Elastic Resistive Force Sensor for Three-Axis Shear and Pressure
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Solution Overview
Problem
Existing force sensors, particularly those measuring shear forces, are costly and lack sensitivity and range, with a need for improved low-cost solutions that can accurately measure both shear and pressure forces.
Innovation Solution
A sensor cell comprising a conductive elastic substrate with variable resistors formed by electrodes and a portion of the substrate between them, where changes in distance between electrodes alter resistance, allowing for the measurement of shear and pressure forces through changes in resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing force sensors based on capacitive or inductive transduction are used, then measurement capability is provided, but cost increases and sensitivity/range are insufficient
Solution Approach 1:
The patent replaces complex capacitive or inductive transduction systems with a simplified resistive sensing mechanism. The conductive elastic substrate forms variable resistors where force-induced deformation changes resistance, eliminating the need for expensive capacitive or inductive components while achieving comparable or superior sensitivity and range for force measurement.
Solution Approach 2:
The patent utilizes the resistivity parameter of the conductive elastic substrate to sense force. By measuring changes in resistance (a parameter) caused by force-induced deformation, the system achieves accurate force measurement without requiring complex transduction mechanisms, thereby reducing cost while maintaining or improving measurement precision.
2Ease of manufacture
If a conductive elastic substrate with variable resistors is used, then cost is reduced and sensitivity is improved, but device structure becomes simpler
Solution Approach 1:
The patent merges the sensing element and the structural substrate into a single integrated component. The conductive elastic substrate serves both as the mechanical structure and as the resistive sensing element, eliminating the need for separate sensing components and thereby simplifying the overall device structure while reducing cost.
Solution Approach 2:
The conductive elastic substrate performs multiple functions: it provides mechanical support, enables force sensing through resistance changes, and forms the variable resistor network. This multi-functionality reduces the number of components needed, simplifying the device structure and reducing manufacturing cost while maintaining high sensitivity.
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 sensor cell provides three-axis force sensing, enabling accurate measurement of shear forces along multiple axes and pressure, with reduced parts and cost, and can be integrated into systems for applications like smart insoles and robotics.
Implementation Method 1
a conductive elastic substrate... a force acting on the substrate causes a change in distance between the electrodes
Implementation Method 2
a change in distance between the electrodes may cause a change in the resistance of the variable resistor... the elastic substrate may have a bulk resistivity that varies in response to strain arising from deformation
Data Source
AI summary
A sensor cell is provided for measuring force, comprising: a conductive elastic substrate (13); and a variable resistor comprising: a first electrode (11a); a second electrode (12); and a portion (130) of the conductive elastic substrate (13) arranged between the electrodes (11a, 12) such that a force acting on the substrate (13) causes a change in distance between the electrodes (11a, 12) thereby changing a resistance of the variable resistor.