Insects may seem like mere pests, but their physical abilities are still beyond even the most sophisticated robots. Engineers at the University of Washington have taken important first steps towards filling that gap by creating a robotic fly that has taken its first independent flaps.
With the right size and speed, robotic insects could do anything from surveying crop growth to inspecting pipes for microscopic leaks. But the electronics needed for this type of sophisticated device have kept robotic insects tethered or weighed down.
“Before now, the concept of wireless insect-sized flying robots was science fiction. Would we ever be able to make them work without needing a wire? Our new wireless RoboFly shows they’re much closer to real life,” says co-author , an assistant professor in the UW Department of Mechanical Engineering in a .
From an engineering standpoint, the greatest difficulty for Fuller's team was flapping wings. If you've ever tried moving your arms up and down rapidly, it's easy to see what a power-draining process flapping can be. Power sources and controllers are too bulky to fit into the fly. It's a fact that kept Fuller's previous device, a robotic bee, tethered to its power source.
The team used a two-pronged approach: lasers and photovoltaic cells. Pointing a narrow invisible laser beam at a photovoltaic cell attached above the RoboFly, Fuller's team then let the cell convert the laser light into energy. On top of that, a custom-built circuit boosts the seven volts coming from the photovoltaic cell to the 240 volts required for flight.
"It was the most efficient way to quickly transmit a lot of power to RoboFly without adding much weight,” says co-author .
In terms of control, a microcontroller acts as the RoboFly's brain. The controller sends the voltage collected in waves to the robot's wings, imitating how a real fly operates.
“It uses pulses to shape the waves. To make the wings flap forward swiftly, it sends a series of pulses in rapid succession and then slows the pulsing down as you get near the top of the wave. And then it does this in reverse to make the wings flap smoothly in the other direction,' says , the lead author and a mechanical engineering doctoral student.
For all of its advances, the RoboFly can currently only takeoff and land. The next steps will involve steering the laser so the RoboFly can stretch its wings a bit and move around.