简介:Inmechanics,bothclassicalandquantum,onestudiestheprofoundinteractionbetweentwotypesofenergy,namely,thekineticenergyandthepotentialenergy.Theformercanbeorganizedasthekinematicmetricontheconfigurationspacewhilethelattercanberepresentedbyasuitablepotentialfunction,suchastheNewtonianpotentialincelestialmechanicsandtheCoulombpotentialinquantummechanicsofatomicandmolecularphysics.Inthispaper,theauthorstudiesthekinematicgeometryofn-bodysystems.Themainresultsaxe(i)theintroductionofacanonicalcoordinatesystemwhichrevealsthetotalamountofkinematicsymmetrybyanSO(З)×O(n-1)actioninsuchacanoniealcoordinaterepresentation;(ii)anindepthanalysisoftheabovekinematicsystembothinthesettingofclassicalinvarianttheoryandbythetechniqueofequivarjantRiemanniangeometry;(iii)aremarkablysimpleformulaforthepotentialfunctioninsuchacanonicalcoordinatesystemwhichrevealsthewell-fittingbetweenthekinematicsymmetryandthepotentialenergy.
简介:Thispaperpresentsakinematicanalysisofthelocomotionofagecko,andexperimentalverificationofthekinematicmodel.Kinematicanalysisisimportantforparameterdesign,dynamicanalysis,andoptimizationinbiomimeticrobotresearch.Theproposedkinematicanalysiscansimulate,withoutiteration,thelocomotionofgeckosatisfyingtheconstraintconditionsthatmaintainthepositionofthecontactedfeetonthesurface.Sothemethodhasanadvantageforanalyzingtheclimbingmotionofthequadrupedmechanisminarealtimeapplication.Thekinematicmodelofageckoconsistsoffourlegsbasedon7-degreesoffreedomspherical-revolute-sphericaljointsandtworevolutejointsinthewaist.Themotionofthekinematicmodelissimulatedbasedonmeasurementdataofeachjoint.Themotionofthekinematicmodelsimulatestheinvestigatedrealgecko’smotionbyusingtheexperimentalresults.Theanalysissolvestheforwardkinematicsbyconsideringthemodelasacombinationofclosedandopenserialmechanismsundertheconditionthatmaintainsthecontactpositionsoftheattachedfeetontheground.Themotionsofeachjointarevalidatedbycomparingwiththeexperimentalresults.Inadditiontothemeasuredgait,threeothergaitsaresimulatedbasedonthekinematicmodel.Themaximumstridesofeachgaitarecalculatedbyworkspaceanalysis.Theresultcanbeusedinbiomimeticrobotdesignandmotionplanning.
简介:WepartitiontheobservedwindfieldintorotationalanddivergentwindfieldstoanalyzethestreamfieldofTy-phoonPolly(No.9216),whichlandedon31August1992andcausedsevereweatherandlargedamageintheeasternChina.Theresultsindicatethatthepreservationoftyphoonintensityafterlandingandtheheavyrainfalltookplaceonthenorthernperipheryoftyphoonareduetothestrongdivergentwindsontheregionsoflowleveljet(LLJ)andhighleveljet(HLJ)aroundthetyphoon.ThedirectionofdivergentwindsintheLLJisperpendiculartotheobservedwind.But,thedirectionofdivergentwindsaroundtheHLJaxisisparalleltotheobservedwinds.Thestreamfunctionandtherotationalwindcorrespondingtothehorizontalvorticitydisplaytheverticalcirculationassociatedwiththeheavyrain,whichisstrongerthantheverticalcirculationaroundthetyphooncenter.Thethree-dimensionaltrajectoriesexhibitthewarmandmoistairparcelsofLLJtravelingnorthwardintotheheavyrainfallregionandascending,thenturningeastwardintheHLJ.
