A control system that integrated electrical signals generated during muscle contractions and using a person's manner of walking resulted in improved real-time control of a powered prosthetic leg for different modes of walking, a new study published on JAMA.
Leg prostheses that provide power are now available in the market, but different ambulation modes require very different control sequences for operating powered prosthetic limbs. Transitioning these powered limbs between different ambulation modes requires patients to slow down, stop, press buttons on an electronic key fob, or perform unrelated body movements.
To maximize benefit from these devices and ensure patient safety, control systems must automatically identify which ambulation mode the patient is using and provide the correct prosthesis response.
The control system developed at the Rehabilitation Institute of Chicago understands the intentions of the wearer and automatically adjusts its motions to fit with where and how the person is walking.
The system is based on electromyography sensors positioned over the muscles of the remaining leg. The signals collected by the sensors are fed into a computer that aggregates them and deduces the wearer's intentions.
The activation of the prosthesis is completely natural and intuitive for the user because the signals come from the very muscles that used to move the original appendage. The system also uses pattern recognition algorithms to predict the next stride and adjusts accordingly to produce the kind of step the wearer intends.