Dual-Return Haptic Actuator for Stable Display Calibration

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Solution Overview

Problem

Conventional haptic actuators in touch-sensitive surfaces of vehicles face operational distortions due to differences between the reference distance and calibration distance after installation, leading to inappropriate haptic feedback and force measurement inaccuracies.

Innovation Solution

A haptic actuator design with a movable part having two surfaces sensitive to electromagnetic fields, connected by a connecting part, and return means to maintain a fixed relative position, ensuring the calibration remains valid post-installation by compensating for position changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single return means is used in conventional haptic actuators, then the structure is simple, but the calibration becomes invalid when the reference distance changes due to installation variations

Engineering Contradiction:
Improveactuator structureVSAvoidcalibration accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The single return means is segmented into two separate return means (first return means and second return means), each positioned at opposite ends of the stator. This segmentation allows independent compensation for distance variations at each end, maintaining calibration accuracy even when the reference distance changes due to installation variations on non-flat surfaces.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each return means is locally positioned at a specific end of the stator (first end and second end), providing localized compensation for distance variations. This local quality approach ensures that each region of the actuator maintains its calibration independently, addressing the non-uniformity caused by installation on curved or non-flat surfaces.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If the reference distance varies after installation due to surface flatness defects, then the actuator can be installed on non-flat surfaces, but the haptic feedback becomes distorted and force measurement becomes inaccurate

Engineering Contradiction:
Improveinstallation flexibilityVSAvoidforce measurement accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The dual return means configuration creates a feedback mechanism where the positions of both surfaces are monitored and compensated. When one surface moves closer to the stator, the other moves farther away, and the system automatically compensates to maintain the calibration relationship, ensuring accurate force measurement and haptic feedback despite installation variations.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system changes the parameter configuration from a single reference distance to two reference distances (first reference distance and second reference distance). This parameter change allows the system to adapt to varying installation conditions while maintaining calibration accuracy through the compensating relationship between the two surfaces.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If the reference distance varies after installation, then installation on different surfaces is possible, but the haptic feedback intensity becomes non-homogeneous across the touch surface

Engineering Contradiction:
Improvesurface compatibilityVSAvoidhaptic feedback homogeneity
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The haptic feedback system is segmented into two independent but complementary components (first return means and second return means), each responsible for one surface. This segmentation allows each component to independently maintain its calibration, ensuring that the overall haptic feedback remains homogeneous across the entire touch surface even when installed on non-flat surfaces.

Inventive Principle:
Principle #1Segmentation

4Manufacturing precision

If adjustment mechanisms are added to correct reference distance variations, then calibration accuracy can be maintained, but the device complexity and space requirements increase

Engineering Contradiction:
Improvecalibration accuracyVSAvoidactuator structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The dual return means configuration enables the actuator to self-compensate for reference distance variations automatically. The system uses its own internal structure (the two surfaces and their respective return means) to detect and correct calibration drift, eliminating the need for external adjustment mechanisms and maintaining calibration accuracy without increasing device complexity.

Inventive Principle:
Principle #25Self-service

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 actuator maintains consistent haptic feedback and force measurement performance by self-compensating for installation-induced distance variations, ensuring accurate calibration without additional adjustments.

Implementation Method 1

a stator comprising at least one solenoid capable of producing at least one electromagnetic field

Methodology Applied
Scientific EffectElectromagnetic field: Electromagnet

Implementation Method 2

Once the electromagnetic field is switched off, the return means then pushes the touch-sensitive surface (and therefore the moving part) back to its reference position

Methodology Applied
Scientific EffectElastic force: Elasticity

Implementation Method 3

the measurement function is performed by measuring, inductively or capacitively, the displacement of the moving part relative to the stator

Methodology Applied
Scientific EffectInductive measurement: Electromagnetic Induction

Data Source

PatentEP4105767B1Haptic actuator and display system comprising said actuator
Publication Date: 2025.07.02 VALEO COMFORT & DRIVING ASSISTANCE
  • EP4105767B1 patent drawingFigure 1~2

AI summary

The invention relates to a haptic actuator (1) comprising: - a stator (100) comprising at least one solenoid (110) capable of producing at least one electromagnetic field, the stator having a first end and a second end; - a movable part (200) comprising a first surface (210) and a second surface (220), the first surface extending opposite the first end, the second surface extending opposite the second end, the relative position of the first surface with respect to the second surface being fixed when the movable part is moved;- a first return means (310) placed between the first surface and the first end so as to return the moving part to a reference position when the moving part is displaced by at least one electromagnetic field, and a second return means (320) placed between the second surface and the second end so as to return the moving part to the reference position when the moving part is displaced by at least one electromagnetic field. A display system including such an actuator is also proposed.