August 11, 2012
Robot Worm Could Eventually Be Your Inevitable Doom
Lee Rannals for redOrbit.com - Your Universe Online
Scientists have engineered a soft autonomous robot that crawls across surfaces similar to how an earthworm moves.
The "Meshworm" robot has an "artificial muscle" that was created from wire made of nickel and titanium. Researchers wound the wire around the tube, creating segments along its length, similar to the segments found on an earthworm.
The team then plied a small current to the segments of wire, squeezing the mesh tube and propelling the robot forward.
Softer robots will be able to explore hard-to-reach spaces and traverse bumpy terrain with no problems.
A challenge scientists have faced in soft robotics is in designing soft actuators to power them. One solution has been to use compressed air. However, the team says air-powered robotics require bulky pumps.
Instead, the team looked to the earthworm for inspiration of the robot design. They noticed how the worm would make its way up by using two main muscle groups, including the circular muscle fibers and longitudinal muscle fibers.
The team set out to design a soft, peristalsis-driven system. They first made a long, tubular body by rolling up and heat-sealing a sheet of polymer mesh. That mesh allows the tube to stretch and contract like a spring.
They also looked for ways to create artificial muscle, which they eventually settled on a nickel-titanium alloy.
"It's a very bizarre material," Sangbae Kim, author of the paper published in the journal IEEE/ASME Transactions on Mechatronics said in a press release. "Depending on the [nickel-titanium] ratio, its behavior changes dramatically."
The researchers created a tightly coiled nickel-titanium wire and wound it around the mesh tube, mimicking the circular muscle fibers of the earthworm.
They also fitted a small battery and circuit board within the tube, generating a current to heat the wire at certain segments along the body.
As the segment reaches a certain temperature, the wire contracts around the body, squeezing the tube and propelling the robot forward.
The researchers developed algorithms to carefully control the wire's heating and cooling, which helps to direct the robotic worm to move in certain patterns.
"You can throw it, and it won't collapse," Kim said in the press release. "Most mechanical parts are rigid and fragile at small scale, but the parts in Meshworms are all fibrous and flexible. The muscles are soft, and the body is soft “¦ we're starting to show some body-morphing capability."