunfortunatelyfrequenthappeningsandverydangerousnaturalphenomena.Inalmosteverymajorearthquakemanyvictimsareburiedundercolapsedbuildings,bridges,roadways,etc.Itisverydifbullet5culttorescuethesepeople,whomaywellbeinjured,hungryandweak.Inaddition,thestructural conditionsundertherubblecanbecomplex,dangerousandunknown.Thus,thereisaprimaryneedtoexploretheseconditionsanddeterminethevictimslocationandtheircondition.Thematterisalsourgentasitisimportanttorescuethosevictimsassonaspossible.Asaresult,rescuerobotshavebeendevelopedtoundertake thesetasks.InanarticlebyTokuda etal.2,aprototypeCUL(CarryandpowerassistrobotforUnspecibullet5edLandform)whichwillbeusedforearthquakerescuemissionshasbeendescribed.Thepaperalsodescribesresultsofexperimentsforafeasibilitystudy.TheexperimentalresultsshowtheeffectivenessoftheCULrescue robotproposed. 2.PROBLEMPRESENTATION2.1.TheshortcomingsofexistingpipelinerobotdesignPipelinerobotsarementionedinalargenumberofpapers.Forexample,arobot systemnamedKARO3(Entwicklungeinesbullet6exibleeinsetzbarenRobotszurintelligentensensor-basiertenKanalinspektion)isequippedwithintelligentmulti-sensors.Theseallowautomaticandreliabledetectionofdamagelocation,itstypeandsize,andgivesuperiorperformancecomparedwiththemajorityofCCTV-based systems.Thesystemhasbeendevelopedfortheprotectionofgroundwaterandsoilagainstcontaminatingmaterialsandliquids.ToyomiandKoichi4havedevelopedamicro-inspectionrobotfor1-inchdiameterpipes.Therobotcanundertakevisualinspectionsinpipesandalsoretrievesmallobjects.GlenandDevon5describea robotthatundertakesautomaticpipeinspectionandhasbeenprovedtobeasuitablealternativetocurrentpipeinspectiontechniques.Theadvantageofthissystemisthatitutilizesestablishedmechatronicprinciplestoproducealow-costdevicecapableofdetectinginerpipedefects.However,alltheserobotscanonlyworkin pipesofbullet5xeddiametersandcannotworkifthewallofthepipeisbrokenorbadlydamaged,ifthepipediametervariesorifthepipecollapsedpartially.2.2.ABrushrobot ApipecrawlingrobothasbeendevelopedattheCenterofIndustrialAutomationandManufacturing(CIAM),SchoolofEngineering,UniversityofDurham.Therobotutilizesaunique,innovativeandpatentedtractionsystem.Theprincipleofthedrivesystemissimple.Thatis,ifabrushwithadiameterslightlylargerthan theboreofapipeisinsertedintoapipe,itsbristlesaresweptbackatanangle.Underthiscondition,itiseasiertopushthebrushforwardsthoughthepipethan Theconceptandresearchofapipecrawlingrescuerobot 341itistopullitbackwards.Thus,iftwobrushareinterconnectedbyareciprocatingcylinder,then,bycyclingthecylinder,itispossiblefortherobottocrawlalongthe pipe6.Thedrivesystemhasbeenawardedpatentsonanearworldwidebasis.MoredetailsaboutthedrivesystemareillustratedinStutchbury6andHan7.MostoftherobotsdevelopedinDurhamarepoweredbypneumaticsandgripthewallofthepipebymeansofmanybristleclusters,hencenamedBrushrobots.Just likeotherpipelinerobotsmentionedearlier,aBrushrobotcanonlyworkinpipeswithinalimiteddiameterrangealthough,unlikemanyoftheothertractionsystems,thebristlemechanismiscapableofdealingwithbrokenonpartiallycollapsedpipes. 2.3.AnimprovedBrushrobotforearthquakerescueandpipelinemaintenanceThisreportoutlinessomeimprovementsontheestablishedBrushrobotprinciple,andadaptsittoworkforthepurposeofearthquakerescueandinseverelydamaged orbrokenpipelines.Thus,itisdesignedtobeabletoalteritsbodyshapetobullet5tthevariablevoidshapesinacolapsedbuildingordifferentdiameterpipeswhosewallsmightbebrokenorinabadcondition.Torealizethesefunctions,asensorsystemfordetectingtheholeshapeandacontrolsystemforalteringtherobotbody shapeisnecessarilyequipped.Forthepurposeofrescue,aCCDcameraneedstobeequippedtoseetheconditionsinthehole.ACO 2detectorisusedfordetectingwhethervictimsarealiveornotandforlocatingtheirpositions.Amicrophoneisequippedforavictimtocommunicatewithrescuepersonnel.Inaddition,anair hosewilbecarriedbytherobotforconditionsofairdebullet5ciency. 