Diagnosing the fault of planetary gearboxes primarily depends on the acceleration signal obtained from the gearbox casing. While the casing acceleration signal is easy to acquire, it is susceptible to interference from vibrations of other components. As a result, the strain signal, which offers a high signal-to-noise ratio (SNR), has gained prominence in recent years. However, there is limited physical knowledge of the strain signal for creating distinct fault diagnosis techniques. This article aims to explore the characteristics of the strain signal and develop a corresponding strain signal processing approach to identify multiple faulty teeth in the sun gear. The circumferential strain of the ring gear is collected by the fiber Bragg grating (FBG) mounted at the end face of the ring tooth root. The frequency distribution of the measured strain signal is revealed by a phenomenological strain model, which is established by summarizing the experimental phenomena. Based on the model, a specific strain preprocessing method, which comprises comb filtering and frequency band selection, is proposed to enhance the fault features in the strain signal. Then, a strain separation strategy is presented to obtain the strain segments linked to each tooth of the sun gear for multi-fault identification. Both simulation and experimental studies are conducted. The frequency distribution of the simulated strain signal closely matches that of the measured strain signal, validating the credibility of the established strain model. Furthermore, the necessity of the steps in the proposed strain processing approach is verified, and a comparison with other relevant methods demonstrates its superior performance.

中文翻译：

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基于唯象应变模型和应变分离的太阳轮多齿缺陷识别

诊断行星齿轮箱的故障主要依靠从齿轮箱获得的加速度信号。虽然壳体加速度信号易于获取，但容易受到其他部件振动的干扰。因此，具有高信噪比（SNR）的应变信号近年来受到重视。然而，用于创建独特的故障诊断技术的应变信号的物理知识有限。本文旨在探讨应变信号的特征，并开发相应的应变信号处理方法来识别太阳轮中的多个故障齿。环形齿轮的周向应变由安装在环形齿根端面的光纤布拉格光栅（FBG）收集。唯象应变模型揭示了测量应变信号的频率分布，该模型是通过总结实验现象而建立的。基于该模型，提出了一种具体的应变预处理方法，包括梳状滤波和频带选择，以增强应变信号中的故障特征。然后，提出了一种应变分离策略，以获得与太阳轮每个齿相关的应变段，以进行多故障识别。进行了模拟和实验研究。模拟应变信号的频率分布与实测应变信号的频率分布紧密匹配，验证了所建立的应变模型的可信度。此外，验证了所提出的应变处理方法中步骤的必要性，并且与其他相关方法的比较证明了其优越的性能。