Development And Application Of Bearing Fault Diagnosis System Based On Wavelet Analysis

The rolling element bearings are universal components in rotating machinery,they play a crucial role in the safety of the locomotive driving.The non-disassembly detection of large-scale equipment is a relatively convenient and effective means in the fault diagnosis of railway machinery and equipment,which can greatly reduce the accident rate."Regulations for the overhaul and management of railway locomotive bearings" has clearly defined that all locomotive bearing inspection stations must be equipped with lifting wheelset detection system of bearings of locomotive running gear.The software of the bearing fault diagnosis system for locomotive running gear developed by this thesis is based on the project background of China Academy of Railway Science.The system software starts with the fault model of the rolling element bearings,bringing out the outstanding advantages of the analytical method of the vibration signal used in diagnosing the early failure of the rolling element bearings.The estimation methods of important parameters such as fault characteristic frequency and natural frequency are introduced to provide the basis for fault diagnosis.In order to make the diagnosis system obtain the fault feature,this thesis introduces and analyzes the implementation steps and specific realization methods of the most widely used resonant demodulation technology used in the fault diagnosis instrument system presently.The conventional bandpass filter in traditional resonant demodulation is further improved.The system software developed by this thesis is implemented through WinForm form program based on Visual Studio platform.The main contents of my work includes:(1)Starting from the present experience of the fault analysis of the rolling bearing,this thesis has designed the function of bearing fault diagnosis combined with simple diagnosis technology based on RMS,Kv of vibration signals and precision diagnosis technology of resonance demodulation.At the same time,important functional modules are designed for measuring scenes.(2)A wavelet analysis is presented for band pass filtering of bearing vibration signals,which effectively solves the problem that the inaccurate preselection of the central frequency and bandwidth of the filter leading to bad effect on signal de-noising.The simulation results of MATLAB are given in the third chapter,which verifies the feasibility and effectiveness of wavelet filtering.In the fourth chapter,the realization effect of wavelet band pass filter designed by software program module is given.(3)The overall application of the system software is analyzed by using the data collected at the scene.The program results show that the software of the bearing fault diagnosis system for locomotive running gear has reached the expected goals,which can meet the needs of railway overhaul site and lay the foundation for the following development of the whole system.