Mechanical engineers at the University of Virginia School of Engineering, who lead a collaboration with biologists from Harvard University, have created the first robotic fish that has been shown to mimic the speed and movements of live yellowfin tuna.
Their scientific review paper, "Tun Robotics: A High Frequency Experimental Platform Exploring the Performance of Swimming Fish," was published September 1
Led by Hilary Bart-Smith, professor in UVA Engineering's Department of Mechanical and Aerospace Engineering, the Robot Fish Project was born of a five-year, $ 7.2 million multidisciplinary university research initiative. The US Office of Naval Research assigned Bart-Smith to study the fast, efficient swimming of different fish. The aim of Bart-Smith's project is to better understand the physics of fish propulsion, research that may eventually inform the development of the next generation of underwater vehicles, which are driven by fish-like systems better than propellers.
Underwater robots are also useful in a variety of applications, such as defense, marine resource exploration, infrastructure inspection, and recreation.
However, before bio-inspired propulsion systems can become viable for public and commercial use in manned and unmanned vehicles, scientists must be able to reliably understand how fish and other creatures move through water.
"Our goal was not just to build a robot. We really wanted to understand the science of biological swimming," said Bart-Smith. "Our goal was to build something that we could test hypotheses about to make biological swimmers so fast and effective."
The team first needed to study the biological mechanics of high performance swimmers. Harvard biology professor George V. Lauder and his research team measured the exact swimming dynamics of yellowfin tuna and mackerel. Using this information, Bart-Smith and her team, researchers Jianzhong "Joe" Zhu and Ph.D. student Carl White, designed a robot that not only moved like a fish underwater but struck its tail fast enough to achieve nearly equivalent speeds.
They then compared the robot they called "Tunabot" to living specimens.
"There are many papers on fish robots, but most of them do not have much biological data in them. So I think this document is unique in the quality of both the robot work and the biological information that married into a paper, "Said Lauder.
" What is so "The great thing about the results we present in the paper is the similarities between biology and the robot platform, not only in terms of swimming kinematics, but also in terms of the relationship between speed and tail frequency and energy performance," said Bart-Smith. "These comparisons give us confidence in our platform and its ability to help us understand more about the physics of biological swimming."
The team's work is based on UVA Engineering's strengths in autonomous systems. The Department of Mechanical Engineering and Aerospace Engineering participates in UVA Engineering's Link Lab for cyber-physical systems, which focuses on smart cities, smart health and autonomous systems, including autonomous vehicles.
The Tunabot Project is an outgrowth of Bart-Smith's second, highly competitive multidisciplinary university research initiative from the Office of Naval Research; In 2008, Bart-Smith received a $ 6.5 million prize for developing an underwater robot modeled on a manta ray.
The test of Tunabot takes place in a large lab in the mechanical and space engineering building at UVA Engineering, in a flow tank that takes up about a quarter of the room, and at Harvard University in a similar facility. The eyeless, finless replica fish is about 10 inches long; the biological equivalent can be up to seven feet long. A fishing line bracket keeps the robot stable while a green laser light cuts across the centerline of the plastic fish. The laser measures the fluid movement of the robot with each sweep of its manufactured tail. As the flow of water in the flow tank speeds up, Tunabot's tail and entire body move in a rapid bending pattern, similar to that of a live yellow fine tuna swimming.
"We see in the fish robotics literature so far that it is really good system that others have done, but the tasks are often inconsistent in terms of choice of measurement and presentation. This is only the current state of the robot field at the moment. Our paper on Tunabot is important because our extensive performance data sets the field very high, "White said.
The relationship between biology and robotics is circular, Lauder said. "One reason I think we have a successful research program in this area is because of the great interaction between biologists and roboticists." Each discovery in one branch informs the other, a type of educational feedback loop that constantly promotes both science and technology.
"We don't suppose biology has evolved into the best solution," Bart-Smith said. "These fish have had a long time to develop into a solution that allows them to survive, specifically, to eat, reproduce and not eat. If we are not limited by these requirements, we can only focus on mechanisms and functions that promotes higher performance, higher speed, higher efficiency. Our ultimate goal is to surpass biology. How can we build something that looks like biology but swims faster than everything you see out there in the ocean? "
Engineers design and build mechanical beam (w / Video)
J. Zhu el al., "Tuna Robotics: A High Frequency Experimental Platform Exploring the Performance of Swimming Fish," Science Robotics (2019). robotics.sciencemag.org/lookup … /scirobotics.aax4615
University of Virginia School of Engineering and Applied Science
Research team unveils "Tunabot", the first robot fish to keep up with tuna (2019, September 18)
retrieved September 19, 2019
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