Neuro-dynamic Control of an above Knee Prosthetic Leg

: The control of a prosthetic leg for above-knee amputees is fraught with several challenges. While the dynamics of the knee-ankle system are complex and unknown, the control problem is exacerbated by the lack of desired joint trajectories as they are dictated by the locomotion needs of the individual. Improper movement of the knee and ankle joints can have serious implications for the safety of the user. Further, dissimilarities in the gait of the amputated side and the intact side can result in gait abnormalities that result in increased metabolic energy consumption and musculo-skeletal pains in the short term, and cardiovascular and other health complications in the long term. In this paper, we propose a novel neuro-dynamic control strategy that can guarantee stable control of the prosthetic limb while minimizing the gait asymmetry between the intact and prosthetic limb. Further, the algorithm learns the unknown elements of the dynamics and adapts to the changing locomotion needs of the individual. The efficacy of the proposed approach is demonstrated through numerical simulations.