譯文

基于可編程序控制器(PLC)設計和實踐的電梯控制系統(tǒng)摘要 本文闡述了nine-storey電梯控制系統(tǒng)的發(fā)展?？刂葡到y(tǒng)采用PLC為控制器，并采用并聯(lián)調(diào)度規(guī)則基于“最小等待時間”來跑兩電梯并聯(lián)模式。本文介紹了基本結構、控制原理和實現(xiàn)方法的PLC控制系統(tǒng)進行了詳細的介紹。給出了梯形圖的關鍵方面的系統(tǒng)。該系統(tǒng)具有外圍電路簡單，運行結果說明，系統(tǒng)的可靠性和性能的提高電簡介隨著建筑技術的發(fā)展，樓房一座比一座高，電梯自然成了高樓大廈垂直運輸?shù)闹匾ぞ?，承載著來往大廈里居住、辦公、參觀的人們可以舒適而又快捷到達目的地的責任。電梯控制系統(tǒng)在每一部電梯的通順安全的運行中必不可少的，它決定電梯什么時候停層、開關門，以及處理緊急安全問題。傳統(tǒng)的電梯控制系統(tǒng)是繼電器控制系統(tǒng)，它存在著諸如電路復雜、故障率高和可靠性差的缺點，很大程度上影響了電梯運行質量。因此，通過企業(yè)的委托，我們用PLC改良了一座住宅樓繼電器控制電梯的電氣控制系統(tǒng)。結果說明，改良后的系統(tǒng)運行更可靠，維修更方便了。這篇論文詳細的介紹了電梯PLC控制系統(tǒng)的基本結構、控制原理和實現(xiàn)的方法。系統(tǒng)結構電梯控制系統(tǒng)的目的在于控制電梯的運動以便符合用戶的需求。它主要包括兩部分：電力驅動系統(tǒng)電力驅動系統(tǒng)包括電梯轎廂、牽引電機、門電機、制動器和開關電路。我們在這采用新型的LC系列AC接觸器代換舊接觸器，用PLC軟接觸器代換大量中間繼電器，保留牽引電機的電路。這樣一來，就有效的克服了原先控制柜響聲大、噪音大等缺點。信號控制系統(tǒng)電梯的控制信號幾乎都來自與PLC。輸入信號有：運行模式、運行的控制信號、轎外呼叫、安全/保護信號、門開/關信號以及平層信號等。像轎內(nèi)外呼叫的記錄、顯示、消除，轎廂位置的判斷，電梯的選層和上下行選擇等所有電梯系統(tǒng)的控制功能都是由PLC系統(tǒng)實現(xiàn)。電梯的PLC信號控制系統(tǒng)框圖如右圖所示。一般來說，電梯運行情況有如下：1〕、一部電梯運行電梯一般有三種工作狀態(tài)：正常模式、防火模式和維護模式。維護模式有最高優(yōu)先級，只有在維護模式撤銷時候，其他模式才開始實行；其次是防火模式，當火警開關打開時，電梯必須馬上返回底層或者基站，當火警開關復位時返回正常模式運行；在正常模式下控制系統(tǒng)的基本任務就是命令電梯上下行、停層或啟動、開門或者關門。不過有一定的約束：每一電梯有對應每層樓的一組九個按鈕布置在轎廂控制面板上，當被按下要電梯來到該層時按鈕就會變亮，當電梯來到該層時按鈕燈滅。每一層〔除了頂層和底層〕有兩個按鈕布置在層控制面板上，一個呼叫上行另外一個呼叫下行，按鈕被按下時變亮，電梯運行到該層時熄滅，之后向呼叫方向運行。分布在轎廂和層控制面板上的按鈕用來控制電梯的運動。電梯不能跳過乘客要離開的樓層，不可以停在無人呼叫的樓層，在運送轎廂內(nèi)需要當前方向的乘客時候電梯不能改變方向，也不相應外呼直到送完，如果電梯沒有被呼叫，就關門?？吭诋斍暗臉菍印！?〕、兩部電梯并聯(lián)運行這種情況下兩部電梯同時服務該大樓，每天分別在上午7點到9點和下午5點到7點運行。電梯每到一層都會檢測是否需要停下，當檢測到停層的需要時就會停靠該層。與此同時為了平衡停層的次數(shù)，兩部電梯的運行會遵循一定的調(diào)度原則。當有一電梯停在或正要停在某一樓層時候，另一電梯就不會?？磕菍?。電梯的正常運行通過電力驅動系統(tǒng)和邏輯控制系統(tǒng)來共同實現(xiàn)的。最小的等待時間算法在電梯系統(tǒng)的調(diào)度中，通常有兩種控制任務。其一是電梯上下行、起停、開關門的基本控制功能。其二是多部電梯并行的控制，組合電梯服務廳門和轎廂呼叫的主要要求是服務到建筑的每一層樓，減少乘客呼叫等待時間，減少乘客上下樓層的時間，相同時間內(nèi)能為更過的乘客服務。電梯的群控有許多調(diào)度算法。如電梯總是相應最近需求的最近鄰域算法，分析對于不相等樓層數(shù)量需要電梯系統(tǒng)的調(diào)度來調(diào)遣電梯的分區(qū)算法，一部電梯服務奇數(shù)樓層另一部服務偶數(shù)樓層的奇偶規(guī)則。最近鄰域算法使得電梯空載移動到下一個呼叫路程最小，通常有著非常小的平均輪

侯時間，可是各人輪侯時間變得很大。分區(qū)算法一般應用在像辦公大樓午餐時間這樣交通頻繁的情形下。相對于辦公大樓、商場，住宅樓和樓層的流量較小。其次人們認為電梯只是純粹的功能性物體，而且對于大多數(shù)人來說，乘坐電梯的經(jīng)驗就是等待。此外，當試圖滿足所有需求時存在大量的問題。鑒于上述原因，我們采用“最小輪侯時間”算法來實現(xiàn)兩部電梯的并行運行。Q2.0M0.0HHHQ0.0THQ2.1 M0.1HHH■Q2.7M0.7T_IHQ3.0M1.0HHH汙Q0.1M0.1Q2.7M0.7T_IHQ3.0M1.0HHH汙Q0.1M0.1HHFHH：Q0.7M0.7HHFHHQ1.0M0.1HHFQ1.6M0.72tnC■!!