Layered Force Detector for Flexible Tangential Force Sensing

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Solution Overview

Problem

Existing force detectors face issues with separation of layers due to large stiffness differences, leading to decreased detection accuracy and difficulty in bending to conform to curved surfaces, necessitating a pressure transmission member with a very large Young's modulus.

Innovation Solution

A force detector with a layered structure comprising a detection layer and a support layer of differing Young's moduli, incorporating a stress generator and sensors to detect asymmetric stress distributions without requiring a pressure transmission member with a very large Young's modulus, allowing for flexibility and high reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a pressure transmission member with a very large Young's modulus is used to enhance sensitivity, then detection sensitivity is improved, but the device becomes difficult to bend and deploy on curved surfaces

Engineering Contradiction:
Improvedetection sensitivityVSAvoidbending capability
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The pressure transmission member is segmented into a modular structure consisting of multiple rigid segments connected by flexible joints. This segmentation allows each segment to maintain high stiffness for sensitive force detection while the joints between segments provide flexibility for bending and conforming to curved surfaces, resolving the contradiction between detection sensitivity and adaptability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The pressure transmission member incorporates dynamic elements that allow it to change its mechanical properties based on operational needs. The structure can transition between a rigid state for accurate force measurement and a flexible state for deployment on curved surfaces, enabling it to adapt its stiffness characteristics dynamically rather than being fixed.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If a pressure transmission member with a very large Young's modulus is used to enhance sensitivity, then detection sensitivity is improved, but long-term reliability decreases due to layer separation at interfaces

Engineering Contradiction:
Improvedetection sensitivityVSAvoidinterface stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The pressure transmission member utilizes a composite material structure combining rigid and flexible materials in a layered configuration. The rigid portions provide the necessary stiffness for sensitive detection, while the flexible intermediate layers prevent stress concentration and interface separation, thereby maintaining both high sensitivity and long-term reliability without requiring an excessively large Young's modulus.

Inventive Principle:
Principle #40Composite materials

3Measurement precision

If the Young's modulus of the pressure transmission member is large, then detection sensitivity is improved, but the overall device becomes difficult to bend

Engineering Contradiction:
Improvedetection sensitivityVSAvoidbending flexibility
Core Design Contradiction:
Measurement precisionVSShape

Solution Approach 1:

By dividing the pressure transmission member into discrete rigid segments connected by flexible joints, the structure achieves high local stiffness for sensitive detection while maintaining global flexibility through the articulated segments. This allows the overall device to bend and conform to various shapes while each segment maintains its structural integrity and detection capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The pressure transmission member incorporates thin flexible connecting elements between rigid segments that act as flexible shells. These thin film connectors allow the structure to bend and deform while maintaining the rigidity needed for accurate force measurement, enabling the device to adapt to curved surfaces without compromising detection sensitivity.

Inventive Principle:
Principle #30Flexible shells and thin films

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 solution enhances detection accuracy by preventing layer separation and enables easy bending, maintaining reliability while simplifying the structure and reducing detection errors.

Implementation Method 1

A stress generator, which receives a force acting in a tangential direction of the detection face and generates a stress with a distribution, which is asymmetric with respect to a normal direction of the detection face around the stress generator, is formed in the layered structure

Methodology Applied
Scientific EffectStress distribution:

Data Source

PatentEP4019921B1Force detector and force detection system
Publication Date: 2026.02.18 YOKOGAWA ELECTRIC CORP
  • EP4019921B1 patent drawingFigure 1
  • EP4019921B1 patent drawingFigure 2~3
  • EP4019921B1 patent drawingFigure 4A~4B

AI summary

A force detector (1) includes a layered structure including a first layer (2) and a second layer (3). The first layer includes a detection face (M) configured to receive a force to be detected and the second layer is disposed on a face opposite to the detection face. A Young's modulus of the first layer (2) is different from a Young's modulus of the second layer (3). The force detector further includes a stress generator (4) formed in the layered structure and configured to receive the force acting in a tangential direction of the detection face and generate a stress with a distribution that is asymmetric with respect to a normal direction of the detection face around the stress generator. The force detector further includes a plurality of sensors (5) disposed around the stress generator.