Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Bio-Inspired Robotic Device Could Aid Ankle-Foot Rehabilitation

22.01.2014
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
This research was sponsored by the Wyss Institute and the National Science Foundation.

Byron Spice | EurekAlert!
Further information:
http://www.cmu.edu

More articles from Life Sciences:

nachricht A novel socio-ecological approach helps identifying suitable wolf habitats
17.02.2017 | Universität Zürich

nachricht New, ultra-flexible probes form reliable, scar-free integration with the brain
16.02.2017 | University of Texas at Austin

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Switched-on DNA

20.02.2017 | Materials Sciences

Second cause of hidden hearing loss identified

20.02.2017 | Health and Medicine

Prospect for more effective treatment of nerve pain

20.02.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>