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:4/13/2017)... , April 13, 2017 According to a ... Identity Authentication, Identity Analytics, Identity Administration, and Authorization), Service, Authentication Type, Deployment ... the IAM Market is expected to grow from USD 14.30 Billion in ... Rate (CAGR) of 17.3%. ... MarketsandMarkets Logo ...
(Date:4/6/2017)... -- Forecasts by Product Type (EAC), Biometrics, ... (Transportation & Logistics, Government & Public Sector, Utilities / ... Facility, Nuclear Power), Industrial, Retail, Business Organisation (BFSI), Hospitality ... looking for a definitive report on the $27.9bn Access ... ...
(Date:4/3/2017)... , April 3, 2017  Data captured ... engineering platform, detected a statistically significant association ... prior to treatment and objective response of ... potential to predict whether cancer patients will ... treatment, as well as to improve both pre-infusion ...
Breaking Biology News(10 mins):
(Date:6/27/2017)... (PRWEB) , ... June 27, 2017 , ... Biodex Medical ... and ambulation aid in one device. This assistive aid lifts patients safely from a ... harness and motorized lift mechanics. The Mobility Assist is the latest in a line ...
(Date:6/26/2017)... VIRGINIA (PRWEB) , ... June 26, 2017 , ... ... today that Melissa Kirkegaard, the former Associate Director of Product Development R&D at ... biological and pharmaceutical products at both start-up and established biopharma companies, has joined ...
(Date:6/23/2017)... ... June 23, 2017 , ... Biova, LLC., the leader in water ... Board of Directors. Dr. Henig will bring a wealth of scientific experience in the ... the Chief Technical and Scientific Officer of four major global companies in the last ...
(Date:6/23/2017)... ... June 23, 2017 , ... The Academy of Model ... University Aviation Association (UAA), the unifying voice for collegiate aviation education, are launching ... teamwork, competition, and success through a STEM-based education platform. , Much like the ...
Breaking Biology Technology: