'Ninja' robot roaches designed for rescue operations
June 9, 2012 10:19pm
One of the most reviled creatures in the household is a model for researchers making robots more maneuverable for potential rescue or military applications.
Scientists at the University of California, Berkeley are studying the cockroach's ability to escape being squashed by suddenly "disappearing" like ninjas —by flipping themselves under a ledge.
"This work is a great example of the amazing maneuverability of animals, and how understanding the physical principles used by nature can inspire design of agile robots," said Ron Fearing, UC Berkeley professor of electrical engineering and computer science.
The UC Berkeley team published the results of the study June 6 in the online, open-access journal PLoS ONE.
In a team-up with UC Berkeley robotics experts, the researchers tried to recreate cockroaches' behavior in a six-legged robot by adding Velcro strips.
Mongeau said he and his colleagues noticed the cockroaches’ newly-identified behavior while studying how they use their antennae to sense and cross gaps.
“As we made the gap wider, they would end up on the underside of the ramp. To the naked eye, it wasn’t clear what was happening, but when we filmed them with a high-speed camera and slowed it down, we were amazed to see that it was the cockroach’s hind legs grabbing the surface that allowed it to swing around under the ledge,” Mongeau said.
“Cockroaches continue to surprise us,” added Full, who discovered in 1997 that when cockroaches run quickly, they rear up on their two hind legs like bipedal humans.
Full said cockroaches have fast relay systems that allow them to move quickly in response to light or motion at speeds up to 50 body lengths per second.
'Equivalent to 200kph'
This is equivalent to 200 kilometers per hour when scaled up to human dimensions, he said.
Such a speed "makes them incredibly good at escaping predators,” he added.
On the other hand, the researchers discovered a similar behavior in lizards, animals that have hook-like toenails.
Also, they have documented geckos using this escape technique in the jungle at the Wildlife Reserves near Singapore.
“This behavior is probably pretty widespread, because it is an effective way to quickly move out of sight for small animals,” Full said.
In Fearing’s lab, Birkmeyer and Hoover attached Velcro to the rear legs of a small cockroach-inspired, six-legged robot called DASH (Dynamic Autonomous Sprawled Hexapod).
The robot was able to reproduce the same behavior as seen in roaches and geckos - they can rapidly reverse direction when encountering a ledge.
Mongeau and McRae had discovered that when the American cockroach (Periplaneta americana) appeared to fall over a ledge, it was actually running at full speed toward the ledge.
It then dove off, and grabbed the edge with its claws, sometimes using only one leg, and swung like a pendulum under the ledge, retaining 75 percent of its running energy.
Mongeau said this pendulum swing subjects the roach to three to five times the force of gravity - similar to what humans feel at the bottom of a bungee jump.
Full found only one well-studied similarity: the tree-swinging behavior of gibbons.
“All this must be put together into a complete package to understand what goes into these animals’ extraordinary maneuverability,” Full said.
Full said some robots today are good at running, some at climbing, but very few are good at both or transitioning from one behavior to the other.
“That’s really the challenge now in robotics, to produce robots that can transition on complex surfaces and get into dangerous areas that first responders can’t get into,” he said.
The work was funded by the National Science Foundation, including the NSF’s Integrative Graduate Education and Research Traineeship (IGERT) program, a Swiss NSF Grant for Prospective Researchers, and the Micro Autonomous Systems Technologies (MAST) consortium, a large group of researchers funded in part by the U.S. Army Research Laboratory that is focused on creating autonomous sensing robots. — TJD, GMA News