Research Of The Aircraft Wire Fault Detecting Method Based On Hilbert-Huang Transformation

Aircraft wire fault is one of the most common faults for the modern civil aircraft. As the perniciousness and hidden of the wire fault, there exit a serious threat to flight safety. It also affected the punctuality of flights to take off and caused economic losses to the airlines.In order to ensure the safety and continuing airworthiness of the aircraft, fault diagnosis and location of aircraft wire must be precise and intelligent.Aircraft wire fault can be divided into two categories: hard and soft faults. Hard faults,which including short-circuit, open circuit and other obvious damage, directly affecting the normal operation of the aircraft electrical system and making a serious threat to the safety of aircraft. Soft faults, which mainly including fray fault, are more subtle in the short term and can not directly cause the aircraft to malfunction. But as the aircraft continued to fly along,the soft faults can eventually lead wires short-circuit and open circuit failure. All of these are the same serious threat to the safety and continued relevance of aircraft. Currently, there are several ways to diagnose and locate hard faults, but there is still room for improvement. For the impedance changes of the soft faults is small, its presence is more difficult to diagnose and locate. But its potential high risk is a threat to the safety and the airworthiness of the aircraft.Therefore, the aircraft fault diagnosis and localization is an urgent subject.To this end, a new method based on Hilbert-Huang transform(HHT) to cope with the aircraft hard and soft fault diagnosis and location is proposed in this thesis. With this method,the time and frequency domain information can be fully used to diagnose and locate the aircraft fault. This can improve the diagnosis and location accuracy, and ensure flight safety and improve maintenance efficiency.Among this, the signal will inevitably be noise interference in the excitation, transmission and the detection process, the empirical mode decomposition of the HHT can be well used to denoising the signal for Emperical Mode Decomposition(EMD) is a good way to decompose the non-stationary and nonlinear signal into a set of stable and linear sequence of data. This could enable more accurate extraction of information on the failure to realize the fault diagnosis and localization wire with Phase Detection with Frequency Domain Reflectometry(PDFDR) and Time and Frequency Domain Reflectometry(TFDR) methods.Finally, with the research of the wire fault diagnosis and location method, the LabVIEW is used to design the fault diagnosis of aircraft wire system. And the precise positioning of wire fault can be achieved.