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Adaptive exact sliding tracking control of high‐order strict‐feedback systems with mismatched nonlinearities and external disturbances
Author(s) -
Xi Changjiang,
Dong Jiuxiang
Publication year - 2020
Publication title -
international journal of robust and nonlinear control
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.361
H-Index - 106
eISSN - 1099-1239
pISSN - 1049-8923
DOI - 10.1002/rnc.5231
Subject(s) - control theory (sociology) , backstepping , tracking error , bounded function , nonlinear system , adaptive control , tracking (education) , mathematics , scheme (mathematics) , computer science , uniform boundedness , control (management) , artificial intelligence , pedagogy , physics , quantum mechanics , psychology , mathematical analysis
Summary This paper investigates the issue of fuzzy‐approximation‐based adaptive exact tracking control for a class of uncertain nonlinear systems with mismatched external disturbances. Due to the existence of unstructured nonlinear functions and unexpected disturