Creepy as heck, but it could save lives!
It is often said that, should the world be eradicated in a nuclear holocaust or frozen in a new ice age, the only living creatures left will be the cockroaches. After all, their ancestors outlived the dinosaurs, and despite our best efforts, no major city in the world is without these pests. Some species can even withstand arctic temperatures by creating their own biological version of antifreeze.
Researchers from the University of California, Berkeley have taken notice of these insects’ talent for survival and are using their adaptability to help design robots that may one day prove useful in search and rescue missions.
The trait researchers have been most interested in is found in the American cockroach (Periplaneta americana), and that is their ability to flatten themselves extremely quickly — enough to pass through tiny crevices.
"What's impressive about these cockroaches is that they can run as fast through a quarter-inch gap as a half-inch gap, by reorienting their legs completely out to the side," said study leader Kaushik Jayaram, who recently obtained his Ph.D. from UC Berkeley and is now a postdoctoral fellow at Harvard University. "They're about half an inch tall when they run freely, but can squish their bodies to one-tenth of an inch — the height of two stacked pennies."
The American cockroach can squeeze through cracks the width of two stacked pennies. Credit: Tom Libby, Kaushik Jayaram and Pauline Jennings. Courtesy of PolyPEDAL Lab UC, Berkeley
Roaches traversing crevices, Jayaram found, can withstand forces 900 times their body weight without injury.
Using the roach technique as inspiration, Jayaram designed a simple and cheap palm-sized robot that can splay its legs outward when squashed, then capped it with a plastic shield similar to the tough, smooth wings covering the back of a cockroach. Called CRAM, for compressible robot with articulated mechanisms, it was able to squeeze into and run through crevices half its height.
"In the event of an earthquake, first responders need to know if an area of rubble is stable and safe, but the challenge is, most robots can't get into rubble," said Robert Full, a professor of integrative biology at UC Berkeley. "But if there are lots of cracks and vents and conduits, you can imagine just throwing a swarm of these robots in to locate survivors and safe entry points for first responders."
The CRAM robot, inspired by cockroaches. Credit: Tom Libby, Kaushik Jayaram and Pauline Jennings. Courtesy of PolyPEDAL Lab, UC Berkeley
Jayaram built the model robot using an origami-like manufacturing technique, now available as an inexpensive kit made by Dash Robotics — a commercial spin-off from previous robotic work at UC Berkeley. Now, more robust versions will be needed for real-world testing.
"This is only a prototype, but it shows the feasibility of a new direction using what we think are the most effective models for soft robots, that is, animals with exoskeletons," Full said. "Insects are the most successful animals on earth. Because they intrude nearly everywhere, we should look to them for inspiration as to how to make a robot that can do the same."