Adaptive Active Disturbance Rejection Control of an Actuated Ankle Foot Orthosis for Ankle Movement Assistance

Foot-drop (FD) is a post-stroke gait disorder characterized by impaired foot lifting during the swing phase. This paper focuses on providing a continuous ankle joint assistance throughout the gait cycle using an actuated ankle foot orthosis (AAFO). The control strategy is based on an adaptive active disturbance rejection controller (AADRC) such that the orthosis provides the only required amount of assistance to complement the human effort needed to perform the walking activity. The proposed controller exhibits adaptability, making it suitable for various subjects without the need for prior parameter identification. To demonstrate its effectiveness, the control strategy is experimentally validated with five healthy subjects and compared to state-of-the-art controllers.