基于分布式应变的三芯光纤形态重构算法研究

为了利用分布式光纤传感技术测量的光纤应变进行三芯光纤三维形态重构,设计 了重构算法, 并利用有限元求解数据进行了验证。首先,设计了三芯光纤曲率和弯曲方向采样值的计算方 法,利用三次 样条插值法构建了曲率和挠率连续函数,基于Frenet-Serret框架设计了弧长参数下的空间 曲线公式；然后 构建了三芯光纤有限元模型,求解并提取了单向弯曲和S形弯曲的光纤应变分布数据,并带 入设计的算法 中进行求解,实现了三芯光纤的三维形态重构；最后通过均方根误差和归一化准确度对重构 误差进行了计 算和分析。结果表明,设计的三芯光纤三维形态重构算法误差控制在0.07%以内。该算法还原效果好,精度高,具有一定的理论和工程应用价值。

Research on morphology reconstruction algorithm of three core fiber based on distributed strain

In order to use the fiber strain measured by distributed optical fiber sensing technology to reconstruct the three-core optical fiber three-dimensional morphology,this paper designed a r econstruction algorithm and uses the finite element solution data to verify it.First,the calculation method of the curvature and the sampling value of the bending direction of the three-core fiber was designed.The curvature and torsi on continuous functions were constructed by the cubic spline interpolation method,and the space curve formul a under the arc length parameters was designed based on the Frenet-Serret framework.The three-core fiber finite element model was solved,and the fiber strain distribution data of unidirectional bending and S-shaped bending w ere solved and extracted,and then brought into the designed algorithm to solve the three-core fiber morphology re construction; finally through the mean square Root error and normalization accur acy are calculated and analyzed for reconstruction error.The results show that the error of the three-core fiber 3D shape reconstruction algorithm d esigned in this paper is controlled within 0.07%.The algorithm has good restoration effect,high precision,and has certain theoretical and engineering application value.