Design Of Doppler Correction Of Trackside Acoustic Signal And Acoustic Testing Platform System

The bogie is an important part of the train,and the bearing is the key component of the bogie.The detection of its failure state under the condition of high-speed operation is a research hotspot at home and abroad.The low-cost and non-contact detection method of rail-side bearing acoustic detection technology has a high degree of feasibility for fault detection of high-speed trains.Due to the relative movement between the detection equipment and the fault sound source,the sound signal produces Doppler distortion,which affects the judgment of the true fault sound signal of the bearing.Therefore,correcting the Doppler distortion signal is the key to acoustic detection.Based on the acoustic theory and the positional relationship between the microphone and the sound source of the bearing,this paper establishes a sound source movement model for a single-point fault of the rail-side bearing;According to the non-linear characteristics between the microphone and the bearing fault sound source in the bearing fault sound source motion model,the time delay of the microphone receiving signal,the motion trajectory of the bearing fault sound source,and the sound pressure of the microphone receiving the fault sound source are analyzed.Change the curve to obtain the Doppler distortion law of the collected signal;According to the signal Doppler distortion law,the interpolation resampling algorithm is used to correct the time-domain distortion signal,and based on the window function to restore the Doppler distortion signal amplitude,the accuracy of the Doppler distortion signal correction algorithm is verified by MATLAB simulation;At the same time,according to the actual train bearing operation,design and build a Doppler correction and acoustic detection platform,and use Lab VIEW software to design an acoustic signal acquisition and detection system to achieve acoustic signal acquisition and storage,data analysis,and Doppler distortion signal correction;Experimental results prove that the Doppler distortion correction method has a certain correction effect on the distorted signal;Through the analysis of engineering examples,the correction method can effectively restore the real fault signal,which shows that the trackside acoustic Doppler distortion correction method has a certain correction effect when applied to the engineering example.