Argentine researchers developing low-cost prosthesis

An advanced German prosthesis

In February 2011, DARPA presented an amazing robotic arm controlled directly by the brain. Robocop is no longer just a Hollywood fantasy but a reality that is close to improving the quality of life of millions. A few months later in Argentina, Aden Diaz Noceda and Diego Beltramone of the Laboratory of Rehabilitation Engineering at the National University of Cordoba, presented ElectroMioPrótesis, an innovative concept that promises to make the latest biomedical technologies a reality for poor and emerging countries.

“What we wanted was to create a robotic prosthesis that is available to our market,” said Diaz. “The latest generation parts cost $8,000 in Argentina- an impossible price for our social security system.

And what they accomplished was amazing: an arm with six degrees of freedom, one for each finger and one at the elbow, made with materials and devices available on the local market. The cost: just $2,500.

But that was just the beginning. The next step was to make the code and designs open-source so that they would be free to other developers and companies wishing to improve or produce their own devices. They say the system is so simple that even an individual could build it without assistance. Although the idea is not original, it adds to a trend that promises to change the biomedical engineering industry. The US-based Open Prosthetic Project has already followed a similar path to the point of linking with the Amistad Foundation and the Cuba-Rada Institute, which works with Cuban doctors who focus on the needs of lower-income countries.

While the technology is not the same as DARPA’s as the arm’s movements are controlled by a patient’s healthy muscles, it is something that has already been extensively tested by biomedical engineers, including Microsoft Research together with universities in Toronto and Washington in order to develop human-computer interfaces. It also requires no intrusive intervention for the patient — one of the parameters that were laid out for the project.

The device is controlled via small electrical impulses sent when healthy muscles contract. These are picked up by electrodes like those used in electrocardiograms, then amplified by the system and sent to a microcontroller. The movements are executed by a servo motor system and force is regulated by sensors in the artificial fingertips to avoid causing damage. As the patient masters more muscle control, the amount of moves that can be executed by the prosthesis increases. As the learning curve can be quite laborious, the Rehabilitation Laboratory has also developed a public training system which uses visual feedback.

“The big remaining challenges are to define an energy-force equation, since more power means less battery life and cosmetic tweeks to make it more like a healthy arm” said Diaz Noceda while expressing confidence that open innovation can bring a quick solution.

Juan can be reached at juan.dalmasso(at)gmail.com