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    25 October 2012, Volume 32 Issue 5 Previous Issue    Next Issue
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    Adaptive Artificial Potential Function Guidance for Dynamic Obstacle Avoidance of Spacecraft
    GAO Peng, LUO Jian-Jun
    2012, 32 (5):  1-8.  doi: 10.3780/j.issn.1000-758X.2012.05.001
    Abstract ( 1564 )   PDF (431KB) ( 1210 )   Save
    Toavoidthedynamicobstaclesduringspacecraftautonomousproximityoperations,afuelsavingandhighaccuracyadaptiveartificialpotentialfunctionguidancemethodfordynamicobstaclesavoidancewaspresented.AsforthesituationthattheGaussianrepulsivepotentialfunctionwasnonzeroatthedesiredposition,acorrectiontermwasmultipliedtoeliminate deviationfromtheequilibriumpoint.Theguidancelawofavoidingdynamicobstacleswasdeducedbasedonthatofthestaticobstaclesavoidance.Then,accordingtotherelationshipbetweenvelocityandgravitygradient,thenegativefeedbackcontrolwasdesignedtomakethegravitygradientadapttothevarianceofvelocity,andtheadaptiveartificialpotentialfunctionguidancelawfordynamicobstaclesavoidancewasobtainedeventually.Toverifythecorrectnessandeffectivenessoftheguidancelaw,aseriesofnumericalsimulationsusingtheprecisemathematicalmodelwerecarriedout.Thesimulationresultsshowthatthecorrectedpotentialfunctioncaneffectivelyimprovetheconvergentprecision;andtheadaptiveartificialpotentialfunctionguidancelawmakesthecontrolpulsesmorereasonable,withsaving30%ofthetotaldeltaV,andistwodegreesmoreaccuratethanthetraditionalartificialpotentialfunctionguidancelaw.
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    Adaptive Attitude Control of Spacecraft with Variable Speed Control Moment Gyroscopes
    TIAN Lin, XU Shi-Jie
    2012, 32 (5):  9-16.  doi: 10.3780/j.issn.1000-758X.2012.05.002
    Abstract ( 1638 )   PDF (453KB) ( 1328 )   Save
    Spacecraft precise attitude control is easily affected by system parameter errors. Adaptive control can estimate parameters reasonably and make the model based controller design more easily. Adaptive parameters are sorted into three groups includingspacecraft main body inertia, VSCMGs gimbal androtor inertia, and their dynamic friction coefficients. The detailed spacecraft attitude dynamics model considering VSCMGs gimbal and rotor friction was transformed according to the parameter groups. The attitude controller, VSCMGs steering law and parameters adaptive updating law were developed by Lyapunov method. Weight matrix was imported into the steering law to relief the gyroscopes singularity problem. Theory analysis and numerical simulation prove that the closed loop control system is global uniformly and ultimately bounded stable. Parameters adaptive updating can effectively reduce angular velocity tracking errors and make attitude quaternion errors converging faster. Parameter estimates can not accurately converge to their real values, but they are all within acceptable scopes.
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    DesignofKu/KaDualbandSharedApertureMicrostripArrayAntenna
    LIU Yang, DONG Tao, WANG Xin
    2012, 32 (5):  17-20.  doi: 10.3780/j.issn.1000-758X.2012.05.003
    Abstract ( 1889 )   PDF (322KB) ( 1578 )   Save
    AnovelKu/Kadualbandsharedaperturemicrostriparrayantennawasproposed.Theantennaelementswereplacedonasinglelayertokeepthestructurecompact.TheKu-bandelementswerefedattheedgesbymicrostriplines,whiletheKa-bandwascoupledfedbyL-shapedaperturesinthegroundplanetorealizecircularpolarization.Thesimulatedandmeasuredresultsdemonstratethefeasibilityoftheproposeddesign.Thesimulatedimpedancebandwidthoftheantennais2.2%forKu-bandand4.3%forKa-bandrespectively,andmeasuredresultsare2.1%and3.4%respectively.TheantennastructureisapplicableforKu/Kadualbandsatellitecommunication.
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    DynamicsInfluenceFactorsAnalysisonTwo-axis-positionMechanismofSatelliteAntennaswithJointClearance
    PAN Dong, WANG Xing-Gui, ZHAO Yang
    2012, 32 (5):  21-26.  doi: 10.3780/j.issn.1000-758X.2012.05.004
    Abstract ( 1482 )   PDF (396KB) ( 1456 )   Save
    iththehighdemandforpointingaccuracyofthesatelliteantenna,thejointclearanceisinevitableduetotheexistenceofthekinematicpairinthetwoaxispositionmechanism.Soitisparticularlyimportanttostudytheinfluenceofthejointclearancetosatelliteantennamechanism.Thetwoaxispositionmechanismwastakenasresearchobject,thecontact dynamicsmodeloftheclearancejointwasestablishedbyapplyingthenonlinearspringdampmodel,andthefrictioneffectwasconsideredbyapplyingtheCoulombfrictionmodel.Thelawthatthedynamiccharacteristicoftwoaxisposition mechanismaffectedbythefactorswasanalyzedbythedynamicsimulationofthevirtualprototype,suchasthesizeofthejointclearanceandthedrivingtorqueintheclearance.Theresultsshowthatlargejointclearanceanddrivingtorquewillreducethepositioningaccuracyandmakethesystemunstable.Itisagoodwaytoincreasethepositioningaccuracythroughoptimizingthestructureofthesatelliteantennamechanism.
