Navigation Links
Soft autonomous robot inches along like an earthworm
Date:8/9/2012

CAMBRIDGE, MA -- Earthworms creep along the ground by alternately squeezing and stretching muscles along the length of their bodies, inching forward with each wave of contractions. Snails and sea cucumbers also use this mechanism, called peristalsis, to get around, and our own gastrointestinal tracts operate by a similar action, squeezing muscles along the esophagus to push food to the stomach.

Now researchers at MIT, Harvard University and Seoul National University have engineered a soft autonomous robot that moves via peristalsis, crawling across surfaces by contracting segments of its body, much like an earthworm. The robot, made almost entirely of soft materials, is remarkably resilient: Even when stepped upon or bludgeoned with a hammer, the robot is able to inch away, unscathed.

Sangbae Kim, the Esther and Harold E. Edgerton Assistant Professor of Mechanical Engineering at MIT, says such a soft robot may be useful for navigating rough terrain or squeezing through tight spaces.

The robot is named "Meshworm" for the flexible, meshlike tube that makes up its body. Researchers 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, much like the segments of an earthworm. They then applied a small current to the segments of wire, squeezing the mesh tube and propelling the robot forward. The team recently published details of the design in the journal IEEE/ASME Transactions on Mechatronics.

In addition to Kim, the paper's authors are graduate student Sangok Seok and postdoc Cagdas Denizel Onal at MIT, associate professor Robert J. Wood at Harvard, assistant professor Kyu-Jin Cho PhD '07 of Seoul National University, and Daniela Rus, professor of computer science and engineering and director of MIT's Computer Science and Artificial Intelligence Laboratory (CSAIL).

Soft-serve robotics

In the past few decades, many roboticists have looked for ways to engineer soft robotic systems. Without bulky, breakable hardware, soft robots might be able to explore hard-to-reach spaces and traverse bumpy terrain. Their pliable exteriors also make them safe for human interaction.

A significant challenge in soft robotics has been in designing soft actuators, or motors, to power such robots. One solution has been to use compressed air, carefully pumped through a robot to move it. But Kim says air-powered, or pneumatic, robots require bulky pumps. "Integrating micro air compressors into a small autonomous robot is a challenge," Kim says.

Artificial muscle from a bizarre material

Instead, Kim and his colleagues looked to the earthworm for design guidance. They noted that the creepy crawler is made up of two main muscle groups: circular muscle fibers that wrap around the worm's tubelike body, and longitudinal muscle fibers that run along its length. Both muscle groups work together to inch the worm along.

The team set out to design a similar soft, peristalsis-driven system. The researchers first made a long, tubular body by rolling up and heat-sealing a sheet of polymer mesh. The mesh, made from interlacing polymer fibers, allows the tube to stretch and contract, similar to a spring.

They then looked for ways to create artificial muscle, ultimately settling on a nickel-titanium alloy. "It's a very bizarre material," Kim says. "Depending on the [nickel-titanium] ratio, its behavior changes dramatically."

Depending on the ratio of nickel to titanium, the alloy changes phase with heat. Above a certain temperature, the alloy remains in a phase called austenite a regularly aligned structure that springs back to its original shape, even after significant bending, much like flexible eyeglass frames. Below a certain temperature, the alloy shifts to a martensite phase a more pliable structure that, like a paperclip, stays in the shape in which it's bent.

The researchers fabricated a tightly coiled nickel-titanium wire and wound it around the mesh tube, mimicking the circular muscle fibers of the earthworm. They then fitted a small battery and circuit board within the tube, generating a current to heat the wire at certain segments along the body: As a segment reaches a certain temperature, the wire contracts around the body, squeezing the tube and propelling the robot forward. Kim and his colleagues developed algorithms to carefully control the wire's heating and cooling, directing the worm to move in various patterns.

The group 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.

As an ultimate test of soft robotics, the group subjected the robot to multiple blows with a hammer, even stepping on the robot to check its durability. Despite the violent impacts, the robot survived, crawling away intact.

"You can throw it, and it won't collapse," Kim says. "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."


'/>"/>

Contact: Sarah McDonnell
s_mcd@mit.edu
617-253-8923
Massachusetts Institute of Technology
Source:Eurekalert

Related biology news :

1. Robot vision: Muscle-like action allows camera to mimic human eye movement
2. Robots get a feel for the world at USC Viterbi
3. Engineered robot interacts with live fish
4. Robotic cats, a kitten mummy and a major UK vet gathering
5. Kessler Foundation implements Ekso Bionics first commercial robotic exoskeleton
6. Under the right conditions, peptide blocks HIV infection at multiple points along the way
7. Gastric bypass surgery alters gut microbiota profile along the intestine
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/18/2017)...  Socionext Inc., a global expert in SoC-based imaging and computing ... M820, which features the company,s hybrid codec technology. A demonstration utilizing ... Inc., will be showcased during the upcoming Medtec Japan at Tokyo ... Las Vegas Convention Center April 24-27. ... Click here for an image ...
(Date:4/13/2017)... According to a new market research report "Consumer ... Administration, and Authorization), Service, Authentication Type, Deployment Mode, Vertical, and Region - ... to grow from USD 14.30 Billion in 2017 to USD 31.75 Billion ... ... MarketsandMarkets Logo ...
(Date:4/11/2017)... BROOKLYN, N.Y. , April 11, 2017 /PRNewswire-USNewswire/ ... identical fingerprints, but researchers at the New York ... University College of Engineering have found that partial ... fingerprint-based security systems used in mobile phones and ... previously thought. The vulnerability lies in ...
Breaking Biology News(10 mins):
(Date:8/10/2017)... Yorba Linda, Ca (PRWEB) , ... August 09, ... ... and exosomes for regenerative medicine applications in the clinic is here. The team ... secreted EVs present in conditioned medium for clinical studies. , Dr. Travis ...
(Date:8/10/2017)... ... August 09, 2017 , ... Okyanos Center for Regenerative Medicine has announced ... Bay Hotel in Freeport, Grand Bahama on September 27, 2017. This daytime event is ... oversight from the Ministry of Health’s National Stem Cell Ethics Committee (NSCEC) and regulations ...
(Date:8/10/2017)... ... August 10, 2017 , ... DrugDev and the ... webinar to demonstrate how Good Clinical Practice (GCP) can be used throughout the ... the webinar will discuss the importance of GCP compliance, how sites are affected by ...
(Date:8/10/2017)... ... August 10, 2017 , ... ... news outlet had initiated coverage on Next Group Holdings, Inc. and see's significant ... markets geared toward those that cannot engage in traditional banking services. According to ...
Breaking Biology Technology: