The performance analysis of power spectrum in a regulating valve′s fault diagnosis

利用小波包分别提取调速阀振动时的正常信号和故障信号的Ar功率谱的特征值,之后利用提取的特征值作为lSSVM的输入,对调速阀的故障进行诊断,取得了良好效果,并与原始信号的效果进行了对比,并阐明了原因。By means of wavelet packet, this paper first extracts features from the AR power spectrum of signals in normal and fault state respectively, then the features are input to a LSSVM as parameters to diagnose faults, and the result is satisfactory.Furthermore, the result is compared with that of primary signals, and the causes are interpreted.国家自然科学基金(50975098);2008福建省重大专项课题(2008HZ0201

Application of three-order diagonal cumulants in fault diagnosis

三阶累量能有效去除高斯噪声,而且其对角累量能有效保持信号特征,由其产生的1(1/2)维谱可以显示信号的二次相位耦合信息。实验中通过计算故障信号和正常信号的三阶对角累量信息,然后利用这些信息进行具体的故障判别。实验结果取得了令人满意的效果。Three-order cumulant can eliminate the Gaussian background noise and keep signals features effectively.The 1(1/2) dimensional spectrum originated from it can display the signal of quadratic phase coupling information.The vibration signals of relief valve in normal and anormal situations were collected in the experiment.Three-order diagonal cumulants of collected signals were calculated out,the feature vector was extracted,and then the fault diagnosis was conducted with least squares vector machine.The experiment indicates that the validity is above 80% and the method is feasible.国家自然科学基金(50975098);福建省教育厅A类科技项目(JA11342

Fault Diagnosis of Reducing Valve with BP Neural Network

提出一种使用bP神经网络检测减压阀故障信号的方法。通过提取减压阀振动时的正常信号和故障信号的均值、标准差、偏度和峰度,作为特征值对建立的bP网络进行训练,再进行故障辨识,取得了令人满意的结果。实验结果证明,利用bP网络进行机械故障检测是可行的。A method of reducing valve fault diagnosis was proposed based on BP neural network.The BP network was built and trained through eigenvalues,such as mean,standard variance,skewness and kurtosis of normal signals and fault signals extracted from reducing valve's vibration.Then fault identifications were made and the results were satisfactory.The experimental results indicate it is feasible to carry out fault diagnosis using BP neural network.国家自然科学基金(50975098);2008福建省重大专项课题(2008HZ0201

Hydraulic valve fault signal detection based on AR parameter

本文提出了一种使用最小支持向量机检测溢流阀故障信号的方法。通过提取溢流阀振动时的正常信号和故障信号,在此基础上进行了Ar建模,并由建立的模型获取了信号的Ar参数,之后利用这些参数作为最小支持向量机的输入进行故障辨识,取得了令人满意的结果。The paper presents the method to adopt least squares support vector machine to detect the overflow valve fault signal,and shows AR modeling by taking normal signal and fault signal during overflow valve vibration and obtains AR parameter of the collected signal based on the model and then adopts these parameters as input for least squares support vector machine to implement fault identification and achieves satisfactory result.国家自然科学基金(50975098);2008福建省重大专项课题(2008HZ0201

Application of complex cumulants slices in mechanical fault diagnosis

复数三阶累量具有不同的定义形式,定义形式不同,其耦合性质也不相同,则由其产生的复数累量切片也包含了信号间不同的耦合信息,实验中利用这些不同的定义方式,对特定的故障信号和正常信号同时采用相同的耦合方式进行故障判别。同时定义了复数三阶累量切片谱,通过切片谱对正常信号和故障信号的耦合特征进行了分析。实验结果表明,随着耦合方式的不同,同一故障的诊断正确率也不相同,从而为特定的故障判别提供了一种可供选择的方法。Complex third-order cumulant has different definition forms.Different forms have different coupling properties, and the generated complex cumulants slices contain different coupling information of signals.In experiments, using the different definitions, the same coupling method is applied to both specific fault signals and normal signals.Furthermore, complex third-order cumulant slices spectrum is defined, and it is used to analyse the coupling features of normal signals and fault signals.Experiments indicate, the detection accuracy rate on the same fault are not the same with the different coupling methods, thus, it provides an alternative method to diagnose the specific fault.国家自然科学基金(No.50975098); 福建省教育厅A类科技项目(No.JA11342

The fractal features of bi-spectral slices applied in fault diagnosis

减压阀是液压系统中的一种重要元件,也很容易发生故障,如何对减压阀发生的故障进行诊断,对于机械系统的维护有着重要意义。首先获取了减压阀振动时的正常信号和故障信号的Ar双谱切片,再根据双谱切片所呈现出的自相似性,分别计算了每组数据的容量维数,并由计算结果进行故障诊断,取得了良好效果。Relief valve is an important component of a hydraulic system,and it is easy to go wrong.How to diagnose the faults is very important for the maintenance of mechanic system.By means of AR model,this paper first acquires the AR bi-spectral slices of signals in normal and fault state respectively,considering the self-similarity of the spectrum,then calculate out the capacity dimension of each data obtained in this experiment.Furthermore,the result is used to diagnose the fault of relief valve,and the diagnosis accuracy is satisfactory.国家自然科学基金(50975098

