Table of Content

25 June 2016, Volume 36 Issue 3 Previous Issue    Next Issue

For Selected:

Download Citations EndNote Reference Manager ProCite BibTeX RefWorks

Toggle Thumbnails

Select

MobilitymanagementinLEOsatellitecommunicationnetworks HE Da-Jian, YOU Peng, YONG Shao-Wei 2016, 36 (3):  1-14.  doi: 10.16708/j.cnki.1000-758X.2016.0034 Abstract ( 1189 )   PDF (1144KB) ( 3085 )   Save Inrecentyears,lowEarthorbit(LEO)satellitecommunicationnetworksattractalotofresearchers'attentionforitsglobalcoverage,shortpropagationdelay,low-powerlinksandgreatinvulnerabilityperformance，etc.Itwillbeanimportantpartofthefutureglobalmobilecommunicationsystems.MobilitymanagementisakeytechnologyforenablingserviceinLEOsatellitecommunicationnetworks.Thecharacteristics,researchstatusandproblemsofmobilitymanagementwereanalyzed.Firstly,abriefclassificationofmobilitymanagementofLEOsatellitecommunicationsnetworkswasprovidedandcharacteristicsdistinguishedfromterrestrialmobilitywirelessnetworkswereanalyzedbasedonthearchitectureandfeaturesofLEOsatellitecommunicationnetworks.Thenthestate-of-the-artmobilitymanagementschemesinLEOsatellitecommunicationnetworksweresummarizedfromlinklayer,networklayerandtransportlayer.AdetaileddescriptionoftheapplicationofMIPv6andSIGMAinLEOsatelliteenvironmentwasgiven.Finally,sometrendsofmobilitymanagementofLEOsatellitecommunicationsnetworkswaspointedout. Related Articles | Metrics

Select

Non-equilibriumnumericalsimulationofalowpowernitrogen/hydrogenarcjet WEI Yan-Ming, HE Qing-Song, WANG Hai-Xing 2016, 36 (3):  15-23.  doi: 10.16708/j.cnki.1000-758X.2016.0035 Abstract ( 855 )   PDF (1595KB) ( 1042 )   Save Thermalandchemicalnonequilibriummodelingsstudywereperformedonalowpowernitrogen/hydrogenarcjet.Separateenergyequationswereformulatedfortheelectronsandtotalspecies,andsevenspeciesnitrogen/hydrogenplasmacompositionofmolecules,atoms,ionsandelectronswasassumed.Someimportantchemicalkineticprocessesofdissociationandionizationwereconsideredinthechemicalnonequilibriummodel.Theplasmapropertieswerecalculatedaccordingtothelocalspeciesnumberdensityandtemperature.Thedistributionoftemperatureandthenumberdensityofeachspeciesinthearcjetwereobtained.Theresultsshowthattheaxisofarcjetisclosetothermalequilibriumandsignificantdeviationfromthermalequilibriumisfoundinthearcattachmentregion.Itisshownthatthespeciesdistributionsofnitrogenandhydrogenaresignificantlydifferentfromthoseattheinletofthruster,whichindicatesthatthereexistthedemixingprocessesinsidethruster.Itisfoundthatthehydrogenspeciesdecreaseatfirstandthenincreasealongtheradialdirectionfromthecentertotheinnerwallofthruster,whilethenitrogencomponentsshowtheoppositetrend.Furtheranalysisshowsthatthespeciesdiffusionsinsidearcjetaredrivenbymolefractiongradientswhichareduetothedissociationandionizationofnitrogenandhydrogenspecies. Related Articles | Metrics

Select

Analysisonflexiblespacemanipulatorsystemassisteddockingofspacestation WEI Qing-Qing, WANG Yao-Bing, TANG Zi-Xin, ZHANG Da-Wei 2016, 36 (3):  24-31.  doi: 10.16708/j.cnki.1000-758X.2016.0036 Abstract ( 1113 )   PDF (1288KB) ( 1278 )   Save Positionerrorsandangleerrorsexistinevitablyinspacemanipulatorsystemassisteddockingofspacecraft.Adynamicandcontrolmodelconcernedthecontactionbetweenthedockingsystemwassetuptosimulatethespacemanipulatorsystemassisteddockingofspacecraft.Theimpedancecontrolsystemassociatedwiththedetailedjointdynamicmodel,jointtorquecontrolsystemwasbuilt.Theresultsshowthatthespacemanipulatorsystemcouldovercometheinitialerrorofthespacecraft,andfinishthejobofspaceassisteddocking.Thecontrolforceturneddownimmediatelyafterthespacecraftwasdocked.Also,thespacemanipulatorsystemcouldholdthepositionandshape. Related Articles | Metrics