3.RESEARCHMETHODOLOGY3.1.Outline ThekeypointforaBrushrobotistoproduceenoughfrictiontodriveitselfandcarrythenecessaryloads.Forthepurposeofearthquakerescue,therobotshouldbeabletopassthroughholesandcracksintheruinsmadebytheearthquake.However,theholesandcracksintheruinsusuallyhaveirregularshapesandsizes.Thus,the robotmustbeabletoalteritsbodyshapeandbullet5ttheholeshapetoproduceenoughfrictionalforce.Torealizetherequirement,itisessentialtoinstallasensorsystemontherobotshead,whichisusedtoroughlydetecttheholeandcrackshapes.InthedesignofthisBrushrobot,fourgroupsofactuatorsneedtobeinstalledaround therobotsbody.Theseactuatorswillchangetherobotsbodyshapeaccordingtosignalsfromthesensorsystem.Duringthisprocedureacontrolsystemwillrecog-nizethesensorssignals,performingcalculationsbasedonthesignalinformationandsendingappropriatecommandstochangetheactuators.UsingaCCDcamera mountedontheheadoftherobot,theconditionsintheholesandcrackscanbeinvestigatedvisually.Amanualcontrolfunctionisalsorequiredtodealwithexcep-tionalcircumstancesinthecaseoffailureoftherobotautomaticcontrolfunction.A 342 Z.WangandE.AppletonsoftwaresystembasedonaPCisalsorequiredtorundatacommunicationandcon-trol,storedata,etc.Morespecibullet5cally,thesoftwareisrequiredtobeabletorecord therobotsroutesandtheholeshapesatdifferenttravelstages.3.2.Robotworkingmechanismtheory 3.2.1.ThemechanismtheoryofanoldBrushrobot. Beforebuildingarealrobotmodel,itisnecessarytodosomecomputersimulationstoprovethefeasibilityofthecontrolalgorithm.MovementofaBrushrobotisachievedbytheutilizationofcurvedbristleasthemeansofpropulsionandsupport,asillustratedinFig.1. Whenthecylinderopens,theleadingbrush,offeringlowerresistancebecauseofthebristlecurvature,movesforwardeasily;thetrailingbrush,becauseofitshigherresistancetobackwardforces,remainsstationary.However,whenthereversehappens,i.e.thecylindercloses,theleadingbrushremainsstationary,whereasthe trailingbrush,nowofferinglowresistance,ispulledforward.Basedonthistheory,theresultanttractiondependsentirelyonthebristlemechanismset-upandcanbeillustratedinthefollowingway.Consideringasinglebristleforthepurposeofsimplicity,whenabristleisputintoapipe,and becauseofitseffectivelateraldimension,itisbentbythepipewall,therewillbeaperpendicularforce Pactingatthetipofthebristle,asshowninFig.2.Whenmovingthecoreofbristles,traction Fshouldequal P.Theprojectionofabristleinthedirectionofthe y-axisismarkedas h.Thelengthofabristleis l.Thechord betweenthetwotipsofthebristleisexpressedas L.Inthethesis6,Stutchburygivestheconclusionthattheoptimumangelbetweenthebristleandpipewallshouldbebetween30 and40toachievethebesttraction F,althoughthisangelwillvarydependinguponanumberoffactors,e.g.lubrication.InRef.7,Hangivesusthe relationbetween handl: hlD2E./QlL: (1) Note:E./D21122sin2213242sin4231352462sin625; andQlD21C122sin22C13242sin423C1352462sin625C: Thevalueofhcanbeobtainedif landareknown.ThethesisbyHangivesatablewhichindicatestheresultsobtainedbyapplying(1),asshownbelowinTable1. 