Robust Control of Lower Extremity Exoskeleton Rehabilitation Robot Based on Nominal Modeling

This research tackles the issue of controlling joint angle tracking in lower extremity exoskeleton rehabilitation robots by presenting a method known as Robust Control of Lower Extremity Exoskeleton Rehabilitation Robots based on the Nominal Model (RC-LEERR-NM). Initially, the dynamics model for the single-leg swing phase of the exoskeleton was developed using the Lagrange method, followed by a thorough analysis of the exoskeleton's gait. The dynamics model was then divided into two components: the nominal model and the robust control, which together form the control terms necessary for the effective management of the exoskeleton system. Additionally, an integral-type Lyapunov function was created to demonstrate that the proposed control system ensures global asymptotic stability. The method's effectiveness was confirmed through simulations and experimental results, which indicated that the RC-LEERRNM method significantly outperforms PID control in terms of dynamic stability and trajectory tracking accuracy, successfully enabling the lower extremity exoskeleton to accurately follow human gait patterns.