Design, Modeling, and Characterization of a Miniature Robotic Fish for Research and Education in Biomimetics and Bioinspiration

TLDR

The paper presents a biomimetic robotic fish with a modular caudal fin designed to study propulsion performance. The authors experimentally characterize the robot’s propulsion across fin geometries, model tail vibrations with modal analysis to relate thrust to oscillatory Reynolds number, and validate performance in free‑swimming tests linking static thrust to terminal speed. The platform is employed in ethorobotics studies of collective fish behavior and in K‑12 educational science activities.

Abstract

In this paper, we present the design of a biomimetic robotic fish with a modular caudal fin and analyze its performance. The robot's propulsion system is experimentally characterized for different caudal fin geometries by using an ad hoc thrust-measurement system. The static thrust produced by the vibrating tail is expressed in terms of the oscillatory Reynolds number and compared with similar findings in the literature. Nonlinear vibrations of the propulsive tail are modeled using modal analysis and classical results from the study of large vibrations of slender cylinders in fluids. This analysis allows for computing the oscillatory Reynolds number in terms of the input parameters to the tail vibration. Free-swimming experiments are performed to investigate the performance and maneuverability of the robot and correlate static thrust with terminal speed. This robotic platform is currently being used in ethorobotics research for investigating collective behavior of gregarious fish species and in educational fun-science activities for K-12 students.