Deformable Force Sensor Cells for Lateral Force Detection

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Solution Overview

Problem

Existing tactile sensors in robotics lack the ability to accurately perceive and manipulate objects due to insufficient sensitivity in determining the lateral direction of external forces, which is crucial for applications like manufacturing and healthcare.

Innovation Solution

A force sensor system with a sensor layer comprising resiliently deformable cells that form enclosures around pockets, each communicating with a pressure sensor, providing pressure signals indicative of internal pressure dependent on the lateral direction of the external force, and a signal processor to analyze these signals for lateral direction and magnitude.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional tactile sensors are used, then the robot can detect contact and pressure, but the lateral direction sensitivity is insufficient

Engineering Contradiction:
Improvelateral direction sensitivityVSAvoidsensor structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The sensor is divided into multiple sensor cells arranged in a matrix, where each cell contains a pocket structure with specific geometric orientation. This segmentation allows different cells to respond to lateral forces in different directions, enabling the system to detect lateral direction through comparative analysis of signals from multiple segmented elements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sensor cells are designed with different local geometric properties - specifically, pockets with different orientations (e.g., some oriented along x-axis, others along y-axis). This local quality differentiation enables each cell to be selectively sensitive to lateral forces in specific directions, improving overall lateral direction detection capability.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If the sensor layer uses uniform sensor cells, then manufacturing is simplified, but lateral direction detection capability is reduced

Engineering Contradiction:
Improvesensor layer fabricationVSAvoidlateral direction sensitivity
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The sensor cells incorporate asymmetric pocket structures with different geometric orientations. Some cells have pockets oriented along the x-axis while others have pockets oriented along the y-axis. This asymmetric design within a uniform manufacturing framework enables the sensor layer to detect lateral forces in multiple directions without requiring complex multi-step fabrication processes.

Inventive Principle:
Principle #4Asymmetry

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 system accurately determines the lateral direction and magnitude of external forces, enhancing the robot's ability to interact with objects by providing precise feedback for actions like gripping and movement.

Implementation Method 1

The sensor cells are resiliently deformable and form an enclosure around a pocket that communicates with a pressure sensor. The inside pressure of a sensor cell is dependent on an external force exerted thereon through the contact sensitive surface.

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

Each sensor cell forms an enclosure around a pocket that communicates with a pressure sensor. The pressure to force relationship is dependent on a lateral direction of the external force, indicating that pressure changes are transmitted from the deformable wall to the internal pocket and detected by the pressure sensor.

Methodology Applied
Scientific EffectPressure transmission: Pascal's Law

Data Source

PatentEP4597059A1Force sensor system and method of manufacturing the same
Publication Date: 2025.08.06 NEDERLANDSE ORG VOOR TOEGEPAST NATUURWETENSCHAPPELIJK ONDERZOEK TNO
  • EP4597059A1 patent drawingFigure 1~1A
  • EP4597059A1 patent drawingFigure 1B
  • EP4597059A1 patent drawingFigure 2

AI summary

A force sensor system (100) is presented herein that comprises a carrier substrate (1), a sensor layer thereon and a signal processor (5). The sensor layer has a contact sensitive surface (11) and comprises a plurality of resiliently deformable sensor cells (3a, 3b,...). The sensor cells each form an enclosure around a pocket (2a, 2b, 2c, 2d) communicating with a pressure sensor (4a, 4b, 4c, 4d) that is configured to provide a respective pressure signal (Spa, Spb,...) indicative for an inside pressure inside the pocket. The inside pressure of a sensor cell is dependent on an external force exerted thereon through the contact sensitive surface according to a pressure-force relationship, wherein the pressure to force relationship is dependent on a lateral direction of the external force for two or more of the plurality of sensor cells in a mutually different manner. The signal processor (5) is configured to receive the pressure signals and to provide an output sensor signal based on the received pressure signals.