Demonstration of Large Curvature Radius Shape Sensing Using Optical Frequency Domain Reflectometry in Multi-Core Fibers

Abstract

In distributed shape sensing, the shape reconstruction error is more and more sensitive to the strain measuring error along with curvature radius of reconstructed shape increasing, which causes a notable challenge for large curvature radius shape reconstructing. In this paper, we demonstrate a large curvature radius shape sensing using optical frequency domain reflectometry (OFDR) in multi-core fibers. We construct a theoretical model of strain measuring error and curvature radius reconstructing errors under different curvature radius. In the experiment, by this reconstructing error model, we optimally select the measurable strain resolution and the sensing spatial resolution to realize the shape reconstruction with a large curvature radius and reconstruct two-dimensional (2D) circle shapes of curvature radii from 5 cm to 100 cm. To verify the accuracy of three-dimensional (3D) shape reconstruction, we present a 3D shape sensing validation method based on 3D printing technology. We fabricate a 3D phantom containing a groove with a variable curvature radius of 5 cm to 100 cm. The presented distributed shape sensing system realize to reconstruct this complicated 3D shape. The root-mean-square error of curvature radius between the reconstructed and designed 3D space curves is 7.2 mm and the mean Euclidean distance is 3.4 mm.

Applications and Development of Multi-Core Optical Fibers

“…Each channel simultaneously measures physical parameters at multiple positions. This continuous monitoring method is suitable for scenarios requiring real-time assessment of the overall system performance, making it applicable to a wide range of engineering applications such as oil well monitoring, geological exploration, pipeline safety monitoring [78][79][80][81][82][83], and aerospace applications [84][85][86][87][88] like wing monitoring and inertial navigation, as well as medical applications like medical robots and minimally invasive interventions [89][90][91][92][93]. The parallel channel structure of multi-core optical fibers provides an ideal platform for distributed sensing, allowing a single optical fiber to achieve efficient measurements at multiple points or along the entire length.…”

Structural deformation and clamping force monitoring of reconfigurable tooling motivated by strain data in aircraft assembly

“…Aiming at eliminating singularity of the Frenet frame when the curve cannot reach third-order continuity or has point with zero curvature, Cui et al [39] and Yi et al [40] introduced parallel frame to the spatial curve reconstruction of multi-core fiber. Chen et al [41] constructed a theoretical model to describe the relationship between the errors of strain measurement and the curvature. Huston and Bond [42] fabricated a novel sensing rosette to determine the curvature tensor of a two-dimensional surface.…”

Experimental Demonstration to Enhance the Curvature Sensitivity of a Fiber Mach–Zehnder Interferometer Based on a Waist-Enlarged Technique Using Polymer

“…Monitoring curvature is vital for innumerable applications, such as reconstructing 2D circle-shaped objects using curvature radius sensing [1], trailing deformation in aircraft [2], and monitoring vital signs [3]. Consequently, fiber optic curvature sensors have been widely researched by academic groups and industries worldwide.…”