Marine animals: the next generation of autonomous underwater vehicle?

AbstractFor millions of years, aquatic species have utilized the principles of unsteady hydrodynamics for propulsion and maneuvering. They have evolved high-endurance swimming that can outperform current underwater vehicle technology in the areas of stealth, maneuverability and control authority. Batoid fishes, including the manta ray, Manta birostris, the cownose ray, Rhinoptera bonasus, and the Atlantic stingray, Dasyatis sabina, have been identified as a high-performing species due to their ability to migrate long distances, maneuver in spaces the size of their tip-to-tip wing span, produce enough thrust to leap out of the water, populate many underwater regions, and attain sustained swimming speeds of 2.8 m/s with low flapping/undulating frequencies. These characteristics make batoid fishes an ideal platform to emulate in the design of a bio-inspired autonomous underwater vehicle. The enlarged pectoral fins of each ray undergoes complex motions that couple spanwise curvature with a chordwise traveling wave to produce thrust and to maneuver. Researchers are investigating these amazing species to understand the biological principles for locomotion. The continuum of swimming motions—from undulatory to oscillatory—demonstrates the range of capabilities, environments, and behaviors exhibited by these fishes. Direct comparisons between observed swimming motions and the underlying cartilage structure of the pectoral fin have been made. A simple yet powerful analytical model to describe the swimming motions of batoid fishes has been developed and is being used to quantify their hydrodynamic performance. This model is also being used as the design target for artificial pectoral fin design. Various strategies have been employed to replicate pectoral fin motion. Active tensegrity structures, electro-active polymers, and fluid muscles are three structure/actuator approaches that have successfully demonstrated pectoral-fin-like motions. This paper explores these recent studies to understand the relationship between form and swimming function of batoid fishes and describes attempts to emulate their abilities in the next generation of bio-inspired underwater vehicles.

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Parameters Identification of the Flexible Fin Kinematics Model Using Vision and Genetic Algorithms

Polish Maritime Research ◽

10.2478/pomr-2020-0025 ◽

2020 ◽

Vol 27 (2) ◽

pp. 39-47

Author(s):

Karolina Jurczyk ◽

Paweł Piskur ◽

Piotr Szymak

Keyword(s):

Autonomous Underwater Vehicle ◽

Kinematic Model ◽

Underwater Vehicle ◽

Future Research ◽

Marine Animals ◽

Kinematics Model ◽

Tail Movement ◽

Flexible Fin ◽

The One ◽

Vision Algorithm

AbstractRecently a new type of autonomous underwater vehicle uses artificial fins to imitate the movements of marine animals, e.g. fish. These vehicles are biomimetic and their driving system is an undulating propulsion. There are two main methods of reproducing undulating motion. The first method uses a flexible tail fin, which is connected to a rigid hull by a movable axis. The second method is based on the synchronised operation of several mechanical joints to imitate the tail movement that can be observed among real marine animals such as fish. This paper will examine the first method of reproducing tail fin movement. The goal of the research presented in the paper is to identify the parameters of the one-piece flexible fin kinematics model. The model needs further analysis, e.g. using it with Computational Fluid Dynamics (CFD) in order to select the most suitable prototype for a Biomimetic Underwater Vehicle (BUV). The background of the work is explained in the first section of the paper and the kinematic model for the flexible fin is described in the next section. The following section is entitled Materials and Methods, and includes a description of a laboratory test of a water tunnel, a description of a Vision Algorithm (VA)which was used to determine the positions of the fin, and a Genetic Algorithm (GA) which was used to find the parameters of the kinematic fin. In the next section, the results of the research are presented and discussed. At the end of the paper, the summary including main conclusions and a schedule of the future research is inserted.

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