微型宽频光纤布拉格光栅振动传感器设计及特性研究

Structural Design and Investigation of Micro-Broadband Fiber Bragg Grating Vibration Sensor

提出了一种小型化、宽频段、高灵敏度的光纤布拉格光栅(FBG)振动传感器,利用毫米级FBG进行传感器结构的微型化设计。采用“杠杆铰链”结构作为应变传递梁,通过质量块尾端镂空的方法,调节整体质量块重心位置,提高了传感器的固有频率,此结构可以在灵敏度小幅度降低的情况下提升传感器的固有频率。为了满足空间相机上传感器小型化的要求,设计了体积为15 mm×15 mm×15 mm的振动传感器,并对其进行了结构设计和有限元仿真分析,完成了传感器的结构优化,兼顾工作频段和灵敏度。通过毫米级FBG刻写、传感器封装完成了传感器的制作。搭建了振动测试系统对传感器的特性进行测试和分析,结果表明:传感器的固有频率约为1250 Hz,激振频率为750 Hz时,传感器的灵敏度大于83.3 pm·g^(-1),横向抗干扰能力较强,交叉灵敏度小于4%。

A miniaturized,wideband,highsensitivity fiber Bragg grating(FBG)vibration sensor is proposed.The millimeterscale FBG is used to design the sensor structure.The“lever hinge”structure is used as the strain transfer beam,and the center of gravity of the entire mass block is adjusted by hollowing out the end of the mass block,which improved the natural frequency of the sensor.This structure increases the natural frequency of the sensor with a slight decrease in sensitivity.In this study,a vibration sensor with a volume of 15 mm×15 mm×15 mm is designed to satisfy the miniaturization requirements of sensors on space cameras,and structural design and finite element simulation analysis were performed.The structural optimization of the sensor is completed,considering the working frequency band and sensitivity.The sensor is fabricated by millimeter FBG writing and sensor packaging.A vibration test system is built to test and analyze the characteristics of the sensor.The results show that the natural frequency of the sensor is approximately 1250 Hz,the sensitivity exceeds 83.3 pm·g^(−1) when the excitation frequency is 750 Hz,the lateral antiinterference ability of the sensor is excellent,and the crosssensitivity is lower than 4%.