Fault diagnosis of hydraulic valve based on capacity dimension of AR power spectrum

减压阀在液压系统中很容易发生故障,对减压阀进行故障诊断对于机械系统的维护有着重要意义。该文首先利用Ar模获取减压阀振动时的正常信号和故障信号的Ar功率谱,根据功率谱所呈现出的自相似性,分别计算了每组数据的容量维数,并由计算结果对液压系统减压阀进行故障诊断,取得了良好效果。The relief valve is easy to break down in hydraulic systems.The fault diagnosis of the relief valve is significant for maintaining the mechanical system.By means of AR model,the AR power spectrum of normal and fault signals from the vibration of the relief valve was acquired respectively.According to the self-similarity of the power spectrum,the capacity dimension of each set of data was calculated in an experiment.The fault diagnosis of relief valve was implemented according to the calculated result.The diagnosis accuracy is satisfactory.国家自然科学基金(50975098

The Effect of Bispectrum Coupling Property on Fault Diagnosis

为了对双谱的耦合性质进行分析,同时利用三阶累积量和双谱对溢流阀进行故障诊断。由于双谱与三阶累积量相比,可以用来描述二次相位耦合,对比实验结果表明,故障的种类不同,其耦合信息对于这些故障判断的影响也不一样。实验中还通过二维小波在不同的方向上对故障信号和正常信号进行特征提取,然后将这些特征值输入支持向量机进行故障判别,实验结果表明,无论考虑耦合因素与否,这些故障信号在不同的频率部分与其正常状态的区分程度都不一样。In order to analyze the coupling properties of bispectrum,both bispectrum and three order cumulants were used to diagnose faults.Compared with three order cumulants,bispectrum concludes the quadratic phase coupling information.The comparative experimental results indicate that,when the kinds of faults were different,the impact of coupling information on the results of fault diagnosis became different too.Furthermore,the features of fault signals and normal signals were extracted by 2-D wavelet in different directions,then these features were input into support vector machine to diagnose the faults,and the results show,whether coupling information were included or not,the corrects of diagnosis were different when all these faults were in different frequencies parts.国家自然科学基金(50975098); 厦门市科技计划项目(3502Z20123013

The Impact of Complex Cumulants'conpling Properties on the Results of Fault Diagnosis

复数三阶累积量具有不同的定义形式,定义形式不同,其包含的耦合信息也不相同。在复数累积量切片以及三阶对角累积量的基础上,定义了三阶累积量切片谱以及三阶对角累积量谱,实验中利用这两种谱的不同的耦合方式,通过计算容量维,对采集的故障信号和正常信号进行故障判别。实验结果表明,两种定义方式的谱,在不同的耦合方式下,对同一故障的诊断正确率结果类似,表明了影响故障诊断结果的不是谱的形式,而是其中包含的不同的耦合信息。Complex third-order cumulant has different definition forms.Different forms conclude different information.Based on three order cumulant slices and diagonal cumulants,complex third-order cumulgant slices spectrum and diagonal cumulant spectrum are defined.In experiments,using the different coupling modes,the capacity dimensions are caculated to diagnose faults.Experiments indicate,the two kinds of spectrum in different modes,the detection accuracy rates on the same fault are similar,thus,the experiments proved that the diagnosis result is not effected by different kinds of spectrum forms,but by the different coupling information included in the spectrum.国家自然科学基金资助项目(50975098); 厦门市科技计划资助项目(3502Z20123013

Application of Complex Bispectral Coupling Properties in Fault Diagnosis

为了提高故障诊断正确率,提出了一种基于复双谱的机械故障诊断方法.这种方法根据复双谱的不同耦合方式进行故障判别.由于耦合方式不同,复双谱包含的信号间的耦合信息也不相同,这些信息可以用来进行故障诊断.在减压阀故障诊断实验中,对特定的故障信号和正常信号同时采用相同的耦合方式,根据二维小波可以有效提取信号中频率信息的特点,利用二维小波提取复双谱中的这些耦合信息的特征值,并将这些特征值输入支持向量机进行故障判别.实验结果表明,随着耦合方式的不同,同一故障的诊断正确率也不相同.To improve the correct rate of fault diagnosis,a method of mechanical fault diagnosis based on complex bispectrum was proposed.This method diagnosed fault according to the different coupling modes of complex bispectrum.Because of different coupling modes,the complex bispectrum contained different coupling information of signals,and the information could be used to diagnose fault.In the fault diagnosis experiment of pressure reducing valve,the same coupling mode was applied to both fault signals and normal signals.Because two dimensional wavelet could effectively extract frequencies information from signals,the features of coupling information in complex bispectrum were extracted by 2-D wavelet,then the features were input into support vector machine to diagnose fault.Experiment results show that the correct rates of the same fault are also different with the different coupling modes.国家自然科学基金资助项目(50975098