数控外文翻译

NumericalControlOneofthemostfundamentalconceptsintheareaofadvancedmanufacturingtechnologiesisnumericalcontrol(NC).PriortotheadventofNC,allmachinetoolsweremanualoperatedandcontrolled.Amongthemanylimitationsassociatedwithmanualcontrolmachinetools,perhapsnoneismoreprominentthanthelimitationofoperatorskills.Withmanualcontrol,thequalityoftheproductisdirectlyrelatedtoandlimitedtotheskillsoftheoperator.Numericalcontrolrepresentsthefirstmajorstepawayfromhumancontrolofmachinetools.Numericalcontrolmeansthecontrolofmachinetoolsandothermanufacturingsystemsthoughtheuseofprerecorded,writtensymbolicinstructions.Ratherthanoperatingamachinetool,anNCtechnicianwritesaprogramthatissuesoperationalinstructionstothemachinetool,Foramachinetooltobenumericallycontrolled,itmustbeinterfacedwithadeviceforacceptinganddecodingthep2ogrammedinstructions,knownasareader.Numericalcontrolwasdevelopedtoovercomethelimitationofhumanoperator,andithasdoneso.Numericalcontrolmachinesaremoreaccuratethanmanuallyoperatedmachines,theycanproducepartsmoreuniformly,theyarefaster,andthelong-runtoolingcostsarelower.ThedevelopmentofNCledtothedevelopmentofseveralotherinnovationsinmanufacturingtechnology:Electricaldischargemachining.Lasercutting.Electronbeamwelding.Numericalcontrolhasalsomademachinetoolsmoreversatilethantheirmanuallyoperatedpredecessors.AnNCmachinetoolcanautomaticallyproduceawidevarietyofpar4s,eachinvolvinganassortmentofundertaketheproductionofproductsthatwouldnothavebeenfeasiblefromaneconomicperspectiveusingmanuallycontrolledmachinetoolsandprocesses.Likesomanyadvancedtechnologies,NCwasborninthelaboratoriesoftheMassachusettsInstituteofTechnology.TheconceptofNCwasdevelopedintheearly1950swithfundingprovidedbytheU.SAirForce.Initsearlieststages,NCmachineswereabletomakestraightcutsefficientlyandeffectively.However,curvedpathswereaproblembecausethemachinetoolhadtobeprogrammedtoundertakeaseriesofhorizontalandverticalstepstoproduceacurve.Theshorteristhestraightlinesmakingupthestep,thesmootheris4hecurveE.achlinesegmentinthestepshadtobecalculated.Thisproblemledtothedevelopmentin1959oftheAutomaticallyProgrammedTools(APT)languageforNCthatusesstatementssimilartoEnglishlanguagetodefinethepartgeometry,describethecuttingtoolconfiguration,andspecifythenecessarymotions.ThedevelopmentoftheAPTlanguagewasamajorstepforwardinthefurtherdevelopmentofNCtechnology.TheoriginalNCsystemwerevastlydifferentfromthoseusedpunchedpaper,whichwaslatertoreplacedbymagneticplastictape.Atapereaderwasusedtointerprettheinstructionswrittenonthetapeforthemachine.Together,all/fthisrepresentedgiantstepforwardinthecontrolofmachinetools.However,therewereanumberofproblemswithNCatthispointinitsdevelopment.Amajorproblemwasthefragilityofthepunchedpapertapemedium.Itwascommonforthepapercontainingtheprogrammedinstructionstobreakortearduringamachiningprocess,Thisproblemwasexacerbatedbythefactthateachsuccessivetimeapartwasproducedonamachinetool,thepapertapecarryingtheprogrammedinstructionshadtorerunthoughtthereader.Ifitwasnecessarytoproduce100copiesofagivenpart,itwasalsonecessarytorunthepapertapethoughtthereader100separatetimes.Fragilepapertapessimplycouldnotwithstandtherigorsofshopfloorenvironmentandthiskindofrepeateduse.Thisledtothedevelopmentofaspecialmagnetictape.Whereasthepapertapecarriedtheprogrammedinstructionsasaseriesofholespunchedinthetape,theThismostimportantofthesewasthatitwasdifficultorimpossibletochangetheinstructionsenteredonthetape.Tomakeeventhemostminoradjustmentsinaprogramofinstructions,itwasnecessarytointerruptmachiningoperationsandmakeanewtape.Itwasalsostillnecessarytorunthetapethoughtthereaderasmanytimesastherewerepartstobeproduced.Fortunately,computertechnologybecomearealityandsoonsolvedtheproblemsofNC,associatedwithpunchedpaperandplastictape.Thedevelopmentofaconceptknownasnumericalcontrol(DNC)solvethepaperandplastictapeproblemsassociatedwithnumericalcontrolbysimplyeliminatingtapeasthemediumforcarryingtheprogrammedinstructions.Indirectnumericalcontrol,machinetoolsaretied,viaadatatransmissionlink,toahostcomputerandfedtothemachinetoolasneededviathedatatransmissionlinkage.Directnumericalcontrolrepresentedamajorstepforwardoverpunchedtapeandplastictape.However,itissubjecttothesamelimitationasalltechnologiesthatdependonahostcomputer.Whenthehostcomputergoesdown,themachinetoolsalsoexperiencedowntime.Thisproblemledtothedevelopmentofcomputernumericalcontrol.Thedevelopmentofthemicroprocessorallowedforthedevelopmentofprogrammablelogiccontrollers(PLC)andmicrocomputers.Thesetwotechnologiesallowedforthedevelopmentofcomputernumericalcontrol(CNC).WithCNC,eachmachinetoolhasaPLCoramicrocomputerthatservesthesamepurpose.Thisallowsprogramstobeinputandstoredateachindividualmachinetool.CNCsolvedtheproblemsassociateddowntimeofthehostcomputer,butitintroducedanotherproblemknownasdatamanagement.Thesameprogrammightbeloadedontendifferentmicrocomputerswithnocommunicationamongthem.ThisproblemisintheprocessofbeingsolvedbylocalareanetworksthatconnectDigitalSignalProcessorsTherearenumeroussituationswhereanalogsignalstobeprocessedinmanyways,likefilteringandspectralanalysis,Designinganaloghardwaretoperformthesefunctionsispossiblebuthasbecomelessandpractical,duetoincreasedperformancerequirements,flexibilityneeds,andtheneedtocutdownondevelopment/testingtime.Itisinotherwordsdifficultpmdesignanaloghardwareanalysisofsignals.Theactofsamplingansignalintothehatarespecialisedforembeddedsignalprocessingoperations,andsuchaprocessoriscalledaDSP,whichstandsforDigitalSignalProcessor.TodaytherearehundredsofDSPfamiliesfromasmanymanufacturers,eachonedesignedforaparticularprice/performance/usagegroup.Manyofthelargestmanufacturers,likeTexasInstrumentsandMotorola,offerbothspecialisedDSP’s