3.2.2.ThemechanismtheoryofanimprovedBrushrobot. AnewlyimprovedBrushrobotusedthesamebrushmechanismastheoldone,butthestructureof Theconceptandresearchofapipecrawlingrescuerobot 343 Figure1.Brushrobotmotionprinciple. Figure2.Bristlemechanismdiagram.Table1. Spreadsheetfortherelationbetween handl(deg) P=PEuler =l h=l 10 1.004 0.1116 0.992320 1.016 0.2193 0.969830 1.035 0.2588 0.932440 1.062 0.4221 0.8787 60 1.152 0.5930 0.697390 1.392 0.7925 0.4189 344 Z.WangandE.Appleton Figure3.Thestructureofonerobotbodymodule.itsbodymodulehasbeenmodibullet5ed.TheoldBrushrobotsbodymoduleisasolidsteelcylindermountedwithhundredsofsteelbristles.Thesteelcylinderistherobot bodycoreofabullet5xeddiameterandthebodycorecannotdoanychangetoitsphysicalshape.However,intheimprovedBrushrobot,athinsteelstripcirclereplacestheoldrobotbodycylinder,asillustratedinFig.3.Insidethestripcircle,fouractuatorsconnectthestripcirclebyjoiningtheactuatorendpointswiththestripcircle.Like theoldrobotbodymodule,hundredsofsteelbristlesaremountedonthesurfaceofthestripcircle.Thenew,improvedrobotbodymodulewithsuchamechanismcanalteritsshapebyactuatorspushinginandout. 3.3.ControlalgorithmforthenewBrushrobotTomakeanimprovedBrushrobottobeabletoalteritsbodyshapeandbullet5tthevoids,ahybridcontrolalgorithmbasedonalook-uptablemethodandthemethodofleast squaresisdeveloped.Themethodthattherobotusetodecideshowtoalteritsbodyshapetobullet5ttheholeisreferencetoadatabullet5le,storedinatable.Thetableiscom-posedofdatabullet5lesandeachbullet5lepresentsonecalculationresultobtainedbyusingABAQUSsoftware.Figure3illustratesthestructureofonerobotbodymodule. Eachrobotbodymoduleiscomposedoffouractuators,athinspringsteelstripcir-cleandhundredsofspringsteelbristlesmountedonthesurfaceofthestrip.Theendpointofeachactuatorisconnectedtothestripsothattheshapeofthesteelstripcirclecanbedeformedbytheactuatorspushinginandout.Ifseveralhundredpoints onthestripcirclearemarked,thepositionofeachpointcanberecordedasapairofcoordinates.Thestripcircleshapecanbeuniquelyrepresentedifallpointscoordi-natescanbeknown.Theshapeofthestripcirclecanbeacquiredfromcoordinatesofthosepointswhenactuatorspushin/outandthestripcircleisdeformedbysuch pushing.Infact,heretheshapeofthestripcirclerepresentstheactualshapeoftherobotbodymodule.Theseshapesarerelatedtoactuatorloadsandconsequentlydebullet6ectionsthatareputontherobotbodyinthedirectionofthe x-axisandy-axisindependently.Thus,therobotbodymoduleshapewillbechangedwithvariedac- tuatorloadsanddebullet6ections.Inthemeantime,thecoordinatesofthepointsontherobotbodymodulewillbechangedbecauseoftherobotbodydebullet6ection.Theco-ordinatesofthosepointscanbecalculatedandpredictedbyusingABAQUS,whenactuatorloadsarealreadyknown.Thisarrayofpointcoordinatespresentstherobot Theconceptandresearchofapipecrawlingrescuerobot 345Table2.Adatabullet5lestoresanarrayofpointcoordinates POINT1 POINT2 POINTnXi X1 X2 XnY 1 Y1 Y2 Ynbodymoduleshapeundersuchactuatorloads.Iftheactuatorloadsarechanged,a newarrayofpointcoordinatescanbeacquiredandthismeansthattherobotbodymodulewillassumeanewshape.Thusbychangingtheactuatorloads,whichareinputvariablesinthecalculationbyABAQUS,manyarraysofpointcoordinatescanbeacquired.Eachofthemuniquelyrepresentsarobotbodymoduleshape.These arraysofpointcoordinatescanbestoredindatabullet5lesandeachdatabullet5leisusedasarecordtoputintoatable.Asaresult,thistableincludesmanyrobotbodymoduleshapesunderdifferentactuatorloads.Similarlyaholeshapecanalsobeuniquelyexpressedasanarrayofcoordinatesofpointsaroundtheholewall.Therobots controlalgorithmisrequiredtobeabletobullet5ndthemostappropriateshapetobullet5ttheholeshapefromthosedatabullet5lesinthetable.Forexample,Table2expressesanarrayofpointcoordinatesstoredasadatabullet5le,whichisarecordintherobotbodyshapetable.A POINT i(iD1;2;:;n/meansapairofcoordinatesofapointontherobotbodyaftertherobotbodyisdebullet6ected.POINTiisexpressedas( Xi;Yi)inthemeaningofthecoordinates,whichisapointontherobotbody.Thecoordinate( x