Before I talk robots, I must share with you a sad story about starfish. One morning my seven year old turned to his Mom and said, you know what I am getting too old for Sponge Bob. The yellow sponge and his best friend the pink starfish have been his faithful companions since toddlers, and now that he is entering second grade he has outgrown them.
Starfish have fascinated people even before Patrick Star became famous. Now, the good scientists at Harvard have taken their passion to a new level with a flexible robot starfish made out of indestructible silicone rubber. that can crawl through fire and over snow even after being run over by a car. The starbot undulates and walks using compressed air that is forced in and out of many tiny pneumatic channels running through its limbs, like a ballon being inflated and deflated. These soft robots, inspired by creatures such as starfish, worms, and squid, could one day squirm through obstacle courses that might prove challenging or impossible for metallic robots (think disaster recovery missions under rubble).
As discussed several times previously on this blog, soft robots are far simpler, faster and cheaper to make than their metallic cousins. The secret is in their rubberiness which makes them resistant to some of the kinds of damage that can impair rigid robots, such as bumps, scrapes, falls, and twists. And, importantly, these new soft bots don’t need tethers connecting them to external air supplies, a factor that limited their predecessors.
This version carries its own air pump. “This is a key milestone on the way to reaching one of the potential applications of soft robotics—a system for search and rescue or other autonomous operations, which would be very difficult to do if you had to rely on a tether,” says lead study author Michael Tolley, a roboticist at Harvard University.
The new four-legged soft robot is a little more than two feet long, making it more than four times bigger than earlier versions and large enough to carry a lithium-polymer battery pack, miniature air compressors, electronic circuits that serve as the robot’s brain, and a lightweight camera to wirelessly transmit video and audio. The scientists used a tougher silicone rubber that can withstand more than twice as much internal air pressure as earlier models. In addition, they added microscopic hollow glass spheres into the silicone rubber to reduce the robot’s weight, while including Kevlar fibers to prevent the robot from bursting because of internal pressure.
“It’s about as stiff as a rubber eraser,” Tolley says.
The robot could operate for up to two hours on a flat surface, walking at speeds of roughly one foot per minute and capable of carrying payloads of up to 17.6 lbs. That’s 60 percent more than the bot’s own weight. In testing, it withstood a snowstorm, a trough of water, direct exposure to flames from a Bunsen burner, and the crushing force of being run over by a car. In sum, the parts cost $1,111.
Roboticist Vytas SunSpiral at NASA Ames Research Center, was impressed. “The ability to make a larger and lighter untethered version of their prior groundbreaking robot is very significant,” he says. “I have been fascinated by soft robots for years, but have been concerned that they would not be able to carry their own compressors and power supplies. This work has demonstrated that it is indeed possible, and I’m very excited to see how future prototypes will build upon this success.
“One weakness in the prototype is that the air pumps are slow, requiring on the order of seconds to work. In the future, Tolley says, perhaps miniature combustion engines could propel them far more quickly. The researchers also say they could make the robots faster by such as tinkering with their feet and their internal network of pneumatic channels. And future versions could have more advanced onboard electronics that allow a robot to sense and react to its environments autonomously.
“Rigid systems are fragile, and most of the robots built to date can only work in very limited and controlled conditions,” SunSpiral says. “Research like this is showing us how to design, build, and control robotic systems which will be far more resilient and adaptable to the complexity of the real dynamic and chaotic world that we all live in.”
So maybe when Nickelodeon hears about this, they will updated the cartoon series to have Patrick Star(bot) partner with Space Ghost…