高精度动态光纤应变传感研究

Study of High-precision Dynamic Optical Fiber Strain Sensing

传统的光纤应变传感技术无法在满足高精度和强环境适应性的同时实现稳定的动态应变传感.为了解决该问题,本文将光干涉原理应用于光纤应变传感,设计了一种强环境适应性的基于干涉结构的高精度光纤应变传感系统,基于扫频干涉信号的互相关系数,该系统可以稳定地探测应变.本文还提出一种动态探测算法,该算法弥补了系统只能探测较小应变的缺陷,大大提升了实际应变的探测范围,同时还实现了动态的应变检测;采用三次样条插值算法,提升了小应变探测的精度.理论分析和仿真模拟表明,在加入白噪声的信号信噪比为15dB时,插值后的探测精度是未插值探测精度的2.3倍,插值后本系统探测结果的最大误差只有约9nε.

Traditional fiber strain sensing technologies can not meet the properties of high precision, good environment adaptability and realize dynamic strain sensing stably at the same time. In order to solve this problem, an optical interference principle was adopted to realize optical fiber strain sensing in this paper, a kind of high-precision dynamic optical fiber strain sensing system with a good environment adaptability based on an interference structure was designed. The system can be used to detect strain stably based on cross correlation coefficient of swept interferometer signal. This paper also proposes the dynamic detecting method that significantly increases practical detection range to overcome the drawback that the system can only detect small strain and realize strain sensing dynamicly. The cubic spline interpolation algorithm was used to improve the accuracy of detection of small strain. Theoretical analysis and simulation experiments show that, the precision of measurements after interpolation is 2.3 times which is higher than that before interpolation, and the maximum measurement error of strain is only 9 nε when the signal to noise ratio is 15 dB.