Nonlinear Extended Observer-Based ADRC for a Lower-Limb PAM-Based Exoskeleton

In lower-limb rehabilitation systems, exoskeleton robots are one of the most important components. These help patients to execute repetitive exercises under guidance physiotherapists. Recently, pneumatic artificial muscles (PAM), a kind actuator that acts similarly human muscles, have been chosen power robot for better human–machine interaction. order enhance performance PAM-based robot, this article implements an active disturbance rejection control (ADRC) strategy with nonlinear extended state observer (NLESO). Moreover, stability closed-loop system is proved by Lyapunov’s theory. Finally, experimental results show proposed strategy, can effectively track desired trajectories even when external disturbance.