简介:Aseriesofadvantagesofsingledifference(SD)andundifferenced(ZD)modelsaregivenascomparedwitythedoubledifferenceezistinSDandZDmodels.Thereparameterizationmethodisprovidedtoresolvethisrankdefectproblembyestimatingsomecombinationsoftheunknownsratherthantheunknownsthemselves.TherepatameterizationofSDandZDfunctionalmodelsisdiscussedindetailwiththeirstochasticmodels.Thetheoreticalcomformationoftheequivalenceofundifferencedanddifferencedmodelsisdescribedinastraightforwardway.TherelationshipbetweenSDandZDresidualsisgivenandverifiedforsomespecialpurposes,e.g.researchonthestochasticalpropertiesofGPSobservations.
简介:Asoneofthemostimportantdailymotoractivities,humanlocomotionhasbeeninvestigatedintensivelyinrecentdecades.Thelocomotorfunctionsandmechanicsofhumanlowerlimbshavebecomerelativelywellunderstood.However,sofarourunderstandingofthemotionsandfunctionalcontributionsofthehumanspineduringlocomotionisstillverypoorandsimul-taneousin-vivolimbandspinalcolumnmotiondataarescarce.Theobjectiveofthisstudyistoinvestigatethedelicatein-vivokinematiccouplingbetweendifferentfunctionalregionsofthehumanspinalcolumnduringlocomotionasasteppingstonetoexplorethelocomotorfunctionofthehumanspinecomplex.Anovelinfraredreflectivemarkerclustersystemwasconstructedusingstereophotogrammetrytechniquestorecordthe3Din-vivogeometricshapeofthespinalcolumnandthesegmentalpositionandorientationofeachfunctionalspinalregionsimultaneously.Gaitmeasurementsofnormalwalkingwereconducted.Thepreliminaryresultsshowthatthespinalcolumnshapechangesperiodicallyinthefrontalplaneduringlocomotion.Thesegmentalmotionsofdifferentspinalfunctionalregionsappeartobestronglycoupled,indicatingsomesynergisticstrategymaybeemployedbythehumanspinalcolumntofacilitatelocomotion.Incontrasttotraditionalmedicalimaging-basedmethods,theproposedtechniquecanbeusedtoinvestigatethedynamiccharacteristicsofthespinalcolumn,henceprovidingmoreinsightintothefunctionalbiomechanicsofthehumanspine.
简介:这研究调查热带大西洋的吝啬的运动学的特征在东方在1月鈥揗arch(JFM)的骚乱,4月鈥揓une(AMJ),7月鈥揝eptember(JAS)和从1968鈥?的10月鈥揇ecember(OND)998。为每个季节,在3鈥?的这些骚乱的优先的轨道0天的乐队时期被计算并且spatialized,以及他们的联系波长,速度和主要时期,哪个在3鈥之间的谎言?天并且在6鈥之间?取决于轨道和季节的天。二条主要轨道在大西洋上被加亮。在OND和JFM期间,这二条轨道很好被分开并且在15掳S和12.5掳N附近在每个半球定位了。从AMJ,到JAS,这些轨道向北方移居;在JAS,他们沿着17.5掳N在北热带大西洋上合并进一个。联系波长地展出一个南方的坡度,与大波长(比4000km大)在赤道附近在5掳N和5掳S之间,并且在这个纬度乐队外面的更小的波长(在2500鈥?之间500km)。阶段速度也从12鈥被发现价值到展览poleward减少吗?ms?1。在北方大西洋轨道上,6鈥?天骚乱被发现从10月从1月发生到5月并且近似到12月。从6月到9月,3个鈥?天波浪统治摘要的活动。在南方大西洋轨道上,在5月和8月之间,摘要的可变性被3鈥?天骚乱,但是从1月主要向4月并且从到12月,两3鈥?天挥动的9月解释,6鈥?白天飘动能发生。关键词摘要的活动-非洲人在东方飘动-热带大西洋
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简介:Time-meanglobalgeneralcirculationdataareemployedtoanalyzethetemporalandspatialvariationsofthemeridionalgradientofzonalmeanpotentialvorticity,thecriticalwavenumbern_sforhorizontalwave-propagation,andthecriticalwavenumberK_cforverticalwave-propagation.Therebythekinematiccharac-teristicsinthepropagationofatmosphericstationarywavesandtheirannualvariationsarestudied.Resultsshowthatinthetropospheren_sandK_cusuallydecreasewiththeincreaseofeitherlatitudeoraltitude.Synopticandnear-resonantRossbywavescouldbetrappedduringtheirupwardandmeridionalpropagations.Thesecharacteristicspossessprominentannualvariations,especiallyintheNorthernHemisphere.Itisfoundthatthespatialandtemporalvariationsofthesekinematiccharacteristicsareingoodagreementwiththoseoftheatmosphericwavepatterns.
