中文摘要：

为自适应实现Morlet小波与故障冲击特征成分的最优匹配,采用基于Shannon小波熵的方法优化带宽参数设计最优Morlet小波。针对最佳尺度求取的难题,利用谱峭度与小波熵均能敏感反映冲击性的特性,提出了基于峭熵比求取最佳尺度。基于此,提出基于最优Morlet小波自适应包络解调的弱故障特征提取方法,该方法首先对信号进行最优Morlet连续小波变换;然后,依据峭熵比自适应地求取最佳尺度并提取最佳尺度的小波系数;最后,对最佳尺度的小波系数取模即可实现对最优频带的包络解调,得到包络谱,从而实现微弱故障特征的提取。实例分析表明：该方法克服了传统包络解调需要人为设定带通滤波器参数的不足,能有效地从强噪背景中提取微弱故障特征。

英文摘要：

In order to achieve adaptive optimal match with the impact component, Shannon wavelet entropy is used to optimize bandwidth parameter of the Morlet wavelet to design the optimal Morlet wavelet. Aimed at obtaining the optimal scale, the approach based on kurtosis entropy ratio to acquire the optimal scale is presented. In addition, the method of extracting weak fault feature based on optimal Morlet wave- let adaptive envelope demodulation is proposed. This method performed optimal transform of continuous Morlet wavelet for signal first, and then adaptively obtained optimal scale and extracted wavelet coefficient of the optimal scale based on kurtosis entropy ratio. Finally, by conducting modulo operation for wavelet coefficient of the optimal scale, envelope demodulation of the optimal frequency band was realized and en- velope spectrum was obtained, so that the extracting of the weak fault feature was realized. The simulation results and analysis show that the method overcomes the defect that the parameters of band-pass filter are selected by experience of the user in conventional envelope demodulation, and effectively extract the weak fault feature.