




已阅读5页,还剩18页未读, 继续免费阅读
版权说明:本文档由用户提供并上传,收益归属内容提供方,若内容存在侵权,请进行举报或认领
文档简介
附录ControlofaNon-OrthogonalReconfigurableMachineToolReuvenKatzJohnYookYoramKorenReceived:January3,2003;revised:September16,2003AbstractComputerizedcontrolsystemsformachinetoolsmustgeneratecoordinatedmovementsoftheseparatelydrivenaxesofmotioninordertotraceaccuratelyapredeterminedpathofthecuttingtoolrelativetotheworkpiece.However,sincethedynamicpropertiesoftheindividualmachineaxesarenotexactlyequal,undesiredcontourerrorsaregenerated.Thecontourerrorisdefinedasthedistancebetweenthepredeterminedandactualpathofthecuttingtool.Thecross-couplingcontroller(CCC)strategywasintroducedtoeffectivelydecreasethecontourerrorsinconventional,orthogonalmachinetools.Thispaper,however,dealswithanewclassofmachinesthathavenon-orthogonalaxesofmotionandcalledreconfigurablemachinetools(RMTs).Thesemachinesmaybeincludedinlarge-scalereconfigurablemachiningsystems(RMSs).Whentheaxesofthemachinearenon-orthogonal,themovementbetweentheaxesistightlycoupledandtheimportanceofcoordinatedmovementamongtheaxesbecomesevengreater.Inthecaseofanon-orthogonalRMT,inadditiontothecontourerror,anothermachiningerrorcalledin-deptherrorisalsogeneratedduetothenon-orthogonalnatureofthemachine.Thefocusofthisstudyisontheconceptualdesignofanewtypeofcross-couplingcontrollerforanon-orthogonalmachinetoolthatdecreasesboththecontourandthein-depthmachiningerrors.Varioustypesofcross-couplingcontrollers,symmetricandnon-symmetric,withandwithoutfeedforward,aresuggestedandstudied.Thestabilityofthecontrolsystemisinvestigated,andsimulationisusedtocomparethedifferenttypesofcontrollers.Weshowthatbyusingcross-couplingcontrollersthereductionofmachiningerrorsaresignificantlyreducedincomparisonwiththeconventionalde-coupledcontroller.Furthermore,itisshownthatthenon-symmetriccross-couplingfeedforward(NS-CC-FF)controllerdemonstratesthebestresultsandistheleadingconceptfornon-orthogonalmachinetools.2004ASMEContributedbytheDynamicSystems,Measurement,andControlDivisionofTHEAMERICANSOCIETYOFMECHANICALENGINEERSforpublicationintheASMEJOURNALOFDYNAMICSYSTEMS,MEASUREMENT,ANDCONTROL.ManuscriptreceivedbytheASMEDynamicSystemsandControlDivisionJanuary3,2003;finalrevisionSeptember16,2003.AssociateEditor:J.Tu.Keywords:machinetool,cross-couplingcontroller,non-orthogonal,RMT1IntroductionCurrentlymanufacturingindustrieshavetwoprimarymethodsforproducingmediumandhighvolumemachinedparts:dedicatedmachiningsystems(DMSs)andflexiblemanufacturingsystems(FMSs)thatincludeCNCmachines.TheDMSisanidealsolutionwhenthepartdesignisfixedandmassproductionisrequiredtoreducecost.Ontheotherhand,theFMSisidealwhentherequiredquantitiesarenotsohighandmanymodificationsinthepartdesignareforeseen.Incontrasttothesetwoextremes,Korendescribesaninnovativeapproachofcustomizedmanufacturingcalledreconfigurablemanufacturingsystems(RMS).ThemainadvantageofthisnewapproachisthecustomizedflexibilityinthesystemtoproduceapartfamilywithlowerinvestmentcostthanFMS.AtypicalRMSincludesbothconventionalCNCmachinesandanewtypeofmachinecalledtheReconfigurableMachineTool.TheEngineeringResearchCenter(ERC)forReconfigurableMachiningSystems(RMS)attheUniversityofMichiganwithitsindustrialpartnershasdesignedanexperimentalReconfigurableMachineTool(RMT)。ThismachineallowsERCresearcherstovalidatemanyofthenewconceptsandmachinetooldesignmethodologiesthathavebeenalreadydevelopedinthecenter.TherearemanytypesofRMTs.Thispaperdescribesanarch-typenon-orthogonalmulti-axisRMTmachine。TheeconomicjustificationofRMTsisgiveninsection2ofthispaper.Acontouringmotionrequiresthatthecuttingtoolmovesalongadesiredtrajectory.Typically,computerizedcontrolsystemsformachinetoolsgeneratecoordinatedmovementsoftheseparatelydrivenaxesofmotioninordertotraceapredeterminedpathofthecuttingtoolrelativetotheworkpiece.Toreducethecontouringerror,whichisdefinedasthedistancebetweenthepredeterminedandtheactualpath,therehavebeentwomaincontrolstrategies.Thefirstapproachistousefeedforwardcontrolinordertoreduceaxialtrackingerrors.however,theyarelimitedwhennon-linearcutsarerequired.Theotherapproachistousecross-couplingcontrolinwhichaxial-feedbackinformationissharedbetweenthemovingaxes.Thecross-couplingcontrollerisusedinadditiontotheconventionalaxialservocontroller.Ateachsamplingtime,thecross-