| High-speed rail vibration signal is a kind of artificial source with high repeatability,its highprecision acquisition and multi-faceted application are the hotspots of current industrial and scientific research.The collection of large-scale vibration signals puts forward higher requirements on the time synchronization between each collection node,so it is necessary to design a high-precision timing system to improve the accuracy of vibration signal collection.On the other hand,the vibration energy of the high-speed rail is relatively large,which will cause harm to the viaduct bridge and the surrounding environment,and may cause unnecessary rail traffic accidents and cause physical and mental harm to surrounding people.Therefore,the application and protection of high-speed rail vibration signals are also urgent problems to be solved.In this paper,the following three aspects of research are carried out in the aspects of signal synchronous clock acquisition,high-speed rail noise active protection and elevated vehicle bridge detection.First of all,in terms of high-precision synchronous timing,a method of using a high-precision clock source to time the central control station of the acquisition network through a 5G communication network is proposed.With the support of the 3GPP protocol,the 5G terminal corrects the time information contained in the 5G NR information block to compensate for the error caused by signal delay;on this basis,a redundancy mechanism is designed to compensate for the time error caused by the generation of local time information and transmission information,so as to realize the synchronous timing of each node from the central control station.The Lora communication module is used to form a grouped centralized network to improve the communication efficiency of the network and reduce maintenance costs.The test results show that this synchronization method can improve the time synchronization accuracy of the acquisition system.Secondly,starting from the basic vibration mechanics model,an idealized high-speed rail vibration signal model is constructed to increase the influence of parameters such as car vibration and track irregularity on track vibration,thereby improving the completeness of the model.With the help of the measured signals collected by the vibration acquisition equipment,the conformity of the model to the simulation of high-speed rail vibration signals is verified.Based on the actual collected vibration signal,after analysis such as synchronous compression wavelet transform,its timefrequency spectrum characteristics are extracted,and the measured vibration signal is compared with the vibration model to analyze the health status of the high-speed rail track in the measured section.The analysis results show that the health of this section of high-speed rail track is good,and this method can provide ideas for elevated track vibration and health monitoring.Finally,in order to eliminate or reduce the impact of high-speed rail noise on the surrounding environment,according to the actual environment of the high-speed rail track,a frequency-domain adaptive algorithm for active noise reduction is proposed and a suitable noise reduction system structure is constructed.The phase estimation and compensation method is introduced into the algorithm,which overcomes the defects of the current active noise reduction time-domain adaptive algorithm,and eliminates the problem of poor noise reduction effect caused by the instability of the secondary channel model in the active noise reduction system.Under the control of the minimum mean square error,the active noise reduction algorithm has great advantages in bandwidth and system stability.The noise reduction effect and real-time performance of the algorithm are verified from two angles of simulation experiment and physical experiment.Experimental results show that the algorithm has a good performance in terms of operation speed and noise reduction effect,whether it is a single frequency signal or a complex actual vibration signal. |
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