Dissertation > Aviation, aerospace > Aviation > Aeronautical Manufacturing Technology > Maintenance and repair of aircraft

Research of the Helicopter Gearbox Malfuction Diagnosis and Prediction Systemr

Author WangWei
Tutor HuChunHai
School Yanshan University
Course Measuring Technology and Instruments
Keywords Helicopter Gear box Failure diagnosis Hilbert/Huang transform EMD analysis Wavelet transform Simulation
CLC V267
Type Master's thesis
Year 2009
Downloads 233
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To the helicopter gearbox failure diagnosis system,the helicopter Health and Usage Monitoring System(Health and Usage Monitoring System,refered to as HUMS) has already been developed abroad. However, in domestic the traditional methods are still in using, such as manual experience judgments or simple devices qualitative judgments which can neither diagnose sophisticated malfunction nor make the early malfunction prejudge. Therefore, the subject of this research has vital significance in secure point as well as strategic point.The probelm of the current helicopter gearbox condition monitoring method is that the structure of helicopter gearbox is complicated while the examination parameter are few. As a result, it is hard to fully reflect running status of the major parts of the gearbox and discover incipient failure of the gearbox. Common failure diagnosis methods are including Vibration Method, Temperature Method, Oil-like Analysis Method and so on. Thereamong, Vibration method not only requires the relatively simple signal detection equipment, but also equips high incipient failure examination ability Therefore, this system will choose vibration as the based method, and temperature method as well as oil-like analysis method as the auxiliary method to do the overall design.This paper elaborated the gearbox vibration mechanism, and dissect vibration signal processing essential method at first. Then it designed a modelling platform with the structural characteristics of helicopter. Three types of sensors will be installed at suitable position, which through the transmitter sensors, signal- amplifier, as well as the lower computer with high-performance ISA bus anti-filtering card, signal sampled holding card and AD card to collect vibration signals, temperature signals, and signals debris into IPC for monitoring, and send vibration signals data through Ethernet for data processing. Wavelet analysis and Hilbert / Huang Transform (HHT) Analysis which suited to deal with non-stationary signals have been chosen in a variety of Vibration signal processing methods and carried a comparison between them. Through Matlab programming Upper PC machine can get a simulation results and it will be able to achieve malfunction diagnosis and prediction after observation and analysis.By means of monitoring Gearbox internal oil temperature and content of the scrap metal in the Gearbox oil exit, the accuracy and credibility of the malfunction diagnosis and prediction can be verified finally. Thus the study of the helicopter gearbox malfunction diagnosis and prediction system has been completed so far.

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