电子水平仪英文文献Word格式.docx

电子水平仪英文文献Word格式.docx

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班号

指导教师

翻译提交日期

哈尔滨工业大学教务处制

StudyonaNewHighAccuracyDual-axisElectronicLevel

Abstract

Thestudyandthedevelopmentofanewdual-axis,highaccuracyandlowcostelec-troniclevelhavebeenintroduced.Inthispaper,theideaoftheoveralldesignisdescribed,andthede-terminationforthemainmechanicalandelectronicparameters,includingtheoveralltesting,hasbeendiscussedindetail.Baseduponthepracticalcharacteristicandthespecificationsoftheinstrument,itwillbewidelyusedinthefieldofmachinetool,automobile,airplaneandshippingmanufactures.

KeyWords:

Electroniclevel;

Platespring;

LVDT;

Tiltmeasurement

1Introduction

Thenewdual-axiselectronicleveliscalledtiltsensortoo.Itisauniquetiltmeasuringsystemcapableofsimultaneouslyrecordingthedegreeanddirectionoftiltwithhighaccuracyupto1arc-sec.withinarangeof400arc-sec.,upto3arc-sec.withinarangeof800arc-sec.Ithasareadingresolutionupto0.1arc-sec.

TheworkingprincipleoftheinstrumentisshowninFig.1.Itiscomposedofthreeparts.Onepartisthecombinationofthesupportframeandthebase.Anotherpartisstationarywork-piece5fixedonthetopofsup-portframe.Thethirdpartistheswingwork-piece2.Thework-pieces5and2areconnectedbyapairofdoubleplatesprings3.Duringmeasurementifthesurfacewhichtheinstrumentissetonistilt,thewholestructureoftheinstrumentwilltilttoo.Buttheswingwork-piece2willmovebackalongthereversedirectiontothetiltbythegravity.Therefore,thecoilandthecoreoftheLVDT（linearvariabledifferentialtransformer）willhaverelativedisplacement,andtherelativedisplacementwillbeconvertedtoanalogvoltageoutput.Thepairofplatespringsareguidewaytokeeptheswingwork-piece2moving.

Fig.1Thestructureoftheelectroniclevel.

Becauseofthesimplestructureoftheinstrument,itisworkingwithoutwearandtear,alsonocrossinfluenceuponthefunctionorprecision.Itissuitableforwidefieldofapplicationinqualityassuranceandengineering,twoexamplesaregivenasfollows.compensatethetiltofameasuredequipmentcanbereached.Thepurposeofusinganotherheadoftheinstrumentisthesameasinaboveexample.

1.1Checkingtheflatnessofmeasuringtables

TheapplicationprocessisshowninFig.2（a）.Oneheadoftheinstrumentissetonastandardtriangularbase.Duringmeasurement,thetriangularbaseismovedagainstarulerstepbystep.Everystepisjustequaltoasidelengthofthetriangle.Twodimensionaltiltdataarepickedupineverystepbyacomputer.Theanotherheadoftheinstrumentissetonacornerofthemeasuredtabletomonitorthedeformationofthewholetable.Usuallythemicro-deformationofthewholetableiscausedbytheweightofthetestinginstrumentwithcontinuousmoving.

Fig.2ApplicationExamples.

1.2Monitoringthelevelorcompensatingthetiltofameasuringequipmentautomatically

ThisapplicationprocessisshowninFig.2（b）.Oneheadoftheinstrumentisseton

theslidestageofameasuredinstrumentoramachinetool.Anotherheadoftheinstrumentissetonthebaseofthemeasuredequipment.Duringtheslidestagemoving,twodimensionalerrorsoftheguideway,pitchandrollerrors,arepickedupautomaticallybyacomputer.Therefore,tomonitorthelevelortocompensatethetiltofameasuredequipmentcanbereached.Thepurposeofusinganotherheadoftheinstrumentisthesameasinaboveexample.

2Theprincipleofoperation

Duringmeasurement,theinstrumentissetuponasurfacetobemeasuredandisadjustedtothezeroindicationwiththreescrews8.Ifthesurfaceistiltedasmallangle角度tothehorizontal,thentheswingpartwillbearaforceFandaforcecoupleM.WiththemultipleinfluenceofFandM,adeflectionYofthedoubleplatespringswillbegeneratedasshowninFig.3.Itcanbeexpressedbytheformula

（1）:

Fig.3Theworkingsituationoftheplatesprings.

Here:

Eistheelasticmodulusofthespring,Iisthemomentofinertia.Also

（bisthewidth，histhethicknessofthesprings）isknown.BecausethetiltangleHis

onlywithin800arc-sec.,F=P×

sinθcanbewrittenasF=P×

θ.Therefore,theformula

（1）becomesto

Upontheformula

（2）,obviouslythedeflectionofthespringsislinearwiththetiltangleθ.

Supposetheabsolutezerooftheinstrumentisjustindicatingtheglobelevel,thenthecenterofthecorewillcoincidewiththecenterofthecoilofaLVDT.Whenatiltθofthesurfacetakeplace,thetwocentersofthecoreandthecoilwillmoverelativelyfollowingtheswingpart.Thelargerofthetiltθwillleadtothelongerofthedistanceofthetwocenters.ThemechanicaldisplacementwillbeconvertedtoabipolardcvoltagebyLVDTanditssubsystemAD598chip.