：■C-izLLSt-i-S-flc-orapkail-call口S-fln口工dm?hall-dL3.7M4.1Me.eI5.3TUTQ4.4 M6.4HFt~C)TQ44M70G.4AHFG.4MMG7HF圖6floor-stopping評估函數(shù)“最小輪侯時間”算法的目標就是在所有呼叫中預測每一電梯的響應時間，并選擇有最短響應時間電梯來服務。當有呼叫的時候，系統(tǒng)根據(jù)〔1〕〔2〕評估函數(shù)計算出每一電梯的函數(shù)值：J(*)=Min[J(l),J(2),...,J(n)] ⑴J(i)=Tr(i)+KTd(i)+KTo(i)i=1,2,...,n 〔2〕J(i)是電梯的評價指標；Tr(i〕指出電梯從當前位置直接移動到相應最近呼叫的地方的時間；To(i〕指出電梯停層時加速和減速的時間；TdG〕是乘客登上電梯或者走出電梯的時間；K表示廳門呼叫和轎內(nèi)呼叫的總和。最小輪侯時間的計算在公式〔2〕中K為定值，To和Td可以通過統(tǒng)計方法獲得。Tr=T*L,T是電梯通過一層樓的時間，L是呼叫樓層和當前樓層的相隔層數(shù)。為了計算L值，我們定義兩部電梯分別為A和B；YA，YB分別表示電梯當前樓層；H是廳門呼叫按鈕按下時相應的鍵值，即H等于呼叫層數(shù)。為PLC的的實現(xiàn)定義4個表:上行廳門呼叫記錄表，下行廳門呼叫記錄表，電梯A的轎內(nèi)呼叫記錄表，電梯B的轎內(nèi)呼叫記錄表。當呼叫按鈕被按下時，對應樓層數(shù)就會記錄在相應的表中。我們以電梯A為例。首先定義變量MA，MB和MW；MA和MB分別表示A或者B同方向上轎內(nèi)呼叫的最值。當電梯A上行時，置MA等于轎內(nèi)呼叫記錄表A中的最大值；當電梯A下行時，置MA等于叫內(nèi)呼叫記錄表A中最小值。MW為同方向A運行中，廳門呼叫的最值。當電梯A上行并且上行呼叫值三YA時，置MW=0；否則，置MW等于上行廳門記錄表A中的最小值。當電梯A下行并且下行廳門呼叫值WYA時，置MA=0；否則，置MW等于下行廳門呼叫記錄表A中最大值。這樣我們就可以根據(jù)YA，H，MA和MW來判斷L值。分如下三種情況：1)廳門呼叫方向和電梯A當前運行方向相反；L=|YA-MA|+|MA-H|〔3〕2)廳門呼叫和運行方向相同并且在電梯前方；L=|YA-H|〔4〕3)廳門呼叫和運行方向相同但在電梯后方；L=|YA-MA|+|MA-MW|+|H-MW|〔5〕第i層的最小輪侯時間可以由〔6〕計算出：Time(i)=TL(i)+KTd(i)+KTo(i)，i=1,2,...,n (6)當呼叫在運行的時候變化時，系統(tǒng)自動計算出每一部電梯的最小輪侯時間，然后分配當前呼叫給有較小值的電梯。當最?。惠喓顣r間相等時，電梯A對于當前呼叫有優(yōu)先權。當其中一部電梯故障或者不能運行時，系統(tǒng)自動退出調(diào)度算法，返回單部電梯運行模式。算法的實現(xiàn)相對于單電梯運行模式，并行電梯運行模式主要是在廳門呼叫處理方法上的不同。前者采用集選控制方法，后者采用調(diào)度原則結合集選控制的方法。這里系統(tǒng)用來控制一棟9層的大樓，我們選擇兩個西門子S7-200PLCs(CPU226)和它的擴展模塊分別控制單部電梯，同時使用PPI協(xié)議來實現(xiàn)兩個PLC的通信。PPI協(xié)議采用主從通信模式，所以我們定義電梯A為主，電梯B為從。兩個PLC通過通信協(xié)議來傳遞諸如當前位置、廳門或者轎內(nèi)呼叫和運行方向等信息。然后用“最小輪侯時間”算法來使系統(tǒng)實現(xiàn)兩部電梯的調(diào)度運行。圖是電梯A轎內(nèi)呼叫最值計算的梯形圖。圖中VB121?VB130是電梯A轎內(nèi)呼叫對應每層樓的寄存地址，Q3.1是電梯A的上行燈，轎內(nèi)呼叫的最值保存在VB120中。

圖4.1電梯最值算法梯形圖參考文獻[1][2][3][4][1][2][1][2][3][4][1][2][3][4]PhilippFriese,JorgRambau(2006).“Online-optimizationofmulti-elevatortransportsystemswithreoptimizationalgorithmsbasedonset-partitioningmodels”.DiscreteAppliedMathematics.．ZhengYanjun,ZhangHuiqiao,YeQingtai,ZhuChangming.(2001).“TheResearchonElevatorDynamicZoningAlgorithmandIt'sGeneticEvolution”.Computer．XiaodongZhu,QingshanZeng(2006).“AElevatorGroupControlAlgorithmforMinimumWaitingTimeBasedOn．DesignandPracticeofanElevatorControlSystemBasedonPLCXiaolingYang1,2,QunxiongZhu1,HongXuCollegeofInformationScience&Technology,BeijingUniversityofChemicalTechnology,Beijing100029,ChinaAutomationCollegeofBeijingUnionUniversity,Beijing,100101,China

