Cockroaches balance themselves without using their brains. That's what a group of researchers at the University of California, Berkeley found out when they performed experiments. Keeping upright has everything to do with how the insects are built – the architecture of their legs. It's also important to robot designers.
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That is not just an interesting bit of information for entomologists. A robot that can balance without having to use its "brain" is a lot more efficient than one that does, because the brain doesn't have to spend time keeping track of things like where the robot's feet are. In fact, one of the recurring challenges of designing a mobile robot is writing an algorithm that keep it from falling over.
Another issue with walking robots is adaptability. For the most part, they aren't all that good at dealing with rough terrain or damage to their legs. Cockroaches, on the other hand, can still walk and run if they lose a leg and don't seem bothered by the landscape.
To uncover just how cockroaches balance, the research team, led by Shai Revzen, now an assistant professor of electrical engineering and computer science, put a cockroach on a tray that was connected to elastic that stretched and contracted. When the tray zoomed to one side, the cockroach was forced to re-balance. It was like walking on a bridge and having it suddenly move 30 feet to one side.
Revzen and his team used video cameras and a computer to trace where the cockroach stepped. By looking carefully at where the roach was in its step-cycle, the researchers could tell whether its nervous system had kicked in to change it. (A separate experiment tested roaches with electrodes attached to their legs to tease out that pattern).
That was when they found that the adjustments came at the end of a step, instead of in the middle. That meant that the nervous system was relying on continuous feedback from the cockroach's surroundings.
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That's were inspiration for new designs for robots comes in. Right now a lot of robots have sensors in their feet to tell where they're stepping. The sensor sends information to the robot's brain, which then adjusts the feet. But the cockroaches do this more efficiently by keeping the brain out of it, at least until they have finished stepping.
Beyond designing robots, this kind of research might shed light on humans, too. How we walk is still a bit mysterious, since it's essentially a controlled fall and it's a pretty complicated activity. Understanding how we do it – and if we do it with continuous feedback or not – could go a long way to designing better prosthetics or therapies for people who have had brain injuries.
The team wrote up their work in the journal Biological Cybernetics.
Credit: Magemore Co., Ltd./Corbis