Microfluidic-based artificial muscles and method of formation
Inventors
Kartalov, Emil P. • Scherer, Axel
Assignees
California Institute of Technology • US Department of Navy
Publication Number
US-11635064-B1
Publication Date
2023-04-25
Expiration Date
2039-06-14
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Abstract
Artificial muscles comprising a body of dielectric elastomer, wherein the body contains a pair of microfluidic networks are presented. Each microfluidic network includes a plurality of channels fluidically coupled via a manifold. The channels of the microfluidic networks are interdigitated and filled with conductive fluid such that each set of adjacent channels functions as the electrodes of an electroactive polymer (EAP) actuator. By using the manifolds as compliant wiring to energize the electrodes, artificial muscles in accordance with the present disclosure mitigate some or all of the reliability problems associated with prior-art artificial muscles.
Core Innovation
The present disclosure introduces artificial muscles composed of a dielectric elastomer body containing a pair of microfluidic networks. Each network includes multiple channels interconnected via a manifold. These channels are interdigitated and filled with conductive fluids to serve as electrodes of electroactive polymer (EAP) actuators. This design leverages the manifolds as compliant wiring to energize the electrodes, addressing reliability problems found in prior-art artificial muscles.
Prior art technologies such as electromagnetics, pneumatics, hydraulics, thermal actuators, and shape-memory alloys have significant limitations like bulkiness, slow response, high power consumption, or difficulty in miniaturization. EAP actuators, while promising, have been hindered by cumbersome fabrication, poor efficiency, durability issues, and complicated interconnection schemes. The invention solves these issues by integrating microfluidic networks filled with conductive fluid within a dielectric elastomer, providing reliable, robust electrodes and wiring.
The disclosed artificial muscles feature electrostatic actuators formed by interdigitated microfluidic channels filled with conductive fluids that act as electrodes separated by dielectric elastomer members. Applying a voltage differential generates an electrostatic force that compresses the dielectric, creating contraction or tension akin to muscle fibers. The invention also includes methods for fabrication using 3D printing or sacrificial materials to create these integrated networks, enabling high-volume reproducibility and enhanced mechanical robustness.
Claims Coverage
The patent claims three independent methods and apparatus covering the configuration, fabrication, and functional operation of artificial muscles employing dielectric elastomer bodies with integrated microfluidic networks filled with conductive fluids.
Integration of interdigitated microfluidic networks within dielectric elastomer body
The body comprises a first microfluidic network (with a manifold and multiple channels) and a second microfluidic network arranged so that the first and second channels are interdigitated and spaced apart. Both networks are filled with electrically conductive liquid or gel such that applying a voltage differential creates attractive forces between adjacent channels.
Fabrication methods using sacrificial elements and 3D printing
Methods include defining sacrificial elements corresponding to the microfluidic networks, forming a nascent body encompassing these elements, and removing the sacrificial material to form channels and manifolds. Alternatively, three-dimensional (3D) printing processes are used to form the body and sacrificial elements or the microfluidic networks directly. The conductive fluid is filled into the networks post-fabrication.
Electrical and fluidic connectivity via manifolds and ports
The microfluidic networks incorporate manifolds fluidically coupling individual channels and ports for filling and electrical connection. This facilitates robust, compliant electrical contact that mitigates failures seen in prior art actuators due to wire breakage or electrode delamination during actuation.
The claims encompass the innovative structure of dielectric elastomer artificial muscles with integrated, interdigitated microfluidic electrode networks filled with conductive fluids, combined with novel fabrication techniques, enabling reliable, high-volume manufacturable artificial muscles with effective electrical interconnections and actuation forces.
Stated Advantages
Conductive-fluid-filled channels act as highly reliable compliant electrodes for electrostatic actuators.
Conductive-fluid-filled manifolds provide flexible and robust electrical wiring that flexes and bends without wire snapping or disconnection.
Formation of microfluidic networks within the muscle body eliminates the need for separate dielectric materials and hard electrodes, simplifying construction.
The fabrication process supports high-volume manufacture via automated processes such as 3D printing and microfabrication techniques, enhancing reproducibility.
Monolithic structures made by 3D printing are sturdier and more robust than prior heterogeneous stacks, allowing higher stress tolerance and safer, reliable force delivery.
Documented Applications
Artificial muscles suitable for use in acoustically quiet propulsion systems for underwater vehicles.
Armored exoskeletons and prosthetics enhancing human strength and capability.
Biomimetic propulsion of unmanned underwater and surface vehicles by mimicking fish fin motions to reduce cavitation and acoustic signature.
Walking robots and biomimetic powered limbs replicating the anatomy and motion range of biological muscles.
Peristaltic pumps and sphincter-like devices producing constrictive forces controlled by voltage-induced electrostatic attraction.
Land locomotion devices inspired by limb anatomy of large walking animals for improved speed, jumping, and cross-country access in vehicles.
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