毕业设计外文翻译.docx
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毕业设计外文翻译.docx
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毕业设计外文翻译
外文翻译
题目
学院
专业
姓名
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指导教师
2016.11.02—2017.5.13
Researchandapplicationofreverseengineeringdesignforautomobilepanel
[Abstract]:
Inthedesignprocessoftheautomobilepanel,reverseengineeringhasbeenmorewidelyused.Takingacarfenderasanexampleofreversedesign,theuseofdigitalphotographyandopticalscan-ning,thepointcloudswereobtainedbytheATOS&TriTopsystembasedopticalprinciples.CharacteristicsforautomobilepanelandtheImagewaresoftwareaboutreverseengineering,detailedreverseengineeringofautomobilepaneldesignforcurveandsurfacebythelargenumberofdatapoints
[Keywords]:
Automobilepanel;Reverseengineering;Surfacereconstruction;Imagewaresoftware
1Introduction
ReverseEngineeringisunderthepremiseoftheonlyproductmodelorphysicalmodelandnoproductdefinitionanddrawings,BymeasuringthedataobtainedinordertoestablishdigitalmodelThesemodelswerethenusedtoanalyzeandcharacterizetheproduct,manufacturingandprocessingprocedures.Asameansofproductdesignandmanufacturing,reverseengineeringhasbeenwidelyusedinrecentyears,especiallyinthefieldofrapiddevelopmentoftheautomobile.Reverseengineeringtechnologyforautomobilemanufacturerstodigest,absorbadvancedtechnology,fastandefficientdevelopmentofnewproductsplayanimportantrole.Comparedwiththetraditionalforwardengineering,thereverseengineeringhastheadvantagesofhighdesignprecision,shortdevelopmentanddesigncycle,easyfollow-upfiniteelementanalysis,optimizationdesignandkinematicssimulation.Combinedwiththepracticalworkexperiencefortheenterpriseservice,thetypicalcarcoverproducts-fenderasanexample,introducedthecarcoverreversedesignprocessandmethod.
23Dpointdataacquisitionautomobilecoveringparts
Withthedevelopmentofrelatedtechnologiessuchassensingtechnology,controltechnology,imageprocessingtechnologyandcomputervisiontechnology,atpresent,therearevariouskindofsurfacegeometrydataacquisitionmethod.Inviewofthelargevolumeandhighprecisionoftheautomobilecover,weusethenon-contactdigitalphotographyandopticalscancombinationofdatacollectionbasedonopticalprinciplesATOS&TriTopsystem,whichistheGermanGOMproductioncompany,iscurrentlytheworld.Oneofthemostadvancednon-contactcoordinatescanningsystem,withawiderangeofmeasurement,scanningspeed,bytheenvironmentalimpactofsmall,stableperformance,easytocarry,easytooperate,etc.,intheautomotiveindustryiswidelyused.Thesystemconsistsoftwomodules,namelyATOSportable3DscannermoduleandTriTopdigitalcameramodule,acombinationofboth,tobecompletedbythemeasurementoflargeworkpieces,toachievethree-dimensionalscanningspeed,andtoachievehighermeasurementaccuracy.Keypointsofscanningtechnologyforautomobilepanel.
2.1Readyforwork
thepartthatneedstobescanedshouldbepre-processedsurfacely,Inordertopreventthehighlightorinadequatereflection,toincreasetheimageofthesurfaceoftheobject,objectattheoutersurfaceshallbeuniformlysprayedwhiteimagingagent,andthenpastethereferencepoint,digitalpointandlengthafterplacedintheabovecalibration,AsshowninFigure1.ATOSusesthereferencepointtechniqueformultiviewregistration,forlargemeasurementmeasurement,inadditiontoplacethereferencepoint,alsoplacedproprietarydigitalpointandafterencodinglengthaftercalibration,theaccuratepositioningofallthe3Dcoordinatesofthereferencepoint,thusreducingtheregistrationerror.
Figure1measuringscale,digitalpointandreferencepoint
2.2CalibrationofATOSsystem
(1)Hardwarecalibration.AfterenteringtheATOSsoftwaresystem,thehardwareofthesystemmustbecalibratedfirstly.ThemainpurposeofthehardwarecalibrationisthateachCCDcameraisingoodworkingconditiontoobtainthebestimagingeffect.Softwarecalibration.Softwarecalibrationisdoneafterhardwarecalibration,Usedtomeasurethespatialdistanceonthecalibrationplatein11differentdirectionsofmeasurement,usedasaspatialrelationshipafterthescan.
