The Vibration Monitoring System Based On The Optical Fiber Sensing And Its Application In Intelligent Pipe Gallery

In recent years,the construction of intelligent pipe galleries has gradually developed and the market is huge.The internal environment of the pipe gallery is complex,the system is huge,and the pressure of protection is great.Once an intrusion occurs,it will lead to irreparable losses.Therefore,the security monitoring system is the most important thing for the construction of the entire intelligent pipe gallery.On the basis of fully considering the environmental characteristics of the underground pipe gallery,in order to reduce the research cost and the rate of false alarm,this thesis carries out the design and function realization of the hardware circuit of the pipe gallery monitoring system and the research of the system alarm pattern recognition algorithm.In this thesis,an optical fiber vibration monitoring system is designed.A fiber with strong anti-interference ability,high stability,and corrosion resistance is used as a sensor.This system is based on the Mach-Zehnder(M-Z)interference technology with high sensitivity,adopts the embedded system,and extracts the signal frequency spectrum characteristic through Fast Fourier Transform(FFT)to carry on the pattern recognition,which meets the security requirements of pipe gallery.Compared with similar products in the industry,the cost is low and the performance is superior.The work of this thesis is mainly in the following five aspects:(1)Analyzes the requirement of the security management system for the pipe gallery,proposes the overall structure of the vibration monitoring system based on optical fiber sensing,and designs the optical path of the system based on the M-Z interference principle.(2)The system hardware circuit is designed and implemented.With the embedded system,two ADs collect data,and the processed data is communicated with the upper computer through a high-speed network port,ensuring no breakpoint transmission of data and reducing development costs.(3)FFT is used to extract the characteristics of the sensing signal in the frequency domain,and neural network is used to identify the pattern of the sensing signal,which improves the accuracy of recognition and reduces the false alarm rate.(4)In the laboratory,a fiber-optic vibration monitoring system based on M-Z interference was set up to test the system functions.The results showed that when there is intrusion behavior,the system can output alarm signals in real time,achieving the expected results.(5)According to the distribution situation of underground pipe galleries in the actual project,as well as environmental factors,the installation design plan was proposed.