为了在微弱故障征兆出现时能通过正常状态对异常进行辨识,针对通常动态系统故障状态样本缺乏的单值分类问题,提出混沌分形特征组合及支持向量数据域描述(support vector data description,SVDD)的动态系统振动异常辨识方法。该方法采用...为了在微弱故障征兆出现时能通过正常状态对异常进行辨识,针对通常动态系统故障状态样本缺乏的单值分类问题,提出混沌分形特征组合及支持向量数据域描述(support vector data description,SVDD)的动态系统振动异常辨识方法。该方法采用误诊和漏诊两种分类错误的SVDD接受者操作特征(receiver operating characteristic,ROC)曲线,通过分析振动混沌分形特征,选取最大Lyapunov指数和关联维数的最优组合,进而建立正常状态样本单值SVDD分类器,并对可提高分类精度的试验验证法优选核函数参数进行了探讨。试验及测试表明,SVDD-ROC方法避免了传统特征选取对具体故障类型样本的依赖性,选取的特征组合对正常和故障样本有较好的自聚类性,SVDD方法仅需要正常状态样本就能辨识异常状态,并且对未知故障也有较好的异常辨识能力。该研究可为动态系统异常状态提供建模与检测的理论基础和设计依据,有效预防突发事故,节约维修成本,提高动态系统的利用率,保障其安全运行,有效降低成本。展开更多
针对现有多类支持向量域数据描述(multi-class support data description,M-SVDD)存在的不足和局限性,提出一种拒绝式转导推理多类支持向量域数据描述(rejected transductive inference M-SVDD,RTIM-SVDD)方法,并将该方法应用于机械加...针对现有多类支持向量域数据描述(multi-class support data description,M-SVDD)存在的不足和局限性,提出一种拒绝式转导推理多类支持向量域数据描述(rejected transductive inference M-SVDD,RTIM-SVDD)方法,并将该方法应用于机械加工故障诊断当中。首先,RTIM-SVDD通过训练寻求一个尽可能包含所有数据样本的最小超球体作为拒绝检测面,来整体学习样本知识或数据描述,并以一定的拒绝度判别新的测试样本,达到故障检测的目的;其次,应用分别包含各个类别样本的多个超球体,来判别满足一定拒绝度的样本,实现多分类问题。对于模糊样本点归属判别关键问题,本文采用一种新的转导推理规则来进行决策。最后,通过一个仿真实验进行验证,结果证明了RTIM-SVDD的可行性和有效性。展开更多
针对滚动轴承在强背景噪声干扰下振动信号故障特征难以提取,以及实际运行中因故障样本缺乏而影响故障诊断准确性的问题,提出了基于固有时间尺度分解(Intrinsic Time Scale Decomposition,ITD)的AR模型振动信号特征提取,与支持向量数据...针对滚动轴承在强背景噪声干扰下振动信号故障特征难以提取,以及实际运行中因故障样本缺乏而影响故障诊断准确性的问题,提出了基于固有时间尺度分解(Intrinsic Time Scale Decomposition,ITD)的AR模型振动信号特征提取,与支持向量数据域描述(Support Vector Data Description,SVDD)相结合的轴承故障诊断方法.首先用ITD将振动信号分解成一系列的固有旋转(Proper Rotation,PR)分量,然后对每一个PR分量建立AR模型,提取模型参数和残差方差构造特征向量,用以建立轴承正常运行的SVDD模型,并以振动信号特征向量偏离SVDD模型的程度来判断轴承的运行状态.将该方法应用于滚动轴承的故障诊断,实验证明了所提方法的有效性.展开更多
In order to improve the incipient fault sensitivity and stability of degradation index in the rolling bearing performance degradation evaluation process,an embedding selection-based neighborhood preserving embedding(E...In order to improve the incipient fault sensitivity and stability of degradation index in the rolling bearing performance degradation evaluation process,an embedding selection-based neighborhood preserving embedding(ESNPE)method is proposed.Firstly,the acquired vibration signals are decomposed by variational mode decomposition(VMD),and the singular value and relative energy of each intrinsic mode function(IMF)are extracted to form a high-dimensional feature set.Then,the NPE manifold learning method is used to extract the embedded features in the feature space.Considering the problem that useful embedding information is easily suppressed in NPE,an embedding selection strategy is built based on the Spearman correlation coefficient.The effectiveness of embeddings is measured by the coefficient absolute value,and useful embeddings are preserved in the early stage of bearing degradation by using the first-order difference method.Finally,the degradation index is established using the support vector data description(SVDD)model and bearing performance degradation evaluation is achieved.The proposed method was tested with the whole life experiment data of a rolling bearing,and the result was compared with the feature extraction methods of traditional principal component analysis(PCA)and NPE.The results show that the proposed method is superior in improving the incipient fault sensitivity and stability of the degradation index.展开更多
文摘针对现有多类支持向量域数据描述(multi-class support data description,M-SVDD)存在的不足和局限性,提出一种拒绝式转导推理多类支持向量域数据描述(rejected transductive inference M-SVDD,RTIM-SVDD)方法,并将该方法应用于机械加工故障诊断当中。首先,RTIM-SVDD通过训练寻求一个尽可能包含所有数据样本的最小超球体作为拒绝检测面,来整体学习样本知识或数据描述,并以一定的拒绝度判别新的测试样本,达到故障检测的目的;其次,应用分别包含各个类别样本的多个超球体,来判别满足一定拒绝度的样本,实现多分类问题。对于模糊样本点归属判别关键问题,本文采用一种新的转导推理规则来进行决策。最后,通过一个仿真实验进行验证,结果证明了RTIM-SVDD的可行性和有效性。
文摘针对滚动轴承在强背景噪声干扰下振动信号故障特征难以提取,以及实际运行中因故障样本缺乏而影响故障诊断准确性的问题,提出了基于固有时间尺度分解(Intrinsic Time Scale Decomposition,ITD)的AR模型振动信号特征提取,与支持向量数据域描述(Support Vector Data Description,SVDD)相结合的轴承故障诊断方法.首先用ITD将振动信号分解成一系列的固有旋转(Proper Rotation,PR)分量,然后对每一个PR分量建立AR模型,提取模型参数和残差方差构造特征向量,用以建立轴承正常运行的SVDD模型,并以振动信号特征向量偏离SVDD模型的程度来判断轴承的运行状态.将该方法应用于滚动轴承的故障诊断,实验证明了所提方法的有效性.
基金The National Natural Science Foundation of Chin(No.51975117)
文摘In order to improve the incipient fault sensitivity and stability of degradation index in the rolling bearing performance degradation evaluation process,an embedding selection-based neighborhood preserving embedding(ESNPE)method is proposed.Firstly,the acquired vibration signals are decomposed by variational mode decomposition(VMD),and the singular value and relative energy of each intrinsic mode function(IMF)are extracted to form a high-dimensional feature set.Then,the NPE manifold learning method is used to extract the embedded features in the feature space.Considering the problem that useful embedding information is easily suppressed in NPE,an embedding selection strategy is built based on the Spearman correlation coefficient.The effectiveness of embeddings is measured by the coefficient absolute value,and useful embeddings are preserved in the early stage of bearing degradation by using the first-order difference method.Finally,the degradation index is established using the support vector data description(SVDD)model and bearing performance degradation evaluation is achieved.The proposed method was tested with the whole life experiment data of a rolling bearing,and the result was compared with the feature extraction methods of traditional principal component analysis(PCA)and NPE.The results show that the proposed method is superior in improving the incipient fault sensitivity and stability of the degradation index.