Flexible Tactile Sensor Array for High-Resolution Force Detection

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Solution Overview

Problem

Current force sensors lack the ability to achieve high force sensing resolution and are limited in spatial resolution and size, especially when mounted on flexible substrates, and they struggle with wireless communication for real-time telemetry, which is crucial for advanced robotic hands and upper limb prosthetics to prevent object slipping.

Innovation Solution

A tactile sensor design featuring an array of electrically conductive strips embedded in insulating layers with a conductive soft polymer intermediate layer, utilizing carbon nanotubes and ionic liquid polymers, connected to an impedance measuring device, allowing for sensitive force detection and wireless communication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If silicon-diaphragm sensors are mounted on flexible substrates or use polyimide layers, then flexibility is improved, but spatial resolution and sensor size control are worsened

Engineering Contradiction:

ImproveflexibilityVSAvoidspatial resolution

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The sensor is divided into multiple discrete force sensing elements arranged in an array, each element being a separate sensing unit. This segmentation allows each element to maintain precise dimensional control while the overall array provides high spatial resolution across the flexible substrate surface.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each force sensing element has locally optimized properties with specific dimensional characteristics, while the overall sensor array maintains flexibility. The local quality of each element ensures precise force measurement capability, while the global structure provides adaptability to curved surfaces.

Inventive Principle:

Principle #3Local quality

2Area of stationary object

If compressible and flexible conductive sheets are used as sensing material, then flexibility and large area coverage are improved, but response resolution and sensor size control are worsened

Engineering Contradiction:

Improvelarge area coverageVSAvoidresponse resolution

Core Design Contradiction:

Area of stationary objectVSMeasurement precision

Solution Approach 1:

The large area sensor is segmented into multiple discrete force sensing elements, each providing high-resolution force measurement. This allows the sensor to cover large areas while maintaining precise response resolution at each sensing point through the array configuration.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The sensor uses a composite structure combining flexible substrate material with discrete force sensing elements. This composite approach enables large area coverage with maintained resolution by integrating multiple sensing elements across the extended surface area.

Inventive Principle:

Principle #40Composite materials

3Measurement precision

If discrete force sensing elements are arranged in an array, then force sensing resolution is improved, but device complexity increases

Engineering Contradiction:

Improveforce sensing resolutionVSAvoidarray configuration

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Multiple force sensing elements are merged into a single integrated array structure that functions as one cohesive sensor unit. This combining approach achieves high force sensing resolution through the array while reducing overall device complexity by integrating the elements into a unified configuration.

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

The sensor provides enhanced sensitivity to applied forces, distinguishes between slip and nonslip events, and enables real-time force measurement at multiple points, improving the dexterity of robotic hands and prosthetics by preventing object slipping.

Implementation Method 1

an intermediate layer of conductive soft polymer material positioned above said first insulating layer and first array of electrically conductive strips

Methodology Applied

Scientific EffectImpedance change: Electrical Resistance

Implementation Method 2

said first and second arrays of electrically conductive strips include conductive nanostructures dispersed in a flexible support material

Methodology Applied

Scientific EffectConduction: Conduction (electrical)

Implementation Method 3

a sensing layer positioned adjacent to the first electrode, wherein the sensing layer comprises a polymerized acrylic semiconductor material

Methodology Applied

Scientific EffectPiezoresistive effect: Piezoresistive Effect

Data Source

PatentUS10156487B2Flexible tactile sensors and methods of making

Publication Date: 2018.12.18 THE UNIVERSITY OF AKRON

AI summary

A tactile sensor includes a first insulating layer having a first array of electrically conductive strips embedded therein and extending in a first direction. An intermediate layer of conductive soft polymer material is positioned above the first insulating layer and the first array of said electrically conductive strips. A second insulating layer having a second array of electrically conductive strips embedded therein, which extend in a second direction which is different than the first direction, is positioned above the intermediate layer. The first array of electrically conductive strips are connected to the second array of electrically conductive strips, and both the first and second array of electrically conductive strips are also connected to an impedance measuring device.