Robotic insect: World's smallest flying robot takes off

Scientists in the US have created a robot
the size of a fly that is able to perform the
agile manoeuvres of the ubiquitous insects.
This "robo-fly", built from carbon fibre,
weighs a fraction of a gram and has super-fast
electronic "muscles" to power its wings.
Its Harvard University developers say tiny
robots like theirs may eventually be used in
rescue operations.
It could, for example, navigate through tiny
spaces in collapsed buildings.
The development is reported in the journal
Science .
Tethered flight: It will take "a few more years"
before the robo-flies will be able to carry a
power source
Dr Kevin Ma from Harvard University and his
team, led by Dr Robert Wood, say they have
made the world's smallest flying robot.
It also has the fly-like agility that allows the
insects to evade even the swiftest of human
efforts to swat them.
This comes largely from very precise wing
movements.
By constantly adjusting the effect of lift and
thrust acting on its body at an incredibly high
speed, the insect's (and the robot's) wings
enable it to hover, or to perform sudden
evasive manoeuvres.
And just like a real fly, the robot's thin,
flexible wings beat approximately 120 times
every second.
The researchers achieved this wing speed with
special substance called piezoelectric material,
which contracts every time a voltage is applied
to it.
By very rapidly switching the voltage on and
off, the scientists were able to make this
material behave like just like the tiny muscles
that makes a fly's wings beat so fast.
"We get it to contract and relax, like biological
muscle," said Dr Ma.
The main goal of this research was to
understand how insect flight works, rather
than to build a useful robot.
He added though that there could be many
uses for such a diminutive flying vehicle.
"We could envision these robots being used
for search-and-rescue operations to search for
human survivors under collapsed buildings or
[in] other hazardous environments," he said.
"They [could] be used for environmental
monitoring, to be dispersed into a habitat to
sense trace chemicals or other factors.
Dr Ma even suggested that the robots could
behave like many real insects and assist with
the pollination of crops, "to function as the
now-struggling honeybee populations do in
supporting agriculture around the world".
The current model of robo-fly is tethered to a
small, off-board power source but Dr Ma says
the next step will be to miniaturise the other
bits of technology that will be needed to create
a "fully wireless flying robot".
"It will be a few more years before full
integration is possible," he said.
"Until then, this research project continues to
be very captivating work because of its
similarity to natural insects. It is a
demonstration of how far human engineering
ingenuity has reached, to be mimicking natural
systems."
Dr Jon Dyhr, a biologist from the University of
Washington who also studies insect flight, said
these flying robots were "impressive feats of
engineering".
"The physics of flight at such small scales is
relatively poorly understood which makes
designing small flying systems very difficult,"
he told BBC News, adding that biological
systems provided "critical insights into
designing our own artificial flyers".