The world’s most intelligent prosthetic limb
24 June 2016
Blatchford developed the first prosthetic limb with integrated robotic control of the knee and foot; a system in which the parts work together like a human leg.
Where previously lower leg prosthetic wearers have had to plan their days meticulously according to the limitations of terrain they can tackle – a walk in the country may be more trouble than it’s worth – the smart robotics in the Linx Limb system constantly monitors and adapts to movements and automatically adjusts to the environment.
The Linx uses a network of sensors across both the knee and foot, which act like human nerves, continuously collecting data on the user, activity, environment and terrain. The central computer then acts like the brain, using this data to adapt the limb’s response using pioneering software called Mi² (Motion integrated intelligence). This means the wearer can walk confidently, knowing that the limb will be at the right speed and support level at all times.
Even simply standing still can be a challenge for lower limb prosthetic wearers, who use a lot of energy and concentration to hold the leg steady, which means that severe back pain is common. The Linx senses when the wearer comes to a standstill and automatically locks so that the wearer can relax, and when they want to move again the sensors immediately leap into action and unlock seamlessly.
When a patient is first fitted with the Linx, a clinician programs its central computer by running through a calibration sequence so that the limb learns how its wearer naturally walks and adapts accordingly. This is done via a Bluetooth connection to a software app that shows in real time what the sensors are picking up as it detects the wearer’s natural speed and movements. A smart algorithm then calibrates the limb automatically in one simple step as the knee and the foot joints 'talk' to each other; previous prosthetics would require each joint to be calibrated in turn in a lengthy process that would often require repeat adjustments.
In England alone, there are currently around 45,000 people who rely on lower limb prostheses, with around 4,000 lower limb amputations carried out each year. Currently only a fraction of these will have access to the latest technology in the Linx as it falls outside NHS budgets; most Linx limbs in use today are benefiting amputees in the US, Germany and Norway. Despite a high price point, the Linx can save money in the longer term, for example by potentially reducing secondary treatments required for back pain, arthritis, falls, and sound-side joint replacements, extending the life of sockets, and potentially lessening the need for carers in the longer term.
MacRobert Award judge, Dr Frances Saunders CB FREng, said: “Trying to mimic exactly how a human limb behaves in all circumstances is almost mission impossible, yet Blatchford has achieved a huge leap forward in making the knee and ankle joints work together as an integrated system, enabling it to adapt immediately to both the actions of the wearer and changes in the environment. The company is changing the way we look at how to model and enhance human locomotion. I expect this technology will have wider implications, and find new uses in the future.”
Video courtesy of the Royal Academy of Engineering.
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