简介：Aroboticfishdrivenbyoscillatingfins,"CownoseRay-I",isdeveloped,whichisindorsoventrallyflattenedshapewithoutatail.Theroboticfishiscomposedofabodyandtwolateralfins.Athree-factorkinematicmodelisestablishedandusedinthedesignofamechanism.Bycontrollingthethreekinematicparameters,theroboticfishcanaccelerateandmaneuver.Forwardvelocityisdependentonthelargestamplitudeandthenumberofwavesinthefins,whiletherelativecontributionoffinbeatfrequencytotheforwardvelocityoftheroboticfishisdifferentfromtheusualresult.Ontheotherhand,experimentalresultsonmaneuveringshowthatphasedifferencehasastrongereffectonswervingthanthelargestamplitudetosomeextent.Inaddition,aspropulsionwavespassfromthetrailingedgetotheleadingedge,theroboticfishattainsabackwardvelocityof0.15m·s-1.

简介：Generallytheunderwaterbio-robotstakethetailfinaspropulsor,andcombinedwithpectoralfintheycanmanoeuvreagilelyandcontroltheirpositionandmovementatwill.Innature,alotoffishesrealizetosuspenditselfinwatertogoforwardandtomovebackupbythepectoralfinmovingcomplexly.Sothatitissignificanttheoreticallyandvaluableforpracticalapplicationtoinvestigatethepropulsiveprincipleandhydrodynamicperformanceofpectoralfin,andfindthemethodutilizingthepectoralfintomanoeuvretheunderwaterbio-robotagilely.Inthispaper,atwodegreeoffreedom(DoF)motionmodelisestablishedforarigidpectoralfin,andthehydrodynamicperformancesofthepectoralfinarestudiedbyuseofthepectoralfinpropulsiveexperimentalplatformdevelopedbyHarbinEngineeringUniversity,simultaneouslythehydrodynamicperformanceofthepectoralfinisanalyzedwhensomeparameterschange.Then,throughthesecondarydevelopmentofFLUENT(CFDcode)software,thehydrodynamicperformancesofrigidpectoralfininviscousflowsarecalculatedandtheresultsarecomparedwiththelatestexperimentalresults.Theresearchinthispaperwillprovidethetheoreticalreferenceforthedesignofthemanoeuvringsystemimitatingpectoralfin,atthesametimewillbecomethefoundationforthedevelopmentofthesmallunderwaterbio-robot.

简介：Inpresent,thereareincreasinginterestsintheresearchonmechanicalandcontrolsystemofunderwatervehicles.Theseongoingresearcheffortsaremotivatedbymorepervasiveapplicationsofsuchvehiclesincludingseabedoilandgasexplorations,scientificdeepoceansurveys,militarypurposes,ecologicalandwaterenvironmentalstudies,andalsoentertainments.However,theperformanceofunderwatervehicleswithscrewtypepropellersisnotprospectiveintermsofitsefficiencyandmaneuverability.Themainweaknessesofthiskindofpropellersaretheproductionofvorticesandsuddengenerationofthrustforceswhichmakethecontrolofthepositionandmotiondifficult.Ontheotherhand,fishesandotheraquaticanimalsareefficientswimmers,posseshighmaneuverability,areabletofollowtrajectories,canefficientlystabilizethemselvesincurrentsandsurges,createlesswakesthancurrentlyusedunderwatervehicle,andalsohaveanoiselesspropulsion.Thefish’slocomotionmechanismismainlycontrolledbyitscaudalfinandpairedpectoralfins.TheyareclassifiedintoBodyand/orCaudalFin(BCF)andMedianand/orpairedPectoralFins(MPF).Thestudyofhighlyefficientswimmingmechanismsoffishcaninspireabetterunderwatervehiclesthrusterdesignanditsmechanism.Therearefewstudiesonunderwatervehiclesorfishrobotsusingpairedpectoralfinsasthruster.Theworkpresentedinthispaperrepresentsacontributioninthisareacoveringstudy,designandimplementationoflocomotionmechanismsofpairedpectoralfinsinafishrobot.Theperformanceandviabilityofthebiomimeticmethodforunderwatervehiclesarehighlightedthroughin-waterexperimentofaroboticfish.

简介：Atatemperatureof23.0~24.8℃,themixedfeedingofJapaneseanchovylarvaewasinitiated24hbeforetheyolk-sacwasexhausted.Thepointofnoreturn(PNR)wasreachedonthe6thdayafterhatching.Onthe4thdayafterhatching,thepectoralangleappearedinbothfedandunfedanchovylarvaealthoughitwasmoreevidentandsharperinthestarvedandthePNRstagelarvaethaninthefedones.Accordingtoobservationsoflarvaecollectedinthesea,thepectoralangleswereevidentnotonlyinthelarvaeof3.62~7.44mminstandardlength,butalsointhelarvaeof2.70mminstandardlengthwithremnantsofyolk.Thepectoralanglesbecamediffusewhenthelarvaereached7.84mmandvanishedat9.86mm.Thepectoralanglecannotbeusedasacriteriontodistinguishhealthyfromstarvinglarvae.