i;yi)isexpressedasthecoordinateofapointontheholewall. diisthedifferencebetweenapointontherobotbodyanditscorrespondingtargetpointontheholewallalongthesamedirection.Iftherobotbodymoduleshapecouldbullet5ttheholeshapeverywell,thatmeansthateach d ishouldbeassmallaspossible.Torealizethis,therobotcontrolalgorithmneedstobullet5ndthesmallest D,whichisthesumofthesquareddistance di.Finally,thecontrolalgorithmwillsearchalldatabullet5lesintherobotbodymoduleshapetableandbullet5nd thebestdatabullet5letominimize D,whichiscalculatedbyusing(3). listheoptimallengthofthebristle,whichisaconstantandcanbeknowbyusingaspreadsheetin6.nisthetotalnumberofpointsaroundtherobotbodymodule. diDx2iCy2iX2iCY2il;.iD1;2;:;n/; (2)DDn iD1 x2iCy2iX2iCY2il2;.iD1;2;:;n/:(3)3.4.Computersimulationofthecontrolalgorithm Totestthefeasibilityofthecontrolalgorithmpresentedabove,anumberofcomputersimulationshavebeenperformedusingMATLAB.Thesimulationresultsshowthatthecontrolalgorithmproposedwillbeeffective.Figures46arebased 346 Z.WangandE.Appleton Figure4.Robotbodymodulebullet5tsasquare:Cindicatesapointoftherobotbodyandindicatesapointoftheholeswall. Figure5.Robotbodymodulebullet5tsanellipse:Cindicatesapointoftherobotbody. Figure6.Robotbodymodulebullet5tsanirregularshape:indicatesapointoftheholeswall. Theconceptandresearchofapipecrawlingrescuerobot 347onsomesimulationresults.Inthesebullet5gures,theholeshapeisexpressedbyanarrayofinterconnectedsymbolsandtherobotbodymoduleshapeisexpressedbyan arrayofinterconnectedsymbolsC.AlsoeachsymbolrepresentsapointontheholewallandeachCsymbolrepresentsapointontherobotbodymodule.InFig.4,theholeshapeisarectangleandtherobotbodycurvebullet5tstheholewell.InFig.5,theholeshapeisanellipseandtherobotbodycurveissimilartothehole shape,butitisrelativelysmallerthanthehole.Thebristlearoundtherobotbodycandealwiththelittledifferencebyelasticdebullet6ection.Figure6showstherobotbodytestedtobullet5tanirregularholeshapeandmostoftherobotbodymodulecurvecanbullet5ttheholebyelasticdebullet6ectionofthebristles;however,therightuppercorner cannotbebullet5ttedbytherobotbodymodulecurve.Toachieveabetterbullet5tting,furtherworkneedstobecarriedonmakinganon-symmetricrobotbody.Fromthesimulationresultsabove,therobotbodymodulecouldalteritsshapetobullet5tsomebasicgeometricshapesandsimpleirregularshapes.Thecontrolalgorithm isbasicallyprovedtobefeasible.Morecomplicatedirregularshapescannotbebullet5ttedwellbyusingthecurrentstructureoftherobotbodymodule.Thiscouldbesolvedbymakinganon-symmetricrobotbodymoduleandusingmoreactuators,whichwillenablerobotbodymoduletochangeintomorecomplexshapestobullet5t variousholeshapes.3.5.Robotcontrolsystem 3.5.1.Controlmodulediagram. ItisenvisagedthatacontrolprogramwillruninaPCandthatasensorsystemwilsendbacksignalsabouttheconstantlychangingholeshape.Afterprocessingthesesignals,thePCmakesthecontroldecisionsandsendscontrolcommandstoeverycontrolmodule.Thenthecontrolmodules willcontrolthemovementsoftheactuatorsaccordingtothosecontrolcommands.Figure7displaysthatarobotcontrolsystemthatincludestwolayersofcontrol.OneisthecontrolfromaPCtoeachcontrolmodule;theotheristhecontrolfromeachcontrolmoduletoitscorrespondingactuator.Inaddition,asensorsystem Figure7.Controlmodulediagram. 348 Z.WangandE.Appleton Figure8.CmunicateswiththePCtocolecttheinformationoftheholeshapeandsendstheinformationtothePC. 3.5.2.Controlboarddiagram. Itisproposedtomakeaprototypeofthisrobotusingeightsteppermotorcontrolboards,16steppermotordriveboards,16steppermotorsandonePCtorunthecontrolsoftware.InFig.8,aschemeisdrawntoexplaintheconnectionsbetweenthesemodules.Eachcontrolboardcancontrol twosteppermotorsandeverysteppermotorneedstobedrivenbyadriveboard.Foursteppermotorsareneededforeachrobotbodymodule,sothatafour-body-partBrushrobotneeds16steppermotorsinall. 