Research On Fully Insulated Multi-cantilever Fiber Grating Vibration Sensor And Its Demodulation System

Vibration signal is one of the important operating conditions of mechanical,chemical and electrical equipment.Its reliable and on-line inspection is of practical significance to ensure safe production.Conventional electrical vibration sensors are not suitable for flammable and explosive and other special work occasions,in the strong electromagnetic field environment susceptible to interference,and the signal transmission distance is limited.The vibration sensor based on fiber Bragg grating has the advantages of strong insulation,corrosion resistance,anti-electromagnetic interference and other significant advantages which can make up for the former lack.This paper designs and develops a fully insulated material multi-cantilever beam Bragg grating vibration sensor and its demodulation system,to overcome the single-cantilever structure of the fiber Bragg grating vibration sensor which is easy to produce deflection and produce corner defects.The main research contents are as follows:(1)This paper analyzes the measurement principle of Bragg grating vibration sensor with multi-cantilever beam,designs a fiber Bragg grating vibration sensor structure and established its sensing model.The structural parameters of the cantilever beam are optimized by static finite element analysis and modal finite element analysis;Developed a fully insulated fiber grating vibration sensor based on 3D printing technology.(2)The optical fiber Bragg grating vibration sensor demodulation system is designed and developed.The working bandwidth of the demodulation system is up to 80nm,the output power is adjustable and the demodulation frequency is up to 5kHz,which realizes the real-time acquisition and processing of the vibration sensor signal.(3)Set up the vibration sensor test platform,carry on the vibration experiment to the sensor and data processing is performed.The sensitivity of the sensor is 6.27pm/g,the linearity is 3.3%,the repeatability error is 6.475%FS,the hysteresis is ±5.19%FS,the natural frequency is 240Hz,and the working bandwidth is up to 170Hz.