叶端振动信号频谱分析的前后向平滑MUSIC法

Blade tip timing is an effective technique for non-oontact Vibration measurement of rotor blades of aeroengines, but its sampling pattern leads to the highly undersampled property of the sampled signals. The anti-aliasing spectrum analysis is required to extract the key indicator of the rotor blade, that is the natural frequency. The improved multiple signal Classification (MUSIC) method using the forward smoothing strategy can achieve anti-aliasing but cannot fully utilize the advantages of the smoothing method. Therefore, a forward-backward smoothing MUSIC method was proposed for BTT signal processing. By establishing the symmetrical placement conditions of the sensors, the forward-backward smoothing was used to replace the forward smoothing to obtain a more accurate autocorrelation matrix estimate, thereby improving the blade natural frequency estimation Performance. Through Simulation and experiments, it is verified that the aliasing and noise suppression capabilities by virtue of the forward-backward smoothing MUSIC method are improved under the same sample number, algorithm parameters, etc.