Flexible Shear Force Sensor Array for Curved Pressure Mapping

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Solution Overview

Problem

Existing pressure imaging arrays can only measure compressive forces and are insensitive to shear forces applied within the plane of the measuring surface, limiting their ability to provide valuable information for applications such as athletic shoe design and multitouch sensor arrays.

Innovation Solution

The integration of three closely spaced compressive force sensing elements around each raised bump allows for the measurement of shear forces by detecting differences in pressure between these elements, and the sensor is organized into flexible strips that can be wrapped around complex curved surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If compressive force sensing elements are arranged in a sparse array to achieve fine pressure measurement accuracy, then measurement precision for compressive force is improved, but the ability to measure shear force is lost

Engineering Contradiction:

Improvepressure measurement accuracyVSAvoidshear force measurement capability

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

Each sensing element is segmented into three closely spaced sub-elements arranged in a triangular pattern around a raised bump. This segmentation allows the system to measure both compressive force (through the bump displacement) and shear force (through differential pressure measurements between the three sub-elements), thereby resolving the contradiction between measurement precision and versatility.

Inventive Principle:

Principle #1Segmentation

2Ease of manufacture

If the sensor array is designed for flat surfaces to achieve manufacturing simplicity, then ease of manufacture is improved, but adaptability to curved surfaces deteriorates

Engineering Contradiction:

Improvesensor array fabricationVSAvoidcurved surface compatibility

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The sensor array is constructed using flexible printed circuit board (FPCB) technology, allowing the array to be bent and conform to curved surfaces such as the human foot. The flexible substrate maintains electrical connections while enabling adaptation to non-planar geometries, thus resolving the contradiction between manufacturing simplicity and curved surface adaptability.

Inventive Principle:

Principle #30Flexible shells and thin films

3Adaptability or versatility

If three closely spaced sensing elements are used around each bump to enable shear force measurement, then shear force measurement capability is improved, but device complexity increases

Engineering Contradiction:

Improveshear force measurement capabilityVSAvoidsensing element arrangement

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The three closely spaced sensing elements are merged into a single functional unit centered around one raised bump. This merging approach allows shear force measurement capability to be added without proportionally increasing overall device complexity, as multiple elements share common structural support and signal processing infrastructure.

Inventive Principle:

Principle #5Merging (Combining)

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 the measurement of both compressive and shear forces on irregular surfaces, enhancing the functionality of pressure imaging arrays and allowing for precise force detection on non-developable surfaces like a human foot.

Implementation Method 1

one or more sensing elements which sense shear force and compressive force on the layer

Methodology Applied

Scientific EffectPiezoresistive effect: Piezoresistive Effect

Data Source

PatentUS12546672B2Apparatus for determining shear forces in regard to a pressure imaging array, single point sensor for shear forces, and method

Publication Date: 2026.02.10 TACTONIC TECHNOLOGIES LLC

AI summary

A sensor having a layer and one or more sensing elements which sense shear force and compressive force on the layer. The sensor having a computer in communication with the one or more sensing elements which causes prompting signals to be sent to the one or more sensing elements and reconstructs shear force and compressive force on the layer from data signals received from the one or more sensing elements. A method for sensing forces. A method for producing a sensor.