Soft Electrohydrodynamic Actuator With Internal Fluid-Driven Deformation
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Solution Overview
Problem
Existing soft actuators face challenges in achieving a balance between safety, reliability, controllability, durability, versatility, quick response, and muscle-like actuation characteristics, with limitations in response speed, efficiency, and portability due to bulky external compressors, unstable high-voltage electrodes, and thermal actuation difficulties.
Innovation Solution
A soft electrohydrodynamic actuator comprising a flexible pouch with a rod electrode and dielectric fluid, an enameled wire, and a planar flexible electrode, which allows for actuation by a high-voltage positive electrode, enabling deformation modes like stretching and bending through varying membrane configurations and materials, and can operate in both air and water environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If fluidic actuators use external compressors or pumps to deliver fluid, then large output forces are achieved, but response speeds are limited and portability is reduced
Solution Approach 1:
The patent extracts and eliminates the external compressor or pump from the system. The soft electrohydrodynamic actuator generates fluid pressure internally through electrohydrodynamic flow of dielectric fluid under an electric field, removing the need for bulky external fluid delivery devices and thereby improving response speed and portability while maintaining output force capability
Solution Approach 2:
The patent replaces the mechanical compression system (compressor/pump) with an electrohydrodynamic system. High-voltage electric fields induce charged droplet formation and ejection from the dielectric fluid, generating internal pressure to deform the flexible pouch, thus substituting mechanical actuation with electrohydrodynamic actuation for faster response
2Speed
If dielectric elastomer actuators use exposed high-voltage electrodes, then fast response speed and large output strain are achieved, but safety and reliability are compromised
Solution Approach 1:
The patent uses a flexible pouch made of elastomeric material as an enclosing shell that contains the dielectric fluid and rod electrode. This flexible shell isolates the high-voltage electrode and dielectric fluid from the external environment, preventing direct contact and electrical breakdown, thereby improving safety and reliability while maintaining the fast response characteristics of dielectric elastomer actuators
Solution Approach 2:
The patent introduces a dielectric fluid as an intermediary substance between the rod electrode and the flexible pouch wall. This dielectric fluid layer acts as an electrical insulator, preventing direct contact between the high-voltage electrode and the conductive flexible pouch, thus eliminating the risk of electrical breakdown while allowing the electric field to effectively actuate the structure
3Force
If smart material actuators use thermal actuation, then large output forces are achieved, but controllability is reduced
Solution Approach 1:
The patent replaces thermal actuation with electrohydrodynamic actuation. Instead of using heat to change material properties and generate force, the system uses high-voltage electric fields to induce charged droplet formation and ejection from dielectric fluid, generating mechanical force through electrohydrodynamic flow. This provides more precise and rapid controllability while maintaining large output forces
Solution Approach 2:
The patent changes the actuation parameter from temperature (thermal) to electric field strength (electrical). By controlling the applied voltage to the rod electrode, the system can precisely control the electrohydrodynamic flow rate and resulting force output, enabling fine-grained control of actuator deformation and response, unlike thermal actuation which has slower and less precise control
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 actuator achieves a combination of safety, reliability, controllability, and quick response with muscle-like actuation characteristics, offering high adaptability and efficient deformation capabilities, surpassing the limitations of prior soft actuators by integrating advantages of fluidic, dielectric elastomer, and smart material actuators.
Implementation Method 1
The high-voltage positive electrode is applied to the rod electrode through the enameled wire to actuate the flow of the dielectric fluid in the closed electrode region and to drive and to deform the flexible pouch
Data Source
AI summary
A soft electrohydrodynamic actuator includes an actuating unit. The actuating unit includes a flexible pouch, a rod electrode, a dielectric fluid, an enameled wire, a hose and a planar flexible electrode. The inner cavity of the flexible pouch is provided with the rod electrode and filled with the dielectric fluid. The hose is hermetically connected to a side of the flexible pouch. The enameled wire is hermetically sleeved in the hose. One end of the enameled wire extends into the inner cavity of the flexible pouch through the hose and is electrically connected to an end of the rod electrode. The other end of the enameled wire is connected to a high-voltage positive electrode. The outer surface of the flexible pouch is coated with a layer of conductive soft material as the planar flexible electrode, or a water environment around the flexible pouch is used as the planar flexible electrode.