介绍微型飞行器的飞行测试

astotheuseofmorphingfordynamiccontrol.Forinstance,studiesneedtobeperformedascertainingifavehiclebemorphedwithsuf cientmagnitudeandbandwidthtocontroltheshortperiodmotion.Inthiscase,theuseofmorphingasaeroservoelasticcontrolforagilityistheissue.

Thispaperconsiderstheuseofmorphingasanaeroservoelasticeffectorforcontrolofamicroairvehicle.Severaltypesofmorphingareactuallyconsideredonseveraltypesofvehicles.Avehiclewith12inwingspanhasthreadsthatcurlthewings.Anothervehiclewith24inwingspanhastorquerodsthattwistthewings.Ineachcase,themorphingisshowntogeneratesigni cantcontrolauthorityformaneuvering.Propertiesofturnsandspinsarehighlightedtodemonstratetheeffectofthisaeroservoelasticcontrol.

II.Morphing

Theconceptofmorphingisafairlybroad-rangingidea.Amorphingaircraftisgenerallyacceptedtobeanaircraftwhoseshapechangesduring ighttooptimizeperformance.6Suchchangesmightincludespan,chord,camber,area,thickness,aspectratio,planformandanyothermetricrelatedtoshape.Themorphingcanevenbeappliedtoacontrolsurfacetoeliminatehinges.29

Thecontinuingmaturationofmaterialsandcontrolstechnologyisleadingtoconsiderationofmoreextremetypesofmorphingforcontrol.Aircraftcanbemorphedinseveralbiologically-inspiredwaysthatareappropriateforcontrol.Forinstance,birdshaveverycomplexwingshapesduring ightwithlargevariationsinsweepandtwistalongtheentirespan.Furthermore,thespanitselfchangesbasedon ightconditionformanybirds.Thecomplicatedmorphingisactuatedusingjoints,suchaselbowandwrist,alongwiththefeatherstoachievemanywingshapes.

ProgramsbyDARPAandNASAhavebeenextensivelystudyingtheconceptofmorphing.Thesestudieshaveshowntheaerodynamicbene ts;however,theuseofmorphingforcontroldesignhasnotbeenstudiedextensively.Thelimitedresearchintocontrolhasactuallyconsideredstaticissues.Anaircraftwithmorphinghasbeenshowntohavegoodperformancewhen xedatdifferentcon gurations.21Controlwasconsideredformorphinginarelatedstudybutonlyconsideredtheamountofactuationenergyneededtocausemorphing.26Theamountofcontrolauthoritywasalsostudiedforsmartmaterialsembeddedinastructureinthecontextofsteady-stateopen-loopcontrolled ight.23

Theissueofcontroldesignformorphingsystemshaspartlybeenoverlookedbecauseofthelackofexperimentaltestbeds.Manymechanismsformorphinghavebeenconstructedbuttheyarenotyetimplementedona ightvehicle.NASAhasconstructedawingwithmorphingcamber.24Asetofsmartsparshasbeenbuiltthatprovidemanytypesofmorphing.19Mechanismshavealsobeenbuiltsuchasatelescopingspartomorphaspectratio20andanin atableactuatortochangesweep.28Ineachcase,themechanismsaretooheavyfora ightsystemsoonlywindtunneltestingofastaticmounthasbeenperformed.Anin atableconcepthasactuallybeentakento ight22butthemorphingisasingleone-timein ationsoisnotusedformaneuveringcontrol.

AprojectparticularlyrelevanttothestudyofmorphingforcontrolistheF/A-18ActiveAeroelasticWing(AAW).15TheAAWisusingwingtwisttoaltertheaeroservoelasticdynamicsandgeneraterollmoments.Themorphingisac-tuallyapassiveeffectresultingfrommovingleading-edgesurfacesofthe exiblewing.Thattestbedusedasimplemechanismtogeneratemorphinginordertostudytheresultingloadsandcontrolissues.

AMAVisanespeciallyappropriateplatformforconsiderationofmorphing.The exibilityofthemembraneenablestheshapeofthewingstobeeasilychanged.Theresultingchangewillobviouslyaffectthedynamicsandactasaneffectortoprovidecontrolauthority.Assuch,themorphingofaMAVaddsverylittlecostbutprovidestremendousbene t.Thispaperwillconsidersimplestrategiestoprovidemorphingtoemphasizecontrolissues.Essentially,themethodsofmorphingarenotconsideredasmuchasthedynamicsofmorphing.

III.VehicleDesign

Small,remotelypilotedvehiclesareadaptedformorphingthroughsimplemodi cationofthestructure.Thevehiclesarebetween10inand24ininwingspananduseavarietyofstructuralmemberstobothwithstand ightloadsandaccomplishmorphingdeformation.Vehiclesofthissizeareespeciallywellsuitedastestbedsforsimplemorphingstrategiesbecauseofthehighstrengthoftheactuatorscomparedto ightloads.LightweightMAVairframes

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