Select

Multi-GNSSRAIMavailabilityalgorithmsandanalysisforpreciseapproach JIANG Hu, YUAN Yun-Bin, WANG Hai-Tao, OUJi-Kun , JIANG Zhen-Wei 2016, 36 (3):  32-40.  doi: 10.16708/j.cnki.1000-758X.2016.0028 Abstract ( 1021 )   PDF (24780KB) ( 479 )   Save Withthecontinuousdevelopmentofglobalnavigationsatellitesystem(GNSS),thecombinedmulti-systemreceiverautonomousintegritymonitoring  (RAIM)hasbeenanimportanttopicbasedonBDS/GPS/GLONASS/Galileo.ThealgorithmofMulti-GNSSRAIMavailabilitywasproposed,andtheavailabilityofacombinedmulti-systemRAIMbasedonsimulatednavigationephemerisofBDS/GalileoandactualnavigationephemerisofGPS/GLONASSwasanalyzedinpreciseapproachprocedures.Resultsshowthatfivegeosynchronousorbit(GEO)satellitesandthreeinclinedgeosynchronousorbits(IGSO)satellitesfromBDSmakeagreatcontributiontoRAIMavailability.TheeightsatellitesimprovethegeometrystructureoftheconstellationinthemostpartsofAsia,AfricaandEurope,andpromoteRAIMavailabilitygreatly.IntheAsia-Pacificregion,theRAIMavailabilityofBDSreaches99.5%,higherthanthatoftheotherthreenavigationsystematAPVIphase.Inpreciseapproachphases(APV-I,APV-IIandCAT-I),theintegratedBDS/GPS/Galileo/GLONASScanmeettherequirementsofRAIMavailabilityinaglobalscale. Related Articles | Metrics

Select

Dynamicsanalysisoflineararraydeployablestructurebasedonscissor-likeelementconsideringjointclearance LI Bo, WANG San-Min, YUAN Ru, ZHI Chang-Jian 2016, 36 (3):  41-49.  doi: 10.3780/j.issn.1000-758X.2016.0020 Abstract ( 1095 )   PDF (1153KB) ( 1547 )   Save Inordertopreciselyresearchthedynamicsperformanceofadeployablestructurebasedonascissor-likeelement,clearanceswereintroducedintooneofalljointsinthescissor-likeelementsothatitwasclosedtotherealmechanism.Thekinematicmodeloftherevolutejointwithclearancewasestablishedbytheprincipleofthemotionbetweenjointelements.ThenormalandtangentialcontactforcesbetweenjointelementsweredescribedbyaGonthiercontactforcemodelandacorrectionalCoulombfrictionmodel.Thecontactforcesbetweenthebearingandthejournalwereconvertedtothemasscentersoflinkandthesliderconnectedbythisclearancejoint.Theconvertedcontactforceandtheadditionaltorquewereintegratedtoageneralizedforceinmotionequationsofthedeployablestructure,andthentheeffectofjointclearancewasintroducedtothescissor-likeelement.Adirectdefaultcorrectionmethodwasusedtodirectlymodifythecoordinatesandspeedsofthesystemtoavoidthenumericalresultsdivergence.Also,thismethodcancontrolthedefaultwithinagivenrangeofaccuracy.Theinfluenceofrevolutejointclearanceonthedynamicperformanceofthelineararraydeployablestructurewaspredictedbymeansofnumericalanalysis,providingareferenceandbasisforthestudyofthemotionaccuracyandmechanismdesignofdeployablestructures.Furthermore,thesimulationresultsextendtheapplicationrangeoftheclearancecollisionmodel,whichishelpfulforengineeringapplications. Related Articles | Metrics

