Upper Extremity Load Reduction for Lower LimbExoskeleton Trajectory Generation Using AnkleTorque Minimization

Abstract

Recently, the lower limb exoskeletons which provide mobility for paraplegic patients to support their daily life have drawn much attention. However, the pilots are required to apply excessive force through a pair of crutches to maintain balance during walking. This paper proposes a novel gait trajectory generation algorithm for exoskeleton locomotion on flat ground and stair which aims to minimize the force applied by the pilot without increasing the degree of freedom (DoF) of the system. First, the system is modelled as a five-link mechanism dynamically for torque computing. Then, an optimization approach is used to generate the trajectory minimizing the ankle torque which is correlated to the supporting force. Finally, experiment is conducted to compare the different gait generation algorithms through measurement of ground reaction force (GRF) applied on the crutches.