4.EXPERIMENTSThisBrushrobotiscomposedofthesamefourmodules.Thus,thelaboratoryexperimentfocusesononerobotbodymodule. 4.1.LaboratoryexperimentonarobotbodymoduleTherobotbodymoduleexperimentaldeviceisshowninFig.9.Thedevicesincludeastraingaugesensor,robotbodymodule,robotactuatorcontrolbox,DCpower supplyandPC.Thestraingaugesensorisusedtodetectthevoidshapes.Thesensorincludes12bullet5ngersequippedwithstraingauges.Thestraingaugecanbeusedtodetectthedebullet6ectionsofthebullet5ngers.Thetouchingpointcoordinatesofthebullet5ngersonthevoidwallcanbeworkedoutbythesedebullet6ections.Withthesecoordinates,a splinealgorithmcanestimatethewholevoidshape.4.1.1.Robotsoftwaresystem. AcomputerprogramwritteninVisualC+wasdevelopedfortherobotprototypeexperimenttocollectsensorsignals,control Theconceptandresearchofapipecrawlingrescuerobot 349 Figure9.Robotexperimentaldevices. Figure10.Robotsoftwareinterface.actuatorsandrealizetheshapechangealgorithm.Figure10illustratestheprogram interface.Theleftwindowshowshowtherobotbodymodulewillalteritsbodyshapetobullet5tthevoid.Theblackinnerlineshowstheoutlineoftherobotbodymoduleandthegreyouterlineshowstheoutlineofthevoidwall.Therightwindowdisplaysthecommunicationworkingstatus;thesteppermotorworkingstatusand controlcommandssenttothesteppermotors.Figure1showstheinterfaceofthedataacquisitionprogram,whichdisplaysthedataacquisitioncardinformation;32analoginputchannelsinsingleendedmodeand16analoginputchannelsindifferentialmode.Only12channelsindifferentialmodeareusedinthisexperiment sincethereareonly12straingaugeoutputsignalstobeconvertedinthisapplication. 350 Z.WangandE.Appleton Figure11.Dataacquisitioninterface.4.1.2.Eperimentalprocedureandresults. ThedeviceshowninFig.9isusedin theexperiment.Tosimulatethevoidshapeandtestthetheory,afew oodenboxesweremadeinafewbasicregulargeometricshapesandanirregulargeometricshape.Actualvoidshapesinarealenvironmentaremuchmorecomplexthansuchsimplegeometricshapes,butitisreasonabletosimplifytheproblemattheinitialstageof therobotdevelopment.Also,theexperimentisdesignedtotestthattherobotbodyshapealgorithmcanworkcorrectly.Thesensorwasonlyaprototypeusedtotestthefeasibilityofrobotshapechangetheoryandneedsfurthertechnicalimprovementstodetectmorecomplicatedvoidshapes.Thus,complicatedvoidshapesinreal environmentsarenotconsideredinthisexperiment.Theregulargeometryboxesintheexperimentincludeasquare,arectangle,atriangleandahexagon.Theexperimentalprocedureistoputtherobotsensorintotheboxwhichsimulatesavoidshape.Thenthedataacquisitioncardcollectstheboxshapeinformationand sendsittothePC.TheprogramrunningonthePCdecideswhatshapetherobotbodymoduleshouldchangeintotobullet5ttheboxshapeascloselyaspossibleandhowtheactuatorsmoveaccordingtothesensorinformation.Aftertheprogramsdecision,theprogramsendsthecontrolcommandtothecontrolmoduleviaRS 232serialcommunicationandthecontrolmodulewillcontrolthesteppermotors,movingasmuchastheprogramdecides.Therobotbodymodulethenneedstobeputintotheboxtoseehowtherobotbodymodulebullet5tsthebox.Theexperimentalprocedureneededtoberepeatedforeachboxindifferentshape. Figure12showstherobotsensorputintoasquareboxtodetecttheboxshape.Figure13showshowtheprogramdecidestherobotbodyschange.Theleftwindowshowsthattherobotbodymoduleneedstobealteredintoasquare.Therightwindowshowsthecontrolcommandssenttothecontrolmodule.Alsteppermotors Theconceptandresearchofapipecrawlingrescuerobot 351 Figure12.Robotsensordetectsasquareboxshape. Figure13.Themostappropriateshapedecidedbyshapechangetheorytobullet5tasqua