改进光纤光栅应变分布解调算法中优化目标函数的理论与方法

Theory and Method for Improving Optimization Objective Function in Demodulation Algorithm of Fiber Bragg Grating Strain Distribution

分析了光纤布拉格光栅(FBG)反射光谱的获取方式,根据反射光谱的特征,提出了利用相关系数改进FBG应变分布解调算法中优化目标函数的理论方法。结合差分进化算法,对改进算法与传统算法的性能进行了对比仿真。仿真结果表明,传统算法仅适用于能获知FBG真实反射率的情况,而改进算法还适用于无法获知FBG真实反射率的情况,所提方法提升了FBG应变分布解调算法的实际应用能力。

The obtainment method of fiber Bragg grating(FBG) reflection spectra is analyzed, and according to the characteristics of reflection spectra, a theoretical method is proposed for improving the optimization objective functions in the demodulation algorithm of FBG strain distributions using correlation coefficients. The performances of improved and traditional algorithms are compared by simulation combined with the differential evolution algorithm. The simulation results show that the traditional algorithm is only suitable for the situation where the true reflectivity of FBG is known, in contrast the improved algorithm can be applied to the situation where the true reflectivity of FBG is unknown. The proposed method can be used to improve the practicality of demodulation algorithms of FBG strain distribution.