Improved layer peeling algorithm to realize FBG non-uniform strain sense demodulation
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摘要: 剥层法是重构光纤Bragg光栅(FBG)参数的常用方法,利用剥层法可以解调FBG非均匀应变。常规剥层法获得的FBG复耦合系数存在误差,为提高非均匀应变解调精度,提出基于剥层法的复耦合系数幅值修正改进方法。新方法在剥层求解当前层复耦合系数后,保留耦合系数相位,对耦合系数幅值进行修正,构成新的复耦合系数用于下一层反射谱的剥层求解。给出了改进算法求解非均匀应变的详细步骤和过程,并进行了仿真实验研究。利用传输矩阵法模拟仿真无应变、应变线性增大、应变线性减小以及二次曲线应变下的FBG反射谱,分别使用常规方法和改进的方法对各反射谱进行应变解调。结果表明:改进的方法获得的应变结果与理论应变有更高的一致性;不同理论应变下,改进的方法获得应变最大误差均值约为原始方法的1/5,均方根误差的均值约为原始方法的1/7,改进的方法解调误差远小于原始方法。Abstract: Layer peeling algorithm is a common method of fiber Bragg grating(FBG) parameter reconstruction, which can be used to demodulate the inhomogeneous strain applying on FBG. The study found that conventional layer peeling algorithm cannot figure out the exact value of complex coupling coefficient, to increase the non-uniform strain demodulation precision, a improved layer peeling algorithm called complex coupling coefficient amplitude correction method was proposed. The improved method retained the phase of coupling coefficient, corrected the amplitude of coupling coefficient, and used the modified complex coupling coefficient on layer peeling calculation of the reflection spectrum. The following 4 reflection spectrums of FBG were obtained by the transfer matrix simulating method: without strain, strain increasing linearly, strain decreasing linearly and strain of quadratic curve, the strain results were calculated by both the conventional method and the improved method. The experiment shows that the strain results of the improved method are consistent with the input strain; With different theoretical strains, mean of the largest error of improved method is about 1/5 of conventional method, the mean of root mean square error is about 1/7 of the conventional one, the error is obviously much smaller.
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[1] Liu Tiegen, Wang Shuang, Jiang Junfeng, et al. Advances in optical fiber sensing technology for aviation and aerospace application[J]. Chinese Journal of Scientific Instrument, 2014, 35(8): 1681-1692. (in Chinese) 刘铁根, 王双, 江俊峰, 等. 航空航天光纤传感技术研究进展[J]. 仪器仪表学报, 2014, 35(8): 1681-1692. [2] [3] [4] Li Yongqian, Wang Yu, Yao Guozhen. Comparative analysis of FBG vibration sensing demodulation method[J]. Study on Potical Communications, 2014, 8(4): 46-50. (in Chinese) 李永倩, 王宇, 姚国珍. 光纤光栅振动解调方法对比分析[J]. 光通信研究, 2014, 8(4): 46-50. [5] [6] Chen Xiaomei, Li Xinliang, Zeng Wu, et al. Investigation of fiber bragg grating for dynamic strain measurement[J]. Aviation Metrology Measurement Technology, 2002, 22(6): 3-7. (in Chinese) 陈晓梅, 李新良, 曾吾, 等. 用纤内Bragg光栅进行动态应变测量的研究[J]. 航空计测技术, 2002, 22(6): 3-7. [7] [8] Dragan C, Limberger H G, Salathe R P. Distributed measurements of fiber birefringence and diametric load using optical low-coherence reflectometry and fiber gratings[J]. Optics Express, 2006, 14(24): 11804-11813. [9] Gagliardi G, Salza M, Ferraro P, et al. Fiber bragg-grating strain sensor interrogation using laser radio-frequency modulation[J]. Optics Express, 2005, 13(7): 2377-2384. [10] [11] Kisa?a P. Measurement of the maximum value of non-uniform strain using a temperature-insensitive fibre Bragg grating method[J]. Opto-Electronics Review, 2013, 21(3): 293-302. [12] [13] [14] Salath R P, Boisrobert C, Botsis I. Fiber Bragg Grating Characterization by Optical Low Coherence Reflictometry and Sensing Applications[M]. Lausanne: EPFL, 2003. [15] Wang K, Wang B, Yan B, et al. Simultaneous measurement of absolute strain and differential strain based on fiber bragg grating fabry-perot sensor[J]. Optics Communications, 2013, 307: 101-105. [16] [17] Peral J E, Capmany J Marti. Iterative solution to the GelFand-Levitan-Marchenko coupled equations and application to synthesis of fiber gratings[J]. IEEE J Quant Electron, 1996, 32(12): 2078-2084. [18] [19] [20] Wang Jing, Wang Zhengfang, Sui Qingmei, et al. Study of FBG strain distribution reconstruction based on improved genetic algorithm dual constraint[J]. Chinese Journal of Lasers, 2012, 39(3): 132-138. (in Chinese) 王静, 王正方, 隋青美, 等. 基于改进遗传算法双重约束的FBG应变分布重构研究[J]. 中国激光, 2012, 39(3): 132-138. [21] Botsis J, Humbert L, Colpo F, et al. Embedded fiber Bragg grating sensor for internalstrain measurements in polymeric materials[J]. Optics and Lasers in Engineering, 2005, 43(3): 491-510. -
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