robots 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. This might be one small flap for a robot, but it’s
one giant leap for robot-kind. The team will present its findings May 23
at the International Conference on Robotics and Automation in Brisbane,
slightly heavier than a toothpick
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. Would we ever be able to make them work without needing
a wire?” 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. So
Fuller’s previous robo-insect, the RoboBee, had a leash — it received
power and control through wires from the ground.
But a flying robot should be able to operate on its own. 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.
“It was the most efficient way to quickly transmit a lot of power to
RoboFly without adding much weight,” said co-author Shyam Gollakota, an
associate professor in the UW’s Paul G. Allen School of Computer Science
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
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,” said co-author Vikram Iyer, a doctoral student in the UW
Department of Electrical Engineering. “On RoboFly, it tells the wings
things like ‘flap hard now’ or ‘don’t flap.'”
Specifically, the controller sends voltage in waves to mimic the
fluttering of a real insect’s wings.
“It uses pulses to shape the wave,” said Johannes James, the lead author
and a mechanical engineering doctoral student. “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
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.
While RoboFly is currently powered by a laser beam, future versions
could use tiny batteries or harvest energy from radio frequency signals,
Gollakota said. That way, their power source can be modified for
Future RoboFlies can also look forward to more advanced brains and
sensor systems that help the robots navigate and complete tasks on their
own, Fuller said.
“I’d really like to make one that finds methane leaks,” he said. “You
could buy a suitcase full of them, open it up, and they would fly around
your building looking for plumes of gas coming out of leaky pipes. If
these robots can make it easy to find leaks, they will be much more
likely to be patched up, which will reduce greenhouse emissions. This is
inspired by real flies, which are really good at flying around looking
for smelly things. So we think this is a good application for our
Mechanical engineering doctoral student Yogesh Chukewad is also a
co-author on this paper. This research was funded by the University of
Washington and a Microsoft student fellowship.