简介:Thestochasticmodelsoftheusualjointsarefirstestablishedthroughintro-ducingtheconceptsof“clearancecharacteristicelement”and“clearancespace”.Afterde-rivingtheprobabilitydensityfunctionofthejointclearanceandmakingtheprobabilisticanalysisoftheresultedkinematicerrors,thesamplingformulasoftheindependentvaria-blesofthejointclearancesarefurtherdeduced.ThroughMonteCarlosimulation,thesta-tisticalcharacteristicsandfrequencyhistogramsofthekinematicerrorsarethenanalysedoncomputer.
简介:ThispaperpresentsadataprocessingstrategyforGPSkinematicpositioningbyusingaGPSactivenetworktomodeltheGPSerrorsindoubledifferenceobservable.Firstly,thedoubledifferenceresidualsareestimatedbetweenthereferencestationsintheactivenetwork.Thentheerrorsatauserstationarepredictedasthenetworkcorrectionstousermeasurements,basedonthelocationoftheuser.Finallyconventionalkinematicpositioningalgorithmscanbeappliedtodeterminethepositionoftheuserstation.Asanexample,continuous24-hourGPSdatainMarch2001hasbeenprocessedbythismethod.Itclearlydemonstratesthat,afterapplyingthesecorrectionstoauserwithinthenetwork,boththesuccessrateforambiguityresolutionandthepositioningaccuracyhavebeensignificantlyimproved.
简介:Radiolarites在有ophiolites的paleogeography,深测术和他们的共存的重建的一个重要角色给一个机会决定collisional地区的构造历史。西南的Neyriz的radiolarite单位是Zagrosaccretionary棱柱的部分并且在Tarbur形成的厚bedded碳酸盐沉积下面放。存在在这个单位以内的各种各样的结构的元素给一唯一为变丑历史上的调查幸运、Zagros碰撞地区的kinematics学习。众多的证据表演那这联合起来在进行中的进化期间经历了不同变丑条件,包括可锻、易碎可锻、易碎的变丑条件。为褶层的轴的飞机的E-W的主要罢工,东方趋势并且褶层轴,boudins颈轴和褶层干扰模式的类型III跳入在transpressional期间是形成的指示物和褶层的进化变丑。学习区域的结构的进化被Neo-Tethyan海洋的岩石圈的一个蘸NEsubduction地区在伊朗的microcontinents下面影响了。这些结构的元素建议高机械的anisotropy和与推进和这个单位的挤出同时合拢的二连续的代在subducted上导致了这个高度不均匀的合拢的单位的形成和进化海洋的外壳。
简介:Inthispaper,inordertoimprovetheaccuracyoftheSyntheticApertureRadar(SAR)satelliteattitudeusingGlobalPositioningSystem(GPS)wide-bandcarrierphase,theSARsatelliteattitudekinematicvectorandKalmanfilterareintroduced.IntroducingthestatevariablefunctionofGPSattitudedeterminationalgorithminSARsatellitebymeansofkinematicvectoranddescribingtheobservationfunctionbytheGPSwide-bandcarrierphase,thepaperusestheKalmanfilteralgorithmtoobtiantheattitudevariablesofSARsatellite.ComparedthesimulationresultsofKalmanfilteralgorithmwiththeleastsquarealgorithmandexplicitsolution,itisindicatedthattheKalmanfilteralgorithmisthebest.
