简介：Amodelhelicopterismoredifficulttocontrolthanitsfullscalecounterpart.Thisisduetoitsgreatersensitivitytocontrolinputsanddisturbancesaswellashigherbandwidthofdynamics.Thisworkisfocusedondesigningpracticaltrackingcontrollerforasmallscalehelicopterfollowingpredefinedtrajectories.Atrackingcontrollerbasedonoptimalcontroltheoryissynthe-sizedasapartofthedevelopmentofanautonomoushelicopter.Someissueswithregardstocontrolconstraintsareaddressed.Theweightingbetweenstatetrackingperformanceandcontrolpowerexpenditureisanalyzed.Overallperformanceofthecontroldesignisevaluatedbasedonitstimedomainhistoriesoftrajectoriesaswellascontrolinputs.

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简介：Inspiredbythecoarse-to-finevisualperceptionprocessofhumanvisionsystem,anewapproachbasedonGaussianmulti-scalespacefordefectdetectionofindustrialproductswasproposed.ByselectingdifferentscaleparametersoftheGaussiankernel,themulti-scalerepresentationoftheoriginalimagedatacouldbeobtainedandusedtoconstitutethemulti-variateimage,inwhicheachchannelcouldrepresentaperceptualobservationoftheoriginalimagefromdifferentscales.TheMultivariateImageAnalysis(MIA)techniqueswereusedtoextractdefectfeaturesinformation.TheMIAcombinedPrincipalComponentAnalysis(PCA)toobtaintheprincipalcomponentscoresofthemultivariatetestimage.TheQ-statisticimage,derivedfromtheresidualsaftertheextractionofthefirstprincipalcomponentscoreandnoise,couldbeusedtoefficientlyrevealthesurfacedefectswithanappropriatethresholdvaluedecidedbytrainingimages.Experimentalresultsshowthattheproposedmethodperformsbetterthanthegrayhistogram-basedmethod.Ithaslesssensitivitytotheinhomogeneousofillumination,andhasmorerobustnessandreliabilityofdefectdetectionwithlowerpseudorejectrate.

简介：Thepaperpresentsamulti-scalemodellingapproachforsimulatingmacromoleculesinfluidflows.Macromoleculetransportatlownumberdensitiesisfrequentlyencounteredinbiomedicaldevices,suchasseparators,detectionandanalysissystems.Accuratemodellingofthisprocessischallengingduetothewiderangeofphysicalscalesinvolved.Thecontinuumapproachisnotvalidforlowsoluteconcentrations,butthelargetimescalesofthefluidflowmakepurelymolecularsimulationsprohibitivelyexpensive.Apromisingmulti-scalemodellingstrategyisprovidedbythemeta-modellingapproachconsideredinthispaper.Meta-modelsarebasedonthecoupledsolutionoffluidflowequationsandequationsofmotionforasimplifiedmechanicalmodelofmacromolecules.Theapproachenablessimulationofindividualmacromoleculesatmacroscopictimescales.Meta-modelsoftenrelyonparticle-correctoralgorithms,whichimposelengthconstraintsonthemechanicalmodel.Lackofrobustnessoftheparticle-correctoralgorithmemployedcanleadtoslowconvergenceandnumericalinstability.AnewFAstLinearCOrrector(FALCO)algorithmisintroducedinthispaper,whichsignificantlyimprovescomputationalefficiencyincomparisonwiththewidelyusedSHAKEalgorithm.ValidationofthenewparticlecorrectoragainstasimpleanalyticsolutionisperformedandimprovedconvergenceisdemonstratedforssDNAmotioninalid-drivenmicro-cavity.

