Active Impedance Control of a lower limb exoskeleton to assist sit-to-stand movement
Weiguang Huo, Samer Mohammed, Yacine Amirat, Kyoungchul Kong
Abstract
As an important movement of the daily living activities, sit-to-stand (STS) movement is usually a difficult task facing elderly and dependent people. To provide appropriate power assistance for the sit-to-stand movement, a novel intention-based Active Impedance Control (AIC) strategy applied on a lower limb exoskeleton is proposed in this paper. The AIC is able to adapt the mechanical impedance of the human-exoskeleton system towards a desired one using the exoskeleton's power assistance. In the AIC structure, a human joint torque observer is designed to estimate the human joint torques using joint angles information instead of electromyography (EMG) or force/torque sensors; a time-varying desired impedance model is proposed according the wearer's lower limb motion ability. Simulations were implemented to illustrate the characteristics and performances of the proposed approach. Experiments with a healthy subject were carried out to evaluate the effectiveness of the proposed method. The experiments show satisfactory results in terms of appropriate power assist based on the wearer's motion intention.
BibTeX
@inproceedings{icra2016_activeimpedancec,
title = {Active Impedance Control of a lower limb exoskeleton to assist sit-to-stand movement},
author = {Weiguang Huo and Samer Mohammed and Yacine Amirat and Kyoungchul Kong},
booktitle = {ICRA 2016},
year = {2016}
}