基于自适应谐波分量提取的航空发动机附件传动系统变速故障诊断方法

针对当前基于无键相阶次跟踪(TLOT)的故障诊断所面临的转速谐波分量提取存在误差累积效应、瞬时相位难以准确估计等问题，本文提出了一种基于自适应谐波分量提取的航空发动机附件传动系统变速故障诊断方法。首先，通过低通滤波和降采样优化搜索空间并提升计算速度，在此基础上利用自相关平均周期进行自适应辛几何模态分解；其次，采用基于替代数据检验的伪谐波分量识别方法，完成转速谐波分量自适应分离结果的稀疏化表征。最后，基于转速谐波分量瞬时相位计算结果，对原始非平稳信号进行等角度重采样，利用傅里叶变换获取阶次谱以实现旋转机械装备的变速故障诊断。通过与典型信号分解方法对比，验证了所提方法的有效性；此外，对法国Safran某型航空发动机扫频试车过程中附件传动系统实测数据进行分析，所得阶次相对误差为0.059%,优于同类方法计算结果，进一步显示了其工程应用价值。

A speed-varying fault diagnosis method for the aero-engine accessory transmission system based on adaptive harmonic components extraction

To address the problems existed in the process of tacho-less order tracking (TLOT) based fault diagnosis, such as the error accumulation effect of harmonic components extraction and the difficulty of accurate instantaneous phase estimation, a speed-varying fault diagnosis method for the accessory transmission system based on adaptive harmonic components extraction is proposed. Firstly, the vibration signal is low-pass filtered and down-sampled for computation speed acceleration. Harmonic components are subsequently extracted by the adaptive symplectic geometry mode decomposition (ASGMD) based on the autocorrelation average periods. Secondly, surrogate data test is applied for pseudo components identification. Therefore, interferences induced by background noise can be filtered out adaptively. Finally, Hilbert transform is applied to obtain the instantaneous phase of the decomposed fundamental harmonic component. The TLOT is conducted to realize fault diagnosis for rotating machinery equipment under speed-varying conditions. The simulation analysis and an experiment from a Safran aero-engine during the frequency sweep test exhibit that the proposed method has a relative error of 0. 059% in TLOT. This result is better than those of conventional approaches. The bright prospect is evaluated in industrial application.