Behold the Cockroach

 

The lowly cockroach has long been vilified as a spreader of disease and a marker of filth and squalor. Most people would rather squash them than invite them to be collaborators. But Chen Li, assistant professor of mechanical engineering, has long taken an opposite stance, housing thousands of these creepy-crawlies in his lab.

Li’s reasoning is simple: The insects have a lot to teach us about movement through complex environments—knowledge that could be pivotal when designing robots to search for victims in the rubble of a collapsed building or to scramble over loose Martian soil.

Most robots developed to navigate through cluttered environments thus far mainly avoid obstacles rather than de

aling with them directly, Li explains. Through a combination of sensors and computer algorithms, devices—like Google’s self-driving car, for example—plan a pathway that allows them to steer clear of anything in their way. But obstacles in the real world aren’t always possible to avoid.

That’s why Li and his colleagues at his Terradynamics Lab are looking to the discoid cockroach, a native of Central America. While scurrying through complex terrain—cluttered with tall grass, leaf litter, rocks, and other impediments—the insects occasionally fall on their backs when trying to surmount a challenging obstacle. How do they get back on their feet to resume their valiant quest?

To find out, Li and his colleagues filmed and watched hours of video of their own discoid cockroaches righting themselves. The researchers observed two different strategies: Energetic cockroaches opened both wings at once, with enough force and by a large enough angle, to push themselves back on their feet. Those that became fatigued after several tries succeeded by asymmetrically opening their wings and rolling themselves upright.

Li’s lab incorporated both strategies into its most recent cockroach-mimicking robotic design, splitting the curved outer shell into two wings that are each controlled by separate motors.

This new research, presented at the 2016 IEEE/RSJ International Conference on Intelligent Robots and Systems in South Korea, was selected as one of only 20 exceptional papers highlighted from more than 800 presentations.

“We still need sensors and computers in robotics,” Li says. “But by learning from these animals, we can design robots to have body shapes or material properties that can deal with the challenges that sensors and computers alone can’t tackle.”

Long-time Facilities Director Tom Simmons marvels at the irony. “I’ve been working for years to keep cockroaches out of our buildings,” he jokes.

 

This article originally appeared in the Summer 2017 edition of JHU Engineering Magazine.