yxl_lmy@sina,zhuqx@AbstractThispaperdescribesthedevelopmentof2nine-storeyelevatorscontrolsystemforaresidentialbuilding.ThecontrolsystemadoptsPLCascontroller,andusesaparallelconnectiondispatchingrulebasedon"minimumwaitingtime"torun2elevatorsinparallelmode.Thepapergivesthebasicstructure,controlprincipleandrealizationmethodofthePLCcontrolsystemindetail.Italsopresentstheladderdiagramofthekeyaspectsofthesystem.Thesystemhassimpleperipheralcircuitandtheoperationresultshowedthatitenhancedthereliabilityandperformanceoftheelevators.IntroductionWiththedevelopmentofarchitecturetechnology,thebuildingistallerandtallerandelevatorsbecomeimportantverticaltransportationvehiclesinhigh-risebuildings.Theyareresponsibletotransportpassengers,living,workingorvisitinginthebuilding,comfortableandefficientlytotheirdestinations.Sotheelevatorcontrolsystemisessentialinthesmoothandsafeoperationofeachelevator.Ittellstheelevatorinwhatordertostopatfloors,whentoopenorclosethedoorandifthereisasafety-criticalissue.Thetraditionalelectricalcontrolsystemofelevatorsisarelay-controlledsystem.Ithasthedisadvantagessuchascomplicatedcircuits,highfaultratioandpoordependability;andgreatlyaffectstheelevator'srunningquality.Therefore,entrustedbyanenterprise,wehaveimprovedelectricalcontrolsystemofarelay-controlledelevatorinaresidentialbuildingbyusingPLC.Theresultshowedthatthereformedsystemisreliableinoperationandeasyformaintenance.Thispaperintroducesthebasicstructure,controlprincipleandrealizationmethodoftheelevatorPLCcontrolsystemindetail.SystemstructureThepurposeoftheelevatorcontrolsystemistomanagemovementofanelevatorinresponsetouser'srequests.Itismainlycomposedof2parts:ElectricpowerdrivingsystemTheelectricpowerdrivingsystemincludes:theelevatorcar,thetractionmotor,doormotor,brakemechanismandrelevantswitchcircuits.HereweadoptedanewtypeofLCseriesACcontactorstoreplacetheoldones,andusedPLC'scontactstosubstitutetheplentyofintermediaterelays.Thecircuitsoftractionmotorarereserved.Thustheoriginalcontrolcabinet'sdisadvantages,suchasbigvolumeandhighnoiseareovercomeefficiently.SignalcontrolsystemTheelevator'scontrolsignalsaremostlyrealizedbyPLC.Theinputsignalsare:operationmodes,operationcontrolsignals,car-calls,hall-calls,safety/protectsignals,dooropen/closesignalandlevelingsignal,etc.AllcontrolfunctionsoftheelevatorsystemarerealizedbyPLCprogram,suchasregistration,displayandeliminationofhall-callsorcar-calls,positionjudgmentofelevatorcar,chooselayeranddirectionselectionoftheelevator,etc.ThePLCsignalcontrolsystemdiagramofelevatorisshowedinFigure1.Informally,theelevatorsbehaviorisdefinedasfollows.