3Designofthemainsystem

Duringdesign,theimportantfactoristocontrolanddecreasethehysteresisofthe

spring.Inordertoreachthisrequirement,twoprinciplesshouldbeobeyed:

First,thematerialofthespringshouldpossesssmallerhysteresis,sowehavechosenakindofspringmadeofNi-Ti-Alseriesalloythatisbetterforthisrequirement.Second,duringwork,themaximumdeflectionYshouldbesmallerthanthemaximumelasticdisplacementofthespringabout4~5times.Themaximumelasticdisplacementofthespringδmaxis:

Hereσistheelasticlimitofthespring.

Also,consideringthewholesizeoftheinstrument,wesetthelengthLofthespringtobe60mm,widthb=25mm,andthicknessh=0.15mm.Accordingtotheformulae

（2）and（3）,wesetthemaximumdeflectionofhespringYtobe0.2mm,withinthemaximumworkingrangeθ=800arc-sec.

Basedontherequirementsoftherangeand0.1arc-sec.resolution,wecangettherequirementsforchoosingLVDT.MiniaturetypeofLVDT,MHRseries（010MHR）,ischosen.ItsspecificationsarelistedinTable1.

Table1

ThecircuitforconjunctionwithLVDTtoconverttransducermechanicalpositiontoa

bipolarvoltagewithahighdegreeofaccuracyandrepeatabilityisshowninFig.4.WechooseanintegratedcircuitchipAD598.TheAD598containsalowdistortionsinewaveoscillatortodrivetheLVDTprimary.TheLVDTsecondaryoutputconsistsoftwosinewavesthatdrivetheAD598directly.TheAD598operatesuponthetwosignals,dividingtheirdifferencebytheirsum,producingascaledbipolardcoutput.Forafull-scaledisplacementofY=0.2mm,thevoltageoutputoftheAD598iscomputedbyformula（4）:

WhereS=126mV/（V#mm）isLVDTsensitivity,Vout=4Visthefullrangeoutputvoltage,dismeasuringrange,hereVA+VB=2.7V.Basedontheformula（4）,wegetthevalueR2=280k

Theoutputdcvoltageisthenconnectedtoa16bitsA/Dconverter9015.ThefullscaleoutputfromAD598is4Vanalog.Sothe800arc-sec.isrespectedwithabout25600bitsdigit.Inordertogetstablereading,theconvertedbitsaredividedby4.Therefore,8bitisequalto1arc-sec.

Fig.4AD598fordualsupplyoperation.

Fig.5Calibrationandoveralltesting.

4Calibrationandoveralltest

ThecalibrationisshowninFig.5.Thedual-axiselectroniclevelissetonameasuringfixture4whichhasbeentested.Whenthefixtureisworking,thereisabout0.1~0.2arc-sec.ofrollmovementaroundthebeamdirectionoftheHPinterferometer.Thetargetofdoubleretroreflectorsissetonthefixturetoo.TheHPinterferomreterandpartoftheanglesystemarefixedonastagewithfixture4together.First,theinstrumentiscalibratedagainstHPlaserwiththenumberofbits.Aftercalibration,theequivalentvaluesbetweenbitsandtiltanglesareknown.Therefore,theread-outoftheinstrumentcanbeexpressedbyanglevalue.WeusethesameapparatusasshowninFig.5todotheoveralltesting.Duringtestingthetopplateofthefixtureisupanddowntomakedifferentanglesthroughturningascrew.Thetestingdataarelistedin

table2.

Table2givesoutthetestingdataforpositivedirectionandpositivereturndirectionofXaxisoftheelectroniclevel.ThereareasetofdataforminusdirectionandtherearetwosetsofdataforYaxisoftheelectroniclevel.AllothertestingresultsarethesameasthedatashowninTable2.Basedonthetestingdata,wecansaythatthemaximumuncertaintyoftheinstrumentwithin300arc-sec.isbetterthan1arc-sec.

5Conclusion

Thenewdual-axiselectroniclevelhasasimplemechanicalstructure,buthighaccuracyandfeasibleforusingandadjustment.Thisachievementisowetothecompactmechanicalbody,afewintegratedcircuitchipwithonlyseveralelectronicexternalpassivecomponentsengagedinthework,alsoowetothequalityoftheplatespring,thebetterlinearityoftheLVDT,thesatisfactorystabilityoftheAD598circuitry.Duetothedual-axisfunctionplusdoublesetscanbeconnectedtogethertodoameasuringproject,thenewelectroniclevelcanensureameasuringprocessmorereliableandmorereasonable.Soitisveryusefulandveryeasyforthewideapplicationsinthefieldofindustry.

References

1WangBaoguang,MaoYunying.Studyonthestructuredesignofahighaccuracy3Dprobe.JournalofTianjinUniversity,1993,

（1）:

76~84

2ChenLincai.Designofprecisioninstrument.1sted.Beijing:

MechanicalIndustryExpress,1991,

3Signalconditioningcomponents&

subsystem.Handbook,ANALOGDEVICES:

13~23

4Linear&

angulardisplacementtransducers.Hand-book,CompanyLucasSchaevitz

一种高精度的新型双坐标电子水平仪的研究

摘要

介绍一种新型的高精度、双坐标、低成本电子水平仪的研究与开发。

论述了其总体设计思想,并对机械、电子等主要参数的确定方法及精度检定等进行了深入的讨论。

通过对仪器的实用性和精度指标的分析,表明该仪器在机床、汽车、飞机和轮船等制造领域有着广泛的应用前景。

关键词:

电子水平仪片簧线性差动式变压器（LVDT）倾斜角度测量

1引言

型的双轴电子水平倾角传感器。

这是一个独特的倾斜测量系统能够同时记