简介：（w,z）参数化是一种新的姿态表示方法,它通过两次垂直的旋转来表示卫星姿态,和描述的运动方程相互解耦,可以分别进行控制,有其独特的优点.本文首先推导了（w,z）参数并给出了运动模型,然后针对非对称微卫星的欠驱动姿态再定位控制,采用微分平滑的方法设计了可行的再定位运动轨迹,给出了相应的跟踪控制律,并以PWM（脉宽调制）喷气系统进行仿真,验证了本文方法的有效性.

简介：Somenewcriteriaforthechaoticlagsynchronizationareproposed.Atfirst,lagsynchronizationschemeforidenticalmaster-slaveLur'esystemsbyreplacingvariablescontrolandtherelevanterrorsystemaregiven,andtherelationsbetweenabsolutestabilityoftheerrorsystemandthechaoticlagsynchronizationaredescribed.Then,basedonaquadraticLyapunovfunction,twonewLur'ecriteriafortheabovechaoticlagsynchronizationareproved.FourcorrespondingfrequencydomaincriteriaarefurtherderivedbymeansofMeyer-Kalman-YacuboviaLemma.Thesefrequencydomaincriteriaareappliedtoanalyzethelagsynchronizationofgeneralmaster-slaveChua'scircuitssothatsomerangesoftheparametersinwhichthemaster-slaveChua'scircuitsachievechaoticlagsynchronizationbyreplacingsingle-variablecontrolareattained.Finally,someexamplesaregiventoverifythetheoreticalresults.

简介：NecessaryandsuffcientconditionsfortheexistenceofaLyapunovfunctionintheLur'eformtoguaranteetheabsolutestabilityofLur'econtrolsystemswithmultiplenon-linearitiesarediscussedinthispaper.Itsimplifiestheexistenceproblemtooneofsolvingasetoflinearmatrixinequalities(LMIs).IfthoseLMIsarefeasible,freeparametersintheLyapunovfunction,suchasthepositivedefinitematrixandthecoefficientsoftheintegralterms,aregivenbythesolutionoftheLMIs.Otherwise,thisLyapunovfunctiondoesnotexist.Somesufficientconditionsarealsoobtainedfortherobustabsolutestabilityofuncertainsystems.Anumericalexampleisprovidedtodemonstratetheeffectivenessoftheproposedmethod.