(1)RunningwithasingleelevatorGenerally,anelevatorhasthreeoperationstates:normalmode,fire-protectionmodeandmaintenancemode.Themaintenancemodehasthehighestpriority.Onlythemaintenancemodeiscanceledcantheotheroperationmodesbeimplemented.Thenextisfire-protectionmode,theelevatormustreturntothebottomfloororbasestationimmediatelywhenthefireswitchacts.Theelevatorshouldturntonormaloperationmodewhenthefireswitchisreset.Undernormaloperationmode,thecontrolsystem'sbasictaskistocommandeachelevatortomoveupordown,tostoporstartandtoopenandclosethedoor.Butishassomeconstraintsasfollows:Eachelevatorhasasetof9buttonsonthecarcontrolpanel,oneforeachfloor.Thesebuttonsilluminatewhentheyarepressedandcausetheelevatortovisitthecorrespondingfloor.Theilluminationiscanceledwhenthecorrespondingfloorisvisitedbytheelevator.Eachfloor,exceptthefirstandthetopfloor,hastwobuttonsonthefloorcontrolpanel,onetorequestanupelevator,onetorequestadown-elevator.Thesebuttonsilluminatewhentheyarepressed.Theilluminationiscanceledwhenanelevatorvisitsthefloor,thenmovesinthedesireddirection.Thebuttonsonthecarcontrolpanelorthefloorcontrolpanelareusedtocontroltheelevator'smotion.Theelevatorcannotpassafloorifapassengerwantstogetoffthere.Theelevatorcannotstopatafloorunlesssomeonewantstogetoffthere.Theelevatorcannotchangedirectionuntilithasservedallonboardpassengerstravelinginthecurrentdirection,andahallcallcannotbeservedbyacargoinginthereversedirection.Ifanelevatorhasnorequests,itremainsatitscurrentfloorwithitsdoorsclosed.(2)ParallelrunningwithtwoelevatorsInthissituation,therearetwoelevatorstoservethebuildingsimultaneously.Itrunsat7amto9amand5pmto7pmeveryday.Whenanelevatorreachesalevel,itwilltestifthestopisrequiredornot.Itwillstopatthislevelwhenthestopisrequired.Atthesametime,tobalancethenumberofstops,theoperationoftwoelevatorswillfollowacertaindispatchingprinciple.Anelevatordoesn'tstopatafloorifanothercarisalreadystopping,orhasbeenstoppedthere.Thenormaloperationofelevatorsisimplementedbycooperationofitselectricpowerdrivingsystemandlogiccontrolsystem.MinimumwaitingtimealgorithmIntrafficofelevatorsystems,therearetwotypesofcontroltaskusually.Theoneisthebasiccontrolfunctiontocommandeachelevatortomoveupordown,tostoporstartandtoopenandclosethedoor.Theotheristhecontrolofagroupofelevators.Themainrequirementsofagroupcontrolsysteminservingboth,carandhallcalls,shouldbe:toprovideevenservicetoeveryfloorinabuilding;tominimizethetimespentbypassengerswaitingforservice;tominimizethetimespentbypassengerstomovefromonefloortoanother;toserveasmany

