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Proceedings Paper

Liquid metal-based bio-inspired capacitive flow sensor
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Paper Abstract

We present a liquid flow sensor inspired by cupula structures found on a variety of fish. Our 5mm x 5mm x 1.75mm artificial cupula uniquely comprises a pair of differential liquid metal capacitors encased in silicone. Deflection of the structure – manually or by fluid flow – increases capacitance on one side and decreases on the other. To fabricate the complex internal structure, a commercial 3D printer is used to create a mold out of a sacrificial wax-like material. After casting uncured rubber, internal mold structures are melted and dissolved away, leaving channels and voids for liquid metal vacuum injection. The measured sensitivity of ~0.05pF/mm is compared to theoretical capacitance versus deflection values based on kinematics. To test behavior under water flow, a custom flow channel consisting of a 7.5mm x 7.5mm cross-section is employed with rates up to 1L/min. The parabolic capacitive response as a function of flowrate is compared to analytic theory based on kinematics and drag as well as to fluid-structure interaction (FSI) simulations using COMSOL. This device has future applications in the control of bio-inspired soft robotics. [Work sponsored by the Office of Naval Research.]

Paper Details

Date Published: 13 March 2019
PDF: 12 pages
Proc. SPIE 10965, Bioinspiration, Biomimetics, and Bioreplication IX, 109650T (13 March 2019); doi: 10.1117/12.2514355
Show Author Affiliations
James P. Wissman, U.S. Naval Research Lab. (United States)
Kaushik Sampath, U.S. Naval Research Lab. (United States)
Charles A. Rohde, U.S. Naval Research Lab. (United States)

Published in SPIE Proceedings Vol. 10965:
Bioinspiration, Biomimetics, and Bioreplication IX
Raúl J. Martín-Palma; Mato Knez; Akhlesh Lakhtakia, Editor(s)

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