proposal 开题报告Word文档下载推荐.docx
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JixueMo
Supervisor
Prof.BingLi
SchoolofMechanicalEngineeringandAutomation
HarbinInstituteofTechnology
June15th,2016
1.INTRODUCTION
Onground,animalsusedifferenttypesoflocomotionsuchaswalking,rolling,running,hoppingandcrawling.Mobilerobotsareusuallyconstructedwithwheelsorlegstomimicthelocomotionofanimals.Thereisavarietyoflocomotionformobilerobots.Thecommonlocomotiontypesformobilerobotsarewheels[1-3].Thewheelsaresimplesttechniquetoimplementmobilityinarobot.Thistacticisrobustandsimpleasitcanuseonlyoneactuatortodrivethewheels.Wheelslocomotionsystemeasilyfailedwhenfacingobstaclestoovercome.Theobstaclesizeof1.5timesthewheeldiametercanbeovercamebyusingwheelslocomotion[4].Thebodyhingesorexpandablewheelsdesignhasbeenproposedtoenabletherobottoovercomelargeobstacles[5].Tracksarealsousedbymobilerobotsthatdonotneedhighspeedandprecisemovementbutneedtotravelthroughroughterrain.Wheeledlocomotionislimitedtotheobstaclesizeascomparedtotherobotbodydimensions.Legslocomotioncanalsobeusedtomoveinunevenground.Thelegsofferimprovedgroundlocomotionwhichisadvantageousinroughterrain[6,7].Thelegslocomotiondesignsaremechanicallymoremultifacetedascomparedtowheelslocomotionandhavemoremovingparts.Thecombinationofwheelsandlegsiswhegslocomotionwhichisusedin[8-10].Legsrobotsarerestrictedbyobstaclesheight.Thelegsclimbingrobotsclimbgraduallyandarelimitedtorelativelysmoothground;
itisthemaindrawbackofclimbingrobots.Groundobstaclescanbeovercamebyusingflyinglocomotion[11-14].Theflyinglocomotionismoreexpensive,ascomparedtoleggedorwheeledlocomotion.
Hoppingisfastestlocomotionongroundandusedbyvariousanimalstoreachathigherplace,overcomeobstacles,travelonroughgroundetc.[15-19].Variousanimalsalsousehoppinglocomotioninanyemergencysituationtosavethemselves;
ashoppingprovidesrapideffectinaveryshorttime.Thecurrenthotissueistodevelophoppingrobots,becauseoftheirgreatmovingabilities.Theadoptionofhoppingtohandlelocomotiononroughground,allowstherobottoovercomeobstacleseveraltimeslargerthanitsownsize;
whichwouldnotbepossiblewithawheeledorleggedlocomotion.Inhoping,steeringandhopangle
aremostimportantelements,becausethefunctionalitiesofsteeringandhopanglecontrolarenecessarytoachievethedesireddirectionanddistance.Tothebestofourknowledge,thereisnosuchfuelpoweredhoppingrobot,whichhasbothfunctionalities.Animalsusetheirlivesensorstoexploretheenvironmentandsurvival.Theresultinginformationisprocessedinthebrainandasoutput,anactionperformedbytheanimalinanymannertosurviveorexplore.Similarly,hoppingrobotscollectinformationofthesurroundings,usinginstalledsensors.Thecollectedinformationisprocessedintherobot’smicrocontrollerknownasbrainandasoutputresult;
itsendsthesignalstoactuatorsanddevicesforperformingallottedtask.
Themainobjectiveofthisprojectistodesignakindofgas-fuelpoweredhoppingrobotwhichhaveexcellentjumpingabilityandcanabsorbthejerks,shocksandhighimpactforcesduringlanding.Thehoppingrobotcanadjustitsattitudewhilehoppingintheairsothattherobotcanlandwithoutdamagingitsinnercomponent.Lastbutnotleast,therobotissupposedtodoautomaticpathplanningandovercomelargeobstaclesefficiently.
2.LITERATUREREVIEW
2.1Hoppinglocomotion
Energysourcesusedinhoppingmechanismsaremainlyelectrical,pneumaticandcombustiveenergy.Mostelectrical-energy-basedhoppingmechanismsareactuatedbyDCmotors.Torealizeajump,acertainupwardvelocityistobeproducedinaveryshorttime,requiringtheactuatortopossesshighinstantaneouspoweraswellaspowertoweightratio.DCmotorsdonothavesuchability;
hence,alargeamountofpotentialenergyneedstobestoredthroughtransmissionchainsinelasticelementswhichcanbereleasedquicklytorealizeajump.ThisapproachwasfoundintheuseofDCmotor-actuatedjumpingrobotswithgearedhoppingmechanisms,suchassix-bar[20]andfour-bar[22]linkagewithpotentialenergystorageelements,suchascoilspring[23],bendingspring[21],torsionspring[22],springhoopandcurvedbeam[33].Thejumpisrealizedthroughthesuddenreleaseofthestoredenergy,byuseoftriggermechanismssuchascam[22],singlewaybearing[24]andsegmentalgear[23],whicharealsopartofthetransmissionchains.
PneumaticenergyofcompressedairwasusedtoactuatethehoppingmechanismintheTITECHrescuerobot[27],whileabipedaljumpingandlandingrobot,Mowgli,wasdevelopedusingpneumaticartificialmuscles[28].Themaindrawbackofthistechniqueisthelowenergydensityofcompressedaircomparedtootherapproaches.
