Whether you love them or hate them, cockroaches are masters of their environment, capable of climbing walls, navigating uneven terrain, and flying despite their sometimes-enormous size. A team at Johns Hopkins University (JHU) decided to see if they could use roaches to inspire robotics capable of navigating an obstacle course. The researchers of the study, published in Proceedings of the National Academy of Sciences, discovered that the animals' movement transitions corresponded to overcoming potential energy barriers and that they can jitter around to traverse obstacles in complex terrain.
Engineers at JHU have a penchant for animal-inspired robotics, as earlier this year they created a bot that could move like a snake. Beyond making extremely cool robots, their designs have the potential to improve response to natural disasters by creating machines that can navigate their way through a complex maze and gather information. Self-driving cars and hoovers are already proficient on flat surfaces, but things get a lot more complicated when you factor in obstacles such as rubble and stairs.
"Search and rescue robots can't operate solely by avoiding obstacles, like a vacuum robot would try to avoid a couch," said Ratan Othayoth, a graduate student in Li's lab and the study's first author, in a statement. "These robots have to go through rubble, and to do so, they have to use different types of movement in three dimensions."
To investigate if a rubble climbing robot could be made, Othayoth created an obstacle course made up of tall, bendable plates mounted on springs that replicate flexible blades of grass in the path of cockroaches. They set the roaches free in the maze and watched how they “pitched” and “rolled” their way past the beams, using this information to create an energy landscape of the roaches’ interaction with the “grass”. A "pitch” is when the roach pitched up their body to push against the beams until they moved aside, a much more tiring movement than when the roaches “rolled” between blades of synthetic grass.
The researchers discovered that in order to reduce energy expenditure, the cockroach's legs would constantly jitter, helping the insect to overcome the energy barrier of transitioning from one kind of movement to the next. To investigate this “jittering” further, the team built a robot to emulate the cockroaches' locomotion and found the more the robot jittered, the more energy it had at its disposal to overcome the energy barrier when switching between pitches and rolls.
"This strategy of 'just shake yourself' is the most naïve way to make transition, though," said Chen Li, physicist, assistant professor of mechanical engineering at The Johns Hopkins University and the paper's senior author. "The animals can – and robots should – add more careful, active adjustments to do it better. That is what we are looking into as the next step."
The success in robot locomotion has even been recognized by Samuel Stanton, program manager at the Army Research Office, an element of the U.S. Army Combat Capabilities Development Command's Army Research Laboratory, as an exciting avenue of development for use in army technologies.