Select

Avariable-fidelitysequentialoptimizationmethodforreentrytrajectoryofspaceplane ZHU Jun-Jie, YU Xiong-Qing*, LUO Dong-Ming, WANG Yu 2016, 36 (3):  50-56.  doi: 10.16708/j.cnki.1000-758X.2016.0032 Abstract ( 886 )   PDF (1164KB) ( 1448 )   Save Avariable-fidelitysequentialoptimizationmethodforreentrytrajectorydesignofaspaceplanewasproposedtoincreaserobustnessandaccuracyoftheoptimization.Theoptimizationprocessconsistedofthreesteps.Firstly,  therewasapreoptimization,inwhichforacoarsediscretecase,theoptimalsolutionofdesignvariablesforeachdiscretizedpointwasobtainedbyusingahybridoptimizationmethod.Secondly,  initialvaluesofthediscretizedpointsinarefineddiscretecasewereobtainedbyusinglinearinterpolationfromthepre-optimizationsolution.Finally,thetrajectoryoptimizationintherefineddiscretecasewasconducted,andmoreaccurateoptimizationresultswereobtained.Ademonstrationexamplewasusedtovalidatetheproposedmethod.Theresultsindicatethatthereentrytrajectoryoptimizationproblemcanbesolvedrobustlywithsatisfiedaccuracyandlesscomputationalburden. Related Articles | Metrics

Select

Anapproachtoanalyzetherangeofsolardisturbanceforattitudesensorofspacecraft CAI Jian, SONG Li-Fang, JIANG Qing-Hua 2016, 36 (3):  57-62.  doi: 10.16708/j.cnki.1000-758X.2016.0029 Abstract ( 783 )   PDF (1576KB) ( 1177 )   Save Thereislimitationtoconfirmingthereasonforthedatachangeofattitudesensorofspacecraftafterthetelemetrydatawerereceived,whichbringstheproblemthatthedatacan′tbeanalyzedintime.Tosolvethisproblem,anapproachwasproposedtostudytherangeofsolardisturbanceforattitudesensorbasedontwoangleparameterswhichreflectrelativepositionbetweenthesunandspacecraft.Therangeofsolardisturbanceforattitudesensorcouldgaininadvanceduetowellregulatedchangeofthetwoparameters.Consequently,whichcouldofferhelpfordatachangeandfailureanalysisofattitudesensor.Furthermore,itisbeneficialtothedesignofspacecraftattitudecontrolsystem,forexample,configurationandinstallationofattitudesensor.Inaddition,thefacultytorestrainsunlightofattitudesensorisvalidatedthroughtheway.Simulationresultsprovethevalidityofthealgorithm. Related Articles | Metrics

Select

Researchonmechanicalcharacteristicsoflunarspaceelevators LI Meng, CHEN Wei-Yue, YANG Sheng, GAO Xu 2016, 36 (3):  63-69.  doi: 10.16708/j.cnki.1000-758X.2016.0030 Abstract ( 913 )   PDF (3142KB) ( 945 )   Save Themechanicalandmasscharacteristicsaredeterminedbythestructureoflunarspaceelevator. Mostofcurrentresearchesaboutlunarspaceelevatorsonlyfocusoncombined-cross-sectionstructure.Variousstructuresoflunarspaceelevatorswereinvestigated.Toanalyzethemechanicalandmasscharacteristics,thedynamicmodelofthespaceelevatorwasestablished.Bysupposingthedensityandstressasconstantrespectively,twodifferentkindsoflunarspaceelevatorscalledfixed-cross-sectionstructureandtapered-cross-sectionstructurewereobtainedandcompared.Theresultsshowthatthemaximumstressoftapered-cross-section-structurecanbedesignedasanyconstantvalue,whichreducestherequirementofmarginstressofthematerial.Asaresult,tapered-cross-sectionstructurealsohastheleastmass,whichcouldbeconsideredastheoptimalchoice. Related Articles | Metrics

