Bionic Knee Joint Structure and Motion Analysis of a Lower Extremity Exoskeleton

Abstract

In order to solve the problem of poor human-machine compliance of wearable lower extremity exoskeleton robots, a modified lower extremity exoskeleton with a four-bar mechanism in the knee joint is proposed and analyzed. The advantages of the four-bar mechanism relative to the traditional two-bar hinge structure are explained by analyzing the physiological characteristics of the human knee joint. In addition, the kinematics of traditional and modified lower extremity exoskeletons are compared. The constraint relationship and motion equations of instantaneous rotating center of the four-bar linkage knee joint are derived. Finally, gait simulations are performed on the two lower extremity exoskeleton models to obtain the position and angle information of the joints. The influence of the four-bar mechanism of bionic knee joint on the lower extremity exoskeleton is described. The simulation results show that the modified lower extremity exoskeleton not only improves the biomimetic performance of knee joint, but also conforms to the characteristics of human gait.