Experimental study of fish-like bodies with passive tail and tunable stiffness

Fuente: arXiv
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Main Authors: Padovani, L., Manduca, G., Paniccia, D., Graziani, G., Piva, R., Lugni, C.
Format: Preprint
Published: 2024
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author Padovani, L.
Manduca, G.
Paniccia, D.
Graziani, G.
Piva, R.
Lugni, C.
author_facet Padovani, L.
Manduca, G.
Paniccia, D.
Graziani, G.
Piva, R.
Lugni, C.
contents Scombrid fishes and tuna are efficient swimmers capable of maximizing performance to escape predators and save energy during long journeys. A key aspect in achieving these goals is the flexibility of the tail, which the fish optimizes during swimming. Though, the robotic counterparts, although highly efficient, have partially investigated the importance of flexibility. We have designed and tested a fish-like robotic platform (of 30 cm in length) to quantify performance with a tail made flexible through a torsional spring placed at the peduncle. Body kinematics, forces, and power have been measured and compared with real fish. The platform can vary its frequency between 1 and 3 Hz, reaching self-propulsion conditions with speed over 1 BL/s and Strouhal number in the optimal range. We show that changing the frequency of the robot can influence the thrust and power achieved by the fish-like robot. Furthermore, by using appropriately tuned stiffness, the robot deforms in accordance with the travelling wave mechanism, which has been revealed to be the actual motion of real fish. These findings demonstrate the potential of tuning the stiffness in fish swimming and offer a basis for investigating fish-like flexibility in bio-inspired underwater vehicles.
format Preprint
id arxiv_https___arxiv_org_abs_2411_10760
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Experimental study of fish-like bodies with passive tail and tunable stiffness
Padovani, L.
Manduca, G.
Paniccia, D.
Graziani, G.
Piva, R.
Lugni, C.
Fluid Dynamics
Robotics
76Z10, 76D05, 92C10
Scombrid fishes and tuna are efficient swimmers capable of maximizing performance to escape predators and save energy during long journeys. A key aspect in achieving these goals is the flexibility of the tail, which the fish optimizes during swimming. Though, the robotic counterparts, although highly efficient, have partially investigated the importance of flexibility. We have designed and tested a fish-like robotic platform (of 30 cm in length) to quantify performance with a tail made flexible through a torsional spring placed at the peduncle. Body kinematics, forces, and power have been measured and compared with real fish. The platform can vary its frequency between 1 and 3 Hz, reaching self-propulsion conditions with speed over 1 BL/s and Strouhal number in the optimal range. We show that changing the frequency of the robot can influence the thrust and power achieved by the fish-like robot. Furthermore, by using appropriately tuned stiffness, the robot deforms in accordance with the travelling wave mechanism, which has been revealed to be the actual motion of real fish. These findings demonstrate the potential of tuning the stiffness in fish swimming and offer a basis for investigating fish-like flexibility in bio-inspired underwater vehicles.
title Experimental study of fish-like bodies with passive tail and tunable stiffness
topic Fluid Dynamics
Robotics
76Z10, 76D05, 92C10
url https://arxiv.org/abs/2411.10760