Fiber Bragg Grating-based sensor system for sensing the shape of flexible needles. (January 2023)

• Record Type: Journal Article
• Authors: Zhang, Leifeng; Li, Changle; Dong, Huijuan; Liu, Xiaojing; Sun, Tong; Grattan, Kenneth T.V.; Zhao, Jie
• Is Part Of: Measurement. Volume 206(2023)
• Publication Date: 2023-01
• Subjects: Fiber Bragg Gratings (FBGs) -- Shape sensing -- Flexible needle -- Local curvature -- Gradient-based optimization; Weights and measures -- Periodicals; Measurement -- Periodicals; Measurement; Weights and measures; Periodicals; 530.8
• DOI: 10.1016/j.measurement.2022.112251
• Languages: English
• ISSNs: 0263-2241

Abstract

Highlights: A new model for calculating local curvature from the wavelength shifts of Fiber Bragg Gratings (FBGs) is developed to improve the robustness of shape sensing. A gradient-based interpolation optimization method is developed and integrated into the complete algorithm for shape sensing, this being used to interpolate the curvature to reduce the difference between the midpoint curvature and the mean curvature experienced. A complete FBG-based shape sensing method for flexible needle is reported including modeling, calibration, signal processing and shape reconstruction. Abstract: Shape sensing is of importance for the manipulation of flexible needles. In this work, a 0.6 mm diameter stylet with five Fiber Bragg Gratings (FBGs) installed as triplets was designed and implemented and a novel model of local curvature was established. A gradient-based optimization method has been integrated into the complete algorithm for shape sensing and this was used to reduce the difference between the midpoint curvature and the mean curvature. The experimental results obtained show that the mean tip errors are 0.35 mm, 0.30 mm, 0.38 mm in the single-bending, double-bending and space-bending experiments, respectively. In a torsion test experiment which was performed, when the rotation angle of the tip was less than 25°, the error seen was less than 0.5 mm. Furthermore, when the needle designed in this work was used to puncture a 60 mm thickness, ex vivo biological tissue, the mean error of the measurement of the needle tip was 0.39 mm.