外文翻译基于DSP技术为机车轴承设计故障诊断监控系统.docx
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外文翻译基于DSP技术为机车轴承设计故障诊断监控系统
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]ShiHuafeng