Optical fiber sensing method and sensing system for straightness of scraper conveyor

Patent metadata

Field	Value
Publication number	US-12392603-B2
Application number	US-202418925107-A
Country	US
Kind code	B2
Filing date	Oct 24, 2024
Priority date	Nov 29, 2023
Publication date	Aug 19, 2025
Grant date	Aug 19, 2025

Abstract

An optical fiber sensing method and sensing system for straightness of the scraper conveyor is provided. The sensing method includes the following steps: obtaining the horizontal strain and vertical strain of the corresponding grating measuring point of the scraper conveyor by the optical fiber shape sensor; calculating the horizontal curvature and vertical curvature of the grating measuring point; inserting multiple interpolation nodes between the curvature values of two adjacent grating measuring points; transforming the horizontal curvature and the vertical curvature into the horizontal coordinate value in the horizontal coordinate system and the vertical coordinate value in the vertical coordinate system respectively; superimposing the horizontal coordinate value and the vertical coordinate value to obtain the three-dimensional spatial coordinate values of the grating measuring point and the interpolation node; and obtaining the curves of the optical fiber shape sensor on the horizontal plane, the vertical plane, and the three-dimensional space respectively.

First claim

What is claimed is:

1. An optical fiber sensing system for implementing an optical fiber sensing method for a straightness of a scraper conveyor, the optical fiber sensing method comprises the following steps:
S 10 : setting an optical fiber shape sensor along the scraper conveyor, and obtaining a horizontal strain and a vertical strain of a grating measuring point of the scraper conveyor by the optical fiber shape sensor; wherein the optical fiber shape sensor comprises a flexible substrate, an optical fiber Bragg grating and a packaging material, and the optical fiber Bragg grating is fixedly encapsulated on a surface of the flexible substrate through the packaging material;
S 20 : according to a conversion formula of a sensing strain of the optical fiber shape sensor and a bending curvature of a neutral axis of the flexible substrate, calculating a horizontal curvature and a vertical curvature of the grating measuring point;
S 30 : inserting a plurality of interpolation nodes between curvature values of two adjacent grating measuring points by a discrete interpolation algorithm;
S 40 : through a slope recursion algorithm, converting each horizontal curvature and each vertical curvature into a horizontal coordinate value in a horizontal coordinate system and a vertical coordinate value in a vertical coordinate system respectively, and superimposing the horizontal coordinate value with the vertical coordinate value to obtain a three-dimensional space coordinate value of the grating measuring point and the interpolation node; and
S 50 : obtaining a curve of the optical fiber shape sensor on a horizontal plane by fitting the horizontal coordinate value, obtaining a curve of the optical fiber shape sensor on a vertical plane by fitting the vertical coordinate value, and obtaining a three-dimensional space curve of the optical fiber shape sensor by fitting the three-dimensional space coordinate value;
wherein the step S 50 comprises obtaining the straightness of the scraper conveyor such that the straightness of the scraper conveyor is obtained by performing the obtaining the curve of the optical fiber shape sensor on the horizontal plane, the obtaining the curve of the optical fiber shape sensor on the vertical plane, and the obtaining the three-dimensional space curve of the optical fiber shape sensor by fitting the three-dimensional space coordinate value; and
the optical fiber sensing system comprising:
the optical fiber shape sensor disposed along the scraper conveyor;
a curvature calculation module, wherein the curvature calculation module is configured to perform the step S 20 ;
an interpolation calculation module, wherein the interpolation calculation module is configured to perform the step S 30 ;
a coordinate calculation module, wherein the coordinate calculation module is configured to perform the step S 40 ; and
a curve fitting module, wherein the curve fitting module is configured to perform the step S 50 .

2. The optical fiber sensing system according to claim 1 , wherein
in the S 20 , when the optical fiber shape sensor bends, the conversion formula between the sensing strain of the optical fiber shape sensor and the bending curvature of the neutral axis of the flexible substrate is as follows:
ε= h·κ·η

wherein ε is the sensing strain of the optical fiber shape sensor, h is a vertical distance from the grating measuring point to the neutral axis of the flexible substrate, η is a strain transfer efficiency of the optical fiber shape sensor, and k is the bending curvature of the neutral axis of the flexible substrate.

3. The optical fiber sensing system according to claim 1 , wherein
in the S 20 , when the optical fiber shape sensor rotates, the conversion formula between the sensing strain of the optical fiber shape sensor and the bending curvature of the neutral axis of the flexible substrate is as follows:

κ
=

ε
θ

h
⁢
η
⁢

cos
⁢

θ

+

ε
θ

⁢

h
⁡
(

1
-

cos
⁢

θ

)

wherein ε θ is the sensing strain of the optical fiber shape sensor after rotation, θ is a rotation angle of the optical fiber shape sensor, h is a vertical distance from the grating measuring point to the neutral axis of the flexible substrate, η is a strain transfer efficiency of the optical fiber shape sensor, and κ is the bending curvature of the neutral axis of the flexible substrate.

4. The optical fiber sensing system according to claim 1 , wherein
in the S 20 , when the optical fiber shape sensor is twisted, the conversion formula between the sensing strain of the optical fiber shape sensor and the bending curvature of the neutral axis of the flexible substrate is as follows:

κ
=

[

(

1
r

+

ε
φ

h
⁢
η

)

2

-

(

φ
l

)

2

]

1
2

-

1
r

wherein ε φ is the sensing strain of the optical fiber shape sensor after torsion, φ is a torsion angle of the optical fiber shape sensor, r is a distance between the optical fiber Bragg grating and a centroid of the flexible substrate, h is a vertical distance from the grating measuring point to the neutral axis of the flexible substrate, η is a strain transfer efficiency of the optical fiber shape sensor, and κ is the bending curvature of the neutral axis of the flexible substra

Assignees

• Univ China Mining
• Yongkang Weichuang Optoelectronic Tech Co Ltd
• Xuzhou Weidean Optoelectronic Tech Co Ltd

Inventors

• Fang Xinqiu
• Chen Ningning
• Liang Minfu
• Wu Gang
• Feng Haotian
• Song Yang
• He Dexing
• Fang Chunyang
• Qiao Fukang
• Wu Yang

Classifications

• G01L1/246

  using integrated gratings, e.g. Bragg gratings · CPC title

• G01B11/27 Primary

  for testing the alignment of axes {(means for centering or aligning a light guide within a ferrule G02B6/3834)} · CPC title

• G01B11/18

  using photoelastic elements · CPC title

• G01B11/24 Primary

  for measuring contours or curvatures · CPC title

• G01B11/002

  for measuring two or more coordinates · CPC title