剪叉式升降机的设计（多级）（含全套CAD图纸）
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上传时间：2018-04-09
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剪叉式
升降机
设计
多级
全套
cad
图纸
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大学毕业设计（外文翻译）ELECTROHYDRAULICPROPORTIONALCONTROLOFTWINCYLINDERHYDRAULICELEVATORSABSTRACTTHELARGESIZEOFTHECABOFANELECTROHYDRAULICELEVATORNECESSITATESTHEARRANGEMENTOFTWOCYLINDERSLOCATEDSYMMETRICALLYONBOTHSIDESOFTHECABTHISPAPERREPORTSTHEDESIGNOFANELECTROHYDRAULICSYSTEMWHICHCONSISTSOFTHREEFLOWCONTROLPROPORTIONALVALVESSPEEDREGULATIONOFTHECABANDSYNCHRONIZATIONCONTROLOFTHETWOCYLINDERSAREALSOPRESENTEDAPSEUDODERIVATIVEFEEDBACKPDFCONTROLLERISAPPLIEDTOOBTAINAVELOCITYPATTERNOFTHECABTHATPROVESTOBECLOSETOTHEGIVENONETHENONSYNCHRONOUSERROROFTHETWOCYLINDERSISKEPTWITHIN2MMWITHACONSTRAINEDSTEPPROPORTIONALDERIVATIVEPDCONTROLLERASOLENOIDACTUATEDNONRETURNVALVE,IEAHYDRAULICLOCK,ISALSODEVELOPEDTOPREVENTCABSINKINGANDALLOWEASYINVERSEFLUIDFLOWKEYWORDSHYDRAULICELEVATORVELOCITYTRACKINGSYNCHRONIZATIONHYDRAULICLOCK1INTRODUCTIONTHEMODERNHYDRAULICELEVATORISCURRENTLYANEXCELLENTANDLOWCOSTSOLUTIONTOTHEPROBLEMOFVERTICALTRANSPORTATIONINLOWORMIDRISEBUILDINGS,ANDINTHOSEAPPLICATIONSREQUIRINGVERYLARGECAPACITIES,SLOWSPEEDSANDSHORTTRAVELDISTANCESTHESEINCLUDESCENICELEVATORSINSUPERSTORESORHISTORICALBUILDINGS,STAGEELEVATORS,SHIPELEVATORSANDELEVATORSFORTHEDISABLED,ETCINMOSTCASES,HYDRAULICELEVATORSCANBEADAPTEDTOARCHITECTURALDESIGNREQUIREMENTSWITHOUTCOMPROMISINGENERGYSAVINGANDEFFICIENCYREQUIREMENTSINADDITION,THEUSEOFFIRERESISTANTFLUIDMAKESTHEHYDRAULICELEVATORASUITABLECHOICEWHENELEVATORSHAVETOOPERATENEARHAZARDSSUCHASFURNACESOROPENFIRESHYDRAULICDRIVESAREUSEDPREFERABLYINELEVATORSWHERELARGEPAYLOADSNEEDTOBECARRIED,SUCHASFORCARELEVATORSORMARINEELEVATORSINHEAVYLOADCASES,ANELEVATORCABUSUALLYHASDIRECTLYACTINGORSIDEACTINGHYDRAULICCYLINDERSTHEDIRECTACTINGARRANGEMENTINVOLVESADEEPPIT,SUBSTANTIALRISKOFCORROSIONOFTHE大学毕业设计（外文翻译）BURIEDCYLINDERSANDTHEDIFFICULTYOFREPLACINGFAILEDCYLINDERPARTSTHUS,INMANYSITUATIONSTHESIDEACTINGHYDRAULICCYLINDERISPREFERRED,DESPITETHEFACTTHATITPROBABLYINCREASESRAILWEARDUETOINSUFFICIENTCABSTIFFNESSINTHEEXTREMECONDITIONS,IEWHENLARGECABSIZESANDUNEVENPAYLOADSAREINVOLVED,THECABSFLEXIBILITYMAYEVENCAUSETHEGUIDESHOESTOSTICKTOTHERAILS,WHICHISVERYDANGEROUSTHEREFORE,INSUCHCASES,AFEASIBLESOLUTIONISTOARRANGETWODIRECTLYACTINGCYLINDERSSYMMETRICALLYONEACHSIDEOFTHECAB,ASSHOWNINFIG1ITSHOULDBENOTEDTHATSMOOTHRUNNINGCANNOTBEIGNOREDBECAUSEPEOPLEMAYBEPARTOFTHEPAYLOADSTHATACCOMPANYTHEFREIGHTTHEMAJORISSUEWHENDESIGNINGACONTROLSYSTEMISTOENSURETHESYNCHRONOUSMOTIONOFTHETWOCYLINDERSTHEERRORDUETOTHENONSYNCHRONOUSMOTIONOFTHETWOCYLINDERSCAUSED,BYANUNEVENLOADUNDEREQUALPRESSURECONTROL,WHICHISGENERALLYUSEDFORELEVATORCONTROLWITHMULTIPLEHYDRAULICCYLINDERS,ISSCHEMATICALLYSHOWNINFIG2ITISOBVIOUSFROMFIG2THATEQUALPRESSURECONTROLISNOTSUITABLEFORASYNCHRONIZEDHYDRAULICELEVATORWHENTHEPAYLOADISLOCATEDONTHERIGHTSIDEOFTHECAB,THELEFTCYLINDER,WITHALIGHTERLOAD,WILLMOVEUPWARDFASTERTHANTHERIGHTONETHESPEEDDISPARITYBETWEENTHETWOCYLINDERSWILLNOTCEASEUNTILTHEREACTIONFORCESACTUATEDBYTHERAILSONBOTHTHELOWERLEFTANDUPPERRIGHTGUIDESHOESATTACHEDONTHECABAREBALANCEDBYTHEHYDRAULICFORCEDIFFERENCETHENONSYNCHRONISATIONOFTHETWOCYLINDERSCANONLYBEREDUCEDBYFLOWCONTROL,IEBYENSURINGTHATTHEFLUIDFLOWSINTOTHETWOCYLINDERSPERUNITTIMEARETHESAME大学毕业设计（外文翻译）THISPAPERPRESENTSANELECTROHYDRAULICSYSTEMFORTHECONTROLOFANELEVATORWITHTWINCYLINDERSTHATARELOCATEDONEACHSIDEOFTHEELEVATORCABTHEDESIGNEDSYSTEMCONSISTSOFTHREEFLOWCONTROLPROPORTIONALVALVESAPDFCONTROLLERISAPPLIEDTOVELOCITYCONTROLWHEREASACONSTRAINEDSTEPPDCONTROLLERGUARANTEESTHEMINIMUMNONSYNCHRONOUSERRORBETWEENTHEMOTIONOFTWOCYLINDERSTHEDESIGNOFANEWLYDEVELOPEDSOLENOIDACTUATEDNONRETURNVALVEIEAHYDRAULICLOCKISALSOPRESENTEDINTHISPAPERINTHISPROJECT,EXPERIMENTSARECONDUCTEDWITHANORMALSIZEPASSENGERCABINSTEADOFBUILDINGANEWLARGESIZECABDUETOCOSTLIMITATIONSINORDERTOACHIEVETHEFLEXIBLECONDITIONOFALARGERCAB,THEDISTANCEBETWEENTHERAILSANDTHEIRCORRESPONDINGGUIDESHOESINTHESIDEDIRECTIONISEXTENDEDSOTHATTHECABHASNOCONSTRAINTSINTHISDIRECTIONMEANWHILE,INTHEFORWARDANDBACKWARDDIRECTION,THECABISCONSTRAINEDBYTHERAILSJUSTLIKEAGENERALPASSENGERELEVATORTHESYNCHRONOUSMOTIONCONTROLOFTHETWOCYLINDERSINSUCHANASSEMBLYISANALOGOUSTOANDEVENMOREDIFFICULTTHANTHATOFALARGERCABWITHNORMALCONSTRAINTS2ELECTROHYDRAULICCONTROLSYSTEMDESIGNTHEREARETWODIFFERENTFLUIDPOWERSYSTEMSGENERALLYUSEDINHYDRAULICELEVATORSTHEFLOWRESTRICTIONSPEEDREGULATIONSYSTEMANDVARIABLEDELIVERYSPEEDREGULATIONSYSTEMINTHEFORMERSYSTEM,THEPUMPRUNSATACONSTANTSPEEDANDTHEVALVEREGULATESTHESPEEDOFTHECYLINDERINBOTHTHEUPWARDANDDOWNWARDDIRECTIONSIN大学毕业设计（外文翻译）THELATTERCASE,THECABISOPERATEDBYVARYINGTHESPEEDOFTHEPUMP,WHICHISDRIVENBYASPEEDCONTROLLEDINDUCTIONMOTORTHEHYDRAULICSYSTEMEMPLOYEDINTHISTWINCYLINDERELEVATORWORKSACCORDINGTOTHEFLOWRESTRICTEDSPEEDREGULATIONPRINCIPLE,INWHICHTHEFLUIDFLOWINTOANDOUTOFTHETWOCYLINDERSISCONTROLLEDBYAPPROPRIATEVALVESETTINGS,WITHTHEOUTPUTOFTHEPUMPKEPTATAFIXEDLEVELINTHISSYSTEM,THEREARETHREEFLOWCONTROLPROPORTIONALVALVES57ASSHOWNINFIG3FLOWCONTROLPROPORTIONALVALVESACTASTHROTTLEVALVESTHATRESTRICTTHEFLUIDFLOWTOASINGLEDIRECTIONTHEYCANGIVEASMOOTHSTEPLESSVARIATIONOFFLOWCONTROLFROMNEARZEROUPTOTHEVALVESMAXIMUMCAPACITYTHEFLOWRATETHROUGHVALVE5REMAINSALMOSTINVARIABLEBECAUSEACOMBINATIONHYDROSTATMAINTAINSACONSTANTLEVELOFPRESSUREDIFFERENCEACROSSTHEPROPORTIONALVALVE,IRRESPECTIVEOFSYSTEMORLOADPRESSURECHANGESINTHECASEOFTHROTTLEVALVES,6AND7INFIG3,THEIRFLUIDFLOWSWILLCHANGEWITHSYSTEMORLOADPRESSURECHANGESVALVE5,HERECALLEDVELOCITYVALVE,CONTROLSTHEVELOCITYOFTHEELEVATORTHEUPWARDMOTIONOFTHECABISDRIVENBYFIXEDDISPLACEMENTPISTONPUMP1WHENMOTOR2STARTSTOWORK,大学毕业设计（外文翻译）THESOLENOIDACTUATEDTWINPOSITIONRELIEFVALVE4UNLOADSTHEOUTPUTFROMPUMP1TOTANK20ANDTHEOPENINGOFVELOCITYVALVE5ISKEPTATITSMAXIMUMVALUETHESOLENOIDOFVALVE4ISAUTOMATICALLYENERGISED,SHIFTINGTHEVALVETOITSCLOSEDPOSITIONANDTHUSSETTINGARELIEFPRESSUREFORTHESYSTEMATTHISSTAGE,THEREGULATIONOFTHECABVELOCITYISACHIEVEDBYADJUSTINGTHEELECTRICCURRENTTHROUGHTHECOILOFVALVE5ATTHECLOSINGOFVALVE5,ALLTHEFLUIDFLOWSINTOCYLINDERS12AND13ANDTHUSTHECABVELOCITYREACHESITSMAXIMUMVALUETHEDOWNWARDMOTIONISCAUSEDBYTHEDEADLOADOFTHECABANDITSPAYLOADSWHENTHECONTROLPANELRECEIVESADOWNWARDCALL,SOLENOIDACTUATEDNONRETURNVALVES10AND11OPENANDTHECABVELOCITYISCONTROLLEDBYVALVE5THELARGERTHEOPENINGOFVALVE5,THEHIGHERTHECABVELOCITYVELOCITYVALVE5DIRECTSPRESSURISEDFLUIDFROMTHECYLINDERSTOTANK20TOLOWERTHECABCHECKVALVE3PREVENTSPRESSURISEDFLUIDFROMDRIVINGTHEPUMPINITSREVERSEWORKINGDIRECTIONSYNCHRONOUSMOTIONOFCYLINDERS12AND13DEPENDSONTHECOMBINEDADJUSTMENTOFTHEFLOWCONTROLVALVES6AND7THESTEADYSTATEFLOWTHROUGHATHROTTLEVALVECANBEREPRESENTEDASWHEREQDENOTESTHEFLOW,XVTHESPOOLDISPLACEMENT,PTHEPRESSUREDROPACROSSTHEVALVEANDK0ISACONSTANTIFTHEPRESSUREDROPPREMAINSCONSTANT,QISINDIRECTPROPORTIONTOXV,WHICHISINDIRECTPROPORTIONTOTHEELECTRICCURRENTTHROUGHTHESOLENOIDCOILTHEFLOWVARIATIONSTHATARECAUSEDBYTHEPRESSUREDROPVARIATIONSCANTHUSBECOMPENSATEDFORBYCHANGINGXVASMENTIONEDABOVE,FLUIDFLOWSTHROUGHTHEFLOWCONTROLPROPORTIONALVALVESINONLYONEDIRECTIONVALVEGROUPS8AND9,EACHOFWHICHCONSISTSOFFOURCHECKVALVES,AREUSEDTOENSURETHATVALVES6AND7WORKINTHEIRNORMALDIRECTIONSSOLENOIDACTUATEDNONRETURNVALVES10AND11ARESPECIALLYDESIGNEDTOPREVENTTHECABFROMSINKING,WHICHISNORMALLYCAUSEDBYTHELEAKAGEOFTHEHYDRAULICCOMPONENTSWHENTHECABSTOPSATALANDINGTHEWORKINGPRINCIPLEOFTHESOLENOIDACTUATEDNONRETURNVALVEWILLBEFURTHEREXPANDEDLATERINTHISPAPERTHEYLOCKTHE大学毕业设计（外文翻译）CABWHENTHEPUMPSTOPSANDTHUSCANBECALLEDHYDRAULICLOCKSHEREONLYWHENTHEIRSOLENOIDSAREENERGIZEDWILLTHECABMOVEDOWNWARDINCASEOFPOWERBREAKSOROTHERHYDRAULICELEMENTFAILURES,EMERGENCYVALVE14LOWERSTHECABATALOWERSPEED3ELECTROHYDRAULICPROPORTIONALCONTROLASUITABLEVELOCITYCURVE,PRESETACCORDINGTODESIGNSPECIFICATIONSSUCHASMAXIMUMACCELERATION,MAXIMUMRATEOFACCELERATIONCHANGEANDMAXIMUMRUNNINGVELOCITY,ETC,ISUSUALLYUSEDTODESCRIBETHERUNNINGPATTERNOFANELEVATORIFTHECABVELOCITYFOLLOWSTHEGIVENCURVEWELL,GOODRIDINGCOMFORTISASSUREDOPENLOOPCONTROLCANNOTACHIEVESUFFICIENTTRACKINGACCURACYBECAUSEOFVARIATIONSINPAYLOADS,FLUIDVOLUMEINCYLINDERSANDFLUIDVISCOSITYTHEREFORE,SPEEDFEEDBACKISNEEDEDTOATTENUATETHEINFLUENCEOFTHEVARIOUSDISTURBANCESONTHEPERFORMANCEOFANELEVATORFURTHERMORE,WITHOUTCLOSEDLOOPCONTROL,THENONSYNCHRONOUSMOTIONOFTHETWOCYLINDERSISINEVITABLEDUETOTHEDIFFERENCESINPAYLOAD,FRICTIONANDHYDRAULICFLOWRESISTANCEBETWEENTHETWOCYLINDERSCONSEQUENTLY,TWOCLOSEDLOOPSAREREQUIREDTOATTAINSPEEDREGULATIONANDSYNCHRONIZATIONCONTROLATTHESAMETIMETHECONTROLBLOCKDIAGRAMOFTHEWHOLESYSTEMISSHOWNINFIG4,WHICHREPRESENTSTHEELEVATORMOTIONINUPWARDDIRECTIONASIMILARBLOCKDIAGRAMCANEASILYBEDEDUCEDFORDOWNWARDMOTIONTHECABVELOCITYISMEASUREDBYANENCODERTHETRANSLATIONALMOVEMENTOFTHECABISTRANSFERREDTOROTATIONOFTHEROTOROFANENCODERBYAPULLEYATWOELEMENTSYNCHROSYSTEMISUSEDTOMEASURETHERELATIVEANGLESBETWEENTHEROTORSOFCONTROLTRANSMITTERCXANDCONTROLTRANSFORMERCTTHUS,THERELATIVEANGLE大学毕业设计（外文翻译）MEASUREDBYTHESYNCHROSYSTEMISPROPORTIONALTOTHEHEIGHTERRORBETWEENTHETWOCYLINDERSASDISCUSSEDABOVE,THECABVELOCITYISONLYDETERMINEDBYVELOCITYVALVE5INFIG3,PROVIDEDTHESYNCHRONIZATIONVALVES6AND7WORKINSTRICTPROPORTIONTOVALVE5INTURN,UNDERTHESAMECONDITION,THEADJUSTMENTOFVALVES6AND7WILLNOTINFLUENCETHECABSVELOCITYHENCE,SPEEDREGULATIONANDSYNCHRONIZATIONCONTROLCANBEREALIZEDSEPARATELY,IEVELOCITYCONTROLLER1ANDSYNCHRONIZATIONCONTROLLER2CANWORKINDEPENDENTLYAPSEUDODERIVATIVEFEEDBACKPDFCONTROLLER,IECONTROLLER1ASSHOWNINFIG4ISAPPLIEDTOSUPPRESSTHEADVERSEEFFECTSOFINTERNALPARAMETERCHANGESSUCHASFLUIDVOLUMEINCYLINDERSANDEXTERNALDISTURBANCESSUCHASPAYLOADANDFLUIDTEMPERATUREVARIATIONSASSHOWNINFIG5,THEPDFCONTROLLERISEASYTOREALIZEANDINSENSITIVETOSYSTEMPARAMETERCHANGESANDEXTERNALDISTURBANCESWHENM1TISSMALLENOUGH,THESATURATEDNONLINEARITYCANBESIMPLIFIEDASWORKINGINITSLINEARSEGMENT,THENTHEPDFCONTROLLERPARAMETERSCANEASILYBEOBTAINEDSUPPOSETHESYSTEMCANBEDESCRIBEDBYTHENTHETHREECONTROLLERPARAMETERSARE大学毕业设计（外文翻译）WHEREIS75167/TS,TSTHESETTLINGTIMEANDKHTHECONSTANTFORADJUSTINGTHEOUTPUTAMPLITUDEOFTHECONTROLLERINSITUTUNINGOFCONTROLLERPARAMETERSISREQUIREDTOENSURETHEOPTIMALPERFORMANCEFIGS6AND7SHOWTHETRACKINGPERFORMANCEOFTHECABSVELOCITYFOLLOWINGTHEGIVENVELOCITYCURVEWITHAFULLPAYLOADANDWITHNOPAYLOAD,RESPECTIVELYTHEDIFFERENCEBETWEENTHEDESIREDVELOCITYPATTERNANDTHEACTUALVELOCITYPATTERNISMAINLYDUETOTHENONLINEARCHARACTERISTICSOFTHEELECTROHYDRAULICPROPORTIONALVALVE5HOWEVER,THEWHOLEVELOCITYPATTERNISVERYCLOSETOTHEDESIGNEDPATTERN,ANDTHUSSATISFACTORYRIDINGCOMFORTCANSTILLBEGUARANTEEDACONSTRAINEDSTEPPROPORTIONALDERIVATIVEPDCONTROLLER,IECONTROLLER2INFIG2,ISUSEDTOOBTAINSYNCHRONOUSMOTIONOFTHETWOCYLINDERSTHEIDEABEHINDTHISPDCONTROLLERISSIMILARTOTHESTEERINGOFABOATWHENROWINGABOATTOKEEPITALONGASTRAIGHTLINE,THEROWEREXERTSFORCEONOARSEACHTIMEACCORDINGTOHOWFARANDHOW大学毕业设计（外文翻译）FASTTHEBOATISGETTINGAWAYFROMTHELINEBECAUSEOFTHEROWERSUNAVOIDABLYDELAYEDRESPONSE,THEDISPARITYBETWEENTHEBOATSREALROUTEANDTHEGIVENROUTECANNOTBEKEPTSMALLANEFFECTIVEALTERNATIVEMETHODINVOLVESTHEROWERAPPLYINGAFRACTIONOFTHEESTIMATEDFORCESEACHTIMETHEOARSAREOPERATEDTHEBOATWILLTHUSAPPROACHTHEGIVENROUTESTEPBYSTEPTILLTHEROUTEERRORAPPROACHESANACCEPTABLEVALUECYLINDER12ISTAKENASTHEREFERENCECYLINDER,WHOSEMOVEMENTHASTOBEFOLLOWEDBYCYLINDER13,SAY,THEFIG8NONSYNCHRONOUSHEIGHTERRORCURVEUNDERVOIDPAYLOADFIG9NONSYNCHRONOUSHEIGHTERRORCURVEUNDERONETONUNEVENLYPLACEDPAYLOADFOLLOWINGCYLINDERTHEBACKLASHOFVALVES6AND7ISSIMILARTOTHEROWERSDELAYEDRESPONSETOTHEBOATSROUTEERRORINEACHADJUSTMENTPERIODOFCONTROLLER2,ITSREALOUTPUTISONLYAFRACTIONOFTHEREQUIREDVALUECALCULATEDBYTHEPDCONTROLLERTHATIS,THELARGEERRORISREDUCEDINEACHSAMPLINGPERIODATACONSTRAINEDSTEPUNTILANACCEPTABLEHEIGHTERRORISREACHEDTHISCONTROLSCHEMEHASPROVENTOBEEFFECTIVEINKEEPINGTHENONSYNCHRONOUSERRORWITHIN2MM,ASSHOWNINFIGS8AND9ITSHOULDBENOTEDTHATIFTHEINITIALNONSYNCHRONOUSERRORDURINGASAMPLINGPERIODIS大学毕业设计（外文翻译）RATHERLARGE,ITWOULDTAKESOMETIMETOREACHANACCEPTABLELEVELOFERRORIFTHENONSYNCHRONOUSERRORATTHEENDOFONEELEVATORRUNCANBERETAINEDATTHEBEGINNINGERROROFTHENEXTRUN,THISPROCESSCANBEAVOIDEDANDTHENONSYNCHRONOUSERRORWILLREMAINATSMALLVALUESTHROUGHOUTALLTHERUNSTOATTAINTHISGOAL,ASINKPROOFDEVICEISNEEDEDSINCETHEDIFFERENTLEAKAGERATESOFTHETWOCYLINDERSWILLDIRECTLYINCREASETHEINITIALERROROFANELEVATOR4CONCLUSIONANELECTROHYDRAULICCONTROLSYSTEMWITHTHREEFLOWCONTROLPROPORTIONALVALVESHASBEENPROPOSEDFORTHECONTROLOFELEVATORVELOCITYANDNONSYNCHRONOUSERRORBETWEENTHECYLINDERSOFATWINCYLINDERHYDRAULICELEVATORAPSEUDODERIVATIVEFEEDBACKCONTROLSCHEMEHASSHOWNTOBEANAPPROPRIATETECHNIQUETOACHIEVEADESIREDVELOCITYPATTERNFURTHERMORE,THISSYSTEMGUARANTEESLOWNONSYNCHRONOUSERRORBYAPPLYINGACONSTRAINEDSTEPPDCONTROLLERTHETESTRESULTSSHOWTHATTHENONSYNCHRONOUSERRORCANBEKEPTWITHIN2MMACERTAINDISCREPANCYBETWEENTHEDESIREDPATTERNANDTHEACTUALVELOCITYPATTERNISDUEMAINLYTOTHEHYSTERESISOFTHEELECTROHYDRAULICPROPORTIONALVALVESANEWSOLENOIDACTUATEDNONRETURNVALVEHASBEENDESIGNED,FABRICATEDANDTESTED,ANDPROVESTOBEAGOODHYDRAULICDEVICEFORPREVENTINGCABSINKING大学毕业设计（外文翻译）电液比例控制的双缸液压升降机摘要一个电液控制的液压升降机的大型机车需要在这个机车的两边安装两个对称的油缸。摘要报道了一种电液系统的设计主要包括三个流体控制比例阀。机车的速度调节和两油缸的同步控制也是呈递的。一个假微分反馈PDF控制器以获得一个机车的速度模式来证实和给定的这个接近。两油缸的非同步性的误差范围在2之内由于有比例控制器来拘泥每一步。一个电磁铁操纵的单向阀,即液压锁,被发明以防止机车下沉并允许反方向流体容易流动。关键词液压升降机速度跟踪同步化液压锁1、引言现代液压升降机目前有一个很优秀的和低成本的方法来解决垂直运输在低或中高层建筑物的这一问题,在这些应用需要非常大的容量,缓慢的速度和短的行进距离。这些包括风景名优美的在超市连锁店或历史建筑电梯、舞台升降机、船电梯和为残疾人用的电梯等。在大多数情况下,液压升降机能适应建筑设计要求的前提下实现节能增效要求。另外,耐高温流体的应用使液压电梯有一个适当的选择当电梯不得不操纵在附近有的危险场合时如熔炉或明火。液压传动最好应用于需要进行大负荷运输的电液升降机,比如车辆升降机或船舶升降机。在重负荷情况下,升降机的驾驶室通常有直接运行和辅助液压缸。这直接的布置涉及一个大的凹陷,埋藏油缸腐蚀的大量危险和更换缸体出现故障的零件困难。因此,在很多情形下辅助液压缸是首选,尽管事实是它可能增加轨道的磨损由于机车刚度不足。