基于二叉树的支持向量机旋转机械故障诊断方法

支持向量机理论最初是针对两类模式识别问题而提出的.在故障诊断领域,多类故障诊断问题更为普遍.针对支持向量机常用的多类分类算法进行了分析,在此基础上提出了一种基于聚类思想的二叉树多类分类算法,并运用该算法对转子模拟试验台几种典型的故障进行了模式识别,实验结果表明新方法能有效地、准确地识别故障模式,比较符合实际工程要求,具有较高的推广性能.     

磷虾算法优化多分类支持向量机的轴承故障诊断

为了提高滚动轴承故障类型诊断准确度,提出了磷虾算法优化多分类支持向量机的轴承故障诊断方法。对于时频域特征参数的提取,将CEEMD算法与小波包优势结合,提出了CEEMD与小波包半软阈值去噪相结合的提取方法;对于特征参数降维,针对轴承振动信号的非线性特点,使用局部线性嵌入算法降维,对降维后特征参数使用模糊C均值聚类进行验证,可以看出LLE降维不仅降低了计算量而且有利于模式识别;将二叉树法与投票法支持向量机结合,给出了混合多分类支持向量机,使用磷虾算法对其进行参数优化。实验验证可知,磷虾算法优化的多分类支持向量机具有很高的输出精度,轴承状态识别准确率为100%,使用粒子群算法优化的支持向量机输出精度低,轴承状态识别准确率为79%。     

基于分层模糊支持向量机的油液磨粒自动识别

提出基于模糊支持向量机的机械设备在用油液磨粒自动识别方法。首先利用K-均值聚类算法对磨粒图像进行分割,提取磨粒的形状尺寸特征参数、边缘细节特征参数、表面纹理特征参数作为其量化表征,分别选择最能反映待识别磨粒特征的参数作为各个二分类器的输入向量;然后结合二叉树法和一对多法间接构造磨粒的分层多类别分类器模型,在训练过程中同时利用粒子群算法优化分类器的参数,建立一种参数自适应的模糊支持向量机分层多类别分类模型。将该模型应用到旋挖钻机在用油液的磨损颗粒识别中,识别率最高达90%。该模型结构简单、分类精度好,在磨粒识别领域较大的工程应用价值。     

基于容错度自适应支持向量机的液压泵故障诊断

针对已有在线故障诊断方法在数据量大、噪声强条件下分类速度较低、分类精度不够高等问题,结合液压泵故障类别数目大、工作环境恶劣的特点,提出了一种适用于混凝土泵车液压泵在线诊断的状态识别算法——容错度自适应支持向量机。该方法主要从四个方面对分类速度做了改进：①引入容错度因子进行模型训练;②优先选择能将某一类故障样本单独分离出来的二分类器;③在满足②的基础上选择平均支持向量机少的分类器;④引入增量学习算法对参数进行自适应调整,提高多故障诊断中对新故障类别和新故障数据的适应性,保证系统的分类精度。通过对混凝土泵车的液压泵故障诊断,证明了该方法在明显提高分类速度的同时保证了较高的分类精度。     

基于支持向量机的矿井提升机制动系统的故障诊断

故障样本缺乏是制约智能故障诊断发展的重要原因,支持向量机是近年来提出的一种基于小样本的统计学习方法.将支持向量机分类算法应用到提升机制动系统的多类故障分类,并与BP神经网络进行对比研究,实验表明,支持向量机算法比BP神经网络具有更好的分类性能,且 "一对多"支持向量机的分类效果是最好的,更适合于提升机制动系统的故障诊断.     

