基于时时能量阶比谱的变转速工况滚动轴承微弱故障诊断研究

Research on fault diagnosis of rolling bearing's weak fault under variable speed conditions based on time-time energy order spectrum

变转速工况下的滚动轴承微弱故障诊断同时面临两个难点:一是滚动轴承的故障特征信号容易被环境噪声和干扰信号淹没;二是滚动轴承故障振动信号的时变特征难以被常规频谱方法提取。针对上述问题提出了基于时时能量阶比谱的滚动轴承故障诊断方法。首先对变转速工况下的滚动轴承微弱故障振动信号进行时时(time-time,TT)变换,在双时域上刻画轴承故障振动信号的时变特征;然后利用提出的时时能量定义计算轴承故障振动信号的时时能量,获得轴承故障振动信号的时时能量信号;最后对时时能量信号进行阶比分析得到轴承故障振动信号的时时能量阶比谱,并根据时时能量阶比谱的阶次特征识别出轴承故障类型。分析了变转速工况下的滚动轴承故障仿真信号和实验测试信号,结果表明:时时能量信号能够有效追踪轴承故障振动信号的时变能量分布,增强故障特征信号的冲击特征,时时能量阶比谱较包络阶比谱抗噪能力更强,为变转速工况滚动轴承微弱故障诊断提供一种有效方法。

The fault diagnosis of rolling bearings weak faults under variable speed conditions faces two difficulties： on the one hand, the rolling bearing＇s weak fault characteristic signal can be easily overwhelmed by ambient noise and interfering signals; on the other hand, the time-varying characteristics of vibration signals cant be extracted by traditional spectrum methods. With above considerations, a new fault diagnosis method of rolling bearings based on time-time energy order spectrum is proposed. Firstly, rolling bearing＇s week fault vibration signal under variable speed condition is analyzed by time-time （TT） transforma-tion, portraying the time varying characteristics of bearings fault signal in dual time domain. Then, the time-time energy signal of original vibration signal is obtained by calculating the time-time energy using the definition of time-time energy which is pro-posed in this paper. Finally, the time-time energy order spectrum can be achieved with the application of order tracking analysis to the time-time energy signal, and then the bearing＇s failure type could be identified according to the order characteristics of the time-time energy order spectrum. The proposed method is used to analyze both a simulated and an experimental rolling bearing fault signal under variable speed conditions. The results demonstrated that the time-time energy signal can track the time var-ying energy distribution of the rolling bearing vibration signal and enhance the impact effect of the faultfeaturing signal. Thus the time-time energy order spectrum has a better performance in antinoise than the envelope order spectrum, which can serves as an effective method for roiling bearing’s weak fault diagnosis under variable speed conditions.