简介:Thepaperbuildsamulti-rigid-bodymodelofhumanwitha4-rigid-bodyfootinthe3DCADsoftwareSolidworks,basedonhumananatomy.Bycontrollingtherotationoftheankleandmajorjointsofhumanbodywhilewalking,theKinematicsimulationwasperformedinthedynamicssimulationsoftwareADAMS.Thepaperanalyzesthesimulateresultsandpointsoutdeficienciesinthecurrentworkandthedirectionofresearcheffortsinfuture.
简介:Inthepresentpaper,thegroundreactionforce(GRF)actingonfootinslowsquatwasdeterminedthroughaforcemeasuringsystem,andatthesametime,thekinematicdataofhumansquatwereobtainedbyanalyzingthephotographedimagesequences.Accordingtotheheightandbodyweight,sixhealthyvolunteerswereselected,threemeninonegroupandtheotherthreewomeninanothergroup,andthefundamentalparametersofsubjectswererecorded,includingbodyweight,heightandage,etc.Basedontheanatomycharacteristics,somemarkerswereplacedontherightsideofjoints.Whilethesubjectsquattedatslowspeedontheforceplatform,thegroundreactionforcesontheforefootandheelforeachfootwereobtainedthroughcalibratedforceplatform.Theanalysisresultsshowthatthereactionforceonheelisgreaterthanthatonforefoot,anddoublefeethavenearlyconstantforce.Moreover,fromprocessingandanalyzingthesynchronouslyphotographedimagesequencesinsquat,thekinematicdataofhumansquatwereacquired,includingmainlythecurvesofangle,angularvelocityandangularaccelerationvariedwithtimeforknee,hipandanklejointsinasagittalplane.Theobtainedresultscanofferinstructivereferenceforphotographingandanalyzingthemovementsofhumanbodies,diagnosingsomediseases,andestablishinginthefutureappropriatemathematicalmodelsforthehumanmotion.
简介:Thispaperproposedanovelhumanoidroboteye,whichisdrivenbysixPneumaticArtificialMuscles(PAMs)androtateswith3DegreeofFreedom(DOF).Thedesignofthemechanismandmotiontypeoftheroboteyeareinspiredbythatofhumaneyes.Themodelofhumanoidroboteyeisestablishedasaparallelmechanism,andtheinverse-kinematicproblemofthisflexibletendonsdrivingparallelsystemissolvedbytheanalyticalgeometrymethod.Asanextension,thesimulationresultforsaccadicmovementispresentedunderthreeconditions.Thedesignandkinematicanalysisoftheprototypecouldbeasignificantsteptowardsthegoalofbuildinganautonomoushumanoidroboteyewiththemovementandespeciallythevisualfunctionssimilartothatofhuman.
简介:ThedetailedkinematicstructureofaheavyraineventthatoccurredinthemiddlereachesoftheYangtzeRiverwasinvestigatedusingdual-Dopplerradarobservation.Avariationalanalysismethodwasdevelopedtoobtainthethree-dimensionalwindfields.Beforetheanalysis,adatapreprocessingprocedurewascarriedout,inwhichthetemporalvariationwiththescanningtimeintervalandtheeffectoftheearthcurvatureonthedatapositionweretakenintoaccount.Theanalysisshowsthatashearlineinthelowerandmiddlelevelsplayedanimportantroleintherainfallevent.Theprecipitationfellmainlyonthesouthendoftheshearlinewheresoutherlyflowprevailedandconvergenceandupdraftwereobvious.Withthemovementanddecayoftheshearline,theprecipitationmovedanddecayedcorrespondingly.