Research on the application of HOC coupling properties in hydraulic faults diagnosis

本文以液压系统常用的液压阀（溢流阀、减压阀、调速阀）为研究对象，基于高阶累积量和高阶谱，采用小波、分形和神经网络等理论方法对液压阀的振动信号进行分析，实现液压阀的故障识别。 液压阀在正常与不同故障状态下工作时，其振动信号通过双谱分析谱图各有差异。正常状态和故障状态的双谱相比，在分布范围和谱峰多少均体现出不同的特性。双谱维切片较双谱更具体更直观地表征液压阀故障信息的频率位置，且计算量也相对减少。两种谱分析方法均十分有效地对液压阀进行故障识别。在此基础上，以高阶累积量的耦合性质理论为依据，将采集的原始信号变换为复数信号，再通过复数高阶累积量的各种不同的耦合方式分析各种故障产生的结果，将正常信号和...In this paper,the usual hydraulic valves (reducing valve, overflow valve and speed-regulating valve) in hydraulic system were studied. Based on higher-order cumulants (HOC), higher-order spectrum (HOS) and its coupling features, wavelet、fractal and neural network theories were used to analyze the vibration signals extracted from hydraulic valves, and the fault recognition were accomplished. Autor...学位：工学博士院系专业：信息科学与技术学院电子工程系_电路与系统学号：2312009015369

DIAGNOSIS of FLOW CONTROL VALVE USING WAVELET PACKET

提出了一种利用小波包检测调速阀故障信号的方法。通过小波的小波包分析将信号按一定的尺度进行划分,不同频率的信号被划分到不同的频段中。由经过预处理的信号经过小波包分解与重构后,可以得到小波包重构图,由图中可以获得故障产生的时间点和频率,再对故障的严重程度进行了量化分析。实验结果表明用小波包理论进行故障检测是可行的。We propose the method of flow control valve fault diagnosis employing wavelet packet analysis.We can filter signals into different frequency band based on wavelet packet.According to the wavelet packet decomposition and reconstruction of preprocessed signal,we can get the wavelet packet reconstruction map,through which the time and frequency of the fault signal could be extracted as to measure the damage extent.The experiment results indicate it is feasible to carry out fault diagnosis using wavelet packet theory.2008福建省重大专项课题(2008HZ0201

Fault Analysis of Overflow Valve Based on High Order Spectrum

提出了一种利用三谱对角切片分析溢流阀故障信号的方法。高阶谱理论上能完全消除高斯噪声的影响,本文由经过预处理的信号经过高阶谱分析后,可以得到三谱对角切片图,由图中可以获得正常信号与故障信号在切片图上的差异。试验结果表明利用高阶谱理论进行故障检测是可行的。A method of overflow valve fault analysis based on high order spectrum was proposed in this thesis.High order spectrum can fully eliminate Gaussian noise theoretically.Via the high order spectrum analysis of preprocessed signal,the trispectrum diagonal slices can be obtained.through which the difference between normal and abnormal signals can be found.The experiment results indicate it is feasible to carry out fault analysis using high order spectrum.2008福建省重大专项课题(2008HZ0201

Complex Cepstral Analysis In Wavelet Based Speech Denoising

小波阈值去噪方法是一种实现简单、效果较好的小波去噪方法。本文在对所采集的带噪语音信号进行了小波阀值去噪以后,利用复倒谱对去噪前后的效果进行了对比,结果显示去噪后的语音信号的复倒谱相对于去噪前的相比,明显降低了峰值,说明小波去噪取得了良好效果。Wavelet threshold denoising method is a simple and efficient way in speech denoising.In the paper,we reduce the noise in the sampled speech signal using wavelet threshold denoising approach,and complex cepstrum is calculated for both original signal and denoised signal.Comparison shows complex cepstrum peak value of denoised signal is significantly lowered.The results indicate that wavelet threshold denoising approach is effective and works well.基金申请人:吴为民;项目名称:语音识别中去噪方法研究;基金颁发部门:福建省教育厅;编号:JA1029

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

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 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

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

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