两点封装的光纤布拉格加速度传感器设计

Design of FBG acceleration sensor based on two-dot coating

提出了一种双半孔梁光纤布拉格光栅(FBG)加速度传感器实现加速度信号测量的方法。首先,建立了两点封装FBG的加速度传感模型,理论分析了加速度与位移敏感点的线性响应。其次,从理论上分析了两点封装方案中FBG的自振特性,讨论了封装光纤的长度和预应力对光纤自振频率的影响。最后,依据FBG的自振特性设计了FBG加速度传感器,并通过实验研究了FBG加速度传感器的线性响应和幅频响应特性。实验结果表明:提出的传感器在10～250Hz具有较好的平坦区,加速度响应灵敏度为41.2pm/G;加速度与波长具有较好的线性关系,线性度为99.8%。同时,该加速度传感器具有较强的方向抗干扰性,轴向交叉灵敏度小于4.8%。

A Double-semicircle Cantilever Beam（DSCB） accelerometer based on a fiber Bragg grating （FBG） was proposed to measure the acceleration signals. Firstly, the model of FBG accelerometer based on the two-dot coating was established, and the linear response between acceleration and dis- placements of sensitive elements was analyzed theoretically. Then, the natural vibration of the FBG based two-dot coating was described, and the effects of the length and prestress of the coated fiber on natural vibration frequency were discussed. Finally, according to the natural vibration of FBG, the FBG accelerometer was designed, and the linear response, amplitude-frequency characteristics, and direction anti-interference of the FBG accelerometer were researched experimentally. Experimental results indicate that the sensor has good flat response from 10-250 Hz, and the sensitivity of the accel- erometer is 41.2 pm/G. Furthermore, the sensor can offer a good linear response in a linear fitting of 99.8% and a good cross-axis anti-interference ability in the cross-axis sensitivity less than 4.8%.