Retractor-type robotic knee prosthesis to maintain flexion posture according to change in circumstances

Abstract

For lower limb amputees, trans-femoral prostheses play an important role not only in regaining the gait ability of amputees, but also daily life activities. In recent years, the use of robotic technology has led to the development of robotic prostheses that provide better safety and comfortness in practicing normal walking. However, since daily activities other than walking rely heavily on the function of the sound leg, it is important not to put excessive burden on the sound leg in a mid-back posture and sit-to-stand motion. Therefore, in this study, in order to reduce the burden on the sound leg while using a prosthesis, we developed a new robotic prosthesis that maintains flexion posture at arbitrary knee angle in circumstances where the burden on the sound leg increases during daily life. Moreover, we proposed a model of daily activities based on finite state machine that represents not only walking, but also all daily activities such as sit-to-stand motion. Finally, we conducted experiments by a user of trans-femoral prosthesis and showed the effectiveness of maintaining flexion posture.

Keywords

• trans-femoral prosthesis
• robotic prosthesis
• flexion posture
• retractor
• finite state machine