简介:这份报纸与滑动模式控制进L1的集成论述一个适应控制计划适应控制建筑学,它提供好追踪表演以及坚韧性againstmatched无常。Slidingmode控制在L1被用作一条适应法律适应控制建筑学,它被看作在估计的状态和真实状态之间的错误动力学的虚拟控制。当维持控制精确性时,在控制法律设计的低通行证的过滤机制在适应法律阻止一个不连续的信号出现在实际控制信号。由把滑动模式控制用作错误动力学的虚拟控制并且介绍低通行证的过滤控制信号,啁啾的效果被消除。在靠近环的适应系统和靠近环的参考书系统之间的性能界限在这份报纸被描绘。数字模拟被提供表明介绍适应控制计划的表演。
简介:Purpose:Thepurposeofthisstudywastocompare4techniquesforarrivalatabaseaftersprintingmaximallytoreachit:slidinghead-first,slidingfeet-first,runningthroughthebasewithoutslowing,andstoppingonthebase.Asecondarypurposeofthestudywastodetermineanyadvantagetheremaybetodivingintofirstbasetoarrivesoonerthanrunningthroughthebase.Methods:Twohigh-definitionvideocameraswereusedtocapture3-dimensionalkinematicsofslidingtechniquesof9intercollegiatebaseballplayers.Anothervideocamerawasusedtotimerunsfromfirstbasetosecondin4counterbalancedconditions:runningthroughthebase,slidinghead-first,slidingfeet-first,andrunningtoastop.Mathematicalmodelingwasusedtosimulatedivingtofirstbasesuchthattheslidewouldbeginwhenthehandtouchesthebase.Results:Baseduponoverallresults,thequickestwaytothebaseisbyrunningthroughit,followedbyhead-first,feet-first,andrunningtoastop.Conclusion:Therewasanon-significanttrendtowardanadvantagefordivingintofirstbaseoverrunningthroughit,butmoreresearchisneeded,andeveniftheadvantageisreal,therisksofexecutingthistechniqueprobablyoutweightheminisculegain.
简介:Modernizationandmaintenanceofadamoftenrequireemptyingthereservoir,aprocessthatcancausemudbankinstabilitiesandenvironmentaldisturbances.Inordertoaddresstheproblemofmudbankcollapsecharacterization,astudyisconductedinpartnershipwiththeLaboratoireNationald'Hydraulique(LNH),asubsidiaryofElectricitédeFrance(EDF).Thispaperpresentsageotechnicalmodelingofsubmergedandemergentmudbankstabilityandacomparisonofthemodelresultswiththemeasurementscarriedoutthroughoutthewholereservoir.
简介:本文利用正规则型理论讨论了一类二维离散动力系统的动力学性质,分析了其正平衡点的稳定性,并讨论了Neimark—Sacker分岔稳定性与方向。通过数值模拟验证了所得结果的正确性。
简介:Seismicsafetyassessmentofgravitydamshasbecomeamajorconcerninmanyregionsoftheworldwhiletheeffectsofverticalseismicaccelerationsontheresponseofstructuresremainpoorlyunderstood.Thispaperfirstinvestigatestheeffectofincludingverticalaccelerationsintheslidingresponseanalysisofgravitydamssubjectedtoarangeofhistoricalgroundmotionrecordsseparatedintwogroupsaccordingtotheirsource-to-sitedistance.Analysesshowedthattheincidenceofverticalaccelerationsontheslidingresponseofgravitydamsissignificantlyhigherfornear-sourcerecordsthanforfarsourcerecords.Thepseudo-static30%loadcombinationrule,commonlyusedinpracticetoaccountforthenon-simultaneousoccurrenceofthepeakhorizontalandverticalaccelerations,yieldedgoodapproximationsoftheminimumsafetyfactorsagainstslidingcomputedfromtime-historyanalyses.Amethodforempiricallyestimatingtheverticalresponsespectrabasedonhorizontalspectra,accountingforthedifferenceinfrequencycontentandamplitudesbetweenthetwocomponentsisinvestigated.Resultsfromanalysesusingspectrumcompatiblehorizontalandverticalsyntheticrecordsalsoapproximatedwelltheslidingresponseofagravitydamsubjectedtoseriesofsimultaneoushorizontalandverticalhistoricalearthquakerecords.
简介:Thestudyoffrictionalpropertiesofhumanskinisimportantformedicalresearch,skincareproductsandtextileexploi-tation.Inordertoinvestigatetheinfluenceofnormalloadandslidingspeedonthefrictionalpropertiesofskinanditspossiblemechanism,testswerecarriedoutonamulti-specimenfrictiontester.Whenthenormalloadincreasesfrom0.1Nto0.9N,normaldisplacementandthefrictioncoefficientofskinincrease.Thefrictioncoefficientisdependentontheload,indicatingthatbothadhesionanddeformationcontributetothefrictionbehaviour.Thedeformationfrictionwasinterpretedusingtheploughmodeloffriction.Whenslidingspeedincreasesfrom0.5mm·s?1to4mm·s?1,thefrictioncoefficientincreasesand'stick-slip'phenomenaincrease,indicatingthathystereticfrictioncontributestothefriction.Thehystereticfrictionwasin-terpretedusingschematicofenergytranslationduringtherigidsphericalprobeslidingonthesoftskinsurface,whichprovidesanexplanationfortheinfluenceoftheslidingspeedonthefrictionalcharacteristicsoftheskin.
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简介:用数值模拟的方法,研究了Host-Parasitoid模型.该模型是一类非线性离散系统,反映了在一定的时间和空间内,寄生虫和寄宿主之间的生存状态.通过调节各种影响下的分岔参数,可以观察到系统具有周期泡,倍周期分叉,间歇混沌和Hopf分岔等复杂非线性动力学现象,揭示了系统通向混沌的途径.利用不同周期遍历下的奇怪吸引子和具有分形边界的吸引盆对系统的非线性特性进行了深入的探讨.最后利用参数开闭环控制法对系统的混沌状态进行了有效的控制.数值仿真和理论分析表明,选择相应的控制参数可将该系统的混沌状态控制到不同的稳定周期运动.