一种聚类分层决策的SVM模拟电路故障诊断方法

支持向量机用于模拟电路多种故障诊断时,其多分类扩展策略与诊断的效率和正确率密切相关。本文提出模糊聚类与支持向量机集成的算法,通过分析电路故障特征数据的空间分布特性,以多级二叉树结构的SVM实现故障的分级诊断。通过对各故障模式两种小波特征的逐次聚类二分获得二叉树,根据F测度为每个节点的SVM选择具有最大分类间隔的故障子类及特征,避免了不可分故障区域的出现,从而优化了SVM的组合策略。采用该方法组建的SVM结构简单,在滤波器电路的故障诊断中获得良好的效果。与几种常用的SVM方法相比,本文方法有效地提高了故障诊断的精度和效率。     

基于多层子支持向量机的多传感器故障诊断

支持向量机从二分类问题出发,构造最优分类超平面,实现基于结构风险最小化的最大间隔分类.然而故障诊断中,故障模式通常都有很多种,而且,判断出故障类型后往往还需要对故障程度进行判断.对于多分类问题,支持向量机已有的算法有"一对一"、"一对多"和"k分类"等.本文借鉴"一对多"算法,构造k个子支持向量机,实现对k个故障模式的分类.在此基础上,构造第二层支持向量机,实现对故障程度的评估.实验表明,基于多层子支持向量机的多传感器故障诊断,能非常成功地实现故障分离和故障评估.     

基于烟花算法优化SVM的变压器故障诊断

提出了一种基于烟花算法优化支持向量机的变压器故障诊断模型。标准的支持向量机是二分类,现对其进行非线性处理及多分类变换,使其能适用于变压器故障分类。针对支持向量机参数难以确定的情况,采用烟花算法优化支持向量机,从而搭建烟花算法优化支持向量机的故障诊断模型。实验分析结果表明,所提方法的故障诊断准确率优于其他算法。最后,进一步将算法用于机器学习的其他标准数据集,证明了该算法具有泛化性。     

基于网格支持矢量机的涡轮泵多故障诊断

支持矢量机是一种基于结构风险最小化原则的机器学习方法,对小样本决策具有较好的学习推广性.由于常规支持矢量机算法是从二类分类问题推导得出的,在解决故障诊断这种典型的多类分类问题时存在困难,为此提出一种网络支持矢量机多类分类算法,用每个类别和其他两个至四个类别构造二类支持矢量机分类器.这些二类支持矢量机分类器组合而成的网格式结构多类分类器,具有容易扩展、重复训练样本少、速度快和识别正确率高的优点.将网格式结构多类分类器应用于涡轮泵试验台多故障诊断获得了令人满意的效果.     

基于支持向量机的车用燃料电池系统故障诊断

为了提高车用燃料电池系统的安全可靠性和可维护性,考虑到其大量完整的故障样本难以获取,提出了一种基于二叉树多分类器的支持向量机故障诊断方法.首先,以自主研发的60 kW车用燃料电池系统为研究对象,分析了其故障机理和特征;然后,融合15种故障征兆参数并进行归一化预处理作为支持向量机的输入,以14种典型故障作为输出,选取径向基核函数并利用粒子群优化算法对支持向量机的惩罚参数和核函数参数进行优化,利用310组样本数据对其进行训练,通过90组测试样本测试实现了其典型故障的识别;最后,将支持向量机和神经网络分别在不同训练样本数下的故障诊断性能进行了对比.仿真结果表明,支持向量机具有较好的故障正判率和泛化能力,可有效用于车用燃料电池系统的多故障诊断.     

Support vector machines-based fault diagnosis for turbo-pump rotor

Most artificial intelligence methods used in fault diagnosis are based on empirical risk minimisation principle and have poor generalisation when fault samples are few. Support vector machines (SVM) is a new general machine-learning tool based on structural risk minimisation principle that exhibits good generalisation even when fault samples are few. Fault diagnosis based on SVM is discussed. Since basic SVM is originally designed for two-class classification, while most of fault diagnosis problems are multi-class cases, a new multi-class classification of SVM named ‘one to others’ algorithm is presented to solve the multi-class recognition problems. It is a binary tree classifier composed of several two-class classifiers organised by fault priority, which is simple, and has little repeated training amount, and the rate of training and recognition is expedited. The effectiveness of the method is verified by the application to the fault diagnosis for turbo pump rotor.     

