Researchers in Dr, Goldfarb’s laboratory at Vanderbilt University have recently unveiled a new bionic leg, which promises to substantially increase mobility for above the knee amputees. The leg is motorized at both the knee and the ankle to give users a more natural gait, as well as the ability to walk up stairs.
In order to further facilitate movement, the leg is outfitted with sensors that can predict which movement the user is going to make. Although not connected directly to the neural system, the sensors dynamically alter the settings of the motors to make it possible for the user to execute a series of pre-patterned activities that include standing, sitting, walking up an incline and, notably, walking up stairs.
Additionally, researchers have included a new ‘anti-stumble’ feature, which, when the leg senses that the user is stumbling, mimics the spinal cord reflex of sticking out the leg and planting the foot on the ground. As of yet, the leg is not capable of executing ‘spontaneous’ activities like dancing, but there is hope that this may be possible in the future.
Just last week, Neurogadget posted an updated story about Zac Vawter who climbed 103 steps to the top of Chicago’s Willis Tower using a bionic limb. However, Dr. Goldfarb notes that the newer version of the leg is still an advancement on the previously demonstrated technology. The newer leg is designed for mass production, and not made specifically for one individual. According to Goldfarb, “There is a big difference between designing a neural system in a lab that will work with one person and developing a system suitable for a mass market.”
The secret behind the success of this leg is that it provides power to both the knee and the ankle, and that it only weighs 9 pounds (less than a biological human leg). These two advances decrease the amount of energy required by the user to move the leg by 30 – 40%. As a result, users equipped with the leg can walk 25% faster on level surfaces then those equipped with a traditional (ie. non-powered) prosthetic. The device can maintain power for 3 hours of normal activity, which amounts to approximately 13-14 kilometres of normal walking.