Faulted gear identification of a rotating machinery based on wavelet transform and artificial neural network

In this paper, a condition monitoring and faults identification technique for rotating machineries using wavelet transform and artificial neural network is described. Most of the conventional techniques for condition monitoring and fault diagnosis in rotating machinery are based chiefly on analyzing the difference of vibration signal amplitude in the time domain or frequency spectrum. Unfortunately, in some applications, the vibration signal may not be available and the performance is limited. However, the sound emission signal serves as a promising alternative to the fault diagnosis system. In the present study, the sound emission of gear-set is used to evaluate the proposed fault diagnosis technique. In the experimental work, a continuous wavelet transform technique combined with a feature selection of energy spectrum is proposed for analyzing fault signals in a gear-set platform. The artificial neural network techniques both using probability neural network and conventional back-propagation network are compared in the system. The experimental results pointed out the sound emission can be used to monitor the condition of the gear-set platform and the proposed system achieved a fault recognition rate of 98% in the experimental gear-set platform.     

An automotive generator fault diagnosis system using discrete wavelet transform and artificial neural network

This paper describes a fault diagnosis system for automotive generators using discrete wavelet transform (DWT) and an artificial neural network. Conventional fault indications of automotive generators generally use an indicator to inform the driver when the charging system is malfunction. But this charge indicator tells only if the generator is normal or in a fault condition. In the present study, an automotive generator fault diagnosis system is developed and proposed for fault classification of different fault conditions. The proposed system consists of feature extraction using discrete wavelet analysis to reduce complexity of the feature vectors together with classification using the artificial neural network technique. In the output signal classification, both the back-propagation neural network (BPNN) and generalized regression neural network (GRNN) are used to classify and compare the synthetic fault types in an experimental engine platform. The experimental results indicate that the proposed fault diagnosis is effective and can be used for automotive generators of various engine operating conditions.     

An application of a discrete wavelet transform and a back-propagation neural network algorithm for fault diagnosis on single-circuit transmission line

This article proposes an application of the discrete wavelet transform (DWT) and back-propagation neural networks (BPNN) for fault diagnosis on single-circuit transmission line. ATP/EMTP is used to simulate fault signals. The mother wavelet daubechies4 (db4) is used to decompose the high-frequency component of these signals. In addition, characteristics of the fault current at various fault inception angles, fault locations and faulty phases are detailed. The DWT is employed in extracting the high frequency component contained in the fault currents, and the coefficients of the first scale from the DWT that can detect fault are investigated, and the decision algorithm is constructed based on the BPNN. The results show that the proposed technique provides satisfactory results.     

Fault diagnostic of induction motors for equipment reliability and health maintenance based upon Fourier and wavelet analysis

The motor is the workhorse of industry. The issues of preventive and condition-based maintenance, on-line monitoring, system fault detection, diagnosis, and prognosis are of increasing importance. This paper introduces fault detection for induction motors. Stator currents are measured by current meters and stored by time domain. The time domain is not suitable for representing current signals, so the frequency domain is applied to display signals. The Fourier transform is employed to convert signals. After signal conversion, signal features must be extracted by signal processing such as wavelet and spectrum analysis. Features are entered in a pattern classification model such as a neural network model, a polynomial neural network, or a fuzzy inference model. This paper describes fault detection results that use Fourier and wavelet analysis. This combined approach is very useful and powerful for detection signal features.This work was presented in part at the 9th International Symposium on Artificial Life and Robotics, Oita, Japan, January 28–30, 2004This work has been supported by “Research Center for Future Logistics Information Technology” hosted by the Ministry of Education in Korea.     

Copyright-proving scheme for audio with counter-propagation neural networks

Protecting the intellectual property rights (IPR) of digital media has become an important issue. In this paper, counter-propagation neural networks (CPN) are applied to audio copyright protection. The db4 filter of the Daubechies wavelet is used on the original audio signals. The coefficients obtained from the 4-level Daubechies (db4) filter and the corresponding copyright information are used to train the CPN. Since the low-frequency components of DWT are robust, most noise is excluded. The CPN has memory and fault tolerance, so most attacks do not degrade the quality of the extracted copyright image. Moreover, the copyright generation procedure and the verification procedure are integrated into the proposed CPN method. Experimental results show that the proposed CPN-based method is robust, inaudible, and authentic.     

Fault gear identification and classification using discrete wavelet transform and adaptive neuro-fuzzy inference

In this paper, an intelligent diagnosis for fault gear identification and classification based on vibration signal using discrete wavelet transform and adaptive neuro-fuzzy inference system (ANFIS) is presented. The discrete wavelet transform (DWT) technique plays one of the important roles for signal feature extraction in the proposed system. The abnormal transient signals will show in different decomposition levels and can be used to recognize the various faults by the DWT figure. However, many fault conditions are hard to inspect accurately by the naked eye. In the present study, the feature extraction method based on discrete wavelet transform with energy spectrum is proposed. The different order wavelets are considered to identify fault features accurately. The database is established by feature vectors of energy spectrum which are used as input pattern in the training and identification process. Furthermore, the ANFIS is proposed to identify and classify the fault gear positions and the gear fault conditions in the fault diagnosis system. The proposed ANFIS includes both the fuzzy logic qualitative approximation and the adaptive neural network capability. The experimental results verified that the proposed ANFIS has more possibilities in fault gear identification. The ANFIS achieved an accuracy identification rate which was more satisfactory than traditional vision inspection in the proposed system.     

An expert system for fault diagnosis in internal combustion engines using probability neural network

An expert system for fault diagnosis in internal combustion engines using adaptive order tracking technique and artificial neural networks is presented in this paper. The proposed system can be divided into two parts. In the first stage, the engine sound emission signals are recorded and treated as the tracking of frequency-varying bandpass signals. Ordered amplitudes can be calculated with a high-resolution adaptive filter algorithm. The vital features of signals with various fault conditions are obtained and displayed clearly by order figures. Then the sound energy diagram is utilized to normalize the features and reduce computation quantity. In the second stage, the artificial neural network is used to train the signal features and engine fault conditions. In order to verify the effect of the proposed probability neural network (PNN) in fault diagnosis, two conventional neural networks that included the back-propagation (BP) network and radial-basic function (RBF) network are compared with the proposed PNN network. The experimental results indicated that the proposed PNN network achieved the best performance in the present fault diagnosis system.     

某型导弹测角仪故障检测的小波分析方法研究

现有的时频分析方法很难检测到某型导弹测角仪故障,针对这个问题,提出测角仪故障检测的连续和离散小波变换相结合的时频分析法.给出该方法提出的过程,分析连续和离散小波变换时烦分析法,将两种分析方法的特点结合起来共同分析测角仪故障时的信号信息.通过仿真实验证明,提出的方法能准确的提取测角仪故障时的信号特征,对测角仪故障的检测是...     

一种基于LabVIEW DSP模块的风机故障诊断系统

设计一种基于图形化开发环境LabVIEW DSP模块的风机故障诊断系统开发方案。方案以32位浮点DSP芯片TMS320C6713为核心,采集风机噪声信号并利用信号的功率谱重心、A声级和小波分解相关频段的能量构成故障诊断的特征向量,以BP网络作为故障的智能分类器,建立起智能诊断系统。实验结果表明,以噪声信号作为诊断对象,采用提升小波和神经网络相融合的诊断与识别技术具有良好的特征提取能力和自适应学习能力,可以准确地识别设备状态。     

A study of fault diagnosis in a scooter using adaptive order tracking technique and neural network

An expert system for scooter fault diagnosis using sound emission signals based on adaptive order tracking and neural networks is presented in this paper. The order tracking technique is one of the important approaches for fault diagnosis in rotating machinery. The different faults present different order figures and they can be used to determine the fault in mechanical systems. However, many breakdowns are hard to classify correctly by human experience in fault diagnosis. In the present study, the order tracking problem is treated as a parametric identification and the artificial neural network technique for classifying faults. First, the adaptive order tracking extract the order features as input for neural network in the proposed system. The neural networks are used to develop the training module and testing module. The artificial neural network techniques using a back-propagation network and a radial basis function network are proposed to develop the artificial neural network for fault diagnosis system. The performance of two techniques are evaluated and compared through experimental investigation. The experimental results indicated that the proposed system is effective for fault diagnosis under various engine conditions.     

基于ART2神经网络的发动机故障诊断方法

发动机的故障诊断是一个动态的故障分类过程,许多故障诊断方法在对动态故障模式进行识别和分类时,存在对未知故障模式无法识别的问题。针对这一问题,引入ART2神经网络,利用db6小波包对发动机气缸盖的振动信号提取的特征向量作为网络的输入,应用实例证明,ART2神经网络不仅能正确识别学习过的故障模式,对突发、未知的故障模式也能很好地识别。     

A self-adaptive data analysis for fault diagnosis of an automotive air-conditioner blower

This paper presents a fault diagnosis system for an automotive air-conditioner blower based on a noise emission signal using a self-adaptive data analysis technique. The proposed diagnosis system consists of feature extraction using the empirical mode decomposition (EMD) method and fault classification using the artificial neural network technique. The EMD method has been developed quite recently to adaptively decompose the non-stationary and non-linear signals. It sifts the complex signal of time series without losing its original properties and then obtains some useful intrinsic mode function (IMF) components. Calculating the energy of each component can reduce the computation dimensions and enhance classification performance. These energy features of various fault conditions are used as inputs to train the artificial neural network. In the fault classification, the probabilistic neural network (PNN) is used to verify the performance of the proposed system and compare with the traditional technique, back-propagation neural network (BPNN). The experimental results indicated the proposed technique performed well for quickly and accurately estimating fault conditions.     

