A Bioinspired Cownose Ray Robot for Seabed Exploration

Fish swimming has attracted attention as a locomotion system with excellent propulsive efficiency. They swim by moving their body, fins, and other organs simultaneously, which developed during evolution. Among their many organs, the pectoral fin plays a crucial role in swimming, such as forward–backward movement and change of direction. In order to investigate the hydrodynamic interaction between pectoral fins and fish bodies, we examined the asymmetric flapping motion of the pectoral fin concerning the body axis and investigated the effect of the pectoral fin on the propulsive performance of the body of a small swimming object by numerical simulation. In this study, the amplitude ratio, frequency ratio, and phase of the body and pectoral fin varied. Therefore, although propulsive performance increased in tandem with the frequency ratio, the amplitude ratio change had negatively affected the propulsive performance. The results revealed that the propulsive performance of the fish was high even in low-frequency ratios when the phase difference was varied. The highest propulsion efficiency increased by a factor of about 3.7 compared to the phase difference condition of 0.

Section: Introductionmentioning

confidence: 99%

Three-Dimensional Numerical Study of Hydrodynamic Interactions between Pectoral Fins and the Body of Aquatic Organisms

Morifusa,

Fukui

2024

“…A large number of features, such as fast speed, agility, high efficiency, and strong adaptability in complex aquatic environments, are extremely fascinating for researchers [ 1 ]. These astonishing capabilities mainly derive from their unique physical structures including morphological characteristics and flexible bodies with powerful musculature, which offer extensive inspiration for the ideal underwater platform development to perform aquatic animal supervision [ 2 ], ocean exploration [ 3 , 4 ], marine environment monitoring and protection [ 5 ], disaster rescue, and so on. The majority of biological fish adopt the BCF (body and/or caudal fin) pattern as their primary propulsion mode to realize high-performance locomotion [ 6 ].…”

Section: Introductionmentioning

confidence: 99%

Design and Analysis of a Novel Bionic Tensegrity Robotic Fish with a Continuum Body

Chen,

Wang,

Xiong

et al. 2024

Biological fish exhibit remarkable adaptability and exceptional swimming performance through their powerful and flexible bodies. Therefore, designing a continuum flexible body is significantly important for the development of a robotic fish. However, it is still challenging to replicate these functions of a biological body due to the limitations of actuation and material. In this paper, based on a tensegrity structure, we propose a bionic design scheme for a continuum robotic fish body with a property of stiffness variation. Its detailed structures and actuation principles are also presented. A mathematical model was established to analyze the bending characteristics of the tensegrity structure, which demonstrates the feasibility of mimicking the fish-like oscillation propulsion. Additionally, the stiffness variation mechanism is also exhibited experimentally to validate the effectiveness of the designed tensegrity fish body. Finally, a novel bionic robotic fish design scheme is proposed, integrating an electronic module-equipped fish head, a tensegrity body, and a flexible tail with a caudal fin. Subsequently, a prototype was developed. Extensive experiments were conducted to explore how control parameters and stiffness variation influence swimming velocity and turning performance. The obtained results reveal that the oscillation amplitude, frequency, and stiffness variation of the tensegrity robotic fish play crucial roles in swimming motions. With the stiffness variation, the developed tensegrity robotic fish achieves a maximum swimming velocity of 295 mm/s (0.84 body length per second, BL/s). Moreover, the bionic tensegrity robotic fish also performs a steering motion with a minimum turning radius of 230 mm (0.68 BL) and an angular velocity of 46.6°/s. The conducted studies will shed light on the novel design of a continuum robotic fish equipped with stiffness variation mechanisms.

“…The soft bodies, good flexibility and strong environmental adaptability of marine organisms inspire new ideas for the development of underwater robots [ 12 ]. After a long period of evolution, fish have adapted to exploit the principle of hydrodynamics to move forward using tail fins or pectoral fins [ 13 , 14 , 15 ], which has become the best way to move in water [ 16 , 17 ]. The propulsion method employed by fish can maintain high maneuverability and change posture according to the changing environment.…”

Section: Introductionmentioning

confidence: 99%

Underwater Undulating Propulsion Biomimetic Robots: A Review

Liu

Leng

et al. 2023

The traditional propeller-based propulsion of underwater robots is inefficient and poorly adapted to practice. By contrast, underwater biomimetic robots show better stability and maneuverability in harsh marine environments. This is particularly true of undulating propulsion biomimetic robots. This paper classifies the existing underwater biomimetic robots and outlines their main contributions to the field. The propulsion mechanisms of underwater biomimetic undulating robots are summarized based on theoretical, numerical and experimental studies. Future perspectives on underwater biomimetic undulating robots are also presented, filling the gaps in the existing literature.