改进的谐波小波包变换及其在弱故障特征提取中的应用

Improved harmonic wavelet packet transformation and its application in weak fault feature extraction

通过引入频谱幅值修正系数改进了通常的谐波小波包变换。改进的谐波小波包变换使得信号分解前后各子带的频谱幅值保持不变,能精确提取相应子带故障调制信号的强度与频率,为机械故障诊断带来了方便。仿真实验和轴承故障诊断实例不仅表明谐波小波包具有一般正交小波包无法比拟的完美的带通滤波性能和极强的微弱特征信号提取能力,而且还表明改进的谐波小波包变换确实使得信号分解前后各子带的频谱幅值保持不变,能精确提取相应子带故障调制信号的强度与频率,有一定的工程应用价值。

By introducing modified coefficients of spectral magnitudes, an improved harmonic wavelet packet transformation was proposed. With the improved harmonic wavelet packet transformation, the spectral magnitudes of subbands of a signal kept from varying after signals decomposition. With, the improved harmonic wavelet packet transformation, the amplitude and frequency of fault modulation signals could be extracted accurately and it became easy to diagnose mechanial faults. The simulation and test results for bearing fault diagnosis showed that the harmonic wavelet packet possesses a perfect band-pass filtering feature and an excellent ability to detect weak signals, the improved harmonic wavelet packet transformation really has good capabilities mentioned above and is valuable for engineering application.