在极端的条件下,即当投入大型机车尺寸和不均匀载荷时,机车的弹性甚至导致滑块粘住两桥底板的两个边,这是很危险的。因此,在这种情况下,一种可行的解决方案是直接安排两个对称的油缸在机车的每一边如图1所示。应该指出的是,运转平稳不容忽视,因为人们可能是部分有效载荷伴随着货运。在设计控制系统时的主要问题是确保两油缸的同步运动。这个错误由于两油缸运动的非同步性造成，被相等压力控制下的不均匀荷载,这通常用于电梯的控制与多个液压缸,如图2所示。很明显,同等的压力控制不适合一个同步的液压电梯。当载荷位于机车的右侧,左边的油缸有轻负荷,会比右面的那个向上运动的速度快。两油缸速度的不一致将不会停止,直到反作用大学毕业设计（外文翻译）力驱动通过栏杆上两个比较低的左边和右上方的导块附着于机车来平衡液压力的差异。两油缸的非同步性只能用流量控制降低,即确保流体流入两油缸的单位时间是相同的。图1两个油缸安排一起运动图2相同压力控制不均匀放置静载荷导致非同步性本文提出了一种电液控制电梯有两缸,位于升降机驾驶室的两边。该系统包括三个流体控制比例阀。一个PDF控制器应用于速率控制然而一个约束一步的PD控制器可保证两油缸运动不同步的最小误差。一种新开发的设计电磁单向阀即液压锁也进行了介绍。在这个项目中,实验被引导用标准性机车代替大型建筑机车,由于费用的局限性。为了实现大型机车的灵活条件,轨道之间的距离与相应的导块侧向延伸,使机车在这个方向没有约束。与此同时,在前方向和后方向,机车被轨道制约,就像一个通用的乘客电梯。同步运动控制的两油缸在这里装配,就好比是比大的驾驶室有正常的约束更困难。2、电液控制系统设计大学毕业设计（外文翻译）有两种比较难的液压传动系统通常应用于液压升降机中。节流调速系统和容积调速系统。在第一个系统中,泵运行以一个恒定的速度并且由阀门来控制和调节油缸上升和下降的速度。在后一种情况下,机车被变速泵操纵,这由速度控制的异步电机驱动。图3双缸液压升降机原理图液压系统应用两缸升降机的动作,根据节流调速,流体流入和流出两缸的多少是通过适当的阀门的设置来控制,与输出的泵保持在一个固定的水平。在这个系统中,有三种流体控制比例阀57,如图3所示。流量控制比例阀就像节流阀,限制流体朝单一方向流动。他们能给一个平滑无级变化的流量控制从近零到阀门的最大容量。通过阀门5的流量恒定不变,因为水压调节器的组合能保持恒定压差穿过流量阀,不管系统或负载压力的变化。节流阀门6和7的情况下,如图3所示。他们流量将会改变如果系统或负载压力发生变化。阀5,这里被称为调速阀可控制升降机的速度。机车的向上的运动是由定量柱塞泵1来控制。当电机2开始工作时,二位电磁换向阀解除阀4对输出泵1输出的卸荷，到油箱20和打开的速度保持在阀门5它的最大价值。阀4的电磁阀的自动供给能量,关闭阀门,并且安装一个减压系统。在这一阶段,机车的速度调节的校准的完成是通过调节通过阀5线圈的电流。在关闭的阀5时,所有的流体流动进入油缸12和13，并且机车的速度达到最大值。下行运动是由机车的静载和它的有效载荷所引起。当控制面板大学毕业设计（外文翻译）收到一个向下的动作的信号,电磁控制单向阀10和11开启，机车的速度控制是通过阀门5来实现。阀5开口越大，机车获得的速度就越快。阀门5引导高压流体从油缸到油箱20再到较低的机车。单向阀3阻止高压流体反向流回。同步运动的油缸12和13取决于流量控制阀6和7的组合调整。通过节流阀调节稳态流动可以用下式表示为上式的Q代表流量,XV活塞杆的位移、P通过阀门的压降和K0是C常数。如果压力降的P不变,流量和活塞杆的位移成正比,这也正比通过电磁阀线圈的电流。流量变化所引起的压降的变化也能因此得到补偿,通过改变活塞杆的位移。如上所述,流体流过的流量控制比例阀只有一个方向。阀组8和9,其中的每一个都由四个单向阀,用于确保阀门6和7工作在正常的方向。电磁单向阀10和11是专门用于防止机车下沉,这通常是引起的泄漏的液压元件当升降机停留在一平台时。电磁单向阀的工作原理,将会在本文后面进一步叙说。当泵停止工作的时候他们会锁住升降机,因此这里被称为液压锁。只有当他们的线圈通电升降机才会向下移动。如果发生电源的中断或其它液压元件的损坏,紧急阀14以较低的速度降下升降机。3、电液比例控制预设一个合适的速度曲线,根据设计规范,如最大加速度、加速度改变的最大比例和最大运行速度等,通常用来形容的运行模式的升降机。如果机车的速度跟随给定曲线,好的乘车舒适性是有保证的。开环控制不能达到足够的跟踪精
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