Tactile Sensor Optical Force Detection With One Photodetector
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Solution Overview
Problem
Optics-based displacement sensors used in robotics are bulky and costly due to the presence of multiple large photo detectors and amplifying circuits.
Innovation Solution
A tactile sensor design featuring a sensing unit with at least two light sources around a photo detector and a reflector, reducing the number of photo detectors and simplifying the structure while maintaining force detection capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple large photo detectors and amplifying circuits are used, then force detection capability is improved, but device size and cost increase
Solution Approach 1:
The patent merges multiple photo detector functions into a single photo detector by using multiple light sources positioned at different locations. Each light source illuminates a different region, and the single photo detector receives reflected light from all regions, effectively combining the detection capabilities of multiple detectors into one unit.
Solution Approach 2:
The single photo detector serves multiple functions by detecting reflected light from multiple light sources simultaneously. It can measure forces in six degrees of freedom (three translational and three rotational) by analyzing light intensity variations from different illumination angles, making it a multi-functional detection element.
2Measurement precision
If multiple large photo detectors and amplifying circuits are used, then force detection capability is improved, but manufacturing cost increases
Solution Approach 1:
The patent reduces the number of expensive photo detectors and their associated amplifying circuits from multiple units to a single unit. This consolidation significantly lowers component costs and simplifies the manufacturing process while maintaining the capability to detect forces in six degrees of freedom.
Solution Approach 2:
Instead of using multiple physical photo detectors, the patent creates multiple virtual detection channels by positioning multiple light sources around a single photo detector. Each light source creates a detection channel that mimics what a separate detector would provide, achieving the same functional result with fewer physical components.
3Measurement precision
If multiple photo detectors are used, then force detection capability is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple detection functions into a single photo detector unit, eliminating the need for multiple separate detector assemblies and their associated mounting structures, wiring harnesses, and circuit boards. This merging dramatically simplifies the overall device structure.
Solution Approach 2:
The patent extracts and eliminates the unnecessary amplifying circuits that would be required for multiple photo detectors. By using a single photo detector, the complex signal amplification and processing infrastructure is greatly reduced, simplifying the electronic subsystem.
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 reduced number of photo detectors leads to a smaller, less costly tactile sensor with faster measurement speed and simpler structure, capable of sensing force in six degrees of freedom.
Implementation Method 1
the sensing unit includes at least two light sources, a photo detector and a reflector
Implementation Method 2
acquiring light intensity measured by a photo detector
Data Source
AI summary
This application discloses a method for detecting a touch event using a tactile sensor including a photo detector disposed on a base of the tactile sensor and evenly disposed around the photo detector on the base, and a reflector disposed above the photo detector and belongs to the field of sensor design. The method includes: acquiring light intensity measured by the photo detector for light generated by each of the at least eight light sources and then reflected the reflector separately; and measuring at least one of magnitude and direction of force exerted on the tactile sensor in six degrees of freedom based on changes in the light intensity. By adopting the combination of a plurality of light sources and one photo detector, the number of photo detectors for use is reduced, so that the volume of the tactile sensor is reduced.