中文摘要：

针对转子不平衡故障和滚动轴承微弱损伤性故障的复合故障诊断问题，提出基于第二代小波的故障诊断方法，进行了复合故障的耦合特征分离和轴承损伤性故障早期微弱信号的特征提取研究。该方法首先应用第二代小波分解与重构原始信号进行信号分解与重构；然后针对分解与重构出的高频共振调制信号进行基于经验模式分解（empirical mode decomposition，EMD）的解调分析，以准确提取调制故障特征；最后针对低频段信号进行频谱分析提取低频非调制故障特征。仿真信号、实验信号及工程实例信号的研究结果表明，该方法能够提取轴承损伤性故障的早期特征。

英文摘要：

Aiming at the composite/complex fault of the rotor failure and wear roller bearing fault, a fault diagnosis method,the second generation wavelet was proposed to separate the coupling features of composite fault and to extract the fault feature of the roller bearings. Firstly original signals were decomposed and reconstructed by using the second generation wavelet. Then the high--frequency modulated signals from the decomposition and restruction of original signal were analyzed by envelop demodulation based on the empirical mode decomposition（EMD）, by which the modulated fault feature was extracted. Non--modulation low--frequency rotor feature was extracted by using FFT to the low --frequency signals from the decomposition and restruction of original signals. Research results of simulation signals, experimental signals and engineering signals indicate that the method can extract the fault feature of scathing roll bearings early.