VIDEO: AQUATIC TINY-FLYING ROBOT
Rewind to 2013, Harvard's diminutive RoboBee became the world's first insect-sized winged robot to demonstrate controlled flight. Fastword to a couple of years later, it morphed into a diving robot that can swim by flapping its wings. The only problem was, it could not get back out of the water. Well, thanks to a "spark" of innovation, now it can.
It weighs just 80 milligrams, the previous version of RoboBee was so light that it had trouble breaking the surface tension of the water, in order to go underwater. The issue was solved by just shutting off its power as it hovered above the water – the power came from an external source by way of a wire tether – and allowing it to plummet down and crash through the surface.
The RoboBee can also break free of the surface when it tries to fly out of the water, thanks to four buoyant outriggers and a central gas collection chamber. The chamber provides enough flotation that the wings are pushed above the surface, at which point the outriggers provide stability.
Having the wings out of the water still isn't enough, though. Once the RoboBee surfaces, electrolytic plates in the chamber convert collected water into combustible oxyhydrogen gas. A sparker inside the chamber then ignites the gas, propelling the robot up off of the water. Unfortunately, it can't resume sustained flight once it gets back in the air – at least not yet – although it is designed to stabilize itself, so that it will land on its feet when it comes back down.
"By modifying the vehicle design, we are now able to lift more than three times the payload of the previous RoboBee," says Yufeng Chen, first author of a paper on the research. "This additional payload capacity allowed us to carry the additional devices including the gas chamber, the electrolytic plates, sparker, and buoyant outriggers, bringing the total weight of the hybrid robot to 175 milligrams, about 90 mg heavier than previous designs. We hope that our work investigating tradeoffs like weight and surface tension can inspire future multi-functional microrobots – ones that can move on complex terrains and perform a variety of tasks."
You can see the latest version of RoboBee in action in the video below: