Nav: Home

SFU researchers build a better bionic hand

May 04, 2016

A Canadian athlete's dream to one day "move" his fingers again after losing an arm in a workplace accident is now within grasp, thanks to a robotic arm prosthesis being developed at Simon Fraser University.

SFU researchers are working with paralympic skier Danny Letain to design a new control system for one of the world's most advanced bionic hands, promising a more intuitive experience for upper limb amputees.

Letain, a former locomotive engineer, lost his left arm below the elbow 35 years ago. He has since used a body-powered prosthesis with a pincer-like split hook, which uses a series of straps that mechanically maneuver the artificial limb.

It's a fatiguing process. "The hook is durable and quick to respond, but controlling it with straps is not natural," he says.

With the SFU team's new control system, Letain already has a variety of different grip patterns that he says work "well beyond" what he could achieve with prosthetic devices.

Letain adds: "With this new system, it feels like I'm opening and closing my hand. The most exciting moment for me was feeling my left index finger and the little finger for the first time since my accident. With the hook you don't use those muscles at all. This system puts my mind to work in a whole new way."

The technology was developed in engineering science professor Carlo Menon's biomedical engineering lab initially to rehabilitate stroke patients. He immediately saw the potential for wider applications, including for amputees.

Menon says there is a high rejection rate with existing robotic prostheses because they are not intuitive. "The problem is in the control systems, which have not significantly advanced in 50 years," he says. "As a result, the robotic prostheses are not very useful for performing everyday tasks, and only about a quarter of amputees use them."

The robotic arm being used by the team to apply its technology is the Bebionic3, on loan from Steeper Prosthetics, a company in Leeds, England that produces bionic hands. The SFU team began working with Letain and staff at Vancouver's Barber Prosthetics in June 2015.

The new system consists of an armband of pressure sensors embedded in the prosthetic socket. These track movements in Letain's remaining muscles as he performs intuitive actions, such as grasping a bottle. Computer algorithms then map the sensor data to decode his intentions and move the prosthesis.

"The more data you give it, the more it will learn," says SFU engineering science alumnus Lukas-Karim Merhi, who is leading the interdisciplinary team, calling themselves M.A.S.S. Impact (Mass Activity Sensor Strip). The system takes incoming data and makes predictions in real time. It also generates computer models to improve future performance.

Brittany Pousett, head of research and development at Barber Prosthetics, says the system "is a completely new approach to picking up signal and controlling an electric prosthesis from someone's body," and could potentially increase the motion available to users.

These functions will be put to the test when the team competes at the inaugural Cybathlon event in Zurich in October 2016. Dubbed the cyborg Olympics, it's an international competition for people with disabilities using robotic technology.

Organizers from the Swiss Federal Institute of Technology hope the event will spur innovations that are useful beyond the competition and allow people with disabilities to regain independence.

Letain will use the technology in an obstacle course for people with powered arm prostheses to perform everyday tasks such as slicing bread and opening jars. The team tested the prototype at the Cybathlon trial held last July and is working to optimize the system for the competition.

The SFU team is the only Canadian team taking part alongside 80 teams from more than 30 countries.

Backgrounder: moving beyond myoelectric solutions

Once the stuff of science fiction, a new generation of advanced prosthetic hands with robotic fingers that move independently can perform tasks requiring precise and delicate movements, such as threading a needle or holding an egg.

But current control systems - the "brains" of the device, including the sensors and software that make it move - are not intuitive. This is because externally powered prostheses, such as myoelectric devices, are typically controlled by electromyogram (EMG) signals generated by muscle contractions in the residual limb.

The system, invented in the 1950s, measures only two electrical signals in the limb. As a result, the user must learn to isolate specific muscles in the biceps or triceps, and then flex them repeatedly to make robotic fingers open or close.

Menon says it is challenging because normally we unconsciously use multiple muscles at the same time to complete a movement. Frustration with the system can lead amputees to abandon these devices.

In response, the SFU team is pioneering the use of a band of pressure sensors that detect intricate muscle movements across the surface of the remaining limb.

Besides being a more intuitive experience amputees do not require extensive training to perform simple functions.

Menon believes the technology could be used in combination with electromyography to become the standard for prosthetics.
About Simon Fraser University

As Canada's engaged university, SFU is defined by its dynamic integration of innovative education, cutting-edge research and far-reaching community engagement. SFU was founded 50 years ago with a mission to be a different kind of university--to bring an interdisciplinary approach to learning, embrace bold initiatives, and engage with communities near and far. Today, SFU is Canada's leading comprehensive research university and is ranked one of the top universities in the world. With campuses in British Columbia's three largest cities - Vancouver, Burnaby and Surrey - SFU has eight faculties, delivers almost 150 programs to over 35,000 students, and boasts more than 135,000 alumni in 130 countries around the world.

Simon Fraser University: Engaging Students. Engaging Research. Engaging Communities.

Simon Fraser University

Related Technology Articles:

How technology use affects at-risk adolescents
More use of technology led to increases in attention, behavior and self-regulation problems over time for adolescents already at risk for mental health issues, a new study from Duke University finds.
Hold-up in ventures for technology transfer
The transfer of technology brings ideas closer to commercialization. The transformation happens in several steps, such as invention, innovation, building prototypes, production, market introduction, market expansion, after sales services.
The ultimate green technology
Imagine patterning and visualizing silicon at the atomic level, something which, if done successfully, will revolutionize the quantum and classical computing industry.
New technology detects COPD in minutes
Pioneering research by Professor Paul Lewis of Swansea University's Medical School into one of the most common lung diseases in the UK, Chronic Obstructive Pulmonary Disease, has led to the development of a new technology that can quickly and easily diagnose and monitor the condition.
New technology for powder metallurgy
Tecnalia leads EFFIPRO (Energy EFFIcient PROcess of Engineering Materials) project, which shows a new manufacturing process using powder metallurgy.
New milestone in printed photovoltaic technology
A team of researchers at Friedrich-Alexander-Universit├Ąt have achieved an important milestone in the quest to develop efficient solar technology as an alternative to fossil fuels.
Gene Drive Technology: Where is the future?
For this episode of BioScience Talks, we're joined by Gene Drive Committee co-chair James P.
Could Hollywood technology help your health?
The same technology used by the entertainment industry to animate characters such as Gollum in 'The Lord of The Rings' films, will be used to help train elite athletes, for medical diagnosis and even to help improve prosthetic limb development, in a new research center at the University of Bath launched today.
Assessing carbon capture technology
Carbon capture and storage could be used to mitigate greenhouse gas emissions and thus ameliorate their impact on climate change.
New technology for dynamic projection mapping
It has been thought technically difficult to achieve projection mapping onto a moving/rotating object so that images look as though they are fixed to the object.

Related Technology Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Jumpstarting Creativity
Our greatest breakthroughs and triumphs have one thing in common: creativity. But how do you ignite it? And how do you rekindle it? This hour, TED speakers explore ideas on jumpstarting creativity. Guests include economist Tim Harford, producer Helen Marriage, artificial intelligence researcher Steve Engels, and behavioral scientist Marily Oppezzo.
Now Playing: Science for the People

#524 The Human Network
What does a network of humans look like and how does it work? How does information spread? How do decisions and opinions spread? What gets distorted as it moves through the network and why? This week we dig into the ins and outs of human networks with Matthew Jackson, Professor of Economics at Stanford University and author of the book "The Human Network: How Your Social Position Determines Your Power, Beliefs, and Behaviours".