New flapping robot swims and flies like a diving bird

Amazing stuff!

"Loons, gulls, puffins, and petrels are some of the 100 species of birds that can both fly and swim. These diving birds can plunge in water to swim after prey, and leap back into the air to fly away. 

Inspired by these naturally aquatic aviators, engineers ... have designed a robot that can swim underwater, then flap out of the water to continue flying through air, much like diving birds. 

The “flapping-wing aerial-aquatic vehicle,” or FAAV, weighs less than 300 grams (about half a pound) and is designed to help scientists study the mechanics that enable diving birds to fly through air and water.  ..."

From the editor's summary and abstract:

"Editor’s summary

Diving birds transition between flying through air and navigating through water by flapping, but the mechanisms by which different species try to do this efficiently is challenging to study. Zufferey et al. developed a flapping-wing robot that can fly in the air and transition to, provide thrust under, and take off from water. The authors found that flight in air requires a higher-frequency wingbeat, and that larger wings do not increase power demands underwater. Performance was evaluated across wing sizes, flapping frequencies, and egression angles in both indoor and outdoor settings. Comparisons showed where various bird species have overlapping behavior and where differences in weight and mechanics affect overall motion. ...

Abstract

Wing-propelled diving birds flap their wings to move through air and water, yet the wing morphology and kinematics that enable this behavior remain poorly understood because of the difficulty of collecting in situ data.

The impact of flapping frequency, wing size, and stiffness on locomotion in—and transition between—the two media are still unknown.

We compared data from diving birds against experiments using a flapping-wing robot capable of flying, swimming, plunge diving, and exiting the water. We show that frequency adaptation, flexible wings, and powerful actuation enable seamless transitions without folding wings or legs, that large wings enhance flight without substantially reducing underwater efficiency, and that tail-body distance and egress angle affect water exit. These results clarify how birds (and robots) balance multifluid locomotion constraints."

New flapping robot swims and flies like a diving bird | MIT News | Massachusetts Institute of Technology "MIT engineers’ design could lead to a new class of aerial-aquatic vehicles for ocean exploration."

A flapping robot swims and flies like a diving bird (original news release by EPFL) "An aerial-aquatic vehicle developed at EPFL and MIT could lead to a new class of devices for ocean exploration."

Leaping out of the water: Aerial-aquatic locomotion with flapping wings (no public access, but this link provides access to the PDF file)