Tuna-Inspired Experimental Platforms Exploring High-Performance Fish Swimming 825 views

Autonomous underwater vehicles perform a growing variety of missions including exploration, surveillance, and defense. Their conventional designs feature rigid hulls and rotary propellers which contrast the flexible bodies and undulatory tails of fish. As a result, fish exhibit exceptional speed, efficiency, and maneuverability often surpassing that of conventional vehicles. This performance difference motivates the design of vehicles taking inspiration from biology. However, a significant gap in performance exists between such bio-inspired vehicles and the high-performance capabilities of fish. Bio-inspired vehicles typically focus on low-speed locomotion with low tail-beat frequencies. The few systems that do achieve high frequencies often remain limited to low speeds. Consequently, current robotic fish are unable to access the high-frequency, high-speed performance space of fish. Furthermore, the energetic costs of most robotic fish exceed those of fish by orders of magnitude while at a fraction of the speed. Here we design and test robotic fish able to explore the high-performance space of fish with biologically realistic energy efficiencies. Our bio-inspired systems achieve this by modeling the morphology and kinematics of yellowfin tuna (Thunnus albacares), which are open-ocean swimmers with extraordinary speed and endurance. We present five generations of fish robots inspired by tuna and compare our results with data for tuna and a diversity of fish species. These Tunabots are research platforms that improve our understanding of high-performance fish swimming. The fifth generation, Tunabot Flex, demonstrates that body flexibility improves speed and efficiency. Our work provides a new baseline for the development of state-of-the-art underwater vehicles that aim to explore a fish-like, high-performance space and close the gap between robotic systems and fish swimming ability.

PHD (Doctor of Philosophy)

Tunabots; Tunabot Flex; Body Flexibility; Biomimicry; Bio-inspired engineering; Tuna; Swimming performance; Midline kinematics; Energetics; Cost of transport; Efficiency; Fin-fin interactions; Locomotion; Biolocomotion; Bio-inspired underwater vehicle; Autonomous underwater vehicle (AUV); High-performance; Fish robotics; Particle image velocimetry (PIV); Effective angle of attack; Strouhal number; Tail-beat frequency; Stride length; Head and tail-beat amplitudes; Dead-drag force and coefficient; Phase difference of caudal fin; Static thrust; Linear acceleration from rest

English

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2022-12-13