毕业设计外文翻译.docx

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

学号

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