Pre-Stretched Electro-Active Polymer Actuator for Pull-In Stability

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Solution Overview

Problem

Existing technologies struggle to maintain electro-active polymers in a pre-stretched state effectively, leading to issues such as pull-in instability and the need for higher activation voltages due to reduced breakdown strength.

Innovation Solution

Mechanically pre-stretch the electro-active polymer film in single or biaxial directions, attach semi-stiff conductors to fix the film in a pre-stretched state, and utilize mechanical connectors at each end, along with a strain measuring mechanism to monitor and stabilize the pre-stretch.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If electro-active polymer film is not pre-stretched, then the structure is simpler and easier to manufacture, but the breakdown strength is reduced and higher activation voltages are required

Engineering Contradiction:

Improvebreakdown strengthVSAvoidmanufacturing complexity

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The electro-active polymer film is mechanically pre-stretched in a single or biaxial direction before use, and semi-stiff conductors are attached to maintain this pre-stretched state. This preliminary action increases the breakdown strength and reduces pull-in instability, allowing the polymer to operate at higher voltages more effectively.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If semi-stiff conductors are attached to fix the polymer in pre-stretched state, then the pre-stretch state is maintained and pull-in instability is reduced, but the device complexity increases

Engineering Contradiction:

Improvepull-in stabilityVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Semi-stiff conductors are attached to the electro-active polymer film to change and maintain the mechanical state of the polymer, fixing it in a pre-stretched configuration. This parameter change stabilizes the polymer structure, reduces pull-in instability, and enables more reliable operation.

Inventive Principle:

Principle #35Parameter changes

3Use of energy by moving object

If the polymer is allowed to contract freely, then the device is simpler to manufacture, but the activation voltage remains high due to reduced breakdown strength

Engineering Contradiction:

Improveactivation voltageVSAvoidmanufacturing complexity

Core Design Contradiction:

Use of energy by moving objectVSEase of manufacture

Solution Approach 1:

The polymer film is pre-stretched and held in this state by semi-stiff conductors before activation, which increases its breakdown strength. This preliminary mechanical conditioning allows the polymer to withstand higher activation voltages more effectively, improving energy utilization.

Inventive Principle:

Principle #10Preliminary action

4Stability of the object's composition

If mechanical connectors are added to couple at the ends of the active region, then the pre-stretch state is maintained, but the device complexity increases

Engineering Contradiction:

Improvepre-stretch state stabilityVSAvoidconnector complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The device is divided into functional segments: the electro-active polymer film, semi-stiff conductors attached to maintain pre-stretch, and mechanical connectors at the ends to couple and stabilize the structure. This segmentation allows each component to perform its specific function while maintaining overall stability.

Inventive Principle:

Principle #1Segmentation

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 method stabilizes the pre-stretch state, reduces pull-in instability, enhances electrical breakdown strength, and lowers the required activation voltage, allowing for efficient conversion between electrical and mechanical energy.

Implementation Method 1

Typically, electro-active polymers are polymers that exhibit a change in size or shape when stimulated by an electric field

Methodology Applied

Scientific EffectElectro-active polymer effect: Electroactive Polymer

Implementation Method 2

attaching a first semi-stiff conductor to a first surface of the electro-active polymer film and a second semi-stiff conductor to a second surface, each semi-stiff conductor is configured to fix the electro-active polymer film in a pre-stretched state

Methodology Applied

Scientific EffectMechanical constraint: Mechanical Force

Implementation Method 3

the isolating layer can prevent voltage breakthrough from the EAP actuator and the solid body

Methodology Applied

Scientific EffectElectrical insulation: Dielectric

Data Source

PatentUS20260047013A1Methods and mechanisms for maintaining an electro-active polymer in a pre-stretch state and uses thereof

Publication Date: 2026.02.12 ELASTIMED LTD

AI summary

In some embodiments, the present invention is directed to an actuator which includes at least the following: a pre-stretched electro-active polymer film being pre-stretched in a single or biaxial planar directions; at least one first semi-stiff conductor attached to a first surface of the pre-stretched electro-active polymer film, wherein the first surface is parallel to the single or biaxial planar stretch directions; at least one second semi-stiff conductor attached to a second surface of the pre-stretched electro-active polymer film, wherein the second surface is opposite to the first surface; where the semi-stiff conductors are configured to: fix the pre-stretched electro-active polymer film in a pre-stretched state and allow the pre-stretched electro-active polymer film to expand; a pair of mechanical connectors coupled to each end of an active region of the pre-stretched electro-active polymer film.