迭代广义短时Fourier变换在行星齿轮箱故障诊断中的应用

短时Fourier变换(STFT)在分析非平稳信号的过程中,受调制系数的影响,时频分布图中的能量扩散至主导频率的周围,降低了时频分布的可读性.运用STFT分析瞬时频率缓变或恒定的信号时,调制系数的影响较小甚至可以忽略不计,而得到能量聚集程度很高的时频分布.根据这一特点,提出了迭代广义短时Fourier变换(IG-STFT),该方法有效改善了时频图的可读性.首先运用迭代广义解调分离出频率恒定的单分量成分,然后运用STFT分析信号的时频分布,最后依据STFT的分析结果和相位函数得到原信号的时频分布.通过行星齿轮箱仿真信号和实验信号分析,验证了该方法在分析非平稳信号中的有效性,准确诊断了齿轮故障.

Application of iterative generalized short-time Fourier transform to fault diagnosis of planetary gearboxes

Due to the effect of the modulation part,the energy diffuses around the surrounding area of dominating frequencies and diminishes the readability of the time-frequency representation when short-time Fourier transform(STFT)is used to process nonstationary signals.However,when the instantaneous frequency slowly changes or is constant,the effect is small and can even be neglected.Thus,the time-frequency representations have high-energy concentration.Based on this feature,a novel method called iterative generalized short-time Fourier transform(IG-STFT)was proposed,which improved the readability of the time-frequency representation.First,the stationary mono-components are separated using iterative generalized demodulation.Then,the time-frequency representations of each mono-component are acquired using STFT.Finally,the time-frequency representation of the original signal is obtained according to the analysis results of STFT and the phase function.The analysis results of a planetary gearbox simulation signal and experimental signals verify the effectiveness of this method for analyzing nonstationary signals and diagnosing gear faults.