Title :
Towards gait-pattern adaptation algorithms for exoskeletons based on the ZMP criterion
Author :
Gomes, Marciel A. ; Silveira, Guilherme L. M. ; Siqueira, Adriano A. G.
Author_Institution :
Dept. of Mech. Eng., Univ. of Sao Paulo at Sao Carlos, Sao Carlos, Brazil
Abstract :
This paper presents a gait-pattern adaptation algorithm for exoskeletons based on the Zero Moment Point criterion. The proposed exoskeleton is developed for lower limbs and based on a commercially available orthosis. The step length and duration are considered as the adaptation parameters, they are computed through minimization based on direct dynamics and considering the orthosis-patient interaction forces. Also, a robust controller based on the ℋ∞ method is designed to attenuate the effects of external disturbances and parametric uncertainties in the trajectory tracking errors. The dynamic model of the actual exoskeleton, with interaction forces included, is used to generate simulation results.
Keywords :
H∞ control; control system synthesis; gait analysis; orthotics; robust control; uncertain systems; ℋ∞ method; ZMP criterion; direct dynamics; exoskeleton; external disturbances; gait-pattern adaptation algorithm; lower limbs; orthosis-patient interaction forces; parametric uncertainties; robust controller design; step duration; step length; trajectory tracking errors; zero moment point criterion; Adaptation models; Exoskeletons; Foot; Heuristic algorithms; Optimization; Robots; Trajectory;
Conference_Titel :
Control Conference (ECC), 2009 European
Conference_Location :
Budapest
Print_ISBN :
978-3-9524173-9-3