Amongthesourcesofenergycurrentlyusedinthesemechanisms,combustivefuelshavethehighestenergydensity,asshownin[34].Theyareofoneortwoordersofmagnitudehigherthaneventhemostadvancedelectricalbatteriesintermsofenergydensity[35].Anexampleoftheuseofcombustivefuelsinahopping-likemechanismisthedieselpilehammerinthebuildingconstructionindustry.Oncecompressed,amixturemadeofairanddieselignites,andtheheavypistonisdrivenupseveralmetershighwithouttheneedforanytransmission.
Duetotheuseofadirectdrivemechanism,ahoppingactuatorpoweredbycombustivefuelscanbesimple,structurallycompactandhasnoneedforanytransmissionsystems.Tothebestofourknowledge,onlySandiaLabinitiatedtheresearchonthehydrocarbonfuel-poweredhoppingmechanism[30]anddevelopedahighperformancewheeledhoppingvehicle[31],andthenanurbanhoppercapableofjumping7.5mhighwasdemonstratedbySandiaLabandBostonDynamics[32].ItwasrecentlyreportedBostonDynamicshasdevelopedtheSandFlea,whichcanjumpfrom1to8m,withgyrostabilization.Unfortunately,muchoftheperformancefiguresortechnicalspecificationwerenotwidelypublishedaboutthesefuel-poweredhoppingrobots,suchasstructuralandworkingparameters,innerstructure,andworkingcharacteristics.
2.2Hoppingrobot
Mobilegroundrobotscanmainlybecategorizedintotwokinds.Oneisthewheelorpedrailrobot,whichhasawideapplicationinthecurrentsociety,suchasexplosiveordnancedisposal(EOD),firefightingandspaceexploration,etc.Theotheristhebioniccrawlingorwalkingrobot,suchassnakerobot,cricketrobot,etc.Thewheelrobothasthebestefficiencybuttheworstadaptability[25].Itcanonlymoveonrelativelyeventerrain,soitsrangeofmotion(ROM)willbeconstrainedseverelyinanunknown,ruggedterrain.Thepedrailmodehasgoodclimbingabilitybutitsefficiencyandflexibilityarelow,andcanonlyovercomesomespecificorsmall-scaleobstacles.Thecrawlingorwalkingrobothasgoodadaptabilitytoterrainbuttheworstefficiencyduetoitscomplicatedtransmissionmechanism,andcannotgetoverobstaclesseveraltimesitsowndimension.Sotheabovemobilerobotscannotmeettheneedsofovercominglargeobstaclesforavarietyofapplicationsfromcelestialbodyexplorationtosurveillanceandrescueoperation,etc.
Robotswithhoppingabilityprovideasolutiontotheproblem.Uptonow,researchershavedevelopedsomehoppingrobots[36-38].Papanikolopoulosetal.presentedminiaturejumpingrobotsforstair-climbing[26].Jumpingisachievedbyelectricallywinchingthesprintfootaroundthebodyandreleasingitsuddenly.Forcelestialexploration,Refs.[39-40]developedthreegenerationsofelectricallyactuatedhoppingrobots,whichreachedhoppingheightof1.2m.Themainproblemofthehoppingrobotactuatedelectricallyislowefficiencybecauseofmanytransmissionmechanismsandthelowenergydensityofbattery,whichwilldecreasethenavigationdura-
tionofrobotsandincreasethepollutionofwastebattery.Tsukagoshietal.presentedajumpingrescuerobotactuatedbycompressedair[41-42].Thisrescuerobotcanjumpover80cmobstaclesandismoreefficientthantheelectricallyactuatedrobot,butcompressedairisstilloflowenergydensity.FuelwastakenasenergysourcebyFisheretal.forhoppingrobotbecauseofitshighenergydensity,whichcanjumpwithaheightofmorethantentimesitsdimension[29],[33].
3.OBJECTIVES
Theobjectivesoftheprojectareto:
∙Designandmanufacturethegas-fuelpoweredactuatorandvalidateitsperformancebyexperiment.
∙Designthemainstructureofthehoppingrobot.Assemblethehoppingrobotwithitscomponentsandthevalidatedgas-fuelpoweredactuator.
∙DesignandmanufacturethecontrolPCBofthehoppingrobot.Realizeitsremotecontrolattitudeadjustingintheair.
∙Proposeeffectivecontrolstrategyandpathplanningalgorithm,realizetheautomationofthehoppingrobot.
4.METHODOLOGY
4.1Explosionmodelingofthecombustionchamber
Thesecondstageoftheexplosionisanadiabaticexpansionprocess,thegasofhightemperatureandhighpressureexpandtomakethecylinderworkssothatthecylindermovesupwards.Supposetheinstantaneouspressureduringtheexplosionprocessis
thevolumeofthecombustionchamberis
thentheequationofquasistaticadiabaticprocessofidealgasis
a——constant;
——adiabaticindexofidealgas,forpolyatomicgas,
;
Supposetheratioofinstantaneousvolume
toinitialvolume
is
then
Attheinitialmoment,
.Whenthecylindermovesupwardsandexhaustgasdischargefr
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