Electro-Active Polymer Pre-Stretching with Semi-Stiff Conductors
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Solution Overview
Problem
Electro-active polymers (EAPs) face challenges in maintaining a pre-stretch state, leading to instability and increased voltage requirements for actuation, due to pull-in instability and low electrical breakdown strength.
Innovation Solution
Mechanical pre-stretching of EAP films in single or biaxial directions, followed by attachment of semi-stiff conductors and mechanical connectors to fix the pre-stretched state, allowing expansion while maintaining conductivity, and using multi-layered structures to enhance strength and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electro-active polymer film is mechanically pre-stretched and fixed in a pre-stretched state, then electrical breakdown strength is enhanced and pull-in instability is minimized, but device complexity increases due to the need for conductors and mechanical connectors
Solution Approach 1:
The patent applies preliminary action by mechanically pre-stretching the electro-active polymer film before use and fixing it in that stretched state using semi-stiff conductors and mechanical connectors. This pre-stretching prepares the polymer in advance to prevent pull-in instability and enhance electrical breakdown strength during actual operation, resolving the contradiction by preparing the system beforehand to avoid complex real-time control needs
2Use of energy by moving object
If electro-active polymer film is mechanically pre-stretched and fixed in a pre-stretched state, then voltage requirements are reduced for activation, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by altering the physical state of the electro-active polymer from relaxed to pre-stretched through mechanical processing. This changes the polymer's electrical and mechanical parameters, reducing the voltage needed for activation while the pre-stretched state is maintained through fixed conductors and connectors that ensure consistent geometric parameters during manufacturing
3Stability of the object's composition
If semi-stiff conductors are attached to fix the EAP in pre-stretched state, then stability is improved, but ease of manufacture decreases
Solution Approach 1:
The patent applies composite materials by combining the electro-active polymer with semi-stiff conductors and mechanical connectors to create a composite structure. This composite approach stabilizes the pre-stretched state of the polymer while the conductors and connectors serve dual purposes: maintaining mechanical stability and providing electrical functionality, thereby balancing manufacturing complexity with performance requirements
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
Stabilizes the actuation of EAPs by minimizing pull-in instability, improving electrical breakdown strength, and reducing the required activation voltage, enabling 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
Data Source
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.