基于低次故障特征阶比系数的变转速滚动轴承等效转频估计算法.pdf

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1、第51卷第3期机械工程学报Vol.51No.32015年2月JOURNALOFMECHANICALENGINEERINGFeb.2015DOI：10.3901/JME.2015.03.121基于低次故障特征阶比系数的变转速滚动*轴承等效转频估计算法王天杨李建勇程卫东(北京交通大学机械与电子控制工程学院北京100044)摘要：基于时频表达的阶比跟踪算法能够帮助实现变转速旋转设备的故障诊断而不依靠转速计的帮助。然而，滚动轴承振动信号的时频表达却因缺少明显且易提取的转频成分使得该算法无法得到应用。为此，引入瞬时故障特征频率作为滚动轴承的等效转频，并提出基于低次故障特征阶比系数

2、的估计算法对其进行提取。根据转频的变化范围确定基本滤波带宽并沿频率轴构造一组带通滤波器对原信号进行带通滤波。计算各带通滤波结果的包络时频谱并提取相应的等效转频趋势线。利用等效转频趋势线对相应的滤波结果进行重采样并计算故障特征阶比包络谱。将各阶比包络谱中与一、二、三次故障特征阶比相对应的幅值之和作为标准确定最优滤波带宽与相应的等效转频趋势线(瞬时故障特征频率趋势线)。利用该趋势线对原始信号进行故障相角域重采样，所得结果故障特征阶比包络谱即可用于滚动轴承的故障诊断。仿真算例和应用实例证明了该算法的有效性。关键词：低次故障特征阶比系数；等效转频；瞬时故障特征频率；变转速；滚动

3、轴承；故障诊断中图分类号：TH113；TH165EquivalentRotationalFrequencyEstimationAlgorithmofFaultyRollingBearingunderVaryingRotationalSpeedBasedontheLowerFaultCharacteristicOrderCoefficientWANGTianyangLIJianyongCHENGWeidong(SchoolofMechanicalElectronicandControlEngineering,BeijingJiaotongUniversity,Beijin

4、g100044)Abstract：Extractionoftherotationalfrequencyisthekeystepofemployingordertrackingbasedonthetime-frequencyrepresentation(TFR)infaultdiagnosisofrotationalmechanicalmachineryundervaryingrotationalspeedtheassistanceofaspeedsensor.However,thelackofobviousandextractablerotationalfrequenc

5、ycomponentsintheTFRofthevibrationsignaloftherollingbearingwillblocktheusageofthisalgorithm.Assuch,anewequivalentrotationalfrequency(ERF)ofIRF,theinstantaneousfaultcharacteristicfrequency(IFCF),isintroduced,andacorrespondingestimationalgorithmbasedonthelowerfaultcharacteristicordercoeffic

6、ientisproposedtoestimatethisERF.Aseriesofband-passfilterswhosefrequencybandscanbedeterminedbytherangeofrotationalfrequencyareconstructedalongthefrequencyaxis.TheERFsofalltheseband-passfilteredresultsarethenextractedfromtheenvelopetime-frequencyrepresentationofthecorrespondingband-passfil

7、teredresults.Thefaultcharacteristicorder(FCO)envelopespectrumsarecalculatedbasedontheresampledversionoftheband-passedfilteredsignalusingthecorrespondingERF.Thelowerfaultcharacteristicordercoefficientwhichequalstotheamplitudesummationofthe1st,the2ndandthe3rdfaultcharacteri