XXX届机械制造专业毕业设计英文翻译Word文档下载推荐.docx

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throughtheapplicationofthesoftwareforsignalanalysisandprocessingandanalysisofpaint-relatedwaveforms;

andthen,throughtherelevantwaveformanalysisandspectrumanalysistodeterminethehealthstatusofmachineryandequipment.

4.2SystemStructureDiagram

Designconceptofthissystemisthetop-downdesign,thefirstdevicetoachievetheoverallplanningfunction,andthendividethetotalworkfunctiontothehardwareandsoftwaresub-modulestorealizethesystemoveralldesignblockdiagramshowninFigure1.

4.3Vibrationspeedsensorselection

Vibrationsensor（Sensor）isacollectioncanbegeneratedbyrotatingmachineryvibrationsignals,accordingtoacertainlawofvibrationsignalsareconvertedtotheircorrespondingphysicalquantityorsignalandanotheroutputdevice,istoachievelarge-scalerotatingmachineryconditionmonitoringofanimportantlinkIfthereisnovibrationsensortotheoriginalvibrationsignalsaccuratelycaptureandconversion,rotatingmachineryconditionmonitoringcannotbeachieved.

Bycollectingvibrationsignalofadifferentnaturecanbeclassifiedasfollows:

acceleration,velocity,displacementandsoon.Vibrationsensorselectionmusttakeintoaccountsensorperformancerequirements;

sensorstaticanddynamiccharacteristics.Vibrationsensorstaticcharacteristicsofthemainparametersare:

linearity,resolutionandsensitivity.Thedynamiccharacteristicsofvibrationsensorsusedittorespondtocertaincriteriatorepresenttheinputsignal.Astherotatingmachineryvibrationsignalsoutputsinusoidalsignal,sothedynamiccharacteristicsofsensorsusedtoindicatethefrequencyresponse.Rotatingmachineryvibrationtestcommonlyusedtypesofsensorsarepiezoelectricsensorsandinertialratesensors.

Piezoelectricsensorsusedfornon-rotatingcomponentsoftheaccelerationmeasurement.Itischaracterizedbytheuseofawidefrequencyrange,usually0.2~10kHz,therefore,itissuitableforhigh-speedrotatingmachineryvibrationtests.Thequalityofpiezoelectricaccelerationsensorissmall,easytoinstallinmechanicalequipment.However,piezoelectricsensorsarehighimpedance,weaksignalsensor,measuringthesitevulnerabletoelectromagnetic,acousticandthermalaircurrentsandotherinterference,sothattheoutputsignalcontainsthepartofnon-vibrationaccelerationmeasurementpointsfromafalsesignal.

Inertialspeedsensorisacontact-typevibrationsensor,itisabsolutelyvibrationvelocityofthedetectedobjectsintomovingpartsmovingrelativetotheabsolutespeedoftheshell,andthenthroughaninternaltransformationtotherelativevibrationvelocitytransformpartsoftheelectromotiveforce,namely,bymeasuringtheelectromotiveforcetocalculatethespeedofrotatingmachineryvibration.Inertialspeedsensorthathashighsensitivityandlowoutputimpedance,butalsotheoutputpowerofastrongsignal,soitisnotsusceptibletoelectromagneticinterferenceafternoon,formorecomplexandrequiresalongleadon-site,stillhighersignaltonoiseratio.Thesensor'

sfrequencyrangebetween0.008~1KHz,nospecialpre-amplifier,installeasytouse.

ThesystemusestheVSSeriesVibrationvelocitysensorshowninFigure4-2,whichmeasuredbearing,chassisorstructureofthevibrationintensityandvibrationintensity.Suchsensorsmeasurethevibrationisrelativetotheabsolutevibrationoffreespace;

itsoutputvoltageisproportionaltothespeedandvibration,socalledvelocitytypevibrationsensors.Canalsoconvertthespeedoftrafficthroughthedisplacementofpointsre-displayprocessing?

Thismeasurementcanrotationorreciprocatingbodytoconductacomprehensiveevaluationofworkingconditions,whichdirectlyinstalledonthemachineoutside,somaintenanceisveryconvenienttouse.

HowItWorks:

VSSeriesVibrationMonitoringspeedsensoristheuseofmagneticinductionprincipletovibrationsignalsconvertedintoelectricalsignals.Itismainlyfromthemagneticcircuitsystem,inertialmass,springdampingcomponents.Thesensorrigidshellsecuredtoamagnet,inertialmass（coilcomponent）,withspringsuspensioncomponentsonthehousing.Work,thesensorinstalledonthemachine,themachinevibrationwhentheworkingfrequencyrangeofthesensor,thecoilandmagnetrelativemovement,cuttingmagneticfieldlines,on-linecircleproducesinducedvoltage,thevoltageisproportionaltothevalueofvibrationvelocity.Thenmatchwiththesecondaryinstrument,whichshowsthattheamountofvibrationvelocityordisplacementsize.

