一种用于周界入侵监测的FBG振动传感器

针对传统周界入侵监测中电学类振动传感器存在 的误报率高、易受电磁干扰和不易实现大面积网络 化和长期可靠的远程监测等不足,研究设计一种基于等强度梁结构的低频光纤布拉格光栅(FBG)振动传 感器。在分析等强度梁振动理论的基础上,推导了基于等强度梁的FBG振动调谐原理。 结合工程应用 实际,确定了等强度梁的结构尺寸,并针对振子质量进行优化设计。采用ANSYS对传感 器进行有限 元分析,得到其一阶谐振频率为94.74Hz。分别采用激振频率为35Hz的振动源对传感器进行振 动试验,试验数据的时域及频域分析结果表明,本文传感器具有良好的动态响应特性,能 够实现对振动频率的准确测量,可以满足特定环境下周界入侵监测的特殊需求。

An FBG vibration sensor used in perimeter intrusion monitoring system

In view of the problems such as high rate of false positives,susceptibility to electromagnetic interference, not easy to achieve a large area network and long-term reliable remote monitor ing of the traditional electric-type vibration sensor in perimeter intrusion monitoring system,a low frequency fiber Bragg grating (FBG) vibration sensor based on uniform strength beam is designed and studied in this pa per.On the basis of uniform strength beam vibration theory,the FBG vibration tuning principle by uniform st rength beam is derived. Combined with practical engineering applications,the uniform strength beam stru cture size and vibrator mass of the sensor are optimized.Using ANSYS software,the first-order resonanc e frequency of the FBG vibration sensor is calculated,which is 94.74Hz.Two different vibration sources with 35Hz and 50Hz excitation frequencies are used to test the FBG vibration sensor.According to the experime ntal data and frequency domain analysis,the results show that this sensor could achieve accurate frequency tes t for the vibration sources,with good response characteristics to meet the special requirement of perimeter intrusion monitoring system in military fields.