20 Propulsive efficiency under water is one of many areas in which nature has had the advantage of hundreds of millions of years of evolution to hone the design of its creatures. Large pelagic fish such as tuna and sharks, and cetaceans such as whales and dolphins, outperform all human made underwater vehicles that aren’t nuclear powered in terms of speed, range and endurance despite having far less power available to them. Dr David Barrett of Olin College of Engineering, in Massachusetts, has dedicated much of his working life to figuring out how the animals do this and creating robotic vehicles that can replicate their feats. He is perhaps best known for his robotic tuna. “I am a biomimetic roboticist, so I copy nature,” he says. One of his more ambitious aims is to create technology that will allow humanity to understand the ocean well enough to stave off climate breakdown. Seeking warp drive It was as a graduate student at MIT’s Department of Ocean Engineering in the first half of the 1990s that his involvement with robots that move like fish began. Here he met Professor Michael S Triantafyllou, who was interested in the fluid mechanics of Gray’s paradox. “Gray’s paradox is basically that Peter Donaldson talks to this marine robotics expert about what we can learn from nature about efficient underwater propulsion Swimming lessons June/July 2023 | Uncrewed Systems Technology Like tuna and many sharks, Dr Barrett’s robot tuna use thunniform locomotion, in which most sideways movement is in the tail and the region that connects the tail to the main body (Images courtesy of Olin College)
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