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    ControlPropertyoftheSpacecraftAttitudeUnderactuatedbyWheels
    GUI Hai-Chao, XU Shi-Jie, JIN Lei, ZHANG Jun
    2012, 32 (5):  27-33.  doi: 10.3780/j.issn.1000-758X.2012.05.005
    Abstract ( 1574 )   PDF (452KB) ( 1028 )   Save
    Smalltimelocalcontrollability(STLC)andstabilizabilityofthespacecraftattitudeunderactuatedbyreactionwheels(RWs)wereinvestigatedwiththewheelspeedsascontrolinputs.Firstly,withthewheelspeedsbeingtreatedasinputs,theconservationconstraintofthetotalangularmomentumofthespacecraftandRWswasdirectlybroughtintothedynamicsofthesystem.ThennonlinearcontrollabilityandstabilizabilitytheorywereutilizedtoanalyzethecontrolpropertyofthisdynamicswithoneandtwoRWsrespectively.TheresultsshowthattheSTLCofthespacecraftattitudeispossibleonlywhentwononcoaxialRWsareavailable.Simultaneously,thesystemcannotbeasymptoticallystabilizedbyatimeinvariantsmoothfeedback,butitstillcanbeasymptoticallystabilizedatleastbyapiecewisecontinuousfeedback.Accordingly,anonsmoothcontrollawbasedonquaternionwasconstructedtostabilizethespacecraftattitudewithwheelspeedsunderthesaturationlimits,whichnotonlyconfirmsthetheoreticaloutcomesbutalsoispracticallyuseful.
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    ModelingMethodforOscillatorFlickerNoiseinKalmanbasedGPSTrackingLoop
    JIN Tian, WANG Li-Hua, HUANG Bing-Sheng
    2012, 32 (5):  34-39.  doi: 10.3780/j.issn.1000-758X.2012.05.006
    Abstract ( 1908 )   PDF (340KB) ( 1649 )   Save
    FrequencydriftcausedbyoscillatorwillpollutecarrierphaseandDopplerfrequencyinGPSreceiver.Therefore,itisnecessarytomodeltheoscillatorerrorinthetrackingsystem.TheflickernoiseerrorofoscillatorcannotbeexactlymodeledinKalmansystem,whichcauseserrorsinthemodeloftraditionalKalmanbasedtrackingloop.Tosolvetheseproblems,thefrequencydomainmodelandnoisecovarianceofoscillatorwereanalyzed,andamethodofexactlymodellingtheflickernoiseintheKalmanbasedtrackingloopwasproposed.RealGPSsatellitedatawasprocessedbyusingthenewoscillatormodeltoverifythevalidity.
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    LEOSpacecraftOrbitAnomalyDetectionBasedonPredictionDispersion
    ZHANG Tao-Tao, BAI Xian-Zong, HAO Jia, CHEN Lei
    2012, 32 (5):  40-46.  doi: 10.3780/j.issn.1000-758X.2012.05.007
    Abstract ( 1589 )   PDF (430KB) ( 1434 )   Save
    detectionmethodbasedonpredictiondispersionwaspresentedtodealwithLEOspacecraftorbitanomalycausedbymaneuvers,collisions,andatmosphericenvironment.Thesemimajoraxisandinclinationwereselectedasorbitcharacteristicparameters.PredictionvaluesoforbitcharacteristicparameterscanbeachievedbyorbitextrapolationbasedonSGP4modelsecularterm.Afterdatasmoothingprocess,predictiondispersionsequencecanbeobtainedbycalculatingthedifferencebetweenpredictionandcatalogvaluesofthecharacteristicparameters.TheorbitanomalywasdetectedthroughthepredictiondispersiondatabasedonMahalanobisdistance.ThedetectionresultsofTerrain2010isconsistentwiththemaneuverhistorypublishedbyNASA,whichindicatethatthemethodpresentedinthispapercandetectthetimes,epochandtypeoforbitanomalyandcanbewidelyappliedtothespacesurveillanceandspacesituationalawareness.
