ScienceTake | Building a Rescue Roach
Humans may never be able to exterminate cockroaches, but they may be able to learn something from them.
The insects might even offer a new model for robots that crawl through rubble to look for survivors or gather information after disasters, according to scientists at the University of California, Berkeley, who reported Monday in Proceedings of the National Academy of Sciences on the extraordinary abilities of the American cockroach, known affectionately to millions of apartment dwellers as the water bug.
Kaushik Jayaram and Robert J. Full, who work on technology inspired by biology, were drawn to the roaches, which average about an inch and a half in length, because of two abilities for which the creatures are renowned. They are fast. And they can get through very small cracks.
The scientists put the insects through a kind of roach Olympics. They ran them through crevices and very small spaces, then even smaller and smaller spaces. And they squashed them flat â not completely, absolutely dead flat, but they subjected them to pressure equivalent to 900 times their body weight.
The bugs could get through a crevice the height of two stackedpennies in less than a second. They survived the squashing. And even when pressed flat enough that their legs splayed, they could still move about 20 body lengths a second. Obviously, Dr. Full said, not only can they get behind your walls and ceilings, but âthey can run at high speedsâ once they get there.
They can tolerate flattening not because the roach exoskeleton is soft, but because it is composed of rigid plates connected by more flexible tissue. When flattened, they resort to a kind of locomotion that hasnât been studied before, Dr. Full said. The splayed legs get enough grip to move the body forward rapidly against the friction it faces from being pressed between surfaces.
Dr. Full said that the value of the research is that the cockroach structure and motion could work better than other, more wormlike designs for robots to explore sites where war or natural disaster has caused buildings to collapse. âThis is the model for soft robots,â he said.
To prove the point, he and Dr. Jayaram built a palm-size prototype with rigid plates connected by flexible membranes and legs that can work in standard running and the splayed crawling that flattened cockroaches do.
No cockroaches were harmed during the experiments, Dr. Full said, not even the ones subjected to the highest pressures. âWe actually ran them and flew them before and after the measurements,â he said, and there was no difference in performance.
That seems only fair; roaches could end up being the source of inspiration for machines that save peopleâs lives.
Besides, who wants to hurt a cockroach?