MIT engineers create new school of robotic fish

MIT researcher Pablo Valdivia Alvarado works in his lab on a robotic fish he co-created.
Schools of robotic fish could one day map the ocean floor, detect pollution or inspect and survey submerged boats or oil and gas pipelines, researchers at the Massachusetts Institute of Technology say.

MIT engineers are showing off the latest generation of so-called robofish 15 years after they built the first one. The latest incarnation is sleeker, more streamlined and capable of mimicking the movements of a real fish. And it’s capable of exploring underwater terrain submersibles can’t, said Pablo Valdivia Alvarado, a mechanical engineer at the school. “Some of our sponsors were thinking of using them for inspection and surveillance,” Alvarado said. “Since these prototypes are very cheap, the idea was to build hundreds — 200, 500 — and then just release them in a bay or at a port, and they would be roaming around taking measurements.” MIT researchers built their first robotic fish, “Robotuna,” in 1994. But Robotuna has gone the way of the dinosaur. Alvarado said the new generation — modeled after bass and trout — cost only a few hundred dollars and have only 10 parts instead of the thousands used in Robotuna.

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At five to 18 inches, the new fish is much smaller than Robotuna and built from a single, soft polymer. And unlike Robotuna, the fish is able to be released in the oceans. “Most of the brains, the electronics, are embedded inside,” said Alvarado, who designed the robofish with fellow MIT engineer Kamal Youcef-Toumi. “We have built prototypes with the battery inside, but for my experiments, for simplicity. We have a lot of prototypes that are simply tethered. We have a cable that runs out from the body and connects to a power supply.” The new generation has withstood harsh conditions in the lab, including two years of testing inside tanks filled with tap water, which is corrosive to standard robots, according to Alvarado, who says the Robotuna inspired him to take the technology to the next level. The oil exploration company Schlumberger helped fund the research, but Alvarado says the U.S. Navy has also expressed interest in the robofish. MIT’s mechanical engineers are now turning their attention to new challenges: A robotic manta ray and a terrestrial robot in the form of a salamander.