Autonomous glider flies like an albatross and cruises like a sailboat

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MIT engineers have designed a robotic glider that can skim along the water’s surface, riding the wind like an albatross while also surfing the waves like a sailboat.

In high wind, the robot is designed to stay aloft, much like its avian counterpart. Where there are calmer winds, the robot can dip a keel into the water to ride like a highly efficient sailboat instead.

The lightweight robotic system is claimed to cover a given distance using one-third as much wind as an albatross and traveling 10 times faster than a typical sailboat. The researchers hope that soon, such compact, speedy robotic water-skimmers may be deployed in teams to survey large swaths of the ocean.

“The oceans remain vastly undermonitored,” says Gabriel Bousquet, who led the design of the robot as part of his graduate thesis. “In particular, it’s very important to understand the Southern Ocean and how it is interacting with climate change. But it’s very hard to get there. We can now use the energy from the environment in an efficient way to do this long-distance travel, with a system that remains small-scale.”

His team designed for the hybrid vehicle, which features a 3-meter wingspan and weighting less than 3kg, added a tall, triangular sail, and a slender, wing-like keel.

According to the team’s calculations through mathematical modelling, the wind-powered vehicle would only need relatively calm winds of about 5 knots to travel at a velocity of about 20 knots (23mph).

The team built a prototype of its design, using a glider airframe designed by Mark Drela, professor of aeronautics and astronautics at MIT. To the bottom of the glider they added a keel, along with various instruments, such as GPS, inertial measurement sensors, auto-pilot instrumentation, and ultrasound, to track the height of the glider above the water.

Bousquet says: “The goal here was to show we can control very precisely how high we are above the water, and that we can have the robot fly above the water, then down to where the keel can go under the water to generate a force, and the plane can still fly.”

Eventually, Bousquet envisions fleets of such vehicles autonomously and efficiently monitoring large expanses of the ocean.