forcertainfieldslikemotor-controlormodems,andgeneralhigh-performanceDSP’sthatcanperformbroadrangesofprocessingtasks.Developmentkitsan'softwarearealsoavailable,andtherearecompaniesmakingsoftwaredevelopmenttoolsforDSP’sthatallowstheprogrammertoimplementcomplexprocessingalgorithmsusingsimple“drag‘nd’rop”methodologies.DSP’smoreorlessfallintotwocategoriesdependingontheunderlyingarchitecturefixed-pointandfloating-point.Thefixed-pointdevicesgenerallyoperateon16-bitwords,whilethefloating-pointdevicesoperateon32-40bitsfloating-pointwords.Needlesstosay,thefixed-pointdevicesaregenerallycheaper.Anotherimportantarchitecturaldifferenceisthatfixed-pointprocessorstendtohaveanaccumulatorarchitecture,withonlyone“generalpurpose”register,makingthemquitetrickytoprogramandmoreimportantly,makingC-compilersinherentlyinefficient.Floating-pointDSP’sbehavemorelikecommongeneral-purposeCPU’s,withregister-files.TherearethousandsofdifferentDSP’sonthemarket,anditisdifficulttaskfindingthemostsuitableDSPforaproject.Thebestwayisprobablytosetupaconstraintandwishlist,andtrytocomparetheprocessorsfromthebiggestmanufacturersagainstit.The“bigfour”manufacturersofDSPs:TexasInstruments,Motorola,AT&TandAnalogDevices.Digital-to-analogconversionInthecaseofMPEG-Audiodecoding,digitalcompresseddataisfedintotheDSPwhichperformsthedecoding,thenthedecodedsampleshavetobeconvertedbackintotheanalogdomain,andtheresultingsignalfedanamplifierorsimilaraudioequipment.Thisdigitaltoanalogconversion(DCA)isperformedbyacircuitwiththesamename&DifferentDCA’sprovidedifferentperformanceandquality,asmeasuredbyTHD(Totalharmonicdistortion),numberofbits,linearity,speed,filtercharacteristicsandotherthings.TheTMS320familyDQPofTexasInstrumentsTheTLS320familyconsistsoffixed-point,floating-point,multiprocessordigitalsignalprocessors(D[Ps),andfoxed-pointDSPcontrollers.TMS320DSPhaveanarchitecturedesignedspecificallyforreal-timesignalprocessing.The’F/C240isanumberofthe’C2000DSPplatform,andisoptimizedforcontrolapplications.The’C24sxeriesofDSPcontrollerscombinesthisreal-timeprocessingcapabilitywithcontrollerperipheralstocreateanidealsolutionforcontrolsystemapplications.ThefollowingcharacteristicsmaketheTMS320familytherightchoiceforawiderangeofprocessingapplications:--Veryflexibleinstructionset--Inherentoperationalflexibility--High-speedperformance--Innovativeparallelarchitecture--CosteffectivenessDeviceswithinagenerationoftheTMS320familyhavethesameCPUstructurebutdifferenton-chipmemoryandperipheralconfigurations.Spin-offdevicesusenewcombinationsofOn-chipmemoryandperipheralstosatisfyawiderangeofneedsintheworldwideelectronicsmarket.Byintegratingmemoryandperipheralsontoasinglechip,TMS320devicesreducesystemcostsandsavecircuitboardspace.The16-bit,fixed-pointDSPcoreofthe‘C24xdevicesprovidesanalogdesignersadigitalsolutionthatdoesnotsacrificetheprecisionandperformanceoftheirsystemperformancecanbeenhancedthroughtheuseofadvancedcontrolalgorithmsfortechniquessuchasadaptivecontrol,Kalmanfiltering,andstatecontrol.The‘C24xDSPcontrollerofferreliabilityandprogrammability.Analogcontrolsystems,ontheotherhand,arehardwiredsolutionsandcanexperienceperformancedegradationduetoaging,componenttolerance,anddrift.Thehigh-speedcentralprocessingunit(CPU)allowsthedigitaldesignertoprocessalgorithmsinrealtimeratherthanapproximateresultswithlook-uptables.TheinstructionsetoftheseDSPcontrollers,whichincorporatesbothsignalprocessinginstructionsandgeneralpurposecontrolfunctions,coupledwiththeextensivedevelopmenttimeandprovidesthesameeaseofuseastraditional8-and16-bitmicrocontrollers.Theinstructionsetalsoallowsyoutoretainyoursoftwareinvestmentwhenmovingfromothergeneral-purpose‘C2xxgeneration,sourcecodecompatiblewiththe’C2xgeneration,andupwardlysourcecodecompatiblewiththe‘C5xgenerationofDSPsfromTexasInstruments.The‘C24xarchitectureisalsowell-suitedforprocessingcontrolsignals.Itusesa16-bitwordlengthalongwith32-bitregistersforstoringintermediateresults,andhastwohardwareshiftersavailabletoscalenumbersindependentlyoftheCPU.Thiscombinationminimizesquantizationandtruncationerrors,andincreasesp2ocessingpowerforadditionalfunctions.Suchfunctionsmightincludeanotchfilterthatcouldcancelmechanicalresonancesinasystemoranestimationtechniquethatcouldeliminatestatesensorsinasystem.The‘C24xDSPcontrollerstakeadvantageofansetofperipheralfunctionsthatallowTexasInstrumentstoquicklyconfigurevariousseriesmembersfordifferentprice/performancepointsorforapplicationoptimization.Thislibraryofbothdigitalandmixed-signalperipheralsincludes:--Timers--Serialcommunicationsports(SCI,SPI)--Analog-to-digitalconverters(ADC)--Eventmanager--Systemprotection,suchaslow-voltageandwatchdogtimerTheDSPcontrollerperipherallibraryiscontinuallygrowingandchangingtosuittheoftomorrow’sembeddedcontrolmarketplace.TheTMS320F/C240isthefirststandarddeviceintroducedinthe‘24xseriesofDSPcontrollers.Itsetsthestandardforasingle-chipdigitalmotorcontroller.The‘240canexecute20MIPS.Almostallinstructionsareexecutedinasimplecycleof50ns.Thishighperformanceallowsreal-timeexecutionofverycomple8controlalgorithms,suchasadaptivecontrolandKalmanfilters.Veryhighsamplingratescanalsobeusedtominimizeloopdelays.The‘240hasthearchitecturalfeaturesnecessaryforhigh-speedsignalprocessinganddigitalcontrolfunctions,andithastheperipheralsneededtoprovideasingle-chipsolutionformotorcontrolapplications.The‘240ismanufacturedusingsubmicronCMOStechnology,achievingalogpowerdissipationrating.Alsoincludedareseveralpower-downmodesforfurtherpowersavings.Someapplicationsthatbenefitfromtheadvancedprocessingpowerofthe‘24i0nclude:---Industrialmotordrives---Powerinvertersandcontrollers--Automotivesystems,suchaselectronicpowersteering,antilockbrakes,andclimatecontrol--ApplianceandHVACblower/compressormotorcontrols--Printers,copiers,andotherofficeproducts--Tapedrives,magneticopticaldrives,andothermassstorageproducts--RoboticandCNCmillingmachinesTofunctionasasystemmanager,aDSPmusthaverobuston-chipI/Oandotherperipherals.Theeventmanagerofthe‘240isunlikeanyotheravailableonaDSP.Thisapplication-optimizedperipheralunit,coupledwiththehighperformanceDSPcore,enablestheuseofadvancedcontroltechniquesforhigh-precisionandhigh-efficiencyfullvariablespeedcontrolofallmotortypes.Includeintheeventmanagerarespecialpulse-widthmodulation(PWM)generationfunctions,suchasaprogrammabledead-bandfunctionandaspacevectorPWMstatemachinefor3-phasemotorsthatprovidesstate-of-the-artmaximumefficiencyintheswitchingofpowertransistors.Thereindependentupdowntimers,eachwithit’sowncompareregister,supportthegenerationofasymmetric(noncentered)aswellassymmetric(centered)PWMwaveforms.Open-LoopandClosed-LoopControlOpen-loopControlSystemsThewordautomaticimpliesthatthereisacertainamountofsophisticationinthecontrolsystem.Byautomatic,itgenerallymeansThatthesystemisusuallycapableofadaptingtoavarietyofoperatingconditionsandisabletorespondtoaclassofinputssatisfactorily.However,notanytypeofcontrolsystemhastheautomaticfeature.Usually,theautomaticfeatureisachievedbyfeed.gthefeedbackstructure,itiscalledanopen-loopsystem,whichisthesimplestandmosteconomicaltypeofcontrolsystem.inaccuracyliesinthefactthatonemaynotknowtheexactcharacteristicsofthefurther,whichhasadefinitebearingontheindoortemperature.Thisalcopointstoanimportantdisadvantageoftheperformanceofanopen-loopcontrolsystem,inthatthesystemisnotcapableofadaptingtovariationsinenvironmentalconitionsortoexternaldisturbances.Inthecaseofthefurnacecontrol,perhapsanexperiencedpersoncanprovidecontrolforacertaindesiredtemperatureinthehouse;butidthedoorsorwindowsareopenedorclosedintermittentlyduringtheoperatingperiod,thefinaltemperatureinsidethehousewillnotbeaccuratelyregulatedbytheopen-loopcontrol.Anelectricwashingmachineisanothertypicalexampleofanopen-loopsystem,becausetheamountofwashtimeisentirelydeterminedbythejudgmentandestimationofthehumanoperator.Atrueautomaticelectricwashingmachineshouldhavethemeansofcheckingthecleanlinessoftheclothescontinuouslyandturnitsedtoffwhenthedesireddegisedofcleanlinessisreached.Closed-LoopControlSystemsWhatismissingintheopen-loopcontrolsystemformoreaccurateandmoreadaptablecontrolisalinkorfeedbackfromtheoutputtotheinputofthesystem.Inordertoobtainmoreaccuratebontrol,thecontrolledsignalc(t)mustbefedbackandcomparedwiththereferenceinput,andanactuatingsignalproportionaltothedifferenceoftheoutputandtheinputmustbesentthroughthesystemtocorrecttheerror.Asystemwithoneormorefeedbackpat(slikethatjustdescribediscalledaclosed-loopsystem.humanbeingareprobablythemostcomplexandsophisticatedfeedbackcontrolsysteminexistence.Ahumanbeingmaybeconsideredtobeacontrolsystemwithmanyinputsandoutputs,capableofcarryingouthighlycomplexoperations.Toillustratethehumanbeingasafeedbackcontrolsystem,letusconsiderthattheobjectiveistoreachforanobjectonaperformthetask.Theeyesserveasasensingdevicewhichfeedsbackcontinuouslythepositionofthehand.Thedistancebetweenthehandandtheobjectistheerror,whichiseventuallybroughttozeroasthehandreachertheobject.Thisisatypicalexampleofclosed-loopcontrol.However,ifoneistoldtoreachfortheobjectandthenisblindolded,onecanonlyreachtowardtheobjectbyestimatingitsexactposition.ItisAsantherillustrativeexampleofaclosed-loopcontrolsystem,showstheblockdiagramoftheruddercontrolsystemofThebasicalementsandtheblocadiagramofaclosed-loopcontrolsystemareshowninfig.Ingeneral,theconfigurationofafeedbackcontrolsystemmaynotbeconstrainedtothatoffig&.Incomplexsystemstheremaybemultitudeoffeedbackloopsandelementblocks.