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基于小波包和神经网络的柴油机气门故障诊断 总被引:1,自引:0,他引:1
通过调整柴油机不同气门间隙模拟故障,利用小波包分解算法对所采集柴油机缸盖表面的振动信号进行频带分解,以小波包频带能量百分比为特征向量,以同一工况下多次采样均值作为标准模式,通过改进BP神经网络实现了对柴油机气门间隙异常的故障诊断. 相似文献
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《仪表技术与传感器》2020,(1)
为了对包装件的疲劳损伤进行预测,基于振动信号,提出一种HHT边际谱特征和相关向量机(RVM)相结合的包装件疲劳损伤预测方法。首先,设计了包装件的振动损伤测试系统并进行试验方案设计,在此基础上采集损伤状态数据;然后采用希尔伯特-黄变换HHT方法及边际谱特征对采集的振动信号进行预处理,采用多距离形态相似度评估方法构建包装件损伤指数;最后,将损伤指数作为相关向量机(RVM)的建模数据,结果表明该模型达到了较好的预测效果,实现了基于振动信号的包装件损伤预测。 相似文献
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陈瑞晶 《中国工程机械学报》2013,(6):547-550
采用BSWA VS302 USB便携式双声道声学振动分析仪对DA462型发动机进行振动试验,试验时分别模拟气门间隙正常与故障状况,采集不同转速时不同气门间隙下发动机表面的振动信号.用db4小波对这些振动信号进行分解,重点分析了发动机排气门落座的冲击信号即D3层信号.分析结果表明:db4小波适合于发动机振动信号分析;发动机气门间隙的变化会引起振动能量的变化,气门落座冲击产生的能量占总能量的比例也会发生很大变化.根据测量不同转速时的能量分布结果和能量比数值,可以判断出当前气门间隙的工作状态,实现发动机在不解体情况下的状态检测. 相似文献
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基于数据挖掘的柴油机气门故障诊断技术研究 总被引:7,自引:0,他引:7
由于柴油机气缸缸盖振动信号具有复杂的时频特性,通过此类信号实现其气门故障的诊断较为困难。尤其在多种故障并发的条件下,故障确诊更为不易。为此,借助遗传算法提出一种基于统计规则的智能数据挖掘技术,对在不同气门状态下采集的大量柴油机气门缸盖振动信号进行知识挖掘,得到了进行多种气门故障确诊的有效诊断特征。试验表明,这一技术智能高效,结果准确无误,具有重要实践意义。 相似文献
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Fault feature extraction has a positive effect on accurate diagnosis of diesel engine. Currently, studies of fault feature extraction have focused on the time domain or the frequency domain of signals. However, early fault signals are mostly weak energy signals, and time domain or frequency domain features will be overwhelmed by strong back?ground noise. In order consistent features to be extracted that accurately represent the state of the engine, bispectrum estimation is used to analyze the nonlinearity, non?Gaussianity and quadratic phase coupling(QPC) information of the engine vibration signals under different conditions. Digital image processing and fractal theory is used to extract the fractal features of the bispectrum pictures. The outcomes demonstrate that the diesel engine vibration signal bispectrum under different working conditions shows an obvious differences and the most complicated bispectrum is in the normal state. The fractal dimension of various invalid signs is novel and diverse fractal parameters were utilized to separate and characterize them. The value of the fractal dimension is consistent with the non?Gaussian intensity of the signal, so it can be used as an eigenvalue of fault diagnosis, and also be used as a non?Gaussian signal strength indicator. Consequently, a symptomatic approach in view of the hypothetical outcome is inferred and checked by the examination of vibration signals from the diesel motor. The proposed research provides the basis for on?line monitoring and diagnosis of valve train faults. 相似文献
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针对齿轮箱故障振动信号大多是多分量的调幅-调频信号,而传统包络分析法又太依赖经验值选取参数的问题,对齿轮箱振动信号的分解方法、包络分析方法以及提取特征值等方面进行了研究,提出了一种基于局部均值分解(local mean de-composition,LMD)的包络谱特征值的方法。该方法首先利用局部均值分解对齿轮箱信号进行了处理,获得了包含有不同频率特征的PF(product function)分量,最后对包含有主要故障信息的第一级PF分量进行了包络分析,提取了包络谱的特征频率,以此来判别齿轮箱的工作状态和故障类型。利用齿轮箱正常状态、局部损伤、磨损故障3种齿轮箱振动信号的实例进行了验证。研究结果表明,利用LMD分解后求取包络谱特征频率的方法能够较为准确地判别齿轮箱的工作状态和故障类型。 相似文献
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Hilbert-Huang变换在滚动轴承故障诊断中的应用 总被引:12,自引:0,他引:12
提出了一种新的滚动轴承故障诊断方法——基于小波系数包络信号的局部Hilbert边际谱方法,在Hilbert—Huang变换的基础上介绍了局部Hilbert谱和局部Hilbert边际谱,并将它应用于滚动轴承的故障诊断中。用小波基将滚动轴承故障振动信号分解,对高频段的小波系数用Hilbert进行包络分析得到包络信号,再对包络信号进行Hilbert—Huang变换求出局部Hilbert边际谱,从局部Hilbert边际谱中就可以判断滚动轴承的故障部位和类型。通过对滚动轴承具有外圈缺陷、内圈缺陷的情况下的振动信号的分析,说明该方法比传统的包络分析方法更能有效地提取滚动轴承故障特征。 相似文献
