UBC Reports | Vol. 49 | No. 9 | Sep.
4, 2003
The future of robots is positively buggy
By Michelle Cook
For all those who’ve ever wanted to be a fly on the
wall, scientists John Madden and Joseph Yan are working to
build low-cost, insect-like robots capable of flying on their
own to do the eavesdropping for you.
The electrical and computer engineering professors paired
up earlier this year for a pilot project to study the feasibility
of using electroactive polymers — high-tech plastics that
can mimic human muscle — in designing robots.
The robosect they envision would resemble a dragonfly in
size and shape, sport two sets of wings, weigh less than a
dime and cost about $1 in materials to make. Equipped with
its own onboard power source and a microconductor for a brain,
it could dart into areas devastated by earthquake to search
for survivors, glide behind enemy lines to do surveillance
work, or conduct power line and other urban inspections. Or
it could simply buzz around the backyard entertaining the
kids.
If it all sounds too sci-fi, Madden and Yan say many of the
technological tools and materials needed to build robosects
already exist. Advanced battery and microtransmitter technologies,
for example, can provide the means to power up and communicate
with such a machine. Researchers in California have gotten
a larger-scale, bird-like robot aloft and, in his previous
work at the University of California, Berkeley, Yan proved
it is possible to generate enough lift with mechanical wings
to get a robot flying.
And then there are the electroactive polymers. These rubber-like
materials expand when a voltage is applied to them, returning
to their original shape when the voltage is cut off. The muscle-like
properties of these materials make them an obvious choice
for the work of imitating biological movements like a dragonfly’s
flapping wings.
“They are capable of doubling their original length,”
says Madden of the newest generation of plastics. “A
human bicep can only contract 20 per cent.”
True, Madden and Yan don’t expect to have any artificial
dragonflies flying around their labs by the end of this project.
But nobody else in the world of robotics research has yet
been able to get an insect-sized robot flying on its own —
and the pair sees that as an open challenge.
“The way we’re hoping to tackle this is to combine
new materials and new actuator technologies — that is, new
methods of getting things to move — that will give us tremendous
advantages in mechanical design and in cost,” says Madden,
who came to UBC last year from MIT.
The pair’s goal isn’t to invent new materials but
to design a cheap robot that could fly by itself. To do this,
they must figure out a way to mimic insect flight.
“It’s one thing to get the robot off the ground
with a wire attached to it and to be able to control it; it’s
another thing to be able to set it free and have it do what
you want,” says Madden.
His job is to assess which of the electroactive polymers
currently available could be used in the mechanical design
of the robosect. The problem is that the range of materials
introduced over the last decade are at different stages of
development and not all their properties are known. Madden
is working to identify these properties and select the best
one for the job.
Yan’s task is to design the robot’s wing mechanism
to match the polymer’s properties so that it can mimic
the dragonfly’s wing motions, and re-create the unsteady
aerodynamics of flapping wings.
Dragonflies and many other insects are able to dart, hover,
move back and forth and even freeze their wings and glide.
Incredible as it may seem, researchers have only recently
begun to understand the mechanics of insect flight.
“One of our big challenges is trying to generate the
correct motions so that the robot will do what we want it
to,” Yan explains. “There have been some breakthroughs
with unsteady aerodynamics, but we’re still at the stage
where simulations aren’t as good as they should be so
we need to copy and measure what the biological organism is
doing.”
So how do you measure a dragonfly’s wing beats?
Yan is using high-speed video camera footage and large-scale
wing models to measure forces acting on the wings.
By the time their pilot project, funded with $35,000 from
the Institute of Robotics and Intelligent Systems (IRIS),
comes to an end in May 2004, Madden and Yan hope to have identified
the most effective electroactive polymer for getting a robotic
dragonfly up in the air.
Assembling a self-propelling seven-centimetre robosect, on
the other hand, is a completely different matter and one best
saved for future research projects.
“To put it together, you need to have micrometer level
resolution in the placement of the parts,” Madden says.
“A typical [human] hair is 100 micrometres in diameter.
We’d need to be able to orient these parts and position
them on about a hundredth of the width of a hair.”
