Capacitive Tactile Sensor Electrode Offset for Force Direction Sensing
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Solution Overview
Problem
Current capacitive tactile sensors face challenges in accurately measuring the magnitude and direction of shearing forces and vertical forces due to limitations in detecting changes in capacitance when substrates are moved relative to each other, particularly in distinguishing between different directions of force application.
Innovation Solution
A capacitive tactile sensor design featuring substrates with electrodes and a dielectric substance, where electrodes are partially overlapping and separated by predetermined intervals, allowing for changes in capacitance to indicate force direction and magnitude through variations in overlapping area and distance, utilizing graphene electrodes and an extensible/compressible dielectric substance like silicone or polymer, with air paths for increased sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If electrodes are completely overlapping, then capacitance measurement is simplified, but the ability to distinguish force direction is lost
Solution Approach 1:
The electrode array is divided into multiple individual electrodes rather than using a single continuous electrode. Each electrode can be independently positioned and measured, allowing the system to segment the measurement into directional components through differential capacitance measurements between adjacent electrodes.
Solution Approach 2:
The patent deliberately introduces asymmetric positioning between first and second electrodes, where they are offset or separated by predetermined intervals rather than being perfectly aligned. This asymmetric arrangement creates direction-dependent capacitance variations that enable force direction discrimination while maintaining measurable capacitance changes.
2Measurement precision
If electrodes are offset or separated by predetermined intervals, then force direction can be distinguished, but capacitance measurement complexity increases
Solution Approach 1:
The system dynamically adjusts measurement strategies based on the asymmetric electrode configuration. By applying forces in different directions and measuring differential capacitance changes across multiple electrode pairs, the system adapts to the offset geometry to extract directional information without requiring complex hardware modifications.
Solution Approach 2:
The same electrode array structure serves multiple functions: it can detect both the magnitude and direction of applied forces, and can measure both shearing and vertical forces through different measurement modes. The offset configuration enables a single sensor structure to perform what would otherwise require multiple specialized sensors.
3Stability of the object's composition
If dielectric substance is rigid, then structural stability is improved, but sensitivity to force changes decreases
Solution Approach 1:
The dielectric substance is implemented as a flexible, extensible, and compressible material rather than a rigid structure. This flexible dielectric layer can deform in response to applied forces, changing the capacitance between electrodes in proportion to the force magnitude while maintaining overall structural integrity and stability of the sensor assembly.
Solution Approach 2:
The dielectric substance's physical parameters (extensibility and compressibility) are specifically selected to optimize the sensor's response to different types of forces. The material parameters are chosen to provide appropriate sensitivity ranges for detecting both small shearing forces and larger vertical forces while maintaining structural stability under various loading conditions.
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
Enables precise measurement of both shearing and vertical forces by distinguishing between different force directions and intensities through capacitance changes, enhancing sensitivity and accuracy in tactile sensing applications.
Implementation Method 1
a capacitive tactile sensor including a first substrate including a plurality of first electrodes; a second substrate including a plurality of second electrodes corresponding to the plurality of first electrodes; and a dielectric substance disposed between the first substrate and the second substrate
Implementation Method 2
a dielectric substance disposed between the first substrate and the second substrate
Implementation Method 3
The dielectric substance may be extensible and compressible
Data Source
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AI summary
A tactile sensor includes a first substrate including a plurality of first electrodes, a second substrate including a plurality of second electrodes corresponding to the plurality of first electrodes, and a dielectric substance disposed between the first substrate and the second substrate, wherein a second electrode corresponding to any one of the first electrodes is offset in one direction with respect to the any one of the first electrodes while a second electrode corresponding to another first electrode neighboring the any one of the first electrodes is offset in another direction.