Ultra-fast escape maneuver of an octopus-inspired robot
Name
Triantafyllou_Ultra-fast escape.pdf
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2.79 MB
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Adobe PDF
Checksum (MD5)
6e44867ab38f6173ed04e667546d6266
Author(s)
Triantafyllou, Michael S.
Weymouth, G. D.
Subramaniam, V.
Date Issued
February 2015
Journal
Bioinspiration & Biomimetics
Publisher
IOP Publishing
Citation
Weymouth, G D, V Subramaniam, and M S Triantafyllou. “Ultra-Fast Escape Maneuver of an Octopus-Inspired Robot.” Bioinspiration & Biomimetics 10, no. 1 (February 1, 2015): 016016.
Version
Original manuscript
Abstract
We design and test an octopus-inspired flexible hull robot that demonstrates outstanding fast-starting performance. The robot is hyper-inflated with water, and then rapidly deflates to expel the fluid so as to power the escape maneuver. Using this robot we verify for the first time in laboratory testing that rapid size-change can substantially reduce separation in bluff bodies traveling several body lengths, and recover fluid energy which can be employed to improve the propulsive performance. The robot is found to experience speeds over ten body lengths per second, exceeding that of a similarly propelled optimally streamlined rigid rocket. The peak net thrust force on the robot is more than 2.6 times that on an optimal rigid body performing the same maneuver, experimentally demonstrating large energy recovery and enabling acceleration greater than 14 body lengths per second squared. Finally, over 53% of the available energy is converted into payload kinetic energy, a performance that exceeds the estimated energy conversion efficiency of fast-starting fish. The Reynolds number based on final speed and robot length is Re ≈ 700 000. We use the experimental data to establish a fundamental deflation scaling parameter σ* which characterizes the mechanisms of flow control via shape change. Based on this scaling parameter, we find that the fast-starting performance improves with increasing size.
MIT Department
Massachusetts Institute of Technology. Center for Ocean Engineering
Massachusetts Institute of Technology. Department of Mechanical Engineering
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Creative Commons Attribution-Noncommercial-Share Alike
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DOI of Published Version
https://doi.org/10.1088/1748-3190/10/1/016016