①sensitivityvaluesare80Hz,thespeedof18mm/scasedeterminationof

②Amplitudelinearity:

"

3%;

transversesensitivityratio:

"

5%

③Direction:

（providesforhorizontaldirection0°

）

Vertical:

90°

±

10°

Horizontal:

0°

④OutputResistance:

≤450;

Insulationresistance:

>

20M

4.4HardwareDesignModule

4.4.1Analogsignalconditioningcircuit

JP1thencollectedtherawvibrationsensorscapturesignalamplificationthroughthefilterintotheanalogcircuitA/DchipforA/Dconversion,inordertohostcomputerfordataprocessing.

1.Signalfiltering

Vibrationsensorwillbeanon-powerrotatingmachineryvibrationsignalsintoelectricalsignals,butthevibrationsignalssuperimposedonthesceneuselessnoise,thesenoiseandvibrationsignalsgeneratedatthesametime,somearemixedwiththeprocessofvibrationsignaltransmission,thenoisesometimeswillbegreaterthantheusefulsignal,therebyinundatingusefulsignal.Ifyoudonoteliminatethem,willberightbehindthesignalprocessinganalysistobringtheerror,andevensometimesleadtowrongconclusions,sothecollectedsignalisfiltered.

Generallydividedintolow-passfilters,highpass,bandpassandbandstopfilter,itsfrequencyresponsecharacteristicsasshowninFigure4-2.

Low-passfilteristhelow-frequencysignalswhilethehigh-frequencysignalsarenotpassedthroughthefilter.High-passfilterandlow-passfilterperformanceisjusttheopposite,namely,high-frequencysignalsthroughthelow-frequencysignalisnotpassed;

band-passfilteristhefrequencyinarangeofthesignalthrough,whileoutsidethescopeofthisCouldnotgetit;

band-stopperformanceandband-passfilteristheopposite,thatis,withinthescopeofacertainfrequencybandsignalisblocked,inwhichthesignaloutsidethepassband..

FieldDynamiccollectedvibrationsignalsareoftenmixedwithalotofuselessnoise,fornoise,itsfrequencyisdifficulttoquantifygiventhesizeofthevalueofdesignaslongasthefilterwhenconsideringhigh-frequencyinterferencesignalsuppression.AccordingtoNyquist'

sLaw,datacollectiondevicesfordataacquisitionfrequencymustbegreaterthantwicethehighestfrequencyvibrationsignal,thesignalcannotoccuruntilthefrequencyaliasingphenomenon,theneedtodesignalow-passfilterforvibrationsignalthrough,filteroutsomehigh-frequencyinterference.Thesimplestlow-passfilterformedbycapacitorsandresistors,showninFigure,AsimpleRClow-passcircuit,thegeneralcallitpassivelow-passfilter.

Thelow-passfilter

Figure4-3showstheRClow-passfiltercircuit,thevoltageloopequation:

Itsgain

Theavailabilityoftheactualgainof

Gainvalueisafunctionoffrequencyinthelowfrequencyarea

Minimal，

Signalpass;

highfrequencyarea

Great，

Signalunreasonable。

Unreasonablewhentheypasswiththeclinicalpointoftimethefrequencyisdefinedasthecut-offfrequency:

2．Signalamplification

Intherotatingmachineryvibrationsignalsmeasurement,thesensor'

soutputsignalisveryweak,generallycannotbedirectlyusedtodisplay,record,orconversion,theneedforamplification,pairsofrotatingmachineryvibrationsignalsmeasurementsystemusesthefollowingcharacteristicsoftheamplifierrequires:

①Frequencybandwidth,andcanenlargeDCsignal；

②Highprecision,goodlinearity；

③Highinputimpedance,lowoutputimpedance

④Lowdrift,lownoise；

⑤Powerfulanti-common-modeinterference。

ICopampiscomposedofhigh-gainanalogelectronicdevices,duetolowprices,combinedflexibleandwidelyused.Analogsignalscanbeproportional,integral,differential,andadditionandsubtractionandotheroperations.Figure4-4shows,LM324ADforOperationalAmplifierchips,withtheR22,andC4compositionamplifiercircuit,thecircuitsetthecapacitorC4istheroleofnegativefeedback:

RFCFisnotlarge,low