Apr 30, 2011

New Robots Curl Up Like Caterpillars and Scoot

When designing a robot with the ability to cover ground quickly, the seemingly slow, fuzzy little insect known as the caterpillar doesn't immediately spring to mind as the creature researchers would take their inspiration from.

Scientists, experimenting with a variety of soft-bodied robots with flexible structures that they hoped would adapt to unpredictable environments, found the robots were hampered by slow speeds. The researchers then looked to the soft-bodied caterpillar for design tips.

For instance, researchers have noticed that some caterpillars have the extraordinary ability to rapidly curl up and roll quickly away from predators, a trick called ballistic rolling that is one of the fastest wheeling behaviors in nature.

Now researchers at Tufts University have designed a caterpillar-like robot that mimics this behavior with lightning speed, capable of curling itself up in less than a tenth of a second. The hope is that such droids might combine the best of limbless robots, which can wriggle into tight areas but are relatively slow, with that of wheeled robots, which are relatively fast but find it hard to get into narrow spaces.


The 4-inch-long (10-centimeter-long) robot is called GoQBot, since it forms a "Q" shape before rolling away at more than a 1.6 feet (0.5 meters) per second, more than 20 times faster than it normally inches along. The automaton is made of silicone rubber with shape memory nickel-titanium alloy coils for muscles, which flex when heated by electrical current. 

The scientists did find that caterpillars don't use the ballistic roll as their main form of locomotionbecause it is effective only on smooth surfaces, often ends unpredictably and demands a large amount of muscle power to quickly roll a body up. 

The researchers noted that a soft robot attempting such tumbling would pick out which terrain might work first and pause between rolls to correct its heading if needed. To store up and quickly release the energy for such rolls, super-capacitors could be used, such as the ones employed in camera flashes, they added.

Roll and rescue

The researchers suggested that robots based on GoQBot could find use in search-and-rescue operations, building inspections and environmental monitoring.

"Due to the increased speed and range, limbless crawling robots with ballistic rolling capability could be deployed more generally at a disaster site such as a tsunami aftermath," said study team member Huai-Ti Lin, a biomimetics roboticist at Tufts University. "The robot can wheel to a debris field and wiggle into the danger for us."

Lin suggested these robots might be deployed in teams in the future.

"You can have a robot like a UAV (unmanned aerial vehicle) scout an area first and then drop swarms of these soft robots to work on the ground," Lin told TechNewsDaily.

The researchers detailed their findings online yesterday (April 27) in the journal Bioinspiration & Biomimetics.