简介:Tofindthedifferenceindynamiccharacteristicsbetweenconventionalmonohullshipandwavepenetratingcatamaran(WPC),aWPCwastakenasanobject;itsdynamiccharacteristicswerecomputedbytransfermatrixmethodandfiniteelementmethodrespectively.Accordingtothecomparisonofthenaturefrequencyresultsandmodeshaperesults,thefactthatFEMmethodismoresuitabletodynamiccharacteristicsanalysisofaWPCwaspointedout,specialfeaturesondynamiccharacteristicsofWPCweregiven,andsomebeneficialsuggestionsareproposedtooptimizethestrengthofaWPCindesignperiod.
简介:Anewmethodofestimatingthefrequency-knownsignalsfromthestrongbackgroundnoisewaspresentedfirst.Thenthenewmethodwasusedinthedemodulationofthedigitalfrequencymodulation(FSK)signals.ThenewdemodulationmethodcancompletethedemodulationoftheFSKsignalsonlywiththecarrierfrequencyandwithoutanycarrierphaseinformation.Thesimulationresultsshowthattheperformanceofanti-noiseofthenewmethodisbetterthanthatoftheincoherentdemodulationmethodandthefluctuationofthecarrierphasehaslittleeffectonthenewmethod.Sothenewdemodulationmethodhasafineprospectinthepracticalapplications.
简介:Inthestrapdowninertialnavigationsystem,theFiberOpticalGyro(FOG)musthavehighprecisiontogiveaccuratenavigationinformation.Inthispaper,adigitalclosedloopdetectionmethodbasedontherampwavemodulatingtechnigueisintroduced.DSPandFPGAhavemanyadvantagesindigitalsignalprocessing.Inthedesign,byusingDSP,acomplexarithmeticoperationiscompletedtomeettheneedsofclosedloopcontrolofFOGwithinashorttime.AllkindsofcontrolsignalsareproducedeasilybyFPGA,underwhichDSPcouldworkproperly.CombiningtheDSPandFPGA,thedetectingmethodisimplementedsuccessfully.Intheend,theresultoftestandperformanceisgiven.FromtheresultwecanconcludethattheprecisionofFOGisimprovedandthenoisesarelimitedtoalowlevel.
简介:Inthispaper,a3Dsourcedistributiontechniqueisusedtocalculatethecoupledmotionsbetweentwoshipswhichadvanceinthewavewiththesamespeed.Thenumericalresultsofcoupledmotionsforafrigateandasupplyshiphaveagoodagreementwiththeexperimentalresults.Basedonthe3Dcoupledmotionsoftwoships,aspectralanalysisisemployedtoclearlyobservetheeffectofspeed,clearanceandwaveheadingonthesignificantrelativemotionamplitude(SRMA)oftwoships.Themethodpresentedinthispaperwillbehelpfultoselectsuitableclearance,speedandwaveheadingforunderwayreplenishmentatsea(RAS).
简介:Thepotentialbasedlowordersurfacepanelmethodisusedtopredictthehydrodynamicperformanceofmarinepropellers.Inpresentmethodthehyperboloidalquadrilateralpanelsareemployedtoavoidthegapbetweenthepanels.TheinfluencecoefficientsofpanelsarecalculatedbyMorino’sanalyticalformulationsforincreasingnumericallycalculatingspeed.Thepres-sureKuttaconditionissatisfiedonthetrailingedgeofpropellerbladebyNewton-Raphsoniterativeprocedure.Thereforethe
简介:InthispaperwepresenttwostrategiesofAUV(AutonomousUnderwaterVehicle)regiondetectionandanapproachtodecomposethedetectionregionaccordingtothedirectionoftheoceancurrent.Inthetaskoflocaldetectionandidentification,thealgorithmagainsttheoceancurrentwasproposed.Inthetasksofclosingobstacle,goingbackormoving,thefuzzylogictheorywasusedtosolvetheeffectofoceancurrent.InoneofourstrategiestheconceptofweightedjourneybasedontheanglebetweenheadingandoceaucurrentissuggestedandtheTSP'sexactoptimalresultisutilizedtosolvetheglobalpathplanning.Simulationsdemonstratethefeasibilityofthisapproach.
简介:Toresearchtheeffectoftheselectionmethodofmulti-objectsgeneticalgorithmproblemonoptimizingresult,thismethodisanalyzedtheoreticallyanddiscussedbyusinganautonomousunderwatervehicle(AUV)asanobject.Achangingweightvtluemethodisputforwardandaselectionformulaismodified.SomeexperimentswereimplementedonanAUV.TwinBurger.Theresultsshowsthatthismethodiseffectiveandfeasible.