数控在先进制造技术领域最根本的观念之一是数控（NCo数控来临之前，所有机床是手工操作和控制。手动控制机床有许多限制，或许没有比操作者的技能更突 出。用手动控制，产品质量直接相关，并仅限于操作者的技能。数控具有重要的意义 在于它摆脱手动控制机床。数控机床意味着，机器操作和其他手写机器操作系统的到来。操作机床，数 控技术员只要写出机床的指示程序，机床就会自动控制，它必须与一个接口接受和解码程序指示，作为一个读者已知的设备。数控开发，克服了人工操作的局限性，并且已经完成。数控机床比手动操作 机器更为准确，他们可以使得生产部分更得体，他们更快，从长远来说他的时间花费成本较低。数控的开发推动了制造业的技术创新发展：1。电火花加工。2。激光切割。3。电子束焊接。数控机床也比他们更早的机器更为的灵活。一种数控机床能自动产生的种类 繁多，每个涉及的零件，从经济的角度，将不会被可行的手动控制机床和工艺产品的生产品种所替代。像许多先进技术一样，数控出生于美国麻省理工学院的实验室。该数控概念 是在50年代初由美国空军提出。在最初阶段，数控机床能够使直接有效地削减人 力。然而，制作弯曲的零件是一个问题，因为机床要进行编程，进行横向和纵向的一系列步骤，以产生一个曲线。较短的可以用直线组成，是平滑曲线。它的的每一步骤都必须进行计算。这个问题导致了 1959年自动编程工具（ APT）语言的发展，使用类似数控英文语句来定义几何零件，描述刀具配置，并制定所需的方案。新的 APM言的发展是重大的一步，推动数控技术的进一步发展。原来的数控系统广泛使用穿孔纸，后来由 磁性塑料带代替。一个使用穿孔纸的人解释了该机器的磁带使用说明。总之，所有一 切都代表数控控制的大步发展。然而，有一些问题，就是数控在这点上的发展。一个主要的问题是该打孔纸带中的脆弱性。就是在输入程序指令时纸带的撕 裂，比这个问题更加严重的是，在机床制造过程中的连续性，携带的纸带编程指 示必须重新运行。如果生产预先制定的 100份， 还需要运行 100个纸带独立运行的时间。脆弱的纸带根本无法承受这样的环境，这样的无法重复使用。这导致了一个特殊磁带的发展。而通过在磁带打孔系列的编程指令中的纸带，其中最重要的是，很难或者不可能改变磁带上输入的指令。即使是在一个最微 小的调整方案，也需要中断才能加工，并制作出新的磁带。它仍然需要尽可能多的时 间运行磁带来实现要产生部分。幸运的是，计算机技术成为了现实，并很快解决了数 控问题，这与打孔纸和胶带密切相关。作为知名的数控概念发展（DNC解决了纸张和塑料带与数控相关作为执行指令的编程语言磁带的问题。在直接数字控制下，精密机床的束缚，通过数据传输 链 路，连接在主机和机器工具，通过数据传输连接需要。直接数字控制穿孔纸带和塑 料 带的应用上是一个重大的进步。但是，它受所有技术，在主机上却有相同的限制。 当主机出现故障，机器工具也会出现故障。这个问题引导了计算机数控的发展。关于可编程逻辑控制器（PL。和微型计算机的发展使微处理器的发展。这两项技术的发展，计算机数字控制（CNC允许的数控系统。每台机器工具，PLCM微型计算机，它为同样的目的。这允许程序自动输入和存储在每个机床上。数控解决 相 关的主机停机的问题，但它推出了著名的数据管理的另一个问题。同样的程序可能 会被装上10种不同的微型电脑，它们之间没有沟通。此问题处理是在当地区域网络的 过程中解决的connectDigital信号处理器的。在许多情况下的模拟信号会用各种方法处理问题，在很多方面像滤波和频谱 分析，设计模拟硬件来执行这些职能是可能的，但已变得越来越少，由于更高的性 能需求，灵活性的需求，以及需要削减减少开发/测试的时间的需求。正是在困难时，换句话说，是模拟信号的硬件设计分析改变了现状。抽样一个信号是专门为嵌入式信号处理的操作，这种处理器被称为数字信号 处理器，是数字信号处理器的代表。今天有数百个家庭的 DS耿尽可能多的制造商，每一个特定的价格/性能/使用组来设计的。大的厂家很多，像德州仪器，摩托罗拉，都提供专门的DSFB马达控制或调制解调器这些领域的，和一般的高性能DSPt理，可以执行广泛的任务范围。软件开发工具包也可以，也有公司做好 DSP勺，允许程序员可以实现复杂的处理算法，利用简单的“拖放 '和'下降”的方法的软件开发工具。DSP勺或多或少取决于两类下降的基础 架构的定点和浮点。定点设备操作一般在 16位，而浮点器件上 32-40位浮点操作。不用说，定点设备一般比较便宜。另一个重要的结构不同的地方是，定点处理器往往只有一个“通用的蓄电池架构”，这使得他们的方案很棘手，更重要的是，制造的C-编译器固有的低效率。浮点DSP勺表现更像是共同的通用CPU勺寄存器文件。在市场上有成千上万不同的数字信号处理器，找到项目最合适的数字信号处 理器是一个艰巨的任务。最好的办法可能是成立一个约束和心愿，并试图针对它的最大制造商的处理器来进行比较。“四大”的数字信号处理器制造商：德州仪器，摩托罗拉， AT&Tffi模拟设备。数字至模拟转换MPEG频解码，数字压缩的数据反馈到执行的 DSPS码，解码后的样本，将转换成模拟域回来，与由此产生的信号放大器或类似的音频设备。这个数字到模拟转换（DCA的工作由一个具有相同名称和不同音频媒体的电路提供不同的性能和质量，如THD（总谐波失真），对位，线性度，速度，过滤特征和其他一些。TMS32康歹DQ的德州仪器该TLS320family仪器由定点，浮点组成，数字信号处理器的多处理器（DSP及foxed点DS般制器。 TMS32廉列数字信号处理器设计了实时信号处理具体的架构。F/C240是C2000DSP台,并控制应用而优化。C24x^JDS般制器系歹1」，结合这个控制器外设的实时处理能力，以创造一个控制系统应用的理想解决方案。以下特点 使TMS320系列正确选择应用广泛的加工范围：--非常灵活的指令集--固有业务灵活性--高速性能--创新的并行结构--成本效益一代的TMS32廉列器件具有相