FBG Torsion Sensor with Bending Prevention
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Solution Overview
Problem
Current sensors face challenges in accurately measuring axial torsion of objects, particularly human bodies, due to difficulties in separating complex forces such as bending, tension, and twisting, and existing methods are prone to errors in real-time classification of wavelength changes.
Innovation Solution
A fiber Bragg grating (FBG) sensor device with a fixing device that includes a bending prevention member, allowing the FBG sensor to experience torsion displacement without bending displacement, thereby enabling precise measurement of torsion in measurement objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If FBG sensors are used to measure axial torsion, then torsion measurement capability is provided, but bending and tension forces are transmitted simultaneously making it difficult to separate complex forces
Solution Approach 1:
The device segments the measurement function by using multiple FBG sensors positioned at different orientations on the measurement object. Each sensor measures a specific component of the complex forces (torsion, bending, tension), allowing the total force state to be decomposed and analyzed separately through data processing.
2Measurement precision
If numerical methods are used to distinguish wavelength changes from bending and twisting, then classification capability is provided, but errors occur due to larger wavelength changes from bending compared to twisting
Solution Approach 1:
The measurement function is segmented across multiple sensors with different orientations. By distributing measurement tasks to multiple sensors, each sensor captures a specific force component, and the combined data allows accurate separation of bending and twisting effects through mathematical processing, avoiding the errors of single-sensor numerical classification.
Solution Approach 2:
The patent introduces an intermediary data processing mechanism that receives wavelength change data from multiple sensors and applies mathematical algorithms to separate the overlapping bending and twisting components. This intermediary processing layer transforms the complex mixed signals into distinct, reliable measurements of each force component.
3Stability of the object's composition
If a fixing device is used to support the FBG sensor, then sensor stability is provided, but bending displacement occurs along with torsion displacement
Solution Approach 1:
The fixing device uses multiple support points distributed around the measurement object to segment the constraint function. This distribution of support points provides stable sensor mounting while allowing selective movement in specific directions, enabling torsion measurement without bending displacement through geometric arrangement of the supports.
4Adaptability or versatility
If multiple sensors are deployed to measure different force components, then comprehensive measurement capability is provided, but device complexity and data processing requirements increase
Solution Approach 1:
The FBG sensor system is designed with multi-functionality where the same type of sensor can measure different force components (torsion, bending, tension) depending on its orientation and position. This universal approach allows comprehensive measurement capability while maintaining consistency in sensor type and signal processing methods, thereby controlling system complexity.
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 proposed solution effectively measures the degree of axial torsion by preventing bending displacement and allowing only torsion displacement, thereby reducing measurement errors and improving the accuracy of torsion measurements in real-time applications.
Implementation Method 1
measuring a degree of torsion of a measurement object by using a fiber Bragg grating (FBG) sensor
Implementation Method 2
detecting a corresponding change in the intensity of optical radiation transmitted through the grating
Data Source
Figure 1A~1B
Figure 2
Figure 3~4
AI summary
Embodiments relate to a torsion sensor device which measures a degree of torsion of a measurement object by using a fiber Bragg gratings (FBG) sensor, the sensor device comprising: an FBG sensor including a sensing unit formed in one section of an elongated optical fiber; and a fixing device for fixing and supporting the FBG sensor to cause displacement of the FBG sensor according to motion of the measurement object, wherein the fixing device includes a bending prevention member to enable the sensing unit to have torsion displacement without bending displacement, according to the motion of the measurement object.