First Untethered Insect-Sized Flying Robot Developed

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An insect-sized flying robot could help with time-consuming tasks like surveying crop growth on large farms or sniffing out gas leaks. These robots soar by fluttering tiny wings because they are too small to use propellers, like those seen on their larger drone cousins. Small size is advantageous: These robots are cheap to make and can easily slip into tight places that are inaccessible to big drones.

But current flying robo-insects are still tethered to the ground. The electronics they need to power and control their wings are too heavy for these miniature robots to carry.

Now, engineers at the University of Washington have for the first time cut the cord and added a brain, allowing their RoboFly to take its first independent flaps.

RoboFly is slightly heavier than a toothpick and is powered by a laser beam. It uses a tiny onboard circuit that converts the laser energy into enough electricity to operate its wings.

“Before now, the concept of wireless insect-sized flying robots was science fiction” said co-author Sawyer Fuller, an assistant professor in the UW Department of Mechanical Engineering. “Our new wireless RoboFly shows they’re much closer to real life.”

The engineering challenge is the flapping. Wing flapping is a power-hungry process, and both the power source and the controller that directs the wings are too big and bulky to ride aboard a tiny robot. Fuller and team decided to use a narrow invisible laser beam to power their robot. They pointed the laser beam at a photovoltaic cell, which is attached above RoboFly and converts the laser light into electricity.

Still, the laser alone does not provide enough voltage to move the wings. That’s why the team designed a circuit that boosted the seven volts coming out of the photovoltaic cell up to the 240 volts needed for flight.

To give RoboFly control over its own wings, the engineers provided a brain: They added a microcontroller to the same circuit. The microcontroller acts like a real fly’s brain telling wing muscles when to fire. Specifically, the controller sends voltage in waves to mimic the fluttering of a real insect’s wings.

Johannes James, the lead author and a mechanical engineering doctoral student, said: “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.”

For now, RoboFly can only take off and land. Once its photovoltaic cell is out of the direct line of sight of the laser, the robot runs out of power and lands. But the team hopes to soon be able to steer the laser so that RoboFly can hover and fly around. Future versions could use tiny batteries or harvest energy from radio frequency signals.