Magnetic Elastomer Linear Actuator for Precision Positioning

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Solution Overview

Problem

Existing linear actuators fail to provide precisely controllable movements over short distances, such as a few millimeters or centimeters, which is necessary for applications like adjusting flaps, mirrors, and robotics, due to limitations in positioning accuracy and high technical effort required by current technologies like electromagnetic and piezo actuators.

Innovation Solution

A linear actuator utilizing a magnetic elastomer composite with an elastomer matrix and magnetizable particles, integrated with an inner and outer magnetic yoke and a coil or permanent magnet, allowing deformation in response to a magnetic field for controlled movement, where the actuator's stroke can be electrically controlled by varying the magnetic field strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If electromagnetic actuators (voice coil) are used, then linear movement can be generated, but positioning accuracy is limited and control is difficult

Engineering Contradiction:
Improvepositioning accuracyVSAvoidcontrol difficulty
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces traditional electromagnetic voice coil actuators with a magnetic elastomer composite actuator that utilizes magnetoelastic effects. The magnetic elastomer composite deforms in response to magnetic field changes, providing direct linear movement without the complex control mechanisms required by voice coils. This substitution maintains the ability to generate linear movement while significantly improving positioning accuracy and ease of control through direct magnetic field modulation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs parameter changes by varying the magnetic field strength applied to the magnetic elastomer composite to precisely control the actuator's stroke length. By adjusting the magnetic field parameters (strength, duration), the system achieves high positioning accuracy for short linear movements. The magnetic elastomer composite responds continuously to magnetic field parameter changes, enabling fine-grained control of movement distance and position.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If piezo actuators are used, then high positioning precision and large forces can be achieved, but travel range is too small and requires travel enlargers that increase complexity

Engineering Contradiction:
Improvepositioning precisionVSAvoidstructural complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses parameter changes by extending the travel range of the magnetic elastomer composite through controlled variation of magnetic field strength and duration. Unlike piezo actuators that require mechanical travel enlargers, the magnetic elastomer composite can achieve larger stroke lengths directly by adjusting magnetic field parameters, thereby maintaining high positioning precision while eliminating the need for additional mechanical components and reducing overall system complexity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies dynamics by making the magnetic elastomer composite properties可调 (adjustable) through magnetic field application. The material transitions between different deformation states based on magnetic field conditions, enabling the actuator to adapt its stroke length and force output dynamically. This dynamic response allows the system to achieve both large travel ranges and high positioning precision without requiring complex mechanical transmission mechanisms.

Inventive Principle:
Principle #15Dynamics

3Ease of manufacture

If electric motors with gears are used, then linear movement can be generated, but technical effort and complexity are high for simple movements

Engineering Contradiction:
Improvetechnical effortVSAvoidstructural complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical motor-gear systems with a magnetic elastomer composite actuator that generates linear movement directly through magnetoelastic deformation. This substitution eliminates the need for rotational-to-linear conversion mechanisms, gears, and associated mechanical components. The actuator can be manufactured as an integrated unit with the magnetic circuit, significantly reducing technical effort and structural complexity while maintaining the ability to generate precise linear movements for applications such as flap adjustment, mirror positioning, and robotic gripper actuation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Measurement precision

If piezo actuators are used, then high positioning accuracy can be achieved, but high electrical control voltages are required

Engineering Contradiction:
Improvepositioning accuracyVSAvoidelectrical control voltage
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent employs parameter changes by operating the magnetic elastomer composite actuator at lower electrical control voltages compared to piezo actuators. The magnetic field required to deform the elastomer composite can be generated at reduced voltages, especially when using optimized magnetic circuits and soft magnetic materials. This parameter change maintains high positioning accuracy while significantly reducing the electrical energy requirements and control voltage levels, making the actuator more energy-efficient and suitable for battery-powered or low-power applications.

Inventive Principle:
Principle #35Parameter changes

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 precisely controllable linear movements with flexible and reversible actuation, reducing the technical effort and cost associated with existing solutions, while providing high positioning accuracy and efficient energy use.

Implementation Method 1

at least one coil and/or at least one permanent magnet or at least one switchable hard magnet for generating at least one magnetic circuit

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

magnetic elastomer composite made of an elastomer and magnetizable particles

Methodology Applied
Scientific EffectMagnetizable particles: Ferromagnetism

Implementation Method 3

magnetic elastomer composite made of an elastomer and magnetizable particles

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3026680B1Linear actuator and use of same
Publication Date: 2020.04.29 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP3026680B1 patent drawingFigure 1~2
  • EP3026680B1 patent drawingFigure 3~4
  • EP3026680B1 patent drawingFigure 5~6

AI summary

The invention relates to a linear actuator comprising at least one magnetic elastomer composite consisting of an elastomer and magnetizable particles, as well as an inner and an outer magnetic yoke, and at least one coil and/or at least one permanent magnet or at least one switchable hard magnet for generating at least one magnetic circuit with an interruption. The linear actuator is used for the controlled movement, adjustment, or alignment of a wide variety of objects, as well as for generating movement in robots and for haptically perceptible elements.