Select

Numericalsimulationoflunarsoiltemperatureconsideringitsvariablethermalproperties LUO Zu-Fen, SONG Bao-Yin, CAO Xi 2016, 36 (3):  70-76.  doi: 10.16708/j.cnki.1000-758X.2016.0031 Abstract ( 843 )   PDF (3142KB) ( 1363 )   Save Thethermaldesignoflunarexplorationdevicesandinstrumentsdependsonrealinformationofthethermalenvironmentofthelunarsurface.UsingthethermalanalysismoduleinANSYS,andconsideringthatthethermalconductivityofthelunarsoilvarieswithbothdensityandtemperatureandthespecificheatisafunctionoftemperature,alunarsoiltemperaturesolvingmodelwasdeveloped.Andthelunarsurfacetemperaturesatthelatitudeof26°andtheequatorwerethencalculatedrespectively.Thetemperaturedistributionofsuperficiallayersattheequatorwasalsodiscussed.Thegoodagreementofthecomputedresultsandthemeasureddatainlunarsurfacetemperaturesrevealsthatthemodelandtheselectedparametersareapplicableandreliable,besides,thefurthermatchedpredictingresultsandmeasureddatawithasomewhatmodifiedlunarsoilconductivitypartlyshowthefunctionofthemodelincalculatingthelunarsoiltemperature.Todiscussthetemperaturedistributionofsuperficiallayersattheequator,thelunarsoiltemperatureandtheheatfluxprofilesatdifferenttimeswereplotted,andtheeffectsofthelunarinnerheatfluxandtheconductivityofthelunarsoilonthesoiltemperaturewerealsoanalyzed,whichmighttheoreticallysupportthethermaldesignsforlunarexplorationdevicesorinstruments. Related Articles | Metrics

Select

InclinationandeccentricitycombinationcontrolmethodusingelectricpropulsionforGEOsatellitestationkeeping LI Qiang, ZHOU Zhi-Cheng, YUAN Jun-Gang, WANG Min 2016, 36 (3):  77-84.  doi: 10.16708/j.cnki.1000-758X.2016.0037 Abstract ( 994 )   PDF (1436KB) ( 1346 )   Save NowadaysmostadvancedGEOsatellitescollocateelectricthrusterswithhighspecificimpulsetoexecutenorth-southstationkeeping,whichcanefficientlydecreasepropellantconsumption.ForGEOsatellites,electricthrustersusuallycontrolsnothingbutinclination,whilebipropellantthrustercontrolseccentricityandmeanlongitude.AimingatthestationkeepingofGEOsatellitewithelectricthruster,asortofcombinationcontrolmethodofinclinationandeccentricityusingelectricthrusterswasproposed.Theoptimizationmodelforsolvingthecontrolequationswasdeveloped.Twokindsofsimplifiedalgorithmwereinducedbyreducingtheoptimizationmodeldimensionality,whichdeeplydecreasethecomputationalcomplexityandwasconvenientforautonomouscomputationofGEOsatellitestationkeeping.Thismethodcanbeusedtosimulatethecombinedinclinationandeccentricitysimultaneouslyandprecisely,whichleadstothereductionofpropellantconsumptionforstationkeeping.Thesimulationresultsindicatethatthecombinationcontrolmethodhastheadvantagesofhighstationkeepingefficiencyandhighcontrolprecision. Related Articles | Metrics

Select

Redundantthrusterconfigurationdesignandcommandallocationalgorithmofmannedmaneuveringunit SHANG Yi-Fan, KANG Zhi-Yu1, ZHANG Qing-Zhan,YANG Dong-Chun 2016, 36 (3):  85-94.  doi: 10.16708/j.cnki.1000-758X.2016.0033 Abstract ( 1442 )   PDF (5229KB) ( 1085 )   Save MannedmaneuveringunitsmadebyAmericanandtheSovietUnionbothusetwosetsofindependentpropulsionsystems,whicharebackupforeachother.Thebackuppropulsionsystemcantaketheplaceofthefailurepropulsionsystem,buttherearenofurthersafeguardsforthebackupsystem.Thetraditionalschemerestrictsthesafetyandextravehicularability.Basedontheconventionalpropulsionmodeanemergencypropulsionmodewasproposed.Differentstrategieswerecarriedoutaccordingtothepositionalrelationshipofthefailuredthrusters.Theremainingeffectivethrusterstoensurethe6-DOFcontrolwerecombined.Calculationandsimulationresultsindicatethat,theemergencypropulsioncancompletethetaskofextravehicularactivitieswithreductionofpropulsion,andtheschemeisfeasible. Related Articles | Metrics