Decoupled Tactile Sensor Cells for Pressure Distribution

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Solution Overview

Problem

Existing tactile sensors cannot accurately measure pressure distributions, as they only detect qualitative contacts and lack local resolution, failing to differentiate between forces acting on separate sensor cells.

Innovation Solution

A tactile sensor design featuring at least two sensor cells with an intermediate region of higher specific resistance, allowing for decoupling and enabling the differentiation of forces acting on each cell, with electrodes connected to a common or separate electrically conductive workpiece made of flexible material that changes electrical volume resistance under mechanical load.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a tactile sensor uses a continuous electrically conductive workpiece without intermediate regions, then the construction is simple, but different forces acting on different sensor cells cannot be separated and local resolution is lost

Engineering Contradiction:

Improveconstruction simplicityVSAvoidlocal resolution

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The continuous electrically conductive workpiece is segmented into multiple sensor cells by introducing intermediate regions with higher specific resistance. These intermediate regions electrically separate the sensor cells while maintaining mechanical continuity, allowing independent measurement of forces on each cell while keeping the overall construction relatively simple.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The intermediate regions are designed with locally different electrical properties (higher specific resistance) compared to the sensor cell regions. This local differentiation in electrical conductivity enables electrical separation of sensor cells without requiring complete physical separation, thus maintaining construction simplicity while achieving measurement precision.

Inventive Principle:

Principle #3Local quality

2Measurement precision

If intermediate regions with higher specific resistance are introduced to decouple sensor cells, then local resolution and force differentiation are achieved, but device complexity increases

Engineering Contradiction:

Improveforce differentiationVSAvoidsensor cell decoupling structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Intermediate regions with higher specific resistance are introduced as intermediary elements between adjacent sensor cells. These intermediaries provide electrical decoupling while maintaining mechanical continuity, enabling force differentiation without requiring complex physical separation structures or additional components.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The specific resistance parameter is varied spatially within the workpiece: sensor cell regions have lower specific resistance for signal generation, while intermediate regions have higher specific resistance for electrical decoupling. This parameter change approach achieves cell separation without adding structural complexity.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If sensor cells are completely electrically isolated, then measurement precision is maximized, but the flexible material cannot maintain structural integrity

Engineering Contradiction:

Improvesignal accuracyVSAvoidstructural integrity

Core Design Contradiction:

Measurement precisionVSStability of the object's composition

Solution Approach 1:

The workpiece is segmented into electrically isolated sensor cells through intermediate regions, yet the flexible material maintains continuous physical structure. This segmentation approach achieves signal accuracy through electrical separation while preserving structural integrity through material continuity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The intermediate regions act as intermediaries that provide electrical isolation between sensor cells while maintaining mechanical connection. The flexible material's inherent properties allow these intermediaries to decouple electrical signals without compromising the overall structural integrity of the sensor.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 pressure distributions and force differentiation, providing improved local resolution and quantitative evaluation of signals, suitable for applications in robotics and security systems.

Implementation Method 1

the flexible material changing its electrical volume resistance under mechanical loads

Methodology Applied

Scientific EffectPiezoresistive effect: Piezoresistive Effect

Data Source

PatentUS8276467B2Tactile sensor with decoupled sensor cells

Publication Date: 2012.10.02 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV

AI summary

The invention relates to a tactile sensor with a sensor cell, wherein a sensor cell comprises an electrically-conducting workpiece made from flexible material and a connection to a first and a second electrode and the flexible material layers the electrical conductivity thereof under mechanical load. According to the invention, pressure distributions can be measured, by providing at least two sensor cells separated by an intervening zone, wherein two adjacent sensor cells are connected to a common first or second electrode and in the intervening zone between a first and a second adjacent sensor cell the electrically conducting workpiece of the first and the second sensor cell are at least partly separated from each other by medium with a greater specific resistance than the specific resistance of the electrically conducting workpieces.