光纤Bragg光栅低频振动传感器的特性研究

Characteristics of low-frequency vibration FBG sensor

设计了一种安装于双圆柱弹性环内并由多条弹性薄片条组装成的桶形骨架作为光纤Bragg光栅(FBG)振动传感器基底的传感结构,振动传感器的谐振频率为440Hz,加速度灵敏度约为76.4pm/g,采用相位载波调制式FBG振动传感器解调系统进行解调。实验结果表明,本文传感器经双圆柱弹性环对横向振动约束处理后,其幅频特性在20～300Hz频率范围内呈现出平坦的水平直线,对应于位相角φ=0处的相频特性曲线也呈现出平坦的水平直线,适合于工程技术中20～300Hz的振动信号实时检测。

A drum-type skeleton base structure of fiber Bragg grating（FBG） vibration sensor is designed,where the FBG is mounted on double cylindrical rings,and the structure consists of a number of flexible sheets.The FBG vibration sensor demodulation system uses phase modulation for demodulating.The experimental results shows that the resonant frequency of the developed FBG vibration sensor is 440 Hz,and the acceleration sensitivity is about 76.4 pm/g.The sensor adopts the double cylinder elastic rings for transverse vibration restraint and then its amplitude-frequency characteristics in the 20-300 Hz frequency range show a flat horizontal line,and the phase-frequency characteristics also show a flat horizontal line at phase angle of φ=0.The proposed sensor is suitable for the low-frequency（20-300 Hz） vibration signal detection.