Artificial Muscle Assembly With Integrated Strain Sensing

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Solution Overview

Problem

Current artificial muscles in soft robotics face limitations due to low actuator power per unit volume and challenges in measuring deformation, with fluidic actuators requiring pressurized gas or liquid and thermally activated polymer fibers being difficult to control and operate inefficiently.

Innovation Solution

An artificial muscle design featuring a housing with an electrode region and expandable fluid region, incorporating a strain sensor and an electrode pair that actuates between non-actuated and actuated states to direct dielectric fluid for expansion, allowing for controlled deformation measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If fluidic actuators are used, then the artificial muscle can achieve soft robotic actuation, but the actuator power per unit volume is limited due to requirements for pressurized gas or liquid supply systems

Engineering Contradiction:

Improveactuator power per unit volumeVSAvoidfluid transport system complexity

Core Design Contradiction:

PowerVSDevice complexity

Solution Approach 1:

The patent extracts the fluid supply system from the external environment and integrates it into the artificial muscle structure itself. The housing contains internal reservoirs and channels that store and transport dielectric fluid, eliminating the need for external pressurized gas or liquid supply systems. This reduces device complexity while maintaining soft robotic actuation capabilities.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent implements a nested structure where the expandable fluid region is contained within the housing, which itself contains the electrode pair and dielectric fluid reservoirs. The strain sensor is integrated into the housing structure. This nested arrangement maximizes actuator power density by efficiently utilizing internal space for multiple functional components.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Ease of operation

If thermally activated polymer fibers are used, then the artificial muscle can achieve actuation, but control is difficult and operational efficiency is low

Engineering Contradiction:

Improvecontrol easeVSAvoidoperational efficiency

Core Design Contradiction:

Ease of operationVSLoss of energy

Solution Approach 1:

The patent replaces thermally activated polymer fibers with an electrostatic actuation system. An electrode pair generates an electric field that attracts dielectric fluid toward the electrode region, causing controlled expansion of the expandable fluid region. This electrostatic mechanism provides precise electrical control and higher operational efficiency compared to thermal activation, while maintaining soft robotic actuation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If conventional artificial muscles are used, then actuation is achieved, but measurement of inflation and deformation is difficult

Engineering Contradiction:

Improvedeformation measurement precisionVSAvoidmeasurement system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines the housing structure with the strain sensor integration. The strain sensor is embedded into the housing walls, allowing direct measurement of deformation as the expandable fluid region expands or contracts. This integrated approach enables precise deformation measurement without adding separate external measurement systems, maintaining simplicity while achieving high measurement precision.

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 solution enhances actuator power per unit volume and enables precise measurement of deformation, providing focused inflation and improved performance in robotic applications.

Implementation Method 1

an electrode pair positioned in the electrode region of the housing... the electrode pair is configured to actuate between a non-actuated state and an actuated state such that actuation from the non-actuated state to the actuated state directs the dielectric fluid into the expandable fluid region

Methodology Applied

Scientific EffectDielectric fluid actuation: Dielectric

Implementation Method 2

expanding the expandable fluid region to deform the strain sensor

Methodology Applied

Scientific EffectFluid expansion: Pressure Increase

Data Source

PatentUS11724384B2Artificial muscles comprising a strain sensor and artificial muscle assemblies comprising the same

Publication Date: 2023.08.15 TOYOTA JIDOSHA KK

AI summary

An artificial muscle including a housing having an electrode region and an expandable fluid region, the housing defining an upper housing portion and a lower housing portion, a strain sensor integrated into at least one of the upper housing portion and the lower housing portion of the housing, a dielectric fluid housed within the housing, and an electrode pair positioned in the electrode region of the housing. The electrode pair includes a first electrode and a second electrode, wherein the electrode pair is configured to actuate between a non-actuated state and an actuated state such that actuation from the non-actuated state to the actuated state directs the dielectric fluid into the expandable fluid region, expanding the expandable fluid region to deform the strain sensor.