An international team of researchers have engineered an autonomous robot that inches along like an earthworm. Its soft, flexible design allows it to squeeze through tight spaces and could one day help make better endoscopes. MIT News explains.
One major challenge in soft robotics has been in designing soft motors to power them. Some have used compressed air that’s carefully pumped through a robot to move it.
Instead, MIT’s Sangbae Kim and colleagues looked for design guidance from an earthworm.
These crawlers are made up of 2 main muscle groups: circular muscle fibers that wrap around the worm’s tube-like body and longitudinal muscle fibers that run along its length.
These worms, snails, sea cucumbers, and even our own digestive tract move by alternatively squeezing and stretching muscles. This mechanism is called peristalsis, and it allows the new robot to crawl across surfaces by contracting segments of its body.
- They made a long, tubular body by rolling up and heat-sealing a sheet of polymer mesh, which allows the tube to stretch and contract like a spring.
- Then they created ‘artificial muscle’ from wire made of nickel and titanium -- a shape-memory alloy that stretches and contracts with heat.
- They wound the wire around the tube, creating segments along its length. This mimics the circular muscle fibers of the earthworm.
- They fitted a small battery and circuit board within the tube and generated a current to heat the wire at certain segments along the body.
- When a small current is applied to the segments of wire, the wire contracts, squeezing the mesh tube and propelling the robot forward.
- They also outfitted the robot with wires running along its length, similar to an earthworm’s longitudinal muscle fibers. When heated, an individual wire will contract, pulling the worm left or right.
And it’s so resilient, it can inch away unscathed from a hammer bludgeoning and a solid foot stomping. Watch a video of Meshworm!
Robots like these may have many useful applications, such as next-generation endoscopes, implants and prosthetics.
The work was published in IEEE/ASME Transactions on Mechatronics.
[Via MIT News]
Image: MIT News Office