Image: Pornthip Pongpakpatporn/Shutterstock
In a somewhat terrifying but beneficial development in drone technology, researchers at Harvard reveal the latest generation of RoboBee.
Picture a drone that can fly, stick to walls, propel itself out of water and safely land at a moment’s notice, yet can fit comfortably in the palm of your hand.
This isn’t the description of a terrifying robot from a dystopian future, but the latest generation of the RoboBee drone developed by researchers at the Harvard John A Paulson School of Engineering and Applied Sciences, and the Wyss Institute for Biologically Inspired Engineering.
In a paper published to Science Robotics, the researchers revealed that the new generation of RoboBee is 1,000 times lighter than any previous aerial-to-aquatic robot and could be used for numerous applications, from search-and-rescue operations to environmental monitoring and biological studies.
Beyond what nature can achieve
Thanks to advances in the science of flotation, this multipurpose air-water microrobot can stabilise on the water’s surface before an internal combustion system ignites to propel it back into the air.
“This is the first microrobot capable of repeatedly moving in and through complex environments,” said Yufeng Chen, first author of the paper.
“We designed new mechanisms that allow the vehicle to directly transition from water to air, something that is beyond what nature can achieve in the insect world.”
The latest version of RoboBee. Image: Yufeng Chen/Harvard SEAS
Designing such a robot at a small scale was no easy feat – because water is 1,000 times denser than air, the wing flapping speed varies widely between the two mediums.
This means that if the flapping frequency is too low, the RoboBee can’t fly; if it is too high, the wing will snap off in water.
To solve this challenge, the Harvard team was able to find a ‘Goldilocks’ combination of wing size and flapping rate by combining theoretical modelling and experimental data.
This resulted in the RoboBee being able to flaps its wings at 220 to 300Hz in air, and nine to 13Hz in water.
Another issue to solve was how the RoboBee would be able to exit water without its surface tension – 10 times the weight of the drone and three times its maximum lift – which would crush it like something hitting a brick wall.
The answer was in attaching the nanobot with four buoyant outriggers and a central gas collection chamber that contains an electrolytic plate. When the RoboBee swims to the surface, this plate converts water into oxyhydrogen, thereby blasting it to freedom.
Speaking of its future, Chen said: “We hope that our work investigating trade-offs like weight and surface tension can inspire future multifunctional microrobots – ones that can move on complex terrains and perform a variety of tasks.”
