局部均值分解在旋转机械振动中的研究与应用

发布时间：2018-07-10 11:32

本文选题：旋转机械故障诊断 + 局部均值分解（LMD）　；参考：《燕山大学》2012年硕士论文

【摘要】：局部均值分解（local mean decomposition，简称LMD）是近几年才出现的一种能够自适应处理信号的时频方法。针对旋转机械振动时产生的非线性非平稳信号，这种信号处理方法显示出了很好的效果，为机械的状态监测和维修提供了有力的理论依据。本文分析了旋转机械产生故障时振动信号的特征，，并用转子试验台模拟了故障的产生。针对此种方法在分解过程中可能产生的问题，文中对端点、滑动平均跨度、循环终止条件进行了分析，提出了新的端点处理方式和迭代终止条件。鉴于经验模态分解（EMD）能够消除Wigner-Vill分布（WVD）中产生的交叉项，本文分析了用局部均值分解来消除WVD中的交叉项，并取得了较好的效果。针对原局部均值分解的各分量精度低的问题，提出了基于分量二次分解的局部均值分解；接着，又提出了基于稳定点的局部均值分解，此种改进方法同时提高了分解后的精度和速度。通过对模拟信号和实际信号的分析，表明对原来局部均值分解中各方面的改进是有效的。最后，将改进后的局部均值分解应用到了工程实际当中；通过将改进方法得到的结果同HG8904C故障诊断系统分析的结果对比，证明了改进方法的有效性和实用性，是可以应用到实际旋转机械的故障诊断之中的。
[Abstract]:Local mean decomposition (local mean decomposition,) is a time-frequency method which can process signals adaptively in recent years. According to the nonlinear and non-stationary signals produced by the vibration of rotating machinery, this signal processing method shows a good effect and provides a powerful theoretical basis for the condition monitoring and maintenance of machinery. In this paper, the characteristics of vibration signals in rotating machinery are analyzed, and the fault generation is simulated by rotor test bed. In view of the possible problems in the decomposition process of this method, the end points, moving average span and cyclic termination conditions are analyzed, and a new endpoint processing method and iterative termination condition are proposed. In view of the fact that empirical mode decomposition (EMD) can eliminate the cross term generated in Wigner-Vill distribution (WVD), the local mean decomposition is used to eliminate the cross term in WVD, and good results are obtained. The local mean decomposition based on the quadratic decomposition of components is proposed to solve the problem of low precision of each component of the original local mean decomposition, and then the local mean decomposition based on the stable point is proposed. This improved method also improves the precision and speed of decomposition. By analyzing the analog signal and the actual signal, it is shown that the improvement of the original local mean decomposition is effective. Finally, the improved local mean decomposition is applied to engineering practice, the results obtained by the improved method are compared with the results of HG8904C fault diagnosis system, and the effectiveness and practicability of the improved method are proved. Can be applied to the actual rotating machinery fault diagnosis.
【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH165.3;TN911.7

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