一种极值搜索的齿轮系统振动信号阶次跟踪方法

An order tracking method for gearbox vibration signal based on searching extremums

在变速工况下,齿轮系统的振动信号具有非平稳性,频谱特征模糊,不利于特征提取和故障诊断。阶次跟踪方法作为一种非平稳信号分析方法,将原信号从时间域转换到角度域,有助于抑制变转速导致的频率模糊现象。广泛应用的计算阶次跟踪分析方法在实现等角度重采样过程中,通过提取瞬时转速积分求取瞬时角位移,或者基于相位解调获取角度‑时间关系,受限于积分累计误差或小的转速跟踪范围。利用齿轮系统啮合振动信号峰峰值对应的等角度间隔特征,提出一种基于时域信号极值搜索的无键相阶次跟踪方法。所提方法不需要通过转速积分获取瞬时角位移,同时允许较大转速变化范围,降低了阶次分析域变换过程的误差,抗噪性能良好,使阶次谱能量集中度和特征成分辨识度得到明显提高。理论分析、仿真对比分析和试验测试结果均验证了所提方法的有效性,适用于变转速工况下的齿轮箱非平稳振动信号频谱分析和故障诊断。

Owing to the varying working speed,the vibration signal of gearboxes inherently exhibits non-stationary characteristics.The resultant fuzzy spectrum is not conducive to feature extraction and fault diagnosis.The order tracking method,as an effective analyzing method for non-stationary signals,is realized by the signal transformed from time domain to angle domain.It’s helpful to improve spectrum discrimination.The widely used computation ordering tracking methods sample signal in equal-angle increment according to the extracting rotating speed or the phase demodulation method are limited by the integral cumulative error or the small tracking speed.According to the equal peak-to-peak angle interval of gear vibration signal,this paper proposes a novel tacholess order tracking method based on searching extremums of time signal.The proposed method doesn’t require the integral process of the rotating speed,and simultaneously allows a wide range of tracking speed.The error caused by the signal transforming process is decreased.The result shows a high concentration in spectrum energy and great discrimination of spectrum characteristics.It is verified by the theoretical analysis,simulation,and experiment.The proposed method can be applied to the gearbox signal analysis and fault diagnosis under varying speeds.