Sheath-Run Artificial Muscles for High Power Density Actuation
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Solution Overview
Problem
Existing artificial muscles, particularly those using carbon nanotube hybrid yarns, face limitations in effectively utilizing input energy due to the guest's location within the yarn's interior, leading to inefficient mechanical power and limited actuation capabilities.
Innovation Solution
The development of sheath-run artificial muscles, where the volume-changing guest is located on the surface of the host yarn, enabling increased actuation efficiency and power density by altering the host-guest topology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the guest is located within the yarn's interior (guest-filled structure), then the muscle can achieve actuation through volume change, but the input energy is not effectively utilized and mechanical power is limited
Solution Approach 1:
The patent inverts the conventional guest-filled structure by placing the volume-changing guest material on the exterior surface of the yarn rather than within the interior. This inversion allows the guest to directly interact with the surrounding environment and efficiently convert volume changes into mechanical work, significantly improving energy utilization efficiency and mechanical power density.
Solution Approach 2:
The patent transitions from a one-dimensional interior placement to a two-dimensional surface placement of the guest material. This dimensional change increases the effective surface area for energy conversion and allows more of the guest material to contribute to actuation, thereby enhancing mechanical power output.
2Shape
If the guest is located within the yarn's interior, then the muscle structure is compact, but the actuation capabilities are limited and energy delivery to the guest near yarn center is inefficient
Solution Approach 1:
The patent inverts the conventional guest-filled structure by placing the volume-changing guest material on the exterior surface of the yarn rather than within the interior. This inversion allows the guest to directly interact with the surrounding environment and efficiently convert volume changes into mechanical work, significantly improving energy utilization efficiency and mechanical power density.
Solution Approach 2:
The patent applies local quality by concentrating the guest material at the yarn surface where it can most effectively interact with the environment. This localized placement ensures that the region with the highest actuation efficiency (the surface) contains the guest material, while the yarn interior maintains its structural integrity.
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
Sheath-run artificial muscles demonstrate enhanced work capacity and power densities, with coiled tensile muscles achieving up to 2 W/g of average contractile power, significantly surpassing human muscle performance and enabling diverse applications from robotics to drug delivery systems.
Implementation Method 1
actuated by an influence source selected from a group consisting of absorption processes, desorption processes, changes in temperature, changes in external pressure, changes in pH, changes in a magnetic field, changes in an electric field, exposure to actinic radiation, electrochemical charge or discharge, chemical reaction
Implementation Method 2
actuated by an influence source selected from a group consisting of absorption processes, desorption processes, changes in temperature, changes in external pressure, changes in pH, changes in a magnetic field, changes in an electric field, exposure to actinic radiation, electrochemical charge or discharge, chemical reaction
Implementation Method 3
The coiled core yarn or fiber can include twist. The sheath can change volume, modulus, or a combination thereof when actuated by an influence source to drive actuation
Data Source
AI summary
Sheath-run artificial muscles (or SRAMs) are described in which the dimensional changes and/or modulus changes of a sheath on the surface of a twisted or coiled host yarn or fiber drives torsional and tensile actuation. The sheath-core artificial muscle includes a sheath on a coiled core yarn or fiber that has inserted twist, in which the sheath does not include a yarn, the coiled core yarn or fiber includes a core yarn or fiber, the sheath can change volume, modulus, or a combination thereof when actuated by an influence source to drive actuation, and the influence source is selected from a group consisting of absorption processes, desorption processes, changes in temperature, changes in external pressure, changes in a magnetic field, changes in an electric field, exposures to actinic radiation, electrochemical charge and discharge, chemical reactions, and combinations thereof. These sheath-run muscles can be used for diverse applications, such as robots, robotic devices, energy harvesters, muscles that enable electrical energy harvesting, comfort-adjusting textiles, comfort-adjusting clothing, bio-powered intelligent muscles that control the release of drugs, muscles for appropriate drug delivery, intelligent muscles that sense their environment and actuate in response, muscles for artificial limbs and orthotic gloves, muscles for haptic applications, muscles that can perform in extreme environments, and muscles for intelligent solar panel positioning.