五连杆机构测量仪与其标定方法分析

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1、万方数据西南交通大学硕士研究生学位论文第1I页AbstractThefive-barmechanismmeasuringinstrumentisakindofparallelmechanismusedtomeasuretheplanarcurves．It’Slightweight，flexibleandwithhilghrepetitionaccuracy．Butthedifficultyinparametercalibrationisneededtobesolved．Researchoferroranalysisandcalibrationinfive-barmechanism

2、measuringinstrumentWasconductedasfollows．First，thispaperintroducesthemechanicalstructureoffive·barmechanismmeasuringinstrument．ThemeasuringinstrumentWasredesignedforthesmallerradiusubwaywheels．TheforwardandreversesolutionmodelformeasuringinstrumentWaswroteoutandthemeasuringfiledoftheinstrumen

3、tWassimulated．Secondly,theanalysisoftheerrorsourcesoftheinstrumentWascarriedout．TheparametererrorandquantizationerrorweresimulatedusingMatlab．Resultsareasfollows：errorcausedbythebarlengtherrorandencoderpositionerrorofparametererrorisabout10‘3mmmagnitude；thequantizationerroranderrorcausedbythe

4、errorinthezeropositionofencoder(3600lines)isin4-0．03mmwhichhasthegreatestimpact．BycompensatingforhalfapulseCanbasicallyeliminatetheoveralltrendofthequantizationerror．Thetransferfunctionbetweenparameterserrorandtheendpositionerrorwasdeducedusingaclosed-loopvectorchainmethodandtheerrormodelofme

5、asuringinstrumentWasestanlished．Accordingtotheerrormodel，sensitivitycoefficientofeveryparameterWascalculated．Theresultsshowedthatthesensitivitycoefficientoftheencoderzeropositionerroristhehighest．Thentheprincipleofthemeasuringwheelradiuscompensationandthetwo-pointmethodoftraditionalradiuscomp

6、ensationmethodwereanalyzed．．FourierserieswasadoptedtofitthecoordinateswhichWasobtainedbyoffsetandquantizationJM3modelstandardcurvetocompensatetheradiu．Theresultshowsthatthismethodimprovedsignificantlycomparedwiththetwo—pointmethod．Theerrorusingderivativeoffittingcurvemethodisin士3×104mill．Fina

7、lly,foursetsofcalibrationsimulationWassetonthepathstraighthorizontalandverticalline，onwhichthecalibrationmodelswereestablishedbasedontheerrormodelestablishedbefore．Thefourtestsare：1)considertheparametererror,doesnotconsiderthequantizationerro