Knee Angle Control System That Responds to Changes in Gait for Robotic Prosthesis

Abstract

While walking with a trans-femoral prosthesis, the prosthetic user needs to acquire a stable gait without abnormal gait, regardless of stride, speed, or slope angle. Conventional knee prostheses control the knee angle to reproduce the gait of healthy person. However, because they do not control based on the gait characteristics of the individual prosthetic user, the prostheses cannot follow the real-time changes in gait pattern, leading 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 the changes in gait pattern by varying the control parameters of the robotic prosthesis. Specifically, we focused on the gait characteristics before one gait cycle and proposed an adaptive gait model that follows the knee joint flexion angle to the real-time gait characteristics. Finally, we conducted clinical experiments by a trans-femoral prosthesis user and showed the effectiveness of proposed method by stabilizing the gait.