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Abstract Elastomer‐granule composites have been used to switch between soft and stiff states by applying negative pressure differentials that cause the membrane to squeeze the internal grains, inducing dilation and jamming. Applications of this phenomenon have ranged from universal gripping to adaptive mobility. Previously, the combination of this jamming phenomenon with the ability to transport grains across multiple soft actuators for shape morphing has not yet been demonstrated. In this paper, the authors demonstrate the use of hollow glass spheres as granular media that functions as a jammable “quasi‐hydraulic” fluid in a fluidic elastomeric actuator that better mimics a key featur of animal musculature: independent control over i) isotonic actuation for motion; and ii) isometric actuation for stiffening without shape change. To best implement the quasi‐hydraulic fluid, the authors design and build a fluidic device. Leveraging this combination of physical properties creates a new option for fluidic actuation that allows higher specific stiffness actuators using lower volumetric flow rates in addition to independent control over shape and stiffness. These features are showcased in a robotic catcher's mitt by stiffening the fluid in the glove's open configuration for catching, unjamming the media, then pumping additional fluid to the mitt to inflate and grasp.
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Bio-inspired design of soft mechanisms using a toroidal hydrostat
"Biology is replete with sott mechanisms ot potential use tor ro botics. Here, we report that a soft, toroidal hydrostat can be used to perform three functions found in both living and engi neered systems: gripping, catching, and conveying. We demon strate a gripping mechanism that uses a tubular inversion to encapsulate objects within a crumpled elastic membrane under hy drostatic pressure. This mechanism produces gripping forces that depend predictably upon the geometric and materials properties of the system. We next demonstrate a catching mechanism akin to that of a chameleon's tongue: the elasticity of the membrane is used to power a catapulting inversion process (= 400 m/s2) to capture flying objects (e.g., a bouncing ball). Finally, we demon strate a conveying mechanism that passes objects through the cen ter of the toroidal tube (~1 cm/s) using a continuous inversion-aver sion process. The hybrid hard-soft mechanisms presented here can be applied toward the integration of soft functionality into robotic systems."
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- Award ID(s):
- 2011754
- PAR ID:
- 10499984
- Publisher / Repository:
- Cell Reports Physical Science
- Date Published:
- Journal Name:
- Cell Reports Physical Science
- Volume:
- 2
- Issue:
- 9
- ISSN:
- 2666-3864
- Page Range / eLocation ID:
- 100572
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1016/j.xcrp.2021.100572
