Soft robots inspired by nature could become our flexible friends

Flexible robots may one day be used for delicate tasks and in hazardous locations strewn with obstacles

Robbie the Robot in the 1950s movie Forbidden Planet may have been endearing in a clunky, metallic way, but negotiating tricky terrain was never his strong point. Now researchers have developed a soft, flexible robot prototype inspired by starfish, worms and squid that overcomes some of the limitations of inflexible robots like Robbie.

Robots have come a long way in the past 50 years, demonstrating a range of impressive skills such as climbing stairs, dancing and playing the violin. Yet most are still made of rigid metallic rods, joints, bearings and motors, which makes them unstable on uneven surfaces and limits their ability to negotiate obstacles.

George Whitesides of Harvard University in Cambridge, Massachusetts, and colleagues have created a pneumatically driven robot made of flexible polymers to address these limitations. "I could see soft robots being especially useful for tasks where you use fingers, like surgery, or in which delicate objects such as raw eggs are being manipulated," said Prof Whitesides.

"They have a low centre of gravity and so should also be more stable. Also in hazardous locations such as a nuclear power plant like Fukushima after an accident, there might be instances in which a wheeled robot would be no good if there are piles of rubble about."

To move about, the prototype robot uses a series of small, inflatable chambers embedded within each of its four legs and its central spine. These chambers are contained within a rubbery polymer layer but bonded to a non-flexible layer so that inflating them bends the robot's skin.

The robot, measuring 18cm across, is programmed to inflate different chambers in specific sequences to move forward, lifting one leg off the ground while leaving the other three planted to maintain stability.

Prof Whitesides's group used different sequences to demonstrate various gaits and to show off the robot's ability to crawl under a glass plate suspended 2cm above the ground in less than a minute.