2.3Acquisitionofpointclouddataofautomobilepanel
TheuseofATOS&Tritopsystem,firstwithhighresolutionTritopdigitalcamerainordertoshootallthereferencepointsandscale.Intheprocessoftakingpictures,eachpictureatleastfiveencoding,eachencodingatleasttoappearinthethreephoto,andthenputallthephotosinsystem,thesystemwillautomaticallylocateallthereferencepoint.UsetheTritopsystemtomeasurethespatiallocationisonlyareferencepoint,butcannotbemeasuredobjectsurfacedata,soalsouseAtosscanningsystemTritopsystemaccordingtothemeasureddataofthereferencepoint,multianglescanning,willcoordinatethedataautomaticallyalignedtotheTritopsystemtoset.Registrationerrorreductionneedsmultipleoverlappingmeasurements.Intheprocessofmeasurement,therewillbeaseriousdiscrepancybetweenthepointcloudandthephysicallocation.Atthispoint,weshoulddeletetheerrorpointcloud,reselectthemeasurementareaandreferencepointformeasurement;theboundarypointcloudisnotcompleteisamajordefectofAtosscanning,sothemeasurementshouldbestrengthenedintheprocessofboundarysurvey.
3Preprocessingof3Dpointclouddataforautomobilepanel
Afterthecompletionoftheaboveautoscan,thescanningpointclouddatawereprocessedbytheATOSscannersoftwareandtheprofessionalreversedesignsoftwareImageware.
3.1PointclouddataprocessingofATOSscannersoftware
Dataprocessingisakeylinkinreverseengineering,anditsresultswilldirectlyaffectthequalityofthelatermodelreconstruction.Pointclouddatapreprocessing,includingnoiseremoval,filtering,grid,smooth,fillholes,etc.
3.1.1Removescatteredpointcloudnoisedata
Thescanningpointcloudcontainsalotofnoise,suchasground,benchbottomoraroundthedebris,thenoisebeforevariouspointprocessingshouldbedeleted.Thepointgroupisenlargedandtransformedtoconvenientlyseethenoiseinthewholethree-dimensionalspace,andthentherandomimageisremovedbyusingthedeletefunctionintherandomsoftware.
3.1.2Pointcloudsimplification
Inthereverseengineeringtechnologyintheacquisitionofthenumberofpointsaregenerallylarge,singlephotoscanningpointscanbeupto400000.Suchalargeamountofdataneedstobeprocessedbeforesurfacereconstructiontoimprovetheoperationspeed.
3.1.3Triangulationofpointclouddata
Itisthekeypointofthegridpointcloudtoestablishthetopologicalrelationshipamongthepointscorrectlyandformthetriangularplaneslice.Inaddition,thenumberoftriangularplaneslicesshouldbereducedreasonablyintheflatsurface,andthedensityoftriangularplaneshouldbeincreasedintherangeofcurvatureofsurface.
3.1.4Holerepairinginscattereddata
Inthemeasurementprocess,willbeanumberofpositioningreferencemodelcausedbythepastecannotgetattachedpartsofthedata,theseholeswillbringmanyproblemstothefollow-uptoprovidedigitalreconstructionsurfaceintegrity,sowemustrepairtheholesinthemeasurementdata.
3.1.5Datasmoothing
Usually,theleastsquaremethod,energymethodandwaveletanalysismethodareused.
ThepointcloudofacertainautomobileouterpanelwaspretreatedbyusingtheAtosscannersoftware.Asshowninfigure2.
3.2PreprocessingofpointclouddatawithImagewaresoftware
ImagewareproducedbyacompanyintheUnitedStates,isawell-knownreverseengineeringdedicatedsoftware,isbeingwidelyusedinautomotive,aerospace,consumerappliances,mold,computerparts,suchasdesignandmanufacturingareas.
Figure2scansacar'spointcloud
3.2.1Alignpointclouddata
Firstofall,wewillgetthepointcloudfilefromtheATOSintotheImageware,pointclouddataalignmentisanimportantpartofdataprocessing.Thereisacertainanglebetweentheinitialpointclouddataandthegeneralthree-dimensionalcoordinatesystem.Inordertofacilitatetheconstructionofthe3Dgeometricmodeloftheautomobilepanel,thepointclouddataandthereferencedatumcoordinatesystemshouldbealigned.
3.2.2Thedataofautomobilefenderpointcloudextraction
Thesurfaceofautomobilecoveriscomposedofanumberoffree-formsurfaces,whicharedifferentinsizeandshape.Thecarbodyincludestopcover,frontandrearfender,bumper,doorandsidewall,rearwalletc..Basedonthereverseengineeringofautomobilepaneldesign,theneedforeachofthepartswerereversedesign,thenconsidertheassemblyrelationshipamongtheparts,isbasedonthedesignprinciples,digitaldesigntocompletethewholecar'sshape.
Takingacarfenderasanexample,theautomobilepartsreversedesignprocessandmethod.Transportdataextractedinthewingfromtheappearancepointofdatatransport,AsshowninFigure3.
Fig.3pointclouddataofcarfender
4Qualityevaluationofsurfacereconstructionandsurfacereconstructionoftheautomotivepanelpartsdatablock
4.1Datablockofautomobilepanelparts
Fig.4areadivisionofcarwingsurfacereconstruction
Intheautomobilepanelpartsinreversedesign,frompointcloudoncegeneratedtomeettherequirementsofthesurfacenotonlyhascertaindifficulties,andevencreated,infairnesscannotmeettherequirements;thereforeweshouldfirstpointclouddataintoblocks,respectively,toconstructthesurface,andthenthroughthebridge,transition,cuttingandotherdetailsthecharacteristicsofprocessingandultimatelygeneratealls
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