Application Of Wavelet Analysis On Automatic Fault Diagnosis Of Tractor's Gearbox

Gearbox is one of the most important elements in a tractor. It is significant to study the condition of monitoring and fault diagnosis of gearbox. This thesis aims at the investigation of feature extraction of vibration signal and automatic diagnosis techniques of gearbox.Firstly, The performances of both advantage and limitation of traditional vibration diagnosis methods of gearbox are analyzed, including feature parameters, frequency analysis and envelop detection.Secondly, this thesis illustrates the indoor load-adding testing system applying on my experiment and explains the simulating blue print of tractor's gearbox fault diagnosis.Thirdly, the CWT (continuous wavelet transform) is applied to vibration signal analysis of "Dongfeng 81A" tractor's gearbox. Practical application shows the validity of CWT (continuous wavelet transform) based on Morlet wavelet. What's more, wavelet package techniques can effectively pick up the useful character information of vibration signal on the wide frequency band range.Thirdly, several key problems in gearbox automatic diagnosis application are studied and the responding solution are presented. Then an artificial neural network is built for the automatic diagnosis of tractor's gearbox.