The Tunabot, a tuna-like experimental robotic platform, provides insights into the dynamics of high-performance aquatic locomotion.

Fish maintain high swimming efficiencies over a wide range of speeds. A key to this achievement is their flexibility, yet even flexible robotic fish trail real in terms performance. Here, we explore how leverage tunable flexibility by using muscles modulate the stiffness tails achieve efficient swimming. We derived model that explains and why tuning affects show maximize efficiency, muscle tension should scale with speed squared, offering simple strategy for fish-like robots. Tuning can...

The manta is the largest marine organism to swim by dorsoventral oscillation (flapping) of pectoral fins. has been considered with a high efficiency stroke, but this assertion not previously examined. oscillatory swimming strokes were examined detailing kinematics fin movements over range speeds and analyzing simulations based on computational fluid dynamic potential flow viscous models. These analyses showed that are asymmetrical up- downstrokes both spanwise chordwise waves interposed into...

Abstract Tunas are flexible, high-performance open ocean swimmers that operate at high frequencies to achieve swimming speeds. Most fish-like robotic systems low (≤3 Hz) resulting in swim speeds (≤1.5 body lengths per second), and the cost of transport (COT) is often one four orders magnitude higher than tunas. Furthermore, impact flexibility on fish remains unknown. Here we design test a research platform based yellowfin tuna ( Thunnus albacares ) investigate role close performance gap...

The manta ray (Manta birostris) is the largest species of rays that demonstrates excellent swimming capabilities via large-amplitude flapping its pectoral fins. In this article, we present a bio-inspired robotic using ionic polymer–metal composite (IPMC) as artificial muscles to mimic behavior ray. robot utilizes two fins generate undulatory motions, which produce thrust for robot. Each fin consists an IPMC muscle in leading edge and passive polydimethylsiloxane membrane trailing edge. When...

Rhythmic motion employed in animal locomotion is ultimately controlled by neuronal circuits known as central pattern generators (CPGs). It appears that these controllers produce efficient, oscillatory command signals entraining to an efficient or economic gait via sensory feedback. This property of great interest the control autonomous vehicles. The objective this study experimentally validate synthesized CPG a tensegrity swimmer. prestressed cables structure provide method simultaneous...

This paper describes a computational study of the hydrodynamics ray-inspired underwater vehicle conducted concurrently with experimental measurements. High-resolution stereo-videos vehicle's fin motions during steady swimming are obtained and used as foundation for developing high fidelity geometrical model oscillatory fin. A Cartesian grid based immersed boundary solver is to examine flow fields produced due these complex artificial pectoral kinematics. Simulations carried out at smaller...

For aquatic animals, turning maneuvers represent a locomotor activity that may not be confined to single coordinate plane, making analysis difficult particularly in the field. To measure performance three-dimensional space for manta ray (Mobula birostris), large open-water swimmer, scaled stereo video recordings were collected. Movements of cephalic lobes, eye and tail base tracked obtain coordinates. A mathematical was performed on data calculate rate curvature (1/turning radius) as...

Abstract For millions of years, aquatic species have utilized the principles unsteady hydrodynamics for propulsion and maneuvering. They evolved high-endurance swimming that can outperform current underwater vehicle technology in areas stealth, maneuverability control authority. Batoid fishes, including manta ray, Manta birostris , cownose Rhinoptera bonasus Atlantic stingray, Dasyatis sabina been identified as a high-performing due to their ability migrate long distances, maneuver spaces...

Abstract Mobuliform swimmers are inspiring novel approaches to the design of underwater vehicles. These swimmers, exemplified by manta rays, present a model for new classes efficient, highly maneuverable, autonomous undersea To improve our understanding unsteady propulsion mechanisms used these we report detailed studies performance robotic that mimic aspects animal propulsive mechanisms. We highlight importance undulatory aspect producing efficient ray and show there is strong interaction...

Growing interest in the development of bio-inspired autonomous underwater vehicles (AUVs) has motivated research understanding mechanisms behind propulsion systems marine animals. For example, locomotive behavior rays (Batoidea) by movement pectoral fins is particular due to their superior performance characteristics over contemporary AUV systems. To better understand mechanics fin propulsion, this paper introduces a biomechanical model that simulates how batoid skeletal structures function...

Scaling laws for the thrust production and energetics of self-propelled or fixed-velocity three-dimensional rigid propulsors undergoing pitching motions are presented. The scaling relations extend two-dimensional presented in Moored & Quinn (2018) by accounting added mass a finite-span propulsor, downwash/upwash effects from trailing vortex system elliptical topology shedding trailing-edge vortices. novel validated with inviscid simulations experiments over range reduced frequencies,...

Abstract Large, pelagic rays (family Myliobatidae) that swim by flapping movements of wing-like pectoral fins use the mobuliform mode swimming. These have with a triangular planform and streamlined cross-sectional geometry would minimize drag. Thrust is produced vertical oscillations spanwise chordwise flexibility. The thrust derived from lift generated fins. Speed modulated changes in oscillatory frequency, whereas amplitude heave remains relatively constant speed. Mobuliform swimming...

Current attempts to build fast, efficient, and maneuverable underwater vehicles have looked nature for inspiration. However, they all been based on traditional propulsive techniques, i.e., rotary motors. In the current study a promising potentially revolutionary approach is taken that overcomes limitations of these methods—morphing structure concepts with integrated actuation sensing. Inspiration this work comes from manta ray (Manta birostris) other batoid fish. These creatures are highly...

In fish, the tail is a key element of propulsive anatomy that contributes to thrust during swimming. Fish possess ability alter stiffness, surface area and conformation. Specifically, region at base tail, caudal peduncle, proposed be location fish stiffness modulation locomotion. Most previous analyses have focused on overall body or not effects changing specifically in robotic models. We used both computational fluid dynamics analysis experimental measurements forces physical models with...