Tapered-Electrode Artificial Muscle for Faster Fluidic Actuation
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Solution Overview
Problem
Current artificial muscles in soft robotics face limitations due to the weight-to-power ratio of rigid components and inefficiencies in fluidic actuators, which hinder their versatility and performance.
Innovation Solution
The design of an artificial muscle with a housing containing a tapered electrode pair that directs dielectric fluid into an expandable region, utilizing a zippering actuation motion to increase force per unit volume, facilitated by tapered tab portions and bridge portions on the electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fluidic actuators are used to power soft robotic devices, then the devices can achieve flexibility and versatility, but the speed and efficiency are limited due to requirements for pressurized fluid supply systems with channels and tubes
Solution Approach 1:
The patent extracts and eliminates the complex fluid transport system (channels and tubes) from the actuator design. The HASEL actuator uses a simplified configuration where electrodes are placed directly within the dielectric fluid-filled chamber, removing the need for external fluid supply systems and enabling faster actuation responses.
Solution Approach 2:
The dielectric fluid serves as an intermediary medium that enables direct coupling between the electrical field (from electrodes) and the mechanical deformation (of the chamber). This intermediary allows energy transfer without requiring complex mechanical linkages or fluid transport infrastructure.
2Ease of operation
If thermally activated polymer fibers are used for actuation, then the artificial muscles can be controlled, but they operate at low efficiencies
Solution Approach 1:
The patent replaces thermal activation mechanisms with direct electrical field activation. Instead of using heat to trigger polymer fiber contraction, the HASEL actuator uses voltage application across electrodes to directly induce dielectric elastomer deformation, eliminating thermal energy losses and improving operational efficiency.
Solution Approach 2:
The actuator changes the activation parameter from thermal (temperature-based) to electrical (voltage-based). This parameter change enables more efficient energy conversion and better controllability through precise voltage control, avoiding the energy waste inherent in thermal activation systems.
3Reliability
If rigid components such as servomotors are used in robotic technologies, then the devices can perform tasks reliably, but the weight-to-power ratio limits their application in soft robotics
Solution Approach 1:
The patent employs flexible dielectric elastomer chambers as the primary structural and functional component. These thin-film flexible structures replace heavy rigid servomotors, achieving both reliability through controlled deformation and reduced weight, thereby improving the weight-to-power ratio for soft robotic applications.
4Device complexity
If conventional electrode designs are used in fluidic actuators, then the structure is simple, but the actuation force per unit volume is limited
Solution Approach 1:
The patent transitions from planar electrode configurations to three-dimensional tapered electrode structures. The tapered geometry creates non-uniform electric field distribution that concentrates force generation in specific regions, increasing the actuation force per unit volume while maintaining relatively simple electrode fabrication.
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
This design enhances the actuation power of artificial muscles by reducing mass and volume while maintaining force, improving control and efficiency over existing technologies.
Implementation Method 1
the electrode pair is actuatable 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
Implementation Method 2
a dielectric fluid is housed within the housing; and the electrode pair is actuatable 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
Data Source
AI summary
An artificial muscle including a housing, an electrode pair positioned in an electrode region of the housing, the electrode pair including a first electrode and a second electrode, the first electrode and the second electrode each including a pair of tapered tab portions and a bridge portion, the tapered tab portions each having a first end proximate to the expandable fluid region and an opposite second end proximate the electrode region, each of the second ends tapering in a direction opposite the expandable fluid region, the pair of tapered tab portions extending parallel to one another to define a gap portion between the pair of tapered tab portions, the bridge portion interconnecting the pair of tapered tab portions, and a dielectric fluid housed within the housing, wherein the electrode pair is actuatable 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 an expandable fluid region of the housing.