Research On Online Diagnosis Method Of Aircraft Bus Cable Fault

With the rapid development of multi-electric aircraft technology,the types of aircraft buses are increasing,and the number of distributions is becoming larger and larger.Intermittent faults in aircraft bus cables are only exposed during the flight of the aircraft,posing a significant safety hazard to the flight of the aircraft.Because the existing off-line detection technology cannot effectively deal with intermittent faults,the research on the online diagnosis of aircraft bus cable faults is of great significance to ensure the safe flight of the aircraft.Based on spread spectrum time domain reflectometry(SSTDR)theory,an online diagnostic method for aircraft bus cable faults is studied.Firstly,the basic principle of SSTDR is deeply analyzed based on the signal attenuation and reflection theory of transmission line,and a scheme for online diagnosis of aircraft bus cable faults is proposed.The detection signals for the aircraft ARINC429 bus and ARINC825 bus are designed according to the aircraft airworthiness standard and the aircraft bus protocol.In order to verify the feasibility of the scheme,the scheme is simulated based on the MATLAB platform,and the results proves that the scheme is effective.Next,the hardware design is based on the PXI bus platform,and virtual instrumentation technology is used for designing software programs.So an experimental system for online diagnosis of aircraft bus cable faults is built.Finally,the experimental system is used to diagnose the fault of the aircraft bus cable.The actual waveform data superimposed by the aircraft bus working signal and the detection signal is obtained by using the experimental system.The time domain and frequency domain methods are applied to analyze the interaction between the aircraft bus working signal and the detection signal,so as to further verify whether it meets the requirements of the aircraft bus protocol and aircraft airworthiness standards.The measurement accuracy analysis is carried out by expanding the experimental samples.The results show that the proposed scheme has great value of engineering application.