自适应Morlet小波降噪方法及在轴承故障特征提取中的应用 .pdfVIP

第 3l卷 第 l2期 2010年 12月 仪 器 仪 表 学 报 Chinese Journal of Scientific Instrument V0J．3l No．12 Dec．2010 自适应 Morlet小波降噪方法及在 轴承故障特征提取中的应用 蒋永华，汤宝平，董绍江 (重庆大学机械传动国家重点实验室 重庆 400030) 摘 要：分析了Morlet小波变换的滤波特性及其时频分辨率，利用 Morlet小波良好的时域和频域特性及奇异值分解技术，提出 了一种基于自适应 Morlet小波和 SVD的降噪方法。针对滚动轴承故障在振动信号中表现为冲击衰减波形的特点，采用修正的 Shannon熵方法同时优化 Morlet小波的中心频率与带宽参数，实现其与冲击特征成分的最优 配；针对根据小波系数矩阵奇异 值曲线的过渡阶段求取最佳变换尺度的方法存在着不够快捷方便的不足，将其与小波系数奇异值比方法相结合来快速方便地 求得最佳变换尺度；最后对信号进行降噪处理提取故障特征。对仿真信号和实际轴承内外圈故障信号的应用分析表明，该方法 具有良好的降噪性能，能有效地提取出滚动轴承的微弱故障特征。 关键词 ：Morlet小波；奇异值分解；奇异值比；微弱特征提取 中图分类号：TH165．3 TN911．2 文献标识码：A 国家标准学科分类代码 ：510．40 Denoising method based on adaptive M orlet wavelet and its application in roling bearing fault feature extraction Jiang YonghHa，Tang Baoping，Dong Sha~iang (The State Key Laboratory ofMechanical Transmission，Chongqing University，Chongqing400030，China) Abstract：The filtering characteristics and time—frequency resolution of Morlet wavelet transform are analyzed．Using excellent characteristics of Morlet wavelet in time domain and frequency domain and singular value decomposition technology，a denoising method based on adaptive Morlet wavelet and SVD is proposed．According to the fact that rolling beating defect can excite vibration waveform with specifc impact component，modified Shannon wavelet entropy is used to optimize the central frequency and bandwidth parameter of the Morlet wavelet to achieve optimal match with the impact component．Then，the method based on the transitional segment of singular curve of wavelet coeficient matrix combined with the method based on singular value ratio is used to obtain the optimal scale for the wavelet transform rapidly and conveniently． Finally，the signal is denoised and the fault feature is extracted． Experimental results and analysis results for roling bearing signals with inner·race and outer·-race faults show that the proposed method is feasible and effective for extracting weak fault feature． Key words：Morlet wavelet；singular value decomposition；