Active Haptic Actuator Structure for Efficient Surface Vibration

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Solution Overview

Problem

Existing haptic actuators for human machine interfaces, particularly in vehicles, require mechanical decoupling, which are inefficient in energy transfer and require complex mechanical decoupling, leading to reduced efficiency and durability, and are not designed for optimal vibration energy transfer to the user.

Innovation Solution

A self-supporting haptic actuator design with a ferromagnetic plate and non-ferromagnetic vibrating plate, using a coil core and leaf springs for mechanical decoupling, eliminating the need for external decoupling and permanent magnets, and allowing efficient vibration in the Z positive direction, reducing energy loss and enabling multiple placements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional mechanical decoupling elements are used to isolate the haptic actuator, then component robustness and durability are improved, but energy transfer efficiency from the actuator to the user's finger deteriorates

Engineering Contradiction:
Improvecomponent robustnessVSAvoidenergy transfer efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent merges the mechanical decoupling function with the actuator housing by integrating a decoupling element directly into the housing structure. This eliminates the need for separate external decoupling components while maintaining both structural robustness and efficient energy transfer to the HMI surface.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces a decoupling element as an intermediary component between the actuator and the housing. This mediator absorbs mechanical stress and protects components while being positioned to minimize energy loss, thereby balancing durability with energy transfer efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the complete HMI box vibrates to provide haptic feedback, then user feedback is achieved, but the energy required for vibrations increases

Engineering Contradiction:
Improvehaptic feedback capabilityVSAvoidvibration energy requirement
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The patent extracts the vibration function from the entire HMI box and localizes it to specific HMI surfaces. By using decoupling elements to isolate the actuator, only the necessary surface areas vibrate, dramatically reducing the total energy required while maintaining effective user feedback.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If floating design of the actuator is used, then component isolation is improved, but force transfer efficiency to the HMI surface deteriorates

Engineering Contradiction:
Improvecomponent isolationVSAvoidforce transfer efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies local quality by creating isolated vibration zones through decoupling elements positioned at specific locations. This allows the actuator to be isolated from the housing while maintaining strong force transfer to the local HMI surface, achieving both protection and efficiency.

Inventive Principle:
Principle #3Local quality

4Adaptability or versatility

If haptic actuators are embedded underneath surface and within enclosure, then HMI integration is improved, but mechanical decoupling complexity increases

Engineering Contradiction:
ImproveHMI integrationVSAvoidmechanical decoupling complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the decoupling function with the existing HMI enclosure structure. By integrating decoupling elements directly into the housing, the design achieves proper mechanical isolation without adding separate complex decoupling mechanisms, thereby simplifying the overall system.

Inventive Principle:
Principle #5Merging (Combining)

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 new design enhances energy transfer efficiency, reduces mechanical complexity, lowers costs, and allows for uniform vibration across larger surfaces, making it suitable for automotive applications.

Implementation Method 1

a coil winding on a bobbin and through which a coil core extends, the coil core being fixed to a base plate; the moveable part comprises a ferrromagnetic plate arranged between the coil core and the base plate, wherein the ferromagnetic plate has a resting state, when no current is applied to the coil winding, with a gap between the ferromagnetic plate and the coil core, and an activation state, when current is applied to the coil winding, with the gap being reduced due to a movement of the ferromagnetic plate away from the base plate and towards the coil core

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

the vibrating plate is fixedly attached to the ferromagnetic plate and moveably attached to the base plate via spring means, wherein the spring means are configured to bring back the ferromagnetic plate to its resting position when no current is applied to the coil winding, from its activation position

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4567566B1Active haptic feedback device, human machine interface and automotive part
Publication Date: 2025.12.17 MOTHERSON INNOVATIONS CO LTD
  • EP4567566B1 patent drawingFigure 1a~1b
  • EP4567566B1 patent drawingFigure 2a~2e
  • EP4567566B1 patent drawingFigure 3a~3c

AI summary

The present disclosure relates to an active haptic feedback device (1) for a human machine interface (100, 200, 300), comprising a fixed part, a moveable part and a vibrating plate, wherein the fixed part comprises a coil winding (10) on a bobbin (11) and through which a coil core (12) extends, which is fixed to a base plate (40); the moveable part comprises a ferromagnetic plate (14) arranged between the coil core (12) and the base plate (40), wherein the ferromagnetic plate (14) has a resting state, when no current is applied to the coil winding (10), with a gap (50) between the ferromagnetic plate (14) and the coil core (12), and an activation state, when current is applied to the coil winding (10), with the gap (50) being reduced due to a movement of the ferromagnetic plate (14) away from the base plate (40) and towards the coil core (12), and the vibrating plate (16) is arranged on the side of the coil core (12) opposite to the side of the ferromagnetic plate (14) such that the coil core (12) is extending at least partly between the vibrating plate (16) and the ferromagnetic plate (14), wherein the vibrating plate (16) is fixedly attached to the ferromagnetic plate (14) and moveably attached to the base plate (40) via spring means (18, 19), wherein the spring means (18, 19) are configured to bring back the ferromagnetic plate (14) to its resting position when no current is applied to the coil winding (10), from its activation position. It also relates to a human machine interface with at least one such device, and an automotive part with at least one such human machine interface.