A team of mechanical engineers at the University of Virginia School of Engineering in collaboration with biologists from Harvard University has developed the first robotic fish that is proven to imitate the speed and movements of live yellowfin tuna.
The research was led by Hillary Bart-Smith, a professor in the UVA Engineering Department of Mechanical and Aerospace Engineering. The robotic tuna was a result of USD 7.2 million multi-disciplinary University Research Initiative awarded by the U.S. Office of Naval Research to study fast and efficient swimming patterns of different species of fish. The project aimed to better understand the physics of fish propulsion. This research could eventually promote the development of the next generation of underwater vehicles, driven by fish-like systems that are better than propellers.
Underwater robots are useful in a range of applications like defense, marine resources exploration, infrastructure inspection, and recreation. Before bio-inspired propulsion systems can become viable for public and commercial use in vehicles, the researchers must understand how fish and other creatures move underwater.
To study the biological mechanics of high-performance swimmers, Harvard biology professor George V. Lauder and his team of researchers measured the swimming dynamics of the yellowfin tuna and mackerel. Using the information, Bart-Smith and her team constructed a robot that not only moved like a fish underwater but managed to reach nearly equivalent speed. The robot named “Tunabot” was then compared to two live specimens.
Tunabot vs. Yellowfin Tuna
The trial run took place in a lab in the Mechanical and Aerospace Building at UVA Engineering, in a flow tank. The eyeless, finless replica fish is 10 inches long, and the biological equivalent can grow up to 7 feet long. A fishing line tether keeps the robot steady and a green laser light cuts across the midline of the robotic fish. The laser measures the fluid motion created by the tail with each sweep. With the current of the water in the flow tank speeding up, the Tunabot’s tail and the whole body moves in a rapid bending pattern, as a yellowfin tuna swims.
According to the researchers, the relationship between biology and robotics is circular. The creation of the robot has been possible due to the successful research and the great interaction between biology and robotics. Each discovery in one branch informs the other, a type of educational feedback loop that is constantly advancing both science and engineering. The researchers aim to focus solely on mechanisms that promote higher performance, higher speed and higher efficiency.