Optical Touch Sensor Using Fiber Bundles for Force Detection
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Solution Overview
Problem
Conventional tactile sensors in robotic systems face limitations in processing data from multiple light sensing elements, leading to cumbersome data processing and inefficient force detection due to the reliance on limited light sources and detection based solely on light levels.
Innovation Solution
A sensing system comprising an intermediate layer, an upper layer with a light source and image sensor, and fiber optic bundles that transmit light and images, utilizing image processing to calculate forces applied by analyzing changes in the upper layer's image frame, which can include pattern, color, or brightness changes, allowing for precise force and pressure detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple light sources and light sensing elements are used to improve force detection precision, then measurement precision is improved, but device complexity increases and data processing becomes cumbersome
Solution Approach 1:
The patent replaces conventional point-by-point light sensing with an optical imaging system using a camera to capture the entire elastic surface. This substitution reduces the number of individual sensing elements from potentially hundreds to a single imaging device, thereby reducing device complexity while maintaining measurement precision through image processing algorithms that analyze light intensity distributions across the captured image.
Solution Approach 2:
The patent creates an optical copy (image) of the elastic surface deformation pattern using a camera. Instead of using multiple physical sensors to detect each point, the system captures a visual copy of the entire surface state and processes this image data to determine force distribution, thereby reducing hardware complexity while preserving measurement capabilities.
2Measurement precision
If multiple light sensing elements are positioned under the elastic surface to improve force detection, then measurement precision is improved, but ease of operation deteriorates due to cumbersome data processing
Solution Approach 1:
The patent replaces complex multi-sensor data aggregation with optical imaging and image processing. The camera captures the entire elastic surface in a single frame, and standard image processing techniques are used to analyze light intensity variations, thereby simplifying data processing operations while maintaining the ability to detect force distribution across the surface with high precision.
3Device complexity
If detection is performed based solely on light level to simplify the system, then device complexity is reduced, but measurement precision deteriorates due to inability to detect forces in various directions
Solution Approach 1:
The patent applies local quality by analyzing spatial variations in light intensity across different regions of the captured image. Instead of using a single light level measurement, the system examines the distribution pattern of light intensities at multiple locations within the image, enabling detection of force magnitude, direction, and distribution across the elastic surface while maintaining relatively simple hardware.
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 system enables accurate detection of forces and pressures applied to the sensor, including vertical and combined forces, with reduced power consumption and improved data processing efficiency, capable of detecting forces applied in various directions and angles.
Implementation Method 1
at least a first fiber optic bundle (5a) comprising a plurality of fiber optic cables positioned such that a tips of which is facing to the light source (2) and other tips of which is facing to the intermediate layer (1), and transmitting the light obtained from the light source (2) to the upper layer (4)
Implementation Method 2
a plurality of second fiber optic cables, a tips of which are separated from surrounding environment via said layer by being located under the layer and being directed towards the layer and other tips of which are in connection with said image sensor so that each second fiber optic cable is paired with one pixel of the image sensor, wherein light beams reflected from the layer are transferred to the image sensor by said second fiber optic cables
Data Source
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AI summary
In the sensing system (S) according to the present invention, a structure is provided which detects the application point, intensity and area of the force and the pressure applied, along with the touch, and the forces applied in vertical direction to the sensor as well as the combined forces, which has reduced power consumption. The said sensing system (S) comprises an intermediate layer (1); a upper layer (4) located on the intermediate layer (1); a light source (2) located under the intermediate layer (1); an image sensor (3) located under the intermediate layer (1); a first fiber optic bundle (5a) comprising a plurality of fiber optic cables positioned such that a tips of which is facing to the light source (2) and other tips of which is facing to the said intermediate layer (1); a second fiber optic bundle (5b) comprising a plurality of fiber optic cables, a tips of which is paired with a pixel of the image sensor (3) and other tips of which is positioned facing to the said intermediate layer (1); a control unit which analyzes the image captured by the image sensor (3) using image processing techniques so as to calculate a force applied on the intermediate layer (1); and a data link (6) for data communication between the image sensor (3) and the control unit.