What can a robot learn from a flightless bird? Lots, it turns out.

A team of scientists studied five species of ground-running bird and found that, large or small, they all traverse terrain in the same way. Their gait will act as a model for the design of running robots.

Jim Usherwood/Royal Veterinary College
A team of scientists from Oregon State University and the Royal Veterinary College studied five species of ground-running bird to better understand their running gaits. They discovered that larger birds such as the ostrich demonstrated the same strategies when crossing terrain as smaller species like the pheasant.

Picture a robot version of the Road Runner.

That's what researchers at Oregon State University are aiming for, and they've found that the best real-­life models for running robots may be birds. The research team worked with scientists from the Royal Veterinary College, studied the movements of ground­-running bird species and uncovered why these not-so-graceful bipeds are impressively efficient when darting from one place to another.

Scientists already understood the basic locomotion of legged animals: the larger an animal gets, the more it tends to run with straighter legs in an attempt to compensate for the increased demand for lower body strength. By contrast, smaller animals tend to crouch more.

Researchers thought that in the case of birds, this scaling effect for posture would also be the case for navigation strategies on uneven terrain. The more compact ones would be better equipped to handle disturbances in their running paths, they reasoned, because their crouched postures would naturally prioritize stability. Bigger birds would focus less on stability and more on keeping internal forces low to ease stress on leg muscles.

The researchers looked at five different species of birds, including bobwhite quails, turkeys, and ostriches. From there, they developed computer models that replicated the behavior of the winged bipeds and found that their hypothesis was incorrect. Despite the large variations in the birds’ body shapes and sizes, their running methods were all quite similar.

"This is a big deal, because it means we've discovered something that is fundamental," Jonathan Hurst, OSU Associate Professor, told the Monitor.

The research group thought that body stability – in the way that we typically define the word – would be a top priority for these birds, but it turned out that this wasn't the case. While they did find that remaining upright is pertinent to their running, they saw that the birds allow their bodies to jostle a bit when sprinting, ­hence their looking somewhat gawky to humans. This apparent lack of coordination turns out to be quite functional.

"They aim not to fall,” says Dr. Hurst. “They aim to limit the peak forces in their muscles and legs - avoid injury.”

And, according to Hurst, it's okay if their upper bodies lurch here and there in the process.

Hurst and his colleagues found that this universal behavior among ground-­running birds consists of about 70 percent vaulting and 30 percent crouching. This combination helps to minimize energy costs and reduce the likelihood a bird will hurt itself.

Scientists have typically built robots with an emphasis on a stable gait. But now with an understanding that more unsteady movements can actually be more energy efficient, Hurst and his team, which includes co­-author and OSU doctoral student Christian Hubicki, can attempt to replicate the birds' movements in running robots.

"We should ultimately be able to encode this understanding into legged robots so the robots can run with more speed and agility in rugged terrain," Hubicki said in a release.

The range of possible applications for running robots with ostrich-­like abilities is wide: from search-­and-­rescue missions in burning buildings to powered prosthetics for amputees.

Because all birds are descended from dinosaurs, these land-loving birds may have been evolving their running gaits for a few hundred million years. And it is something quite natural for these birds that scientists will now use to set a new standard for future robot design: a more relaxed definition of stability.

"What they are accomplishing is really quite elegant," said Hurst in a release.

The study’s findings were published last week in the journal Experimental Biology.

You've read  of  free articles. Subscribe to continue.

Dear Reader,

About a year ago, I happened upon this statement about the Monitor in the Harvard Business Review – under the charming heading of “do things that don’t interest you”:

“Many things that end up” being meaningful, writes social scientist Joseph Grenny, “have come from conference workshops, articles, or online videos that began as a chore and ended with an insight. My work in Kenya, for example, was heavily influenced by a Christian Science Monitor article I had forced myself to read 10 years earlier. Sometimes, we call things ‘boring’ simply because they lie outside the box we are currently in.”

If you were to come up with a punchline to a joke about the Monitor, that would probably be it. We’re seen as being global, fair, insightful, and perhaps a bit too earnest. We’re the bran muffin of journalism.

But you know what? We change lives. And I’m going to argue that we change lives precisely because we force open that too-small box that most human beings think they live in.

The Monitor is a peculiar little publication that’s hard for the world to figure out. We’re run by a church, but we’re not only for church members and we’re not about converting people. We’re known as being fair even as the world becomes as polarized as at any time since the newspaper’s founding in 1908.

We have a mission beyond circulation, we want to bridge divides. We’re about kicking down the door of thought everywhere and saying, “You are bigger and more capable than you realize. And we can prove it.”

If you’re looking for bran muffin journalism, you can subscribe to the Monitor for $15. You’ll get the Monitor Weekly magazine, the Monitor Daily email, and unlimited access to CSMonitor.com.