HASEL Transducer Structure for Self-Healing Soft Actuation
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Solution Overview
Problem
Existing soft actuators, such as pneumatic and dielectric elastomer actuators, face limitations in speed, efficiency, scalability, and reliability due to fluid drag, dielectric breakdown, and electrical ageing, making them unsuitable for high-performance applications.
Innovation Solution
Hydraulically Amplified Self-Healing Electrostatic (HASEL) transducers utilize an electro-hydraulic mechanism with liquid dielectrics to combine fluidic and electrostatic actuation, enabling high-performance, self-sensing, muscle-mimetic actuators that can scale actuation force and strain, and feature self-healing capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If pneumatic actuators are used for soft robotics, then versatility and prevalence are improved, but fluid drag limits bandwidth and efficiency
Solution Approach 1:
The patent replaces pneumatic actuators with dielectric elastomer actuators (DEAs) that use electrostatic forces instead of pneumatic pressure. This substitution eliminates fluid drag and associated valves/channels, directly improving bandwidth and efficiency while maintaining versatility through programmable actuation patterns.
Solution Approach 2:
The patent introduces a hybrid pneumatic-electric system where a pneumatic chamber provides pre-tensioning force to the dielectric elastomer, while electrical actuation provides precise control. This combination leverages the versatility of pneumatic systems while overcoming their speed limitations through electrical triggering.
2Force
If dielectric elastomer actuators are used to deliver high forces, then actuation force is improved, but dielectric breakdown and electrical ageing reduce reliability
Solution Approach 1:
The patent incorporates a pneumatic chamber that provides pre-tensioning force to the dielectric elastomer before electrical actuation. This mechanical pre-loading reduces the electric field stress required for actuation, cushioning against dielectric breakdown and extending operational reliability.
Solution Approach 2:
The patent creates a composite actuator system combining dielectric elastomer layers with a pneumatic chamber and conductive electrodes. This multi-material composite structure distributes mechanical and electrical stresses, reducing the risk of dielectric breakdown while maintaining high actuation forces.
3Ease of operation
If untethered pneumatic actuators are used, then portability is improved, but response speed decreases
Solution Approach 1:
The patent replaces slow pneumatic response mechanisms with fast electrical actuation of dielectric elastomers. The electrical field can be switched on and off rapidly, enabling fast response speeds while maintaining portability through integration of power electronics and flexible battery packs.
Solution Approach 2:
The patent employs periodic electrical signaling to control actuator response, enabling rapid on/off cycling that achieves fast response speeds. The periodic electrical actuation complements the portable untethered design by providing precise temporal control without requiring tether connections.
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
HASEL actuators provide reliable, high-performance actuation with self-sensing capabilities, overcoming limitations of current soft actuators by using hydraulic principles to generate large forces and strains while recovering from dielectric breakdown.
Implementation Method 1
electrostatic forces between the first and second electrodes upon application of a voltage to the first and second electrodes draws the first and second electrodes towards each other to displace the liquid dielectric within the enclosed internal cavity
Implementation Method 2
electrostatic forces between the first and second electrodes upon application of a voltage to the first and second electrodes draws the first and second electrodes towards each other to displace the liquid dielectric
Data Source
AI summary
An electro-hydraulic actuator includes a deformable shell defining an enclosed internal cavity and containing a liquid dielectric, first and second electrodes on first and second sides, respectively, of the enclosed internal cavity. An electrostatic force between the first and second electrodes upon application of a voltage to one of the electrodes draws the electrodes towards each other to displace the liquid dielectric within the enclosed internal cavity. The shell includes active and inactive areas such that the electrostatic forces between the first and second electrodes displaces the liquid dielectric within the enclosed internal cavity from the active area of the shell to the inactive area of the shell. The first and second electrodes, the deformable shell, and the liquid dielectric cooperate to form a self-healing capacitor, and the liquid dielectric is configured for automatically filling breaches in the liquid dielectric resulting from dielectric breakdown.