Fiber Optic Accelerometer Cantilever Design
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Solution Overview
Problem
Existing fiber optic sensors are complex, costly, and limited in frequency range and directional measurement, requiring two optical fibers and skilled personnel for assembly, with poor resolution for high-frequency detection and limited directional sensitivity.
Innovation Solution
A fiber optic accelerometer design featuring a hollow body with a cantilever section of optical fiber, a fiber optic splitter, a light source, and a photo detector, where the cantilever section moves relative to a reflective target upon acceleration, changing light intensity measured by the photo detector, allowing for universal directional measurement and low-cost production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two optical fibers are used in the sensor construction, then the sensor can detect light energy from different directions, but the device complexity and manufacturing cost increase significantly
Solution Approach 1:
The patent combines the functions of two separate optical fibers into a single optical fiber by integrating a beam splitter and mirror system within the sensor housing. This allows one optical fiber to perform both the function of transmitting light to the target and receiving reflected light, thereby reducing construction complexity while maintaining detection capability.
Solution Approach 2:
The single optical fiber in the invention serves multiple functions: it acts as both the illumination fiber (transmitting light to the target) and the collection fiber (receiving reflected light). The beam splitter and mirror system enable this multi-functionality, allowing one fiber to replace what traditionally required two separate fibers.
2Device complexity
If a two-face mirror reflecting body is used with large light travel distance, then the sensor structure is simplified, but the measurement resolution deteriorates for high frequency detection
Solution Approach 1:
The patent introduces a movable reflective target that can be positioned at variable distances from the optical fiber tip. This dynamic adjustment capability allows optimization of the light travel distance based on measurement requirements, enabling high resolution for high frequency detection while maintaining structural simplicity. The movable target can be positioned to achieve the optimal distance for the specific application.
3Measurement precision
If optical fibers are arranged in specific orientations, then acceleration can be measured in specific directions, but the adaptability for measuring acceleration in multiple directions requires multiple sensors
Solution Approach 1:
The sensor design enables a single sensor unit to measure acceleration in multiple directions by utilizing the movable reflective target and adjustable optical path. The system can detect acceleration along the optical axis and, with appropriate positioning and orientation of the reflective target, can measure acceleration in multiple directions, replacing the need for multiple fixed-orientation sensors.
Solution Approach 2:
The movable reflective target allows dynamic repositioning to measure acceleration in different directions. By adjusting the position and orientation of the reflective target, the same sensor can be adapted to measure acceleration along different axes, providing versatility without requiring multiple fixed sensors.
4Strength
If metal components are used in the sensor construction, then the structural strength is improved, but the sensor cannot withstand extreme temperatures and production costs increase
Solution Approach 1:
The patent employs composite material construction, combining non-metallic materials (such as ceramics or high-temperature polymers) with optimized structural designs to achieve both strength and temperature resistance. The hollow body and internal components are constructed from materials selected for their high-temperature stability and mechanical strength, eliminating the need for metal components while maintaining structural integrity in extreme temperature environments.
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 design achieves a wide frequency range, high sensitivity, and low self-noise with simplified construction, using non-metallic materials for extreme temperature resistance and reduced production, installation, and maintenance costs.
Implementation Method 1
One fiber channels light energy from a light source to a sensing object that moves under the influence of sound or vibration/acceleration. The second fiber channels the reflected light energy modulated by these movements to a light detector
Implementation Method 2
a reflective target disposed within and supported at a second end of the hollow body so as to be axially aligned with the second end of the optical fiber when no force is applied to the accelerometer; whereby upon vibration or acceleration of the accelerometer the cantilever section moves such that its position relative to the reflective target changes thereby reducing the instantaneous intensity of light reflected by the target into the second end of the optical fiber
Implementation Method 3
a photo detector arranged for receiving light conveyed through the optical fiber via a second branch of the optical splitter and measuring an intensity of the received light
Data Source
AI summary
A fiber optic accelerometer has a hollow body that supports an optical fiber therein so as to form a cantilever section, a fiber optic splitter coupled to a first end of the optical fiber and a light source for directing light into the optical fiber via a first branch of the optical splitter. A photo detector receives light conveyed through the optical fiber via a second branch of the optical splitter and measures an intensity of the received light. A reflective target supported at a second end of the hollow body is axially aligned with the second end of the optical fiber in the absence of force. Upon acceleration the cantilever section moves such that its position relative to the reflective target changes thereby reducing the instantaneous intensity of light reflected by the target into the second end of the optical fiber and measured by the photo detector.