The latest RoboBee can fly, swim and explode out of water
Since 2013, Harvard researchers have been developing the RoboBee; a tiny robot bee that started out as a flying bot and learned how to stick to walls last year using static electricity. Now, the tiny machines have learnt to swim.
Researchers have revealed the latest version of RoboBee. Standing at only two centimetres tall, the lightweight machine is 1,000 times lighter than any previous flying and swimming robot.
The new robot is described in a paper in the journal Science Robotics, and the team behind its new design hope it’ll be used in a variety of applications, from search and rescue operations to studying the environment.
“This is the first microrobot capable of repeatedly moving in and through complex environments,” said Dr Yufeng Chen, who was a graduate student in the Microrobotics Lab at SEAS when the research was conducted, and is the 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.”
Because the robot is so tiny, getting over the surface tension of water was a tricky task. The problem was fixed by attaching four floating aids, ‘floaties’, and achamber that converts water into oxyhydrogen.
The chamber helps push the wings out of the water, and the ‘floaties’ keep the robot stable when it is on the surface.
“By modifying the vehicle design, we are now able to lift more than three times the payload of the previous RoboBee,” says Chen. “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 miligrams, about 90mg 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.”
Oxyhydrogen from the water also doubles up as fuel for the robot.
“Because the RoboBee has a limited payload capacity, it cannot carry its own fuel, so we had to come up with a creative solution to exploit resources from the environment,” says Elizabeth Farrell Helbling, graduate student in the Microrobotics Lab and co-author of the paper. “Surface tension is something that we have to overcome to get out of the water, but is also a tool that we can utilize during the gas collection process.”
The robot can’t quite go straight from the water to flying, but this is one of the team’s aims.
“The RoboBee represents a platform where forces are different than what we – at human scale – are used to experiencing,” says Robert Wood, Professor of Engineering and Applied Sciences at Harvard and senior author of the paper. It also had to learn exactly how quickly to flap is wings, the perfect balance between flying through air and dense water.
“While flying the robot feels as if it is treading water; while swimming it feels like it is surrounded by molasses,” said Wood. “The force from surface tension feels like an impenetrable wall. These small robots give us the opportunity to explore these non-intuitive phenomena in a very rich way.”