复小波共振解调频带优化方法和新指标  

New Procedure and Index for the Parameter Optimization of Complex Wavelet Based Resonance Demodulation

作　　者：张龙[1] 熊国良[1] 黄文艺[1] 

机构地区：[1]华东交通大学机电工程学院,南昌330013

出　　处：《机械工程学报》2015年第3期129-138,共10页Journal of Mechanical Engineering

基　　金：国家自然科学基金(51205130;51265010);江西省教育厅(GJJ12318);江西省自然科学基金(20132BAB216029)资助项目

摘　　要：滚动轴承发生局部故障时,其振动信号中将出现周期性发生的脉冲响应。共振解调被广泛用于从振动信号中提取此类冲击响应特征,但其首要问题是确定带通滤波器的中心频率和带宽。现有的频带优化方法存在计算量大且优化指标只考虑信号中冲击成分的强弱、而未考虑脉冲发生的周期性特征等缺点。针对不足,确定了以中心频率为主带宽为辅的频带参数优化方法,并提出了一个既能反映信号中冲击成分的存在及强弱又能突出冲击发生的周期性特点的频带优化新指标——包络谱峰值因子,该因子定义为包络谱最大值与有效值之比。将此方法和新指标应用于复平移Morlet小波共振解调的频带优化,通过轴承疲劳试验数据分析及工程实际应用并与峭度、平滑度指标和山农熵进行比较,验证了该方法和指标在最优频带确定中的有效性和优越性。Local defects in bearings give rise to periodic impulses in vibrations. Resonance demodulation is widely adopted to extract such impulse train from vibrations. In order for the resonance demodulation to be used to good effect, various optimization procedure and index have been introduced to optimize the frequency band of resonance demodulation. Unfortunately, most of the optimization procedures available are computationally intensive, whilst the indices only depict the existence and level of an impact without considering its periodical occurrence. Targeted at such deficiencies, a procedure which searches for optimal center frequency with a high resolution while bandwidth with a low resolution is presented so as to alleviate computation burden. Moreover, a new index termed crest factor of envelope spectrum is formulated as the ratio of the maximum value to the root mean square of envelope spectrum, taking into account both the level and periodicity of impulses. The proposed procedure and index is employed to optimize the parameters of complex shifted Morlet wavelet for bearing defect diagnosis, and results on bearing run-to-failure experiment and filed data are in favorable of them in comparison with kurtosis, smoothness index and Shannon entropy.

关 键 词：共振解调 小波滤波 MORLET小波 频带优化 

分 类 号：TN132[电子电信—物理电子学]