passengersaspossibleinagiventime[1].Q2.0M0.0l-floOTC-illHFrIHl-floOTC-illQ0.0THQ2.1 M0.1HHH■Q2.7M0.7T_IHQ3.0M1.0HFrIH牡Q2.7M0.7T_IHQ3.0M1.0HFrIH牡Q0.1M0.1HHF牡Q0.7M0.7HHFHHQ1.0M0.1HHFQ1.6M0.7y-flo口廣c?山upk-all-c.=dl出口B-fl口口Td1?1?M4.1M6.6I5.3THH卜汩卜G4Q4.4 H6.4HFt~()TM67HFFigure6Theelevator'sfloor-stoppingTherearemanydispatchingalgorithmsforelevator'sgroupcontrol.SuchasNearest-neighborAlgorithm[2],whichtheelevatoralwaysservetheclosetrequestnext;ZoningAlgorithm[3]whichbyanalyzingthetrafficofelevatorsystemwithunequalfloorandpopulationdemandtodispatchtheelevator;andOdd-evenrule,whichanelevatoronlyservestheoddfloorandtheotheronlyservestheevenfloor.TheNearest-neighborAlgorithmminimizesthelengthoftheelevator'semptymovetothenextrequest.Itusuallyhasverysmallaveragewaitingtimes,butindividualwaitingtimescanbecomequitelarge[2].TheZoningAlgorithmusuallyusedinbuildingswhichhasheavytrafficsituations,suchastheofficebuildingatlunchtime.Comparedtotheofficebuildingandshoppingmall,thetrafficflowofresidentialbuildingsisrelativelylowandevenineveryfloor.Secondly,peopleusuallythinkofelevatorsaspurelyfunctionalobjectsandtheexperienceofridinganelevatoristimewaitedformostofthem.Furthermore,thereexistimmenseproblemswhenattemptingtosatisfyallrequirements.Consideringallofthereasonsabove,weadoptedthe“minimumwaitingtime”algorithmtorealizethe2elevators'parallelrunning[4].EvaluationfunctionThegoalofthe“minimumwaitingtime”algorithmistopredicttheeachelevator'sresponsetimeaccordingtoallcalls,andselecttheelevatorwhichhastheshortestresponsetimetoserve.Whenthereisacall,thesystemcalculatesoutthefunctionvaluesofeachelevatoraccordingtheevaluationfunctionshowedin(1)and(2):J(*)=Min[J(l),J(2),…,J(n)](1)J(i)=Tr(i)+KTd(i)+KTo(i)i=1,2,...,n(2)J(i)istheevaluationindexofeachelevator;Tr(i)denotesthetimeoftheelevatordirectlymovingtothedestinationcorrespondingthelatestcallfromitscurrentfloor;To(i)denotestheadditionalaccelerationanddecelerationtimeofafloor-stopoftheelevator;Td(i)denotestheaveragetimeofthepassengerboardingandalightingtheelevator;andKisthesumofhall-callsandcar-calls.Butwhenahall-callandacarcallcorrespondsthesamefloor,theKisonlycalculatedonetime.CalculationofminimumwaitingtimeInequation(2),Kisacertainvalue,ToandTdcanbeobtainedbymeansofstatistics.Tr=T*L,whereTdenotestheaveragetimeoftheelevatorpassingbyonefloor;Ldenotesthedesiredfloorsoftheelevatorfromcurrentfloortothehall-callfloor.InordertocalculatetheLvalue,wedefinedthe2elevatorsareAandBrespectively;YA,YBdenotesthecurrentfloorofelevatorAandBrespectively.Histhecorrespondingkeyvaluewhenahall-callbuttonispressed,andH=floornumberofthehall-call.Wedefined4tablesforthePLCrealization:uphall-callregistrationtable,downhall-callregistrationtable,car-callregistrationtableofAandcar-callregistrationtableofB.Whenacertaincallbuttonispressed,itsfloorvalueisrecordedincorrespondingtable.HerewetakeelevatorAasanexample.First,definethevariableMA,MBandMW.WhereMA,MBdenotestheextremevalueofcar-callswithsamedirectionofAorB'smovementrespectively.WhenelevatorAisup-moving,setMAisequaltothemaximumvalueincar-callregistrationtableA;whenelevatorAisdown-moving,setMAisequaltotheminimumvalueincar-callregistrationtableA.MWdenotestheextremevalueofhall-callswithsamedirectionofA'smovement.WhenelevatorAisup-movingandup-hall-callvalue>YA,setMW=0;otherwise,setMWisequaltotheminimumvalueinup-hall-callregistrationtableA.WhenelevatorAisdown-movingandup-hall-callvalue<YA,setMW=0;otherwise,setMWisequaltothemaximumvalueindown-hall-callregistrationtableA.Thus,wecandeterminetheLvalueaccordingtoYA,H,MAandMW.Thereare3situations:Whenthehall-call'sdirectionisoppositetoelevatorA'smovement:L=|YA-MA|+|MA-H|(3)Whenthehall-call'sdirectionissameaselevatorA'smovementanditisinthefrontofelevatorA:L=|YA-H|(4)Whenthehall-call'sdirectionissameastheelevatorA'smovementanditisinthebackofelevatorA:L=|YA-MA|+|MA-MW|+|H-MW|(5)Sothei-thfloor'sminimumwaitingtimecanbecalculatedby(6)asfollows:Time(i)=TL(i)+KTd(i)+KTo(i)i=1,2,...,n(6)Whenthecallschangeduringtheoperationofelevators,thesystemcalculatestheminimumwaitingtimeofeachelevator.Thenitallocatesthecurrentcalltotheelevatorwhichhassmallvalue.Whentheeachelevatorhasthesamevalue,thenthecurrentcallispriortoelevatorA.Whenanelevatoriswrongornotinservice,thesystemcanexitthedispatchingalgorithmandturnstoasingleelevatorrunningmode.AlgorithmrealizationComparedwithsingleelevatorrunningmode,theparallel