Research On Helicopter Rotor Imbalance Fault Diagnostic And Its Experimental System

Since health and usage monitoring system(HUMS)is applied to helicopters,it has played an important role in the reliability,safety and maintainability.As the main component of generating lift and manipulation,the rotor system is one of the important system monitored by HUMS.Along with the development of electronic technology,the sensors in HUMS are increasingly rich,for example,there are many acceleration sensors on the fuselage,main gear,engine and so on.As a convenient and fast way to diagnose the rotor system imbalance fault,this thesis focus on the diagnosis of the rotor based on model helicopter and light and small MEMS(Micro-Electro-Mechanical System)3-axis acceleration sensor.This thesis mainly consist of the follows:(1)Model helicopter testing system design.Appropriate model helicopter and testing hardware were chosen and the vibration testing system software needed for sampling and storage is developed by using ARM assembly language,embedded C language and C++ language.The vibration testing system is arranged based on the available space and structure.(2)Vibration test.Test data is acquired by the vibration system by setting several kinds of rotor system imbalance fault.The effectiveness of the vibration testing system is verified.The pre-processing of the sampled data is done for the convenience of features extraction and fault diagnosis.(3)Fault feature extraction and diagnosis.Wavelet transform and fast Fourier transform(FFT)is used to extract the fault features,than these features are used for fault diagnose by back propagation neural network(BPNN).The effectiveness of wavelet transform and fast Fourier transform method and the Model helicopter testing system is proved.