Fault diagnosis of spur bevel gear box using discrete wavelet features and Decision Tree classification

The wavelet transform (WT) is used to represent all possible types of transients in vibration signals generated by faults in a gear box. It is shown that the transform provides a powerful tool for condition monitoring and fault diagnosis. The vibration signal of a spur bevel gear box in different conditions is used to demonstrate the application of various wavelets in feature extraction. In present work, a discrete wavelet, Daubechies wavelets (db1–db15) is used for feature extraction and their relative effectiveness in feature extraction is compared. The major steps in pattern classification are feature extraction and classification. This paper investigates the use of discrete wavelets for feature extraction and a Decision Tree for classification. J48 Decision Tree algorithm has been used for feature selection as well as for classification. This paper illustrates the powerfulness and flexibility of the discrete wavelet transform to decompose linear and non-linear processing of vibration signal.     

一种推挽式电路故障诊断方法的仿真研究

提出了基于小波变换和神经网络的推挽式电路故障诊断方法。先仿真得到各种故障状态下的输出电压信号,然后对输出电压信号进行Daubechies小波变换获取多尺度低频系数和高频系数,并对小波系数进行处理提取故障特征量,最后利用故障特征矢量训练神经网络确定了推挽式电路故障诊断的神经网络模型。仿真结果表明基于小波变换和神经网络的推挽式电路故障诊断方法取得了较好的效果。     

基于小波-神经网络的汽轮机转子故障诊断

结合小波变换和神经网络技术,本文首先利用小波包对故障信号进行分解,然后将归一化后的数据用于RBF神经网络进行汽轮机转子故障分类.MATLAB实验仿真表明小波分析和RBF神经网络的结合在汽轮机转子常见故障的诊断中是很有效的.     

基于小波和统计检验的瞬态成分检测的方法及应用

将连续小波变换技术和统计检验结合用于检测信号中具有一定时频分布的瞬态成分,指出连续小波变换具有分离信号中瞬态成分和噪声的作用。提出一种基于连续小波变换和统计检验的瞬态成分检测的“逐步去除法”。将“逐步去除法”用于齿轮箱振动中的瞬态成分的检测与提取,能比较有效地检测出瞬态成分;基于连续小波变换反演的瞬态成分估计能比较有效地表示设备的状态。     

基于谐波小波包的旋转机械故障诊断新方法

针对旋转机械的故障振动信号通常为复杂的动态非平稳信号,提出一种基于谐波小波包和Elman神经网络的故障诊断新方法。应用谐波小波包对信号进行分解,提取倍频能量特征向量,代入Elman神经网络,实现故障分类。通过试验分析及与BP网络的诊断结果对比,表明该方法在旋转机械的故障诊断方面具有显著优势。     

小波包在故障诊断中的应用

主要研究小波包变换和神经网络相结合的故障诊断技术。首先利用小波包的多分辨率分析的特点,对故障信号进行多尺度的分解,正交和归一化处理后,根据主成份分析原理提取故障特征向量作为神经网络的训练样本,设计故障类型识别器。仿真结果证实了该方法的有效性和可行性。     

基于小波神经网络的组合故障模式识别

提出了一种基于小波神经网络的组合故障模式识别方法.针对以歼击机为代表的非线 性系统中存在的多重并发故障,构造了一个多层的小波神经网络,在输入层对残差信号进行二进 离散小波变换,提取其在多尺度下的细节系数作为故障特征向量,并将其输入到神经网络分类器 进行相应的模式分类.仿真结果表明,本文方法为多重并发故障的诊断提供了有效的方法和途径.     

基于改进型小波神经网络的往复泵故障诊断

为了对往复泵的故障进行正确诊断,提出了基于改进型小波神经网络的往复泵故障诊断方法。以往复泵单个泵缸内的压力信号作为系统特征信号通过小波包分解来提取故障特征向量,同时将此特征向量作为改进型神经网络的输入,利用改进型神经网络对故障做进一步的精确实时诊断。文中对小波神经网络采用的优化算法是：动量因子和学习率自适应调整相结合的梯度下降法,该方法可以提高学习速度并增加算法的可靠性。通过对往复泵液力端多故障诊断实例的检验表明,该系统故障诊断正确率达到了93％以上。