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FAULT DIAGNOSIS APPROACH FOR ROLLER BEARINGS BASED ON EMPIRICAL MODE DECOMPOSITION METHOD AND HILBERT TRANSFORM 总被引:2,自引:0,他引:2
Yu Dejie Cheng Junsheng Yang Yu College of Mechanical Automotive Engineering Hunan University Changsha China 《机械工程学报(英文版)》2005,18(2):267-270
Based upon empirical mode decomposition (EMD) method and Hilbert spectrum, a method for fault diagnosis of roller bearing is proposed. The orthogonal wavelet bases are used to translate vibration signals of a roller bearing into time-scale representation, then, an envelope signal can be obtained by envelope spectrum analysis of wavelet coefficients of high scales. By applying EMD method and Hilbert transform to the envelope signal, we can get the local Hilbert marginal spectrum from which the faults in a roller bearing can be diagnosed and fault patterns can be identified. Practical vibration signals measured from roller bearings with out-race faults or inner-race faults are analyzed by the proposed method. The results show that the proposed method is superior to the traditional envelope spectrum method in extracting the fault characteristics of roller bearings. 相似文献
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为了提高发动机故障分类的准确率和成功率,提出了基于角域信号特征统计量的发动机故障分类方法。包括:利用编码器进行发动机振动信号的等角度采样;采用小波包分析和相关系数法获取发动机角域信号的特征阶次;选取特征阶次信号的能量比、标准差比、谱能量比及谱均值比4组参数作为角域信号特征统计量来提取发动机故障特征;采用支持向量机法对发动机故障进行分类。连杆轴承配合间隙故障的台架试验结果证明:相比于传统的分类方法,该方法明显提高了发动机故障分类的准确率。 相似文献
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分形维数在内燃机振动诊断中的应用 总被引:4,自引:0,他引:4
将分形理论引入内燃机的振动诊断中,根据内燃机的配气定时,着重研究了缸盖振动信号中对应燃烧段的数据,计算其关联维数,将关联维数用于刻划内燃机缸盖在气门不同状态时表现的非线性行为,从而进行故障诊断与分类。结果表明,当气门在不同状态时,缺盖振动信号中对应燃烧段数据的关联维数是不同的,可以将其作为判断气门漏气的一个诊断特征量。 相似文献
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针对柴油机故障诊断方法中的信号时频表征及特征提取问题,提出一种基于振动信号快速稀疏分解与二维时频特征编码识别的柴油机智能故障诊断方法。首先,为了获得时、频聚集性优良的时频图像,提出一种随分解残差信号自适应更新Gabor字典的改进匹配追踪(adaptive matching pursuit,简称AMP)算法,利用AMP算法将柴油机振动信号分解后叠加各原子分量的Wigner-Ville分布,获取原信号的稀疏分解时频图像;然后,为提取时频图像的特征参量,提出了双向二维非负矩阵分解(two-directional,2-dimensional non-negative matrix factorization,简称TD2DNMF)算法,用于对时频图像的幅值矩阵进行特征编码,获取蕴含在时频图像内部的低维特征,并利用最近邻分类器实现了时频图像的自动分类识别。将提出的方法应用于4种不同状态柴油机气门故障的诊断试验中,结果表明,该方法能够获得无交叉项干扰、聚集性好的时频图像,使各时频分量的物理意义更加明确,并改进了传统图像模式识别中的特征参数提取方法,是一种有效的柴油机故障诊断方法。 相似文献
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Wear detection in gear system using Hilbert-Huang transform 总被引:1,自引:0,他引:1
Fourier methods are not generally an appropriate approach in the investigation of faults signals with transient components.
This work presents the application of a new signal processing technique, the Hilbert-Huang transform and its marginal spectrum,
in analysis of vibration signals and faults diagnosis of gear. The Empirical mode decomposition (EMD), Hilbert-Huang transform
(HHT) and marginal spectrum are introduced. Firstly, the vibration signals are separated into several intrinsic mode functions
(IMFs) using EMD. Then the marginal spectrum of each IMF can be obtained. According to the marginal spectrum, the wear fault
of the gear can be detected and faults patterns can be identified. The results show that the proposed method may provide not
only an increase in the spectral resolution but also reliability for the faults diagnosis of the gear. 相似文献