A hybrid powered ankle exoskeleton for walking

We proposed a hybrid powered ankle exoskeleton. It can be able to supply positive mechanical power to the user during the swing phase of gait. The hybrid powered ankle exoskeleton was composed of a pair of compressed springs and a cable-driven actuator fasted to the shin. It was lightweight, and permitted the cable-driven actuator to provide the forces at the biological level to the ankle joint. Meanwhile the compressed spring also provide power (the power is different according to ankle angles.) to the ankle joint. The hybrid powered ankle exoskeleton was driven by the lithium battery attached to the waist and controlled by motor controller fixed on the transmission. By analyzing the characteristic of the lower limbs motion, the kinematics of the exoskeleton is analyzed and the dynamic model of the lower limb is built. Velocity-force control strategy aims at the change of the angle position. Based on the normal gait, the kinematics simulation of the ankle was built in MATLAB/Simulink.