Squishy Robots Could Aid Rescue Workers
A flexible robot inspired by squids and other soft-bodied animals can crawl without the aid of wheels or treads.
CREDIT: George Whiteside
Soft robot starfish that can squirm past obstacles could one day help rescue trapped disaster victims, scientists now suggest.
Inventors routinely fashion mobile robots that use treads or wheels to move around. Such robots are often heavy and expensive, and their rigid metallic parts can limit their range and make it hard to navigate difficult terrain.
To overcome such limitations, scientists have now built a flexible robot from soft, elastic plastics and silicone rubbers. The four-limbed robot was inspired by creatures such as squid, worms and starfish that thrive despite lacking hard skeletons.
"It is an approach to extending the idea of robots machines that do work or tasks that people can't or don't want to do to imitate groups of simple, soft animals," researcher George Whitesides, a chemist at Harvard University, told InnovationNewsDaily.
The researchers control each of the robot's legs by driving compressed air in and out of a series of pneumatic channels running through the limbs. In this manner, they could make the robot crawl and undulate through an obstacle course that likely would hinder most rigid metallic robots. For instance, they could squeeze the robot underneath a glass plate elevated just an inch or so (2 centimeters) above the ground in less than a minute the robot normally stood up to 2 inches high (5 cm) when crawling, but could flatten itself to approximately a half-inch (0.9 cm) thick.
"One can get very interesting, complex and potentially useful kinds of motions from very simple actuation basically blowing up a balloon," Whitesides said.
This soft type of robot was far simpler, faster and cheaper to make than conventional hard robots, scientists added. The fact they are rubbery also means they are resistant to much of the kind of damage that can impair rigid droids, such as bumps, scrapes, falling on rocks or twisting from getting caught in rubble.
"They can go into places where people don't want to go because they are too dangerous disaster relief," Whitesides suggested. "They can be assistants to humans in some procedures for example, perhaps surgery, where manipulating tissue may require some delicacy. They are light, so they can be carried easily in deflated form, and move across soft or unstable terrain."
The soft robots do currently run on external air supplies, "and for many applications that will be fine," Whitesides said. "For robots that have to move on their own, one could imagine a small compressor carried by the robot, or perhaps a cylinder of compressed air, to power the system."
The materials that soft robots currently are made from render them more susceptible to cuts and punctures and less capable of supporting loads as large as rigid droids can handle, researchers cautioned. Still, using tougher materials could help address both problems, they said.
"The question with any new technology is, 'What is it really good for?'" Whitesides said. "We'll find out as we go along."
Whitesides and his colleagues detailed their findings online Nov. 28 in the Proceedings of the National Academy of Sciences.