一种新的机械系统故障分类器

提出了一种利用支持矢量机对机械系统故障进行分类的新方法;以二值分类为基础,开发了基于支持矢量机的多值分类器。并以齿轮的多种故障分类为例,进行了实际应用验证。结果表明,该方法具有很好的分类能力和较高的计算效率,不需要对原始数据进行预处理就可达到满意的效果,适合于机械故障诊断中的多故障分类。该方法的应用,为故障诊断技术向智能化方向发展提供了新的途径。     

运用改进二叉树SVM算法的柴油机振动诊断

提出了一种改进的二叉树支持向量机(support vector machines,简称SVM)算法,用以克服二叉树SVM构造时各级正类样本选择缺乏理论指导的问题。基于最易分割类应最先分割的思想,该方法在定义特征参数类识别率概念的基础上,首先逐级计算每个特征参数对各级SVM所对应各类训练样本的类识别率,然后选择类识别率综合排序结果处于第1位的样本类作为相应级SVM的正类。从缸盖振动信号包络幅值域参数和小波包分解频带能量百分比参数中选取了对气阀故障较为敏感的9个特征,形成了诊断特征向量,使用常用的1-a-r,1-a-1,DDAG以及改进的二叉树SVM多分类方法对6种气阀间隙状态进行了诊断,结果表明,本文提出的改进二叉树SVM方法具有最好的分类效果。     

Optimal feature selection using genetic algorithm for mechanical fault detection of induction motor

Time-domain vibration signals are measured in all horizontal, axial, and vertical directions for induction motor mechanical fault diagnostics. Many features are extracted from these signals. The problem is how to find the good features among the feature set in order to receive reliable classifications. Based on specific distance criteria, a genetic algorithm (GA) is introduced to reduce the number of features by selecting optimized ones for fault classification purpose. A decision tree and multi-class support vector machine are used to illustrate the potentiality and efficiency of this selection method. Comparisons show that the diagnostic systems after selecting specific features perform better than the original system.     

Automatic progressive damage detection of rotor bar in induction motor using vibration analysis and multiple classifiers

There is an increased interest in developing reliable condition monitoring and fault diagnosis systems of machines like induction motors; such interest is not only in the final phase of the failure but also at early stages. In this paper, several levels of damage of rotor bars under different load conditions are identified by means of vibration signals. The importance of this work relies on a simple but effective automatic detection algorithm of the damage before a break occurs. The feature extraction is based on discrete wavelet analysis and autocorrelation process. Then, the automatic classification of the fault degree is carried out by a binary classification tree. In each node, comparing the learned levels of the breaking off correctly identifies the fault degree. The best results of classification are obtained employing computational intelligence techniques like support vector machines, multilayer perceptron, and the k-NN algorithm, with a proper selection of their optimal parameters.     

高炉炼铁液压系统应用

以一钢铁企业为调查基础,以高炉炼铁液压系统的常见故障诊断及处理为分析思路,对该系统在炼铁工艺上的应用进行深入分析。通过研究,对高炉炼铁液压系统的常见故障进行了总结,为提高炼铁工艺提供了依据。     

支持向量机在船舶主机诊断中的应用

为了简化船舶主机故障诊断,提高诊断效率,文章采用了支持向量机的故障诊断原理,通过小波包分解提取信号的特征参数,再将特征量送入故障分类器中进行训练,即可得出诊断结果。当数据样本较少时,采用支持向量机与采用神经网络诊断相比,具有算法简单、故障分类能力强的优点。     

Fault diagnosis using binary tree and sphere-structured support vector machines

A new method (BSSVM) using binary tree and sphere-structured support vector machines (SSVM) is presented for fault diagnosis. It constructs the hyper-planes step by step according to binary tree, partitions a class in every step and eliminates blind areas which are not insuperable for other multi-class methods of SVM. 4 common faults are created by a test-bed of rotor, their vibration signals are collected and transformed to frequency domain by FFT, then the spectrum energy in 8 bands divided by their total energy are taken as the energy distributions. With PCA, the 8-dimensional energy distributions are converted to 2-dimensional fault samples which can hold more than 80% useful information of the primary data. With the fault samples, the new method is tested and compared with several other multiclass methods of SVM, and experimental results show that the new method has higher speed and better accuracy than other similar ones.