Cockroach research may provide engineers with the key to search-and-rescue robots that will be more capable of operating in challenging uneven or rocky terrain.

The research team -- led by Shai Revzen, an electrical engineering, computer science, ecology and evolutionary biology professor at the University of Michigan -- revealed that when running cockroaches are shoved sideways, they start to recover their balance and movement before their nervous system directs a response from their legs.

'The animals obviously have much better mechanical designs than anything we know how to build.'

— University of Michigan professor Shai Revzen

By understanding cockroach movement patterns, the team believes it could improve how machines and their “neurology” work together.

“The fundamental question is, ‘What can you do with a mechanical suspension versus one that requires electronic feedback?’ The animals obviously have much better mechanical designs than anything we know how to build,” Revzen wrote in Biological Cybernetics.

“But if we could learn how they do it, we might be able to reproduce it.”

Approximately 70 percent of Earth’s land surface cannot be traveled using the wheeled or tracked vehicles. Revezen believes a legged approach may open up operations in this terrain.

In 41 trials, his team used a squad of 15 cockroaches running one by one across a small bridge onto a placemat-sized cart. The cart was pulled back, like a slingshot. As the roach ran they unleashed the cart, which hurtled toward the cockroach and slammed it sideways to destabilize it.

“The force was equivalent to a sumo wrestler hitting a jogger with a flying tackle … [but] cockroaches are much more stable than humans,” Rezven said.

In the team’s experiments, the roaches maintained their footing by using their momentum and the biomechanics of their legs. If the cockroaches relied on impulses from their central nervous system instead, it took three times longer than the researchers expected.

“What we see is that the animals’ nervous system is working at a substantial delay… for some reason, the nervous system is waiting and seeing how it shapes out,” Rezven said.

The results of these experiments may mean brains adapt their gait only at a “whole-step interval” rather than at any point in between steps.

In robotics, a computer often guides the machine’s movements by providing continuous feedback from feet sensors.

Rather than using a continuous feedback approach, their research suggests bi-pedal robots may benefit from more stability while using less energy by capitalizing on a periodic feedback approach like cockroaches to execute walking.