毕业论文基于DSP技术为机车轴承设计故障诊断监控系统英文翻译.docx

毕业论文基于DSP技术为机车轴承设计故障诊断监控系统英文翻译.docx

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毕业论文基于DSP技术为机车轴承设计故障诊断监控系统英文翻译

原文：

DesignofFaultDiagnosisMonitorSystemfortheLocomotive

BearingsBasedonDSPTechnology

Abstract

Therollingbearingisoneofthekeypartsofthelocomotiverunningcomponents,becauseitconditionisdirectlyrelatedtotheperformanceandsafetyoflocomotive.Inthispaper,themonitorsystemforthelocomotivebearingsbasedonDSPTMS320LF2407Aisdesigned.Thissystemdiagnosestherollingbearingfaultusingvibrationanalysismethod.ItisbasedoncomprehensiveresonancedemodulationandfastFouriertransformtechnique,anditadopts"relatedmethods"tohandletheresultoftheFFT.Iteffectivelyimprovestheresponsecharacteristics,sensitivity,differentiateandmeasurementaccuracyofthebearingfailuremonitorsystem,anditcanfulfillthemonitorandpredictionofthetransientfaultinthecourseofthelocomotiverunning.

Keywords:

resonancedemodulationtechnology;digitalsignalprocessor;relatedmethods

I.Introduction

Thehighersafetyisrequiredtothetrainsbecauseitsspeedisraisedconstantly.Bearingfaultisoneofthemajorfactorscausingeventfultrafficaccidentsandaffectingrailsafety.Currentlytherailwaysystemusuallyusesthebearingtemperaturedetectortomonitorthelocomotivebearingcondition.Theoreticalanalysisandalotofpracticeshowthatthebearingtemperaturedetectorcanpreventaccidentsfromoccurringtosomeextent,butmostofthebearingfaultisnotsensitivetotemperature.Whenthetemperatureofthebearingisbeyondtherangeandthesystemgivesanalarm,theworsedamageofthebearinghasoccurred,andeventheincidenthadhappened.Therefore,tofindthefaultmoreearlyandaccurately,themoreadvancedmonitoringmeansmustbeadopted.Mostofthebearingfaultisverysensitivetovibrationsignal.Thefaultcancausevibrationofthebearingincreased.Comparedwithmonitoringthetemperatureofbearing,theanalysisandprocessingresultstothevibrationsignalhasmoreadvantagethanthetemperaturemeans.

II.Systemcomposingandworkprocess

Basedontheneed,themonitorofthebearingfaultmonitoringsystemtothelocomotivebearingsetstwodetections:

itinerationdetectionsandfixeddetections.Theitinerationdetectionisusedinthenormalconditions,andthefixeddetectionisusedforthecontinuousmonitoringofthefaultbearing.Thesystemadoptsspecialcompositesensortocollectthevibrationofthebearingandthetemperaturesignalatthesametime.Afterthedataprocessing,thecorrespondingfaultlevelsandriseintemperaturearegot.Thedataacquisitionunitisdesignedinthissystem.Alarminformationwillbetransmittedtoallcarriagesthroughinterfacessothatthestaffcanhandledintime,andthesametime,thefaultdataandtherelatedinformationofthetrainsuchasthecurrentlocationandspeedwillbetransmittedtothedispatchcenterthroughGPS,whichisconvenienttoadoptcorrespondingmeasures.ThesystemblockdiagramisinFig.1.

III.Thekeytechnologyofthedesignforthemonitoringsystem

A.Thespectrumanalysismeansfordiagnosingbearingfault

Undernormalcircumstances,allpartsoftherollingbearing（innercircle,outercircle,roller,holdingframe）willretainthestablerelativemovementstate.Ifthesurfaceofsomeelement（exceptforholdingframe）hascrack,andthiscrackisinthesurfaceoftherollingadjacentcomponent,theinstantaneousvibrationimpulsemustbeproduced.

AssumedthatthenumberoftherollerinthebearingisZ;thediameteroftherollerisd;theaveragediameterofthebearinginnercircleandthebearingoutercircle（thediameteroftherollerrevolutionpath）isD;thefrequencyofthebearingrotationisf0.Assumedthattheinnercircleisfixedandtheoutercircleiscircumvolved,thevibrationfrequencybroughtbythesurfacedefectsofdifferentbearingcomponentscanbederived.

Thesefrequenciescanbecalledthefaultcharacteristicsfrequencyoftheinnercircle,outercircleandtheroller.

