An Investigation into the Effects of Load on Several Gear Fault Diagnostic Techniques

摘要

An investigation of the load effect on a number of well-known gear fault diagnostic techniques is presented in this paper. The motivation for this study comes from the requirement for an in-flight diagnostic system of helicopter transmissions that is capable of detecting and diagnosing faults under various flight/loading conditions. For this purpose, the continuous wavelet transform is examined and compared with the residual kurtosis technique and short-time Fourier transform technique (spectrogram) in terms of their abilities to detect faults under different loads. The results show that residual kurtosis is load dependent and only capable of detecting gear cracking under a relatively large load. The effectiveness of the spectrogram is constrained by its constant resolutions across the time-frequency domain. The wavelet analysis, however, is effective in diagnosing gear cracking under various loading conditions. A brief theoretical description of the wavelet transform is also presented.