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    ImprovedHaloOrbitControlMethodBasedonPoleAssignment
    CHAO Ning, LUO Xiao-Ying, LI Yan-Jun
    2012, 32 (5):  47-53.  doi: 10.3780/j.issn.1000-758X.2012.05.008
    Abstract ( 1573 )   PDF (424KB) ( 1161 )   Save
    Basedonsmalldeviationtheory,theno-perturbation3-bodydynamicequationswerelinearizedandtheerrorlinearmodelwas deduced.Basedonthepoleassignmenttheoryoflinearsystem,stationkeepingforperturbedhaloorbitnearL1pointinEarth-MoonsystemwasachievedthroughdesigningtheclosedlooppoleassignmentstatefeedbackmatrixKbychoosing standardorbitstatevectorasclosedlooptargetpole.Aimedatthecontrolerrorcausedbysinglecontrollevelofthreeaxis in  K ,adesignmethodofvariablefeedbackmatrixKcoefficient(VKC)consideringthescaleoforbitinjectionwasproposed.TheexperimentsshowthattheVKCmethodwhichimprovedcontroleffectoforiginalcontrolmethodanddecreasedtrackingvariancesumunderdifferenterrorlevelsisavailable.
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    SpaceEnvironmentSynergisticEffectonSpacecraft
    SHEN Zi-Cai, QIU Jia-Wen, DING Yi-Gang, LIU Yu-Ming, ZHAO Chun-Qing
    2012, 32 (5):  54-60.  doi: 10.3780/j.issn.1000-758X.2012.05.009
    Abstract ( 1614 )   PDF (555KB) ( 1204 )   Save
    Thenecessityofstudyonsynergisticeffectofspaceenvironmentsisanalyzed.Somesynergisticeffectssuchaselectron, protonandultraviolet,atomicoxygenandultraviolet,atomicoxygenandspacedebris,discharginginducedbyspacedebrisand contaminationinducedbyspaceenvironmentwerediscussed.Thepresentstateandperspectivesofstudyonsynergisticeffects werediscussedandproposed.Someadvicesandcountermeasuresofsystemicstudyonmechanism,simulation,testmethod,forecastingtechniqueweregiven.
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    OptimizationofEarthMarsLowThrustTrajectoryBasedonArtificialImmuneAlgorithm
    PENG Kun, XU Shi-Jie, GUO Lin-Li, WANG Ping
    2012, 32 (5):  61-68.  doi: 10.3780/j.issn.1000-758X.2012.05.010
    Abstract ( 1606 )   PDF (424KB) ( 1375 )   Save
    TheEarth-Marslow-thrusttrajectorywasoptimizedbyArtificialImmuneAlgorithm.Firstly,thesystemmodelofEarthMarslowthrusttrajectorywasestablishedandnormalized.Secondly,theoptimizationproblemoflowthrusttrajectorywasconvertedintoa nonlinearprogrammingviaparameterizationandpenaltyfunction.Finally,aGAIA(GuidingArtificialImmuneAlgorithm)was proposed tosolvethisoptimizationproblem.SimulationresultsshowthattheGAIAhasfastconvergencerateandhighoptimization precision.Moreover,GAIAalgorithmavoidsmanyshortcomings,suchasinitialvaluesensitivity,illconditionedgradientandlocal convergence.TheeffectivenessofGAIAforlowthrusttrajectoryoptimizationisvalidated.
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    OrbitMaintenanceTechnologyandImplementforHJ-1 A/BConstellation
    LIU Long-Fei, WANG Xing-Ling, BAI Zhao-Guang, TAN Tian, YU Gang
    2012, 32 (5):  69-75.  doi: 10.3780/j.issn.1000-758X.2012.05.011
    Abstract ( 1431 )   PDF (363KB) ( 1551 )   Save
    InordertomaintaintheformationofHJ-1A/Bconstellation,ensureCCDcamerascoverChina′sterritoryorrevisittheglobalin 48hours,andmeetthedemandsofChina′sdisastermonitoringandglobalterrestrialobserving,anorbitmaintenancestrategy consideringbothgroundtrackandconstellationphasewasdeveloped.Duringtheprocessofdisasterreductionandenvironment protection,revisitandcoveragecharacteristicsaremorecriticalthanstrictgroundtrackmaintenance,sotheorbitmaintenancestrategymainlyconsidertheconstellationphase.Itreducestheorbitmaintenancetimeandoperationrisk,savesthefuel,benefitslifespanofHJ-1A/B.Inthelast3moreyears,theorbitmaintenanceworkwasfullycompletedthroughonlytwice operations.
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    RoutingAlgorithmforNavigationConstellationBasedonEvolvingGraphModel
    WANG Yan, LIU Bo, YU Wan-Rong, ZHAO Bao-Kang
    2012, 32 (5):  76-83.  doi: 10.3780/j.issn.1000-758X.2012.05.012
    Abstract ( 1715 )   PDF (466KB) ( 1520 )   Save
    Fornavigationconstellationequippedwithdirectionalantennaswhichperformsdeterministiclinkscheduling,inter-satelliteroutingprobleminnotfully-connectedconstellationwasstudied.Firstly,thedynamictopologyofnavigationconstellationwasmodeledbasedontheevolvinggraphtheory,andthecorrespondingdatastructurewasgivenlater.Secondly,aroutingalgorithmtocomputetheearliestjourneywasproposed,thenthestepsandthecomplexityofthealgorithmwerediscussed.Finally,theaveragetimecostandaveragehopsofearliestjourneywereshownbysimulationundergivenparameters.Theimpactof startingtimeonearliestjourneywasalsodiscussed.
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