Gait Deviation Correction Method for Gait Rehabilitation With a Lower Limb Exoskeleton Robot

Abstract

Exoskeleton robots play an essential role in the gait rehabilitation of lower limbs in stroke patients. Existing lower limb exoskeleton robots commonly employ reference trajectories to perform gait rehabilitation training for patients. However, a significant gait deviation may occur between the gait trajectory of the wearer and the reference trajectory due to the following reasons. They are the physically flexible connection and the applied compliance control strategy between the wearer and the exoskeleton. This paper proposes a gait deviation correction method (GDCM) to decrease the gait deviation for lower limb exoskeleton robots. First, the gait curves of the exoskeleton and the wearer were obtained by using the clinical gait analysis (CGA) curve as a reference trajectory for the exoskeleton. Then, a gait correction model was trained by a database containing the CGA curve, the gait trajectory of both the exoskeleton and wearer obtained from 15 participants, and their body feature parameters such as height, weight, and hip-length. Finally, the gait correction model was introduced into the control system to modify the input trajectory of the exoskeleton. The experimental results showed that the gait trajectories of the wearer’s hip and knee after correction were closer to the CGA curve than without modification. The minor gait trajectory deviation should lead to a better efficacy of the training with the robot if the reference trajectory is assumed to be optimal.