B.Resonancedemodulationtechnology

Wecancollectvibrationsignalusingtheresonanceofthebearingcomponents,anddetecttheenvelopeofthefaultsignalusingenvelopdetector,whichcanfulfilltheanalysistothefaultcharacter.Thisiscalled“resonancedemodulationtechnology”.Thecomponentsurfacessuchastheinnercircle,theoutercircleandtherolleroftherollingbearingareeasilydamagedinlocalplaceinthecourseofoperation（suchaspittingandpeelingoff,cracking,scratchingetc.）.Ifthesurfaceofsomebearingcomponentshavelocaldamageandtherollingobjectpressesthefaultdotinthecourseofcarriedoperation,itmustbringimpact.Buttheimpactlastsashorttime,andthefrequencyrangeoftheenergydivergenceiswide,sotheenergywithinthescopeofvibrationfrequencyissmall.Duetothewidebandwidthoftheimpulse,itiscertainlythatitincludeshighfrequencyintrinsicvibrationinspiringbyintrinsicfrequencyoftheinnercircle,outercircle,roller,holdingframeonrollingbearings.Theresonancedemodulatesignalisseparatedbyband-passfilterofcenterfrequencyequaltoitsintrinsicfrequency.Thentheenvelopedemodulationiscarriedthroughtothereattenuationoscillatorywaveusingsoftwareorcircuit,thefrequencycomponentofthehighfrequencyattenuationvibrationiswipedoff.Weonlyobtainlow-frequencyenvelopesignalwiththeinformationofthefaultcharacter.Thespectrumanalysisoftheenvelopesignaliscarriedthroughbydigitalsignalprocessor,wecanobtainveryhighfrequencyresolutionratioandcaneasilyfindthefrequencyofthecorrespondingfaultimpact,therebywecanfulfilltodiagnosetothebearingfault.

Withresonancedemodulationtechnology,theelectricresonatorwhichresonantfrequencyismuchhigherthannormalvibrationfrequencyandlimitedhigh-harmonicfrequencyisdesigned.Therefore,itcaneffectivelyrestrainthelow-frequencysignalincludingnormalvibrationsignal.Theresonanceresponsemagnifiesthesignalamplitudeoftheimpulsesignalandthetimeofitsoscillationislonger,thusthefaultsignalisbroadenedinthetimedomainsignal.Aftertheenvelopedetectionandlow-passfilter,thelow-frequencyresonancedemodulationsignalwithhighsignal-to-noiseratioisexported.Inthesignalprocessingsystemshowninfigure2,thebearingcomponentbringsresonanceundertheimpact,formthecontinuousattenuationoscillation.Toresearcheachattenuationoscillation,wecanseethatitsfrequencyisthenaturalfrequencyofbearingcomponents,theamplitudeofattenuationoscillationisrelatetointensityoffaultimpact.Theamplitudeofenvelopesignaloftheattenuationoscillationreflectsthesizeofthefault,andtherepeatfrequencyoftheenvelopedependsonthefaultlocation.Systemhastheperformanceofanti-jammingofthelowfrequencyvibration,highsignal-to-noiseratio.

C.Envelopedetection

Abearingwithfaultinthecourseofrollingwillbringregularvibration.Differentfaulthasdifferentcharacterfrequency.Thecharacterfrequencysystemdetectingisthefrequencyofthesignalenvelope（thefrequencywhichisaccruedbythecollisionofthefaultonbearingelement）,notthevibrationfrequencyofthebearing.Whenweanalyzethefaultsignal,theresonantfrequency（carrierwave）mustberemovedbyenvelopedemodulation.Becausetheenvelopesignalhasfullyincludedallinformationofthefault,removingcarrierwavewillnothaveanyadverseimpactontheanalysis.

IV.Hardwareandsoftwaredesign

ThehardwareblockdiagramofthemonitorforthebearingfaultisshowninFig.3.

Thecircuitincludestwoparts:

thevibrationsignalpretreatmentsandthebearingstateanalysis.Thesignalpreprocessingpartfulfillstheamplification,conversion,resonancedemodulationofthesignal;thebearingstateanalysispartfulfillsspectrumanalysisofthesignal,"correlationmethod"processing,faultgradingprocessing,thebearingsstatusreportandcommunicatingwithperipheralequipmentandsoon.

TherearemainlythreekindsofFFTalgorithmtorealizeinDSP:

（1）onlyincludingadditionandsubtractionoperationswithoutoperationsofthepluralrotationfactor;

（2）includingtheoperationofthepluralrotationfactor;（3）theoperationofbitslocationinversion.Afterdataisprocessedbythisway,theworkloadofvibrationcomponentcalculationinDSPisreducedevidently.Thereal-timecapacityofsystemresponsecanbeadvanced.

Modularizationdesignisadoptedinthedesignofthesoftware,whichincludescollectionsofthevibrationsignalandthetemperatureincrementsignal,A/Dconversions,datapretreatments,FFTtransforms,calculationsofthepowerspectrum,judgmentsofthefaultgrading,savesofthedata,displaysofthedataandtransmissionsofthedata.Thetaskdispatchiscarriedthroughbythewayofeventtriggersandtimetriggers.Toremovetheinterference,the“correlationmeans”processingtotheresultsofFFTtransformiscarriedout,whichassurethefaultsignalpickedupeffectively.

V.Conclusion

FFTmethodsofvibrationsignalisadoptedinsystemdesign,atsametimedifferentialtemperaturemeasurementmethodsisaddedintosystemtojudgesynthetically.ThehighcapabilityDSPcompletessignalprocessing.Thissystemcancommendablysatisfytherequirementforreal-timeprocessing.Itmonitorsthesignalofvibrationsandtemperatureswithcombininglocomotivemonitorandgroundanalysis.Theearlierdiagnosisandalarmforlocomotivebearingsfaultcanbegiveninordertoassurelocomotiverunningsafely.

REFERENCES

[1]WangDezhi,Thediagnosisandmaintainofrollingbearing[M],Beijing:

ChinaRailwayPublishingHouse,1994,

[2]Shi