Robust Active Disturbance Rejection Control via Control Lyapunov Functions: Application to Actuated-Ankle–Foot-Orthosis

摘要: Abstract In this paper, the problem of trajectory tracking, for an Actuated-Ankle–Foot-Orthosis(AAFO) to assist gait paretic patients, is addressed. The control strategy based on system’s flatness property, which allows development Active Disturbance Rejection Control (ADRC). For purpose, Extended State Observer (ESO) designed estimate on-line unknown disturbances and canceled by injecting output ESO into feedback loop. A stability analysis estimation error dynamics carried out in Input-to Stability (ISS) framework, stating observer’s robustness. On other hand, design existence a Lyapunov Function (CLF) Sontag’s formula. discloses that tracking controller ISS, i.e. robustly stable. Finally, effectiveness ADRC validated performing real-time tests with healthy subject walking treadmill at self-selected speed. experimental results validate theoretical analysis.