Featured Research

from universities, journals, and other organizations

Bio-inspired robotic device could aid ankle-foot rehabilitation

Date:
January 21, 2014
Source:
Carnegie Mellon University
Summary:
A soft, wearable device that mimics the muscles, tendons and ligaments of the lower leg could aid in the rehabilitation of patients with ankle-foot disorders such as drop foot, said a robotics expert. Scientists have now developed an active orthotic device using soft plastics and composite materials, instead of a rigid exoskeleton.

A bio-inspired robotic device could aid ankle-foot rehabilitation.
Credit: Image courtesy of Carnegie Mellon University

A soft, wearable device that mimics the muscles, tendons and ligaments of the lower leg could aid in the rehabilitation of patients with ankle-foot disorders such as drop foot, said Yong-Lae Park, an assistant professor of robotics at Carnegie Mellon University.

Park, working with collaborators at Harvard University, the University of Southern California, MIT and BioSensics, developed an active orthotic device using soft plastics and composite materials, instead of a rigid exoskeleton. The soft materials, combined with pneumatic artificial muscles (PAMs), lightweight sensors and advanced control software, made it possible for the robotic device to achieve natural motions in the ankle.

The researchers reported on the development in the journal Bioinspiration & Biomimetics.

Park, who did the work while a post-doctoral researcher at Harvard's Wyss Institute for Biologically Inspired Engineering, said the same approach could be used to create rehabilitative devices for other joints of the body or even to create soft exoskeletons that increase the strength of the wearer.

The robotic device would be suitable for aiding people with neuromuscular disorders of the foot and ankle associated with cerebral palsy, amyotrophic lateral sclerosis, multiple sclerosis or stroke. These gait disorders include drop foot, in which the forefoot drops because of weakness or paralysis, and equinus, in which the upward bending motion of the ankle is limited. Conventional passive ankle braces can improve gait, but long-term use can lead to muscle atrophy because of disuse.

Active, powered devices can improve function and also help re-educate the neuromuscular system, Park said. "But the limitation of a traditional exoskeleton is that it limits the natural degrees of freedom of the body," he added. The ankle is naturally capable of a complicated three-dimensional motion, but most rigid exoskeletons allow only a single pivot point.

The soft orthotic device, by contrast, enabled the researchers to mimic the biological structure of the lower leg. The device's artificial tendons were attached to four PAMs, which correspond with three muscles in the foreleg and one in the back that control ankle motion. The prototype was capable of generating an ankle range of sagittal motion of 27 degrees -- sufficient for a normal walking gait.

The tradeoff, however, is that the soft device is more difficult to control than a rigid exoskeleton. It thus required more sophisticated sensing to track the position of the ankle and foot and a more intelligent scheme for controlling foot motion, Park said. Among the innovations in the device are sensors made of a touch-sensitive artificial skin, thin rubber sheets that contain long microchannels filled with a liquid metal alloy. When these rubber sheets are stretched or pressed, the shapes of the microchannels change, which in turn causes changes in the electrical resistance of the alloy. These sensors were positioned on the top and at the side of the ankle.

Park said additional work will be necessary to improve the wearability of the device. This includes artificial muscles that are less bulky than the commercially produced PAMs used in this project. Park said a subsequent project, which will be presented at an upcoming technical conference, used flat, strap-like actuators instead of the cylindrical PAMs.

The device has yet to be tested on patients to determine its performance as a rehabilitative tool.

A video of the device is available on YouTube: http://www.youtube.com/watch?v=IbXRiTbuDvY


Story Source:

The above story is based on materials provided by Carnegie Mellon University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Yong-Lae Park, Bor-rong Chen, Nιstor O Pιrez-Arancibia, Diana Young, Leia Stirling, Robert J Wood, Eugene C Goldfield, Radhika Nagpal. Design and control of a bio-inspired soft wearable robotic device for ankle–foot rehabilitation. Bioinspiration & Biomimetics, 2014; 9 (1): 016007 DOI: 10.1088/1748-3182/9/1/016007

Cite This Page:

Carnegie Mellon University. "Bio-inspired robotic device could aid ankle-foot rehabilitation." ScienceDaily. ScienceDaily, 21 January 2014. <www.sciencedaily.com/releases/2014/01/140121113446.htm>.
Carnegie Mellon University. (2014, January 21). Bio-inspired robotic device could aid ankle-foot rehabilitation. ScienceDaily. Retrieved April 18, 2014 from www.sciencedaily.com/releases/2014/01/140121113446.htm
Carnegie Mellon University. "Bio-inspired robotic device could aid ankle-foot rehabilitation." ScienceDaily. www.sciencedaily.com/releases/2014/01/140121113446.htm (accessed April 18, 2014).

Share This



More Matter & Energy News

Friday, April 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Small Reactors Could Be Future of Nuclear Energy

Small Reactors Could Be Future of Nuclear Energy

AP (Apr. 17, 2014) — After the Fukushima nuclear disaster, the industry fell under intense scrutiny. Now, small underground nuclear power plants are being considered as the possible future of the nuclear energy. (April 17) Video provided by AP
Powered by NewsLook.com
Horseless Carriage Introduced at NY Auto Show

Horseless Carriage Introduced at NY Auto Show

AP (Apr. 17, 2014) — An electric car that proponents hope will replace horse-drawn carriages in New York City has also been revealed at the auto show. (Apr. 17) Video provided by AP
Powered by NewsLook.com
Honda's New ASIMO Robot, More Human-Like Than Ever

Honda's New ASIMO Robot, More Human-Like Than Ever

AFP (Apr. 17, 2014) — It walks and runs, even up and down stairs. It can open a bottle and serve a drink, and politely tries to shake hands with a stranger. Meet the latest ASIMO, Honda's humanoid robot. Duration: 00:54 Video provided by AFP
Powered by NewsLook.com
German Researchers Crack Samsung's Fingerprint Scanner

German Researchers Crack Samsung's Fingerprint Scanner

Newsy (Apr. 16, 2014) — German researchers have used a fake fingerprint made from glue to bypass the fingerprint security system on Samsung's new Galaxy S5 smartphone. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins