Design Of Signal Acquisition System Based On Single-coil Vibrating Wire Sensor

With the construction of major infrastructure projects such as bridges,dams,and tunnels in our country,the structural health monitoring of buildings has become more and more important.How to effectively monitor the quality of buildings and realize engineering safety warnings has become an urgent problem to be solved.Vibrating wire sensor plays a very important role in structural health monitoring.It is the preferred sensor for geotechnical engineering load measurement.Its working principle is to convert external load into frequency signals.It is durable,has a long transmission distance,and The output signal is stable and other advantages.However,the vibrating wire sensor has problems such as difficulty in starting vibration and weak response signal.How to achieve reliable start-up and fast and accurate reading is the problem that needs to be solved in this paper.In response to the above problems,the thesis takes the single-coil vibrating wire sensor as the research object,and designs a signal acquisition system based on the STM32single-chip microcomputer as the main control chip.The system realizes the functions of automatic data acquisition,processing,storage,display,and transmission.The main work of the thesis is as follows:In terms of hardware design,the signal acquisition system designed in this article consists of two parts: drive module and main control module.The driving module mainly completes the driving work of the vibrating wire sensor,and realizes the necessary excitation process and vibration picking process for collecting the frequency signal of the vibrating wire sensor.The excitation circuit,analog switching circuit,vibration picking circuit,power supply circuit are designed.The main control module is used to complete the work of outputting excitation signals,reading response signals,storing data,transmitting data,etc.It is mainly composed of the minimum system of STM32 single-chip microcomputer,real-time clock circuit,power supply circuit,OLED display module,SD card storage module,ESP8266 wireless communication module And other composition.In terms of software design,in order to improve the driving ability of the excitation signal,this paper proposes an improved frequency sweeping method based on low-voltage frequency sweeping technology.The frequency sweeping scheme for the first excitation and double excitation is designed,and a traditional frequency meter is used.The response signal is read by two methods: and equal precision frequency meter.Analyze and compare the above two different frequency measurement methods to achieve fast and accurate reading of the response signal of the sensor.This improved frequency sweeping method is easy to implement,convenient for single-chip control,and has obvious advantages in measuring some vibrating wire sensors that are not easy to vibrate.In terms of experimental verification,the circuit simulation was completed by using Multisim software,and the PCB design,component welding,circuit board debugging and other work were completed on the basis of ensuring the accuracy of the circuit,and the experimental verification work was completed in combination with the actual vibrating wire sensor.The data collected by the single-chip microcomputer was analyzed and uploaded to the cloud in real time,which verified the stability of the signal acquisition system.The experimental results show that the signal acquisition system designed in this paper has strong driving ability,accurate reading,good stability,and has good engineering promotion value.