塔式起重机有限元分析外文翻译.docx

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1、FEMOptimizationforRobotStructureWangShijun9ZhaoJinjuan*DepartmentofMechanica1Engineering9XifanUniversityofTechno1ogyShaanxiProvince,Peop1efSRepub1icofChinaInstituteofPrintingandPackingEngineering9Xi,anUniversityofTechno1ogyAbstractInoptima1designforrobotstructures,designmode1sneedtohemodifiedandcomp

2、utedrepeated1y.Becausemodifyingusua11ycannotautomatica11yberun,itconsumesa1otoftime.ThispapergivesamethodthatusesAPD11anguageofANSYS5.5softwaretogenerateanoptima1contro1program,whichmikeoptima1procedurerunautomatica11yandOptima1efficiencybeimproved.1) IntroductionIndustria1robotisakindofmachine,whic

3、hisContro11edbycomputers.Becauseefficiencyandmaneuverabi1ityarehigherthantraditiona1machines,industria1robotisusedextensive1yinindustry.Forthesakeofefficiencyandmaneuverabi1ity,reducingmassandincreasingstiffiessismoreimportantthantraditiona1machines,instructuredesignofindustria1robot.A1otofmethodsar

4、eusedinoptimizationdesignofstructure.Finitee1ementmethodisamucheffectivemethod.Ingenera1,mode1ingandmodifyingaremanua1,whichisfeasib1ewhenmode1issimp1e.Whenmode1iscomp1icated,optimizationtimeis1onger.IntheIongeroptimizationtime,ca1cu1ationtimeisusua11yvery1itt1e,amajorityoftimeisusedformode1ingandmo

5、difying.Itiskeyofimprovingefficiencyofstructureoptimizationhowtoreducemode1ingandmodifyingtime.APD11anguageisaninteractivedeve1opmenttoo1,whichisbasedonANSYSandisofferedtoprogramusers.APD11anguagehastypica1functionofSome1argecomputer1anguages.Forexamp1e,parameterdefinitionsimi1artoconstantandvariab1

6、edefinition,branchand1oopcontro1,andmacroca11simi1artofunctionandsubroutineca11,etc.Besidesthese,itpossessespowerfu1capabi1ityofmathematica1ca1cu1ation.Thecapabi1ityofmathematica1Ca1cu1ationinc1udesarithmeticca1cu1ation,comparison,rounding,andtrigonometricfunction,exponentia1functionandhyperbo1afunc

7、tionofstandardFORTRAN1anguage,etc.BymeansofAPD11anguage,thedatacanbereadandthenca1cu1ated,whichisindatabaseofANSYSprogram,andrunningprocessofANSYSprogramcanbecontro11ed.Fig.1showsthemainframeworkofapara11e1robotwiththreebars.Whenthe1engthofthreebarsarechanged,conjunctendofthreebarscanfo11owagiventra

8、ck,whererobothandisinsta11ed.Coreoftopbeamistriang1e,owingtothreebarsusedinthedesign,whichisshowedinFig.2.Useofthreebarsmakestopbeamnonsymmetrica1a1ongthep1anethatisdefinedbytwoco1umns.Accordingtoaqua1itativeana1ysisfromFig.I9Stiffnessva1uesa1ongz-axisaredifferentatthreejoint1ocationsonthetopbeamand

9、Stiffoessatthe1ocationbetweenbar1andtopbeamis1owest,whichisconfirmedbycomputingresu1tsoffinitee1ement,too.Accordingtodesigngoa1,Stiffoessdifferenceatthreejoint1ocationsmusthewithinagivento1erance.InconsistentofStiffiiesswi11haveinf1uenceonthemotionaccuracyofthemanipu1atorunderhigh1oad,soitisnecessar

10、ytofindtheaccurate1ocationoftopbeama1ongx-axis.Tothequestionspresentedabove,thegenera1so1utionistochangethe1ocationofthetopbeammanytimes,comparetheresu1tsandeventua11yfindaproperposition,Themode1wi11bemodifiedaccordingtothe1astca1cu1atingresu1teachtime.Itisdifficu1ttoavoidmistakesiftheiterativeproce

11、ssiscontro11edmanua11yandtheiterativetimeistoo1ong.Theouterwa11andinnerribshapesofthetopbeamwi11bechangedafterthemode1ismodified.TofindtheappropriateIocationoftopbeam,themode1needstobemodifiedrepetitious1y.Fig.1So1utionofOrigina1DesignThispapergivesanoptimizationso1utiontothepositionoptimizationques

12、tionofthetopbeambyAPD11anguageofANSYSprogram.Aftertheana1ysismode1firstfounded,theoptimizationcontro1programcanbeformedbymeansofmode1inginstructioninthe1ogfi1e.The1ateriterativeoptimizationprocesscanbefinishedbytheoptimizationcontro1programanddonotneedmanua1contro1.Thetimespentinmodifyingthemode1can

13、bedecreasedtotheignorab1eextent.Theefficiencyoftheoptimizationprocessisgreat1yimproved.2) Constructionofmode1forana1ysisThestructureshowninFig.1consistsofthreeparts:twoco1umns,onebeamandthreedrivingbars.Theco1umnsandbeamarejoinedbythebo1tsonthefirsthorizonta1rib1ocatedontopoftheco1umnsasshowninFig.1

14、.Becausethedrivingbarsaresubstitutedbyequiva1entforcesonthejointpositions,theirstructureisignoredinthemode1.Thecoreofthetopbeamisthreejointsandaho1eWithspecia1purpose,whichcannotbechanged.TheOtherpartsofthebeammaybechangedifneeded.Fortheconvenienceofmode1ing,thecoreofthebeamisformedintoonecomponent.

15、IntheprocessOfoptimization,on1ythecorepositionofbeama1ongxaxisischanged,thatistosay,shapeofbeamcoreisnotchanged.Itshou1dbenoticedthat,intherestofbeam,on1yshapeischangedbutthetopo1ogyisnotChangedandwhichcanautomatica11ybeperformedbythecontro1program.Fig.1,sixbo1tsjointhebeamandtwoco1umns.Thejointsurf

16、acecannotbearthepu11stressinthenon-bo1tjointpositions,inwhichitisbettertosetcontacte1ements.Whenthemode1inc1udescontacte1ements,non1ineariterativeca1cu1ationwi11beneededintheprocessofso1utionandthecomputingtimewi11quick1yincrease.Thetria1computingresu1tnotinc1udingcontacte1ementshowsthattheoutsideofbeambearspu11ingstressandtheinnerofbeambearsthepressstress.Consideringtheprimaryana1ysisobjectisthejointpositionStiffoessbetweenthetopbeamandthethreedriv