Researchers at Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and the Wyss Institute for Biologically-Inspired Engineering at Harvard have developed a robot that can fly, dive in and out of water, and land safely. This is the first microrobot capable of repeatedly moving in and through complex environments. The robot is 1,000 times lighter than any previous aerial-to-aquatic robot, and is an early prototype for performing search and rescue missions, research studies and environmental monitoring.

Getting out of the water has been a challenge for robots with such light weight and small size as the force from surface tension feels like an impenetrable wall. To solve this problem, researchers outfitted the robot with a tiny combustible rocket, giving it the power needed to break the water’s surface tension. A pair of tiny electrolytic plates converts water into oxyhydrogen, a combustible gas fuel, and the gas fills a chamber in the robot’s interior which is lit by an internal sparker.

The setting of a wingbeat frequency under different environments was another challenge. Given that water is 1,000 times denser than air, the wing flapping speed must vary widely to make sure the robot wings can both fly in air and not snap off in the water. By combining theoretical modeling and experimental data, the researchers scaled the design to allow the robot to operate repeatedly in air and water at two different wing-flapping speeds.

There are some anticipated advancements from the research team on the robot's design. The robot cannot yet fly immediately upon propulsion out of water due to the lack of onboard sensors and limitations in the current motion-tracking system. The team aims to enhance that area in future research.

Click here to see how the robot can fly, swim and take off from water.