Design And Research Fiber Bragg Grating Vibration Sensor For High-temperature

Vibration monitoring in harsh environments such as high temperatures is widespread in aerospace,oil well mining,bridge construction,and industrial control.The real-time and accurate acquisition of vibration parameters is of great significance to the reliable and efficient operation of the system.The fiber Bragg grating(FBG)vibration sensor has more and more advantages in the field of high temperature vibration measurement because of its simple structure,anti-corrosion,small size,anti-electromagnetic interference,and long distance measurement.In this paper,a cantilever fiber Bragg grating vibration sensor that can be used in a high-temperature environment is designed,and an active temperature-compensated demodulation method is proposed for the high-temperature fiber Bragg grating vibration sensor.The performance of the sensor is verified by building a high temperature vibration test platform,and the sensor can achieve simultaneous measurement of temperature and vibration signal under high temperature environment.The main research contents are as following:(1)In this paper,a quartz cantilever fiber grating vibration sensor is designed for high temperature environment,which can measure the vibration signal under high temperature.By studying and analyzing the sensing principles of cantilever beam structure and fiber grating,the vibration sensor sensing model is simulated from three aspects of structural design,thermodynamics and optical sensing,and the dynamic performance of high temperature vibration sensor is analyzed.(2)Based on the principle of grating vibration demodulation,an active temperature compensation feedback control demodulation method is designed,and the sensor processing and high temperature vibration sensing system are introduced.By setting up the PID feedback control system,the laser wavelength can be adjusted continuously to stabilize the grating Offset point,and the temperature and vibration signals can be monitored simultaneously.(3)By building a high-temperature vibration test system platform,the vibration parameters of the sensor at room temperature and high temperature are tested.The experimental results show that the high-temperature fiber Bragg grating vibration sensor designed in this paper has a resonance frequency of 382.5 Hz,a sensitivity of 132.33 m V/g,a nonlinearity of 3.33%,and a temperature coefficient of 0.01307 nm/?.The temperature and vibration signals at 400 ? are measured simultaneously.The practicality and reliability of the sensor at room temperature and high temperature were tested and verified.Through the correction of sensor temperature drift and sensitivity,to achieve the effect of sensor temperature decoupling analysis.