基于角度偏差自校正的光纤形状传感结构与方法设计

Design of Fiber Shape Sensing Structure and Method based on Angle Deviation Self-correction

摘要:

光纤形状传感中FBG的放置角度误差会影响曲率的计算精度,从而增大形状反演的误差。为了实现传感胶棒的角度自校正,设计了一种自校正形状传感结构,在传感胶棒的感知截面上布设9个FBG,以120°等角度间隔作为基准位置,分别提取±10°位置上的应变,从而完成FBG响应与角度偏差的函数映射。提出了一种基于角度偏差自校正算法,通过适应度函数完成对传感参量a与k的阈值优化,实现任意角度偏差的自校正。仿真分析不同a与k条件下的响应关系发现,a具有很好的线性变化特性,k仅随主敏感FBG波动的特性。单截面实验中,加载0-100N应力变化后,9个FBG的平均响应度介于[-1.012me/N, 0.987me/N]。响应度的正负可以表征弯曲方向,相邻FBG的响应也具有很好线性度。组合截面实验中,根据反演结果重建传感胶棒三维结构,输出各点位坐标和应力值信息。

Abstract:

The placement angle error of FBG in fiber optic shape sensing can affect the accuracy of curvature calculation, thereby increasing the error of shape inversion. In order to achieve self-correction of the angle of the sensing rubber rod, a self-correction shape sensing structure was designed. Nine FBGs were deployed on the sensing cross-section of the sensing rubber rod, with 120 ° equal angle intervals as the reference positions, and strains were extracted at ± 10 ° positions, thereby completing the functional mapping of FBG response and angle deviation. A self-correction algorithm based on angle deviation is proposed, which optimizes the threshold of sensing parameters α and k through the fitness function to achieve self-correction of any angle deviation. Simulation analysis of the response relationship under different α and k conditions reveals that α has good linear variation characteristics, and k only fluctuates with the main sensitive FBG. In the single section experiment, the average response of 9 FBGs was between [-1.012me/N, 0.987me/N] after loading 0-100N stress changes. The positive or negative response can characterize the bending direction, and the responses of adjacent FBGs also have good linearity. In the composite cross-section experiment, the three-dimensional structure of the sensing rubber rod is reconstructed based on the inversion results, and the coordinates and stress values of each point are output.