简介：QuestionsconcerningthefunctionalroleofthehollowregionofthebutterflyPyrameisatalanta(L.)scaleareexperimentallyinvestigated.Attentionwasinitiallydirectedtothisproblembyobservationofthecomplexmicrostructureofthebutterflyscaleaswellasotherstudiesindicatinghigherliftonbutterflywingscoveredwithscale.Theaerodynamicforcesweremeasuredfortwooscillatingscalemodels.ResultsindicatedthattheaircavityofanoscillatingmodelofthePyrameisatalanta(L.)scaleincreasedtheliftbyafactorof1.15andreducedthedampingcoefficientsbyafactorof1.38.Themodificationoftheaerodynamiceffectsonthemodelofbutterflyscalewasduetoanincreaseofthevirtualairmass,whichinfluencedthebody.Thehollowregionofthescaleincreasedthevirtualairmassbyafactorof1.2.Thevirtualmassofthebutterflyscalewiththehollowregionwasrepresentedasthesumofairmassoftwoimaginarygeometricalfigures:acircularcylinderaroundthescaleandaright-angledparallelepipedwithinthehollowregion.TheinteractionmechanismofthebutterflyPyrameisatalanta(L.)scalewithaflowwasdescribed.Thisnovelinteractionmechanismexplainedmostgeometricalfeaturesoftheairpermeablebutterflyscale(invertedV-profileoftheridges,nozzleofthetipedge,hollowregion,andopeningsoftheupperlamina)andtheirarrangement.

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简介：Climbingrobotsareofpotentialuseforsurveillance,inspectionandexplorationindifferentenvironments.Inparticular,theuseofclimbingrobotsforspaceexplorationcanallowscientiststoexploreenvironmentstoochallengingfortraditionalwheeleddesigns.Toadheretosurfaces,biomimeticdryadhesivesbasedongeckofeethavebeenproposed.Thesebiomimeticdryadhesivesworkbyusingmulti-scalecompliantmechanismstomakeintimatecontactwithdifferentsurfacesandadherebyusingVanderWaalsforces.Fabricationoftheseadhesiveshasfrequentlybeenchallenginghowever,duetothedifficultyincombiningmacro,microandnanoscalecompliance.Wepresentanallpolymerfootdesignforusewithahexapodclimbingrobotandafabricationmethodtoimprovereliabilityandyield.Ahighstrength,low-modulussilicone,TC-5005,isusedtoformthefootbaseandmicroscalefibresinonepiecebyusingatwopartmold.Amacroscalefootdesignisproducedusinga3Dprintertoproduceabasemold,whilelithographicdefinitionofmicroscalefibresinathickphotoresistformsthe‘hairs’ofthepolymerfoot.Theadhesionofthesiliconefibresbythemselvesorattachedtothemacrofootisexaminedtodeterminebeststrategiesforplacementandremovaloffeettomaximizeadhesion.Resultsdemonstratethesuccessfulintegrationofmicroandmacrocompliantfeetforuseinclimbingonavarietyofsurfaces.

简介：Overthelastdecade,computationalmethodshavebeenintensivelyappliedtoavarietyofscientificresearchesandengi-neeringdesigns.Althoughthecomputationalfluiddynamics(CFD)methodhasplayedadominantroleinstudyingandsimu-latingtransportphenomenainvolvingfluidflowandheatandmasstransfers,inrecentyears,othernumericalmethodsforthesimulationsatmeso-andmicro-scaleshavealsobeenactivelyappliedtosolvethephysicsofcomplexflowandfluid-interfaceinteractions.Thispaperpresentsareviewofrecentadvancesinmulti-scalecomputationalsimulationofbiomimeticsrelatedfluidflowproblems.Thestate-of-the-artnumericaltechniques,suchaslatticeBoltzmannmethod(LBM),moleculardynamics(MD),andconventionalCFD,appliedtodifferentproblemssuchasfishflow,electro-osmosiseffectofearthwormmotion,andself-cleaninghydrophobicsurface,andthenumericalapproachesareintroduced.Thenewchallengingofmodellingbiomi-meticsproblemsindevelopingthephysicalconditionsofself-cleanhydrophobicsurfacesisdiscussed.