couplingcontrollercalculatesthecurrentcontourerrorandgeneratesacommandthatmovesthetooltowardtheclosestpointonthedesiredtoolpath.Thiscontrolstrategyofthecross-couplingcontroller(CCC)effectivelydecreasesthecontourerror.Advancedcontrolmethodshavebeenappliedtofurtherimprovethecontrolpropertiesoftheoriginalcross-couplingcontroller(CCC).AnoptimalCCCissuggestedin,toimprovethecontrollerperformancewhenhighcontouringspeedswererequired.Anothermethodtoovercomethesameproblemforhighercontourfeedratesisaddressedin,whichusesadaptivefeederatecontrolstrategytoimprovethecontrollerperformance.Thelatesttrendofcross-couplingcontrollerimprovementistheapplicationoffuzzylogic.Allthesemethods,however,donotworkformachineswithnon-orthogonalaxes.Surfacecut(e.g.,acircularcutintheX-Yplane)ona3-axisorthogonalmillingmachinerequiresamotionoftwoaxes(e.g.,XandY).However,surfacecutsinthenon-orthogonalRMTrequiresimultaneousmotionofallthreeaxes.Therefore,inadditiontothecontourerror,thismotioncreatesanothererror,calledthein-deptherror,whichisintheZdirection.Thiserroraffectsthesurfacefinishqualityoftheworkpiece.Whilecontouring,thetooltipoftheRMThasnotonlytofollowthepredeterminedpath,butalsotocontrolcontinuouslythedepthofcut.Thesimultaneouscontrolofbotherrors,theconventionalcontourerrorandthein-deptherror,requiresanewcontrolstrategysincethestandardCCCalgorithmscannotbedirectlyapplied.Inotherwords,theRMTcontroldesignproblemrequiresanewcontrolapproachthatisabletocorrectsimultaneouslytwotypesofcuttingerrors.Thisproblemhasnotbeenaddressedintheliterature.Inthispaper,wedescribethreetypesofcontrollersaimedatreducingthecontourandin-deptherrorsimultaneously.Firstweinvestigateasymmetricalcross-coupling(S-CC)controller,whichunfortunatelydoesnotshowgoodperformanceinreducingbotherrors.Thepoorperformanceisduetotheconflictingdemandsinreducingthetwoerrorsandthelackofinformationsharingbetweenthetwopairsofaxes(X-YandY-Z),whichareresponsibleforerrorcompensation.Toovercomethisproblem,therequiredmotioninformationofonepairofaxesisfedforwardtotheother.Thisidearesultsintwonewcontrollertypes,symmetricalcross-couplingfeedforward(S-CC-FF)controllerandnon-symmetricalcross-couplingfeedforward(NS-CC-FF)controller.Finally,theinfluenceofthereconfigurableangularpositionofthecuttingtoolonsystemstabilityisinvestigated.2MachineCharacteristicsandtheControlProblemInthissectionweexplaintheeconomicadvantageoftheRMT,anddevelopthemathematicalrepresentationofthecontourerrorandthein-deptherror.aMachineCharacteristicsTypicalCNCmachinetoolsarebuiltasgeneral-purposemachines.Theparttobemachinedhastobeadaptedtoagivenmachinebyutilizingprocessplanningmethodologies.Thisdesignprocessmaycreateacapitalwaste:SincetheCNCmachineisdesignedattheoutsettomachineanypart(withinagivenenvelope),itmustbebuiltwithgeneralflexibility,butnotallthisflexibilityisutilizedformachiningaspecificpart.TheconceptofRMTsreversesthisdesignorder:Themachineisdesignedaroundaknownpartfamily.Thisdesignprocesscreatesalesscomplex,althoughlessflexiblemachine,butamachinethatcontainsallthefunctionalityandflexibilityneededtoproduceacertainpartfamily.TheRMTmaycontain,forexample,asmallernumberofaxes,whichreducescostandenhancesthemachinereliability.Therefore,inprinciple,aRMTwithcustomizedflexibilitywouldbelessexpensivethanacompar
温馨提示
- 1. 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
- 2. 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
- 3. 本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
- 4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
- 5. 人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对用户上传分享的文档内容本身不做任何修改或编辑,并不能对任何下载内容负责。
- 6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
- 7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。
最新文档
- 《电工》高级练习题(含参考答案)
- 细节管理提升护理质量
- AI大模型赋能港口设施数字运维一体化智能解决方案
- 重症监护患者夜间睡眠
- 网络服务器配置与管理(微课版) 习题及答案
- 2025年全民科学素质竞赛网络知识竞赛试题库及答案(共150题)
- 销售策划目的试题及答案
- 河北省张家口市普通高中学业水平选择性模拟考试三模 英语试题(含答案)
- 2025年山东省泰安市东平县(五四学制)中考三模历史试题(含答案)
- 2025【合同范本】租赁合同解除协议模板
- DB36_T 420-2019 江西省工业企业主要产品用水定额(高清无水印-可复制)
- 车间精益改善总结报告课件(PPT 19页)
- 中小学教育惩戒规则(试行)全文解读ppt课件
- TCECS 850-2021 住宅厨房空气污染控制通风设计标准
- 《冬病夏治工作指南》
- 布鲁克纳操作手册
- 印度尼西亚煤炭购销合同
- GB∕T 25119-2021 轨道交通 机车车辆电子装置
- 2022年国网输变电工程质量通病防治工作要求及技术措施[1]
- 三年级美术下册16奇石教学设计1浙美版
- 支气管分段亚段及及支气管镜检查
评论
0/150
提交评论