Scientists have created “Tunabot” – the first robotic fish which matches the speed and motion of the yellowfin tuna.
Tuna are extremely strong swimmers, with yellowfin tuna reaching speeds of over 46 mph.
Tunabot is part of a project to better understand the physics of fish propulsion – research that could eventually inform development of the next generation of underwater vehicles, driven by fish-like systems better than propellers.
The team first needed to study the biological mechanics of high-performance swimmers. Harvard biology professor George V. Lauder and his team of researchers precisely measured the swimming dynamics of yellowfin tuna and mackerel. Using that data, Professor Hilary Bart-Smith and her team, research scientist Jianzhong “Joe” Zhu and Ph.D. student Carl White, constructed a robot that not only moved like a fish underwater, but beat its tail fast enough to reach nearly equivalent speeds.
The tests of Tunabot take place in a large lab in the Mechanical Engineering building at University of Virginia Engineering, in a flow tank that takes up about a quarter of the room: Harvard University had a similar facility. The eyeless, finless replica fish is roughly 10 inches long; the biological equivalent can get up to seven feet long. A fishing line tether keeps the robot steady, while a green laser light cuts across the midline of the plastic fish. The laser measures the fluid motion shed by the robot with each sweep of its fabricated tail. As the current of water in the flow tank speeds up, the Tunabot’s tail and whole body move in a rapid bending pattern, similar to the way a live yellowfin tuna swims.
Tuna robotics: A high-frequency experimental platform exploring the performance space of swimming fishes J. Zhu1, C. White1, D. K. Wainwright2, V. Di Santo2, G. V. Lauder2 and H. Bart-Smith1. Science Robotics 18 Sep 2019: Vol. 4, Issue 34, eaax4615 DOI: 10.1126/scirobotics.aax4615