UBC Reports | Vol. 49 | No. 9 | Sep. 4, 2003

Robo-Fly

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.”