Amputation surgery is one of the most traumatic experiences a person can go through. Losing a limb is not only a huge psychological burden, it brings along a whole range of daily inconveniences and can even damage other parts of the body (due to back strain, for example). Prosthesis are being developed to replace missing limbs: from a pirate’s wooden leg in the past to carbon or electronic prosthesis today. Considering the evolution there has been already, these artificial limbs are still far from offering the same levels of comfort, flexibility, reliability or dexterity a human limb obtained after millions of years of evolution.
Over the past decades, technology and research have greatly expanded the functionality and aesthetics of prosthetic feet. Today, amputees have a wide array of feet from which to choose. Various models are designed for activities ranging from walking, dancing and running to cycling, golfing, swimming and even skiing. Heavier wood and steel materials are now replaced by lightweight plastics, metal alloys and carbon-fiber composites. Many of those can even store and return some of the energy generated during walking, giving the amputees some extra support.
” The majority of prostheses available are non-articulated: they feel as comfortable as walking with closed ski-boots. “
However, despite all these advances, today’s prosthetic feet are still unable to mimic the natural functions of an intact ankle-foot. The majority of prostheses available are even non-articulated: they feel more or less as comfortable as walking with closed ski-boots. On the long run, the unnatural behavior of a prosthesis leads to overcompensation and other physical problems such as severe back pain or sore muscles.
The Ankle Mimicking Prosthetic (AMP-) Foot project started nearly 10 years ago, within the walls of the Robotics & Multibody Mechanics (R&MM) research group at the Vrije Universiteit Brussel. The aim was simple: use robotic technologies inspired by our own human body to develop innovative prosthetic feet and to improve amputees’ life quality. A decade and four prototypes later, the state-of-the-art in bionic feet has been pushed one level further. We are happy to present our new prototype for the first time.
The technology of the AMP-Foot prostheses relies on two innovative mechatronical systems. The first one provides seamless, adaptable, and more importantly, natural responses to different terrains, stride lengths, walking speeds and walking slopes which increases the overall stability and comfort of the wearer in daily life situations. The second system provides active propulsion, hereby taking over the lost functions of the calf muscles and Achilles tendon during walking. The foot basically gives the amputee the extra push a normal leg also provides. The combination of both systems brings us one step closer to mimicking an intact ankle-foot.
The prosthesis that we will present at the Cybathlon on 8 October 2016 only uses the first innovative system, which provides natural adaptability of the prosthesis to different terrains and slopes. By participating at the race we see an opportunity to compare our technology to the state-of-the-art devices, side by side, in daily life situations. But once again; for us there is only one race that really matters: the one to prosthetic devices that act and react as a sound human leg.