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Redundant Input Safety Tracking for Omnidirectional Rehabilitative Training Walker with Control Constraints
Author(s) -
Sun Ping,
Wang Shuoyu
Publication year - 2017
Publication title -
asian journal of control
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.769
H-Index - 53
eISSN - 1934-6093
pISSN - 1561-8625
DOI - 10.1002/asjc.1335
Subject(s) - control theory (sociology) , backstepping , actuator , tracking error , trajectory , computer science , nonlinear system , tracking (education) , stability (learning theory) , bounded function , engineering , control engineering , control (management) , adaptive control , artificial intelligence , mathematics , psychology , mathematical analysis , pedagogy , physics , quantum mechanics , astronomy , machine learning
This study proposes a nonlinear safety tracking method based on redundant degrees of freedom with control constraints to protect against actuator faults that may occur in robotic rehabilitative walkers. A redundant input model with uniform actuator faults is constructed by separating the corresponding columns of the control matrix, and an adaptive robust control method is presented to deal with the separated term that is considered in relation to the extrinsic bounded interference that occurs on robotic walker systems. Based on the backstepping technique, an adjustable control law can be designed to maintain stability in terms of solving linear matrix inequality. The trajectory tracking error performance and the velocity tracking error performance are derived simultaneously. As an application, simulation results confirm the effectiveness of the proposed method and verify that the walker can provide safe sequential motions even when one wheel actuator fails.