Optical Fiber Flatness Roller for High-Resolution Strip Measurement

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional flatness rollers in rolling operations, particularly for thin metal sheets, suffer from insufficient spatial resolution, sensitivity, and dynamic bandwidth, leading to inadequate flatness control and high maintenance and production costs.

Innovation Solution

A flatness roller design featuring a cylindrical body with radially extending cavities and slots, equipped with optical fiber deformation sensors arranged at specific angles to enhance sensitivity and measurement precision, allowing for simultaneous deformation measurement along a generatrix and reduced lateral couplings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional flatness rollers are used, then the structure is simple and manufacturing is easy, but the spatial resolution, sensitivity, and dynamic bandwidth are insufficient

Engineering Contradiction:
Improvespatial resolutionVSAvoidstructure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The roller body is divided into multiple independent slats (e.g., 10 slats) that can deform independently. Each slat is separated by slots that prevent lateral coupling, allowing each slat to respond independently to local forces from the sheet. This segmentation enables high spatial resolution measurement while maintaining a relatively simple overall roller structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Conventional mechanical sensors are replaced with optical fiber deformation sensors (FBG - Fiber Bragg Grating). These optical sensors measure deformation through optical wavelength changes rather than mechanical contact, providing higher sensitivity and dynamic bandwidth without significantly increasing structural complexity. The optical fibers are embedded within the slats to measure their deformation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If conventional sensors are used in flatness rollers, then the device is simple to manufacture, but the sensitivity and dynamic bandwidth are insufficient for thin sheet measurement

Engineering Contradiction:
ImprovesensitivityVSAvoidmanufacturing complexity
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The optical fiber sensors are nested within the slats during manufacturing. The FBG sensors are embedded in the slats before the final roller assembly is completed, integrating the sensing function into the structural components themselves. This approach increases sensitivity while avoiding the need for separate sensor mounting procedures that would complicate manufacturing.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

Traditional mechanical strain gauges are replaced with optical fiber Bragg grating sensors. The optical sensors detect deformation through changes in reflected wavelength caused by strain in the fiber, providing superior sensitivity and dynamic response characteristics. This substitution enables precise measurement of thin sheet deformations without the limitations of mechanical sensor systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If slots are added to separate slats, then lateral couplings are reduced and measurement accuracy improves, but manufacturing complexity increases

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidmanufacturing complexity
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The roller body is segmented into discrete slats separated by slots cut through the roller. These slots physically isolate adjacent slats, preventing lateral force transmission between them. The slots are integrated into the roller manufacturing process, allowing the segmented structure to be produced as a single piece rather than assembling multiple components, thus limiting the increase in manufacturing complexity.

Inventive Principle:
Principle #1Segmentation

4Measurement precision

If optical fiber sensors are embedded in slats, then simultaneous deformation measurement is achieved with high spatial resolution, but device complexity increases

Engineering Contradiction:
Improvespatial resolutionVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Multiple FBG sensors are combined within a single optical fiber, with each grating positioned at different locations along the fiber corresponding to different slats. This allows simultaneous measurement of deformation across multiple slats using a single fiber bundle, achieving high spatial resolution while reducing the number of separate sensor connections and signal processing channels required.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The optical fiber sensors are nested within the slats during manufacturing. The FBG sensors are embedded in the slats before the final roller assembly is completed, integrating the sensing function into the structural components themselves. This approach increases sensitivity while avoiding the need for separate sensor mounting procedures that would complicate manufacturing.

Inventive Principle:
Principle #7Nested doll (Nesting)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The improved flatness roller achieves sufficient sensitivity to detect microdeformations in thin sheets, enhancing the accuracy of flatness control and reducing maintenance and production costs through increased measurement precision and robustness.

Implementation Method 1

each optical fiber being configured to receive an interrogation signal, each deformation sensor of each optical fiber being configured to transmit, depending on the signal interrogation received by the corresponding optical fiber, an optical response wave representative of a deformation of the deformation sensor along the corresponding measurement axis

Methodology Applied
Scientific EffectOptical fiber deformation sensing: Optical Fibre

Data Source

PatentEP3755476B1Flatness roller, system for measuring flatness and associated rolling operations line
Publication Date: 2022.03.16 ARCELORMITTAL SA
  • EP3755476B1 patent drawingFigure 1~3
  • EP3755476B1 patent drawingFigure 2
  • EP3755476B1 patent drawingFigure 4~5

AI summary

This flatness roller (18) comprises a body (20) comprising at least one cavity (28) opening onto an outer surface (24) of the body (20) via a plurality of slots (30), two successive slots (30) defining between them a lamella (32), each lamella (32) being connected to the body (20) by two attachments, the flatness roller (18) also comprising at least one optical fiber (54) comprising at least one deformation sensor (22) having a measurement axis, each deformation sensor (22) being housed in a cavity (28) and secured at an attachment of a lamella (32), the measurement axis forming an angle of less than or equal to 20° with a plane orthogonal to an axis of revolution (X-X) of the body (20), each deformation sensor (22) being configured to send an optical response wave representative of a deformation of the deformation sensor (22) along its measurement axis.