Bioinspired Propulsion System for a Thunniform Robotic Fish

Abstract

The paper describes a bioinspired propulsion system for a robotic fish model. The system is based on a combination of an elastic chord with a tail fin fixed on it. The tail fin is connected to a servomotor by two symmetric movable thrusts simulating muscle contractions. The propulsion system provides the oscillatory tail movement with controllable amplitude and frequency. Tail oscillations translate into the movement of the robotic fish implementing the thunniform principle of locomotion. The shape of the body and the tail fin of the robotic fish were designed using a computational model simulating a virtual body in an aquatic medium. A prototype of a robotic fish was constructed and tested in experimental conditions. Dependencies of fish velocity on the dynamic characteristics of tail oscillations were analyzed. In particular, it was found that the robot’s speed increased as the frequency of tail fin oscillations grew. We also found that for fixed frequencies, an increase in the oscillation amplitude lead to an increase in the swimming speed only up to a certain threshold. Further growth of the oscillation amplitude lead to a weak increase in speed at higher energy costs.

Underwater Undulating Propulsion Biomimetic Robots: A Review

“…Compared with the anguilliform model, the fluctuation range is small, but the caudal fluctuation frequency is high. The propulsion of thunniform fish comes from the tail fin [ 43 ]. Based on hydrodynamic models, thunniform propulsion has been estimated to produce mechanical efficiencies in the range of 80–90% [ 18 , 44 , 45 ].…”

“…The Gliding Robotic Dolphin combined the advantages of dolphins and underwater gliders, which not only increased the speed of the robots but also enabled the smooth gliding motion and attitude adjustment of the robot [ 84 ]. Although the Single−Motor−Actuated Robotic Fish [ 85 ] and Thunniform Robotic Fish [ 43 ] had a simple structure, they performed well in terms of motion and maneuverability.…”

“…The Mackerel Robot designed by Li Wen used this simulation model to analyze the relationship between amplitude, efficiency and propulsion speed [ 88 ]. As shown in Figure 4 , a simulation of the kinematic body drag distribution of a robot fish was carried out by Iliya Mitin et al [ 43 ]. Finite element analysis of the kinematics and hydrodynamics of a robot fish was carried out by Qimeng Liu et al [ 92 ].…”

A Survey on Reinforcement Learning Methods in Bionic Underwater Robots

“…The application of bionic underwater robots, characterized by low power consumption, high maneuverability, and environmental friendliness, has become a rapidly developing research field. In the past decades, research into bionic underwater robots, by imitating the shape, swimming patterns, and behaviors of fish, has achieved promising results concerning propulsion mechanisms [ 1 , 2 ], bionic propulsion design [ 3 , 4 , 5 , 6 , 7 , 8 ], high performance optimization [ 9 , 10 , 11 , 12 ], and other aspects. Furthermore, extended research involving motion control, target tracking, and underwater navigation has been conducted for bionic underwater robots.…”

Design of a Bioinspired Underwater Glider for Oceanographic Research

“…Wang et al [ 51 ] developed an underwater torpedo-shaped glider with a caudal fin to enable bidirectional maneuverability. Mitin et al [ 52 ] presented a work which describes a bioinspired propulsion system based on the thunniform principle for a robotic fish, which uses a combination of elastic components with a fixed tail fin.…”