Title: Novel adaptive iterative observer based on integral backstepping control of a wearable robotic exoskeleton

Authors: Brahim Brahmi; Maarouf Saad; Cristobal Ochoa-Luna; Mohammad H. Rahman; Abdelkrim Brahmi

Addresses: Department of Electrical Engineering, École de technologie supérieure, Montreal, Quebec, Canada ' Department of Electrical Engineering, École de technologie supérieure, Montreal, Quebec, Canada ' The School of Physical & Occupational Therapy, McGill University, Quebec, Canada; Centre for Interdisciplinary Research in Rehabilitation of Greater Montreal, Montreal, Quebec, Canada ' The Department of Mechanical Engineering, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA ' Department of Electrical Engineering, École de technologie supérieure, Montreal, Quebec, Canada

Abstract: Assisted control seeks to help subjects to perform physical movements of the body, which they cannot do by themselves. Passive rehabilitation therapy is very important and vital after the stroke accident. In this functioning mode, the subject is completely passive during the movement. The robot brings the injured upper arm of the patient to perform repetitive therapeutic exercises. In this case, the subject's force and the uncertainties caused by repetitive motion, such as mechanical and actuator fatigue, are considered as external disturbances that negatively influence the performance of the exoskeleton robot. To ensure the stability, robustness, and accuracy of the robot, a robust iterative observer based on nonlinear integral backstepping control was implemented with designed exercises performed by subjects. Experimental results show the effectiveness of the proposed control to deal with the external force and repetitive/periodic uncertainties.

Keywords: backstepping control; iterative control; force observer; physical therapy; uncertainty; external disturbances; passive rehabilitation mode; joint space trajectory; Cartesian space trajectory; stroke accident.

DOI: 10.1504/IJCAT.2019.100132

International Journal of Computer Applications in Technology, 2019 Vol.60 No.2, pp.154 - 164

Received: 23 May 2017
Accepted: 25 Apr 2018
Published online: 10 Jun 2019 *

Full-text access for editors Full-text access for subscribers Purchase this article Comment on this article