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

TL;DR

This paper introduces a novel gait trajectory generation method for lower limb exoskeletons that minimizes ankle torque to reduce the force exerted by the user, enhancing balance and comfort during walking on flat ground and stairs.

Contribution

The paper presents a new optimization-based gait trajectory algorithm that minimizes ankle torque without increasing system complexity, improving user safety and comfort.

Findings

Reduced ground reaction force on crutches during experiments

Effective ankle torque minimization in gait trajectories

Improved balance and reduced user effort during walking

Abstract

Recently, the lower limb exoskeletons which providemobility for paraplegic patients to support their daily life havedrawn much attention. However, the pilots are required to applyexcessive force through a pair of crutches to maintain balanceduring walking. This paper proposes a novel gait trajectorygeneration algorithm for exoskeleton locomotion on flat groundand stair which aims to minimize the force applied by the pilotwithout increasing the degree of freedom (DoF) of the system.First, the system is modelled as a five-link mechanism dynam-ically for torque computing. Then, an optimization approachis used to generate the trajectory minimizing the ankle torquewhich is correlated to the supporting force. Finally, experimentis conducted to compare the different gait generation algorithmsthrough measurement of ground reaction force (GRF) appliedon the crutches