Design Of Three Component Low Frequency Vibration Sensor Based On Genetic Programming

Low frequency vibration sensors are mainly used in geological exploration,mine safety,bridges and tunnel monitoring and other scenarios.At present,the development of low-frequency vibration sensor is an important research direction in the field of microseismic signal monitoring.Improving the low-frequency response performance of electromagnetic vibration sensor is a technical difficulty right now.This thesis focuses on the design of three component electromagnetic low-frequency vibration sensor,and carries out research in three aspects:the design of three component low-frequency compensation network based on genetic programming,the acquisition and storage of three component low-frequency vibration signal,and the overall performance evaluation of low-frequency vibration sensor system.Aiming at the problem that the low-frequency compensation technology of force balance feedback improves the low-frequency response of the electromagnetic vibration sensor yet causes the unevenness of the system’s amplitude-frequency response.We first analyze the frequency-domain model of the electromagnetic vibration sensor and the design goal of the low-frequency compensation network analog circuit.After completing the abstraction of the tree coding circuit and the construction of the corresponding function set,a suitable genetic operation is designed for the automatic evolutionary of the analog circuit.Through establishing a reasonable circuit abstract fitness evaluation function,the goal of automatically evolving three component low-frequency compensation network is finally realized through genetic programming algorithm.On this basis,the effectiveness verification of zero pole,frequency response curve and group delay of low-frequency compensation network system is completed based on SPICE model,and the hardware system is constructed considering the requirements of power consumption and noise design.In order to solve the problem that the vibration wave collected by single component geophysical equipment can not provide fine geological structure information,the development of three component low-frequency vibration signal acquisition and storage system is completed based on low-frequency compensation network and embedded system.Comprehensively analyzing the performance requirements of system power consumption and acquisition accuracy,the device is selected to build,analog-to-digital conversion function and data storage module function circuit.After completing the construction of microseismic signal acquisition and storage hardware platform.The configuration method of multi-channel and high-precision analog-to-digital conversion module and SPI data transmission protocol are studied.Finally,the software development of corresponding data storage,analog-to-digital conversion and data acquisition functions is completed by using DMA mode,interrupt mode and polling mode.In order to evaluate the performance of the designed three-dimensional low-frequency vibration sensor system,tests are carried out mainly focusing on functional integrity and acquisition accuracy.In terms of functional integrity test,the low-frequency vibration signal of the standard low-frequency vibration calibration test platform is collected.After the collected signal is recovered,it is verified that the designed system has complete and effective function in low-frequency vibration signal acquisition and storage;In addition,the signals collected in the outdoor test are analyzed in frequency domain and time domain to further verify the acquisition ability of the system for microseismic signals.In terms of acquisition accuracy test,the performance comparison test is carried out with Sinopec geophysical equipment i-nodall,which is widely used in the actual production environment under the condition of field industrial explosion.Through the analysis of the signals collected in the production environment in frequency domain and time domain,it is found that the designed system has significantly improved its low-frequency signal acquisition ability while maintaining the high-frequency response ability.