Retractor-type Robotic Knee Prosthesis with Controllable Knee Angle

While walking with a transfemoral prosthesis, the user must maintain a stable gait without abnormalities, regardless of stride, speed, or slope angle. Conventional knee prostheses control the knee angle to replicate the gait of a healthy person. However, because they do not control the angle based on the gait characteristics of the individual user, they cannot follow real-time changes in gait pattern, which leads to gait disturbance. Therefore, in this study, we developed a knee angle control system that automatically adapts the flexion angle of the knee joint to changes in gait pattern by varying the control parameters of a robotic prosthesis. Specifically, we focused on the gait characteristics or the prior gait cycle and propose an adaptive gait model that follows the knee joint flexion angle to respond to real-time gait characteristics. Finally, we conducted clinical experiments with a transfemoral prosthesis user and successfully demonstrated the effectiveness of our proposed method in stabilizing the user’s gait.