Flexible Haptic Interface Using Non-Newtonian Fluid

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Solution Overview

Problem

Existing flexible haptic interfaces struggle to generate varied and complex haptic effects on deformable surfaces due to limitations in substrate rigidity and spatial resolution, particularly when using non-Newtonian fluids.

Innovation Solution

A flexible haptic interface utilizing a chamber filled with a non-Newtonian fluid and actuators on a deformable support, controlled by a circuit to modulate fluid viscosity and generate tactile sensations, allowing for varied haptic effects through localized viscosity changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a rigid structure is used to support the substrate for haptic effects, then haptic effect generation is improved, but flexibility is substantially limited

Engineering Contradiction:

Improvehaptic effect generationVSAvoidflexibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent uses a flexible substrate that can deform without requiring rigid structural support. The haptic interface is integrated directly into the flexible substrate, allowing the entire assembly to maintain flexibility while still generating haptic effects through controlled deformation of the substrate and fluid manipulation.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent incorporates a fluid chamber filled with non-Newtonian fluid that responds to mechanical excitation. By using fluid dynamics and rheological properties, the system generates haptic effects without relying on rigid mechanical structures, thereby maintaining flexibility while achieving reliable haptic feedback.

Inventive Principle:

Principle #29Pneumatics and hydraulics

2Reliability

If loudspeakers are used to generate haptic effects through fluid, then haptic effects are produced, but spatial resolution is relatively low

Engineering Contradiction:

Improvehaptic effect productionVSAvoidspatial resolution

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

Instead of using a single loudspeaker, the patent employs multiple independent actuators distributed across the flexible substrate. Each actuator can be controlled independently to create localized haptic effects at specific positions, significantly improving spatial resolution while maintaining reliable haptic effect production.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different mechanical excitations to different local regions of the flexible substrate through distributed actuators. Each actuator creates haptic effects tailored to its local position, enabling precise spatial control and high resolution tactile feedback across the surface.

Inventive Principle:

Principle #3Local quality

3Ease of operation

If piezoelectric actuators are mounted on flexible substrate, then vibrotactile buttons are produced, but substrate must be supported by rigid structure

Engineering Contradiction:

Improvevibrotactile button productionVSAvoidflexible nature

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent integrates piezoelectric actuators directly into the flexible substrate without requiring rigid structural support. The actuators are mounted in a manner that allows the substrate to remain flexible and deformable, enabling vibrotactile button production while preserving the flexible nature of the overall device.

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

Enables the creation of complex haptic effects on flexible surfaces with high spatial resolution, simulating different degrees of hardness and textures, suitable for direct or indirect user contact.

Implementation Method 1

a chamber containing a non-Newtonian fluid and delimited at least partially by a flexible wall whose outer face defines a touch surface capable of being contacted by a user, a plurality of actuators carried by a flexible support and arranged so as to transmit local mechanical excitation to the fluid

Methodology Applied

Scientific EffectNon-Newtonian fluid viscosity variation: Non-Newtonian Fluids

Implementation Method 2

A shear-thickening fluid, for example, will see its viscosity increase in response to mechanical stress

Methodology Applied

Scientific EffectShear-thickening: Shear Thickening

Implementation Method 3

a control circuit connected to the actuators and configured to modulate the signals sent to the actuators in order to mechanically induce a modification of the rheology of the fluid and generate a haptic sensation perceptible by the user on the touch surface

Methodology Applied

Scientific EffectRheology modification: Non-Newtonian Fluids

Data Source

PatentEP4060461B1Flexible haptic interface

Publication Date: 2025.06.25 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES

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Figure 6~7A

AI summary

Flexible haptic interface (1), comprising: - a chamber (2)1 containing a non-Newtonian fluid (3) and delimited at least partially by a flexible wall (2a) whose outer face defines a touch surface (S) capable of being contacted by a user, - a plurality of actuators (5) carried by a flexible support (2b) and arranged so as to transmit a local mechanical excitation to the fluid (3), and - a control circuit (4) connected to the actuators (5) and configured to modulate the signals sent to the actuators in order to mechanically induce a change in the rheology of the fluid and generate a haptic sensation perceptible to the user on the touch surface (S).