Dielectric Elastomer Self-Sensing via Plane Approximation

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Solution Overview

Problem

Existing self-sensing methods for dielectric elastomers are limited by accuracy under non-stationary conditions, sensitivity to noise, and complexity, particularly in portable applications, and often require assumptions that do not hold true, making them unsuitable for practical implementation.

Innovation Solution

A method that introduces a small-scale oscillation to the voltage difference between electrodes, measuring potential difference and series current, and deriving feedback parameters like capacitance and leakage current through regression analysis, allowing for real-time estimation of the dielectric elastomer's state without the need for additional sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If discrete rigid sensors are attached to the dielectric elastomer, then feedback regarding mechanical output is obtained, but the cost and mass of the device increase and motion is inhibited

Engineering Contradiction:
Improvefeedback informationVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The dielectric elastomer itself serves as the sensing element by utilizing its inherent electrical properties (capacitance, impedance) that change with mechanical deformation. This self-sensing capability eliminates the need for separate sensors, reducing device complexity and mass while maintaining feedback functionality

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The dielectric elastomer performs multiple functions simultaneously: it acts as both the actuating element (converting electrical energy to mechanical energy) and the sensing element (providing feedback through electrical property changes). This multi-functionality reduces the need for separate components

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If prior art self-sensing methods are used, then feedback parameters are obtained, but accuracy deteriorates under non-stationary conditions and noise sensitivity increases

Engineering Contradiction:
Improvefeedback capabilityVSAvoidmeasurement accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

A small-scale oscillation is introduced to the voltage difference across the electrodes. This oscillation enables dynamic estimation of electrical parameters through regression analysis, improving measurement accuracy under non-stationary conditions by capturing the system's response to controlled perturbations

Inventive Principle:
Principle #18Mechanical vibration

Solution Approach 2:

The method implements a feedback mechanism where measured electrical parameters (potential difference, current) are used to dynamically estimate capacitance and other state variables through regression analysis, continuously updating the system model to maintain accuracy

Inventive Principle:
Principle #23Feedback

3Reliability

If prior art self-sensing methods are used, then feedback parameters are obtained, but the method complexity and hardware requirements increase

Engineering Contradiction:
Improvefeedback capabilityVSAvoidmethod complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The dielectric elastomer system uses its own electrical characteristics for sensing, eliminating the need for external sensors and complex measurement apparatus. The inherent capacitance and impedance changes provide the feedback signal directly

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The method utilizes changes in electrical parameters (capacitance, impedance, current) of the dielectric elastomer itself as the sensing mechanism. By monitoring these natural parameter changes during actuation, the system obtains feedback without additional hardware

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 accurate and efficient estimation of key parameters like capacitance, equivalent series resistance, and leakage current, improving control and monitoring capabilities across a wide range of conditions, reducing the need for assumptions and simplifying hardware design.

Implementation Method 1

Electrical charge accumulates on the electrodes 12 in the manner of a capacitor and an electrostatic pressure is generated that results in a through-thickness compression and in-plane expansion of the membrane

Methodology Applied
Scientific EffectElectrostriction: Electrostriction

Implementation Method 2

The electrical properties of dielectric elastomer sensors such as capacitance, electrode resistance, and the equivalent parallel resistance of the dielectric membrane change in response to external stimuli such as mechanical deformation

Methodology Applied
Scientific EffectCapacitance change with strain: Capacitance

Data Source

PatentEP2630672B1Dielectric elastomer self-sensing using plane approximation
Publication Date: 2016.04.20 AUCKLAND UNISERVICES LTD
  • EP2630672B1 patent drawingFigure 1(a)~2
  • EP2630672B1 patent drawingFigure 3~4
  • EP2630672B1 patent drawingFigure 5~6

AI summary

The present invention provides a method for obtaining feedback parameters related to the state of a dielectric elastomer (DE). The method comprises introducing a small-scale oscillation to the voltage difference between electrodes of the DE, monitoring or repeatedly measuring several measurable electrical characteristics of the DE, deriving other relevant data from the measurements, deriving an equation for a plane of best fit through the relevant data when defined as orthogonal axes, and deriving the feedback parameters from coefficients of the plane equation. The method thus provides important feedback regarding the capacitance, leakage current and/or electrode resistance of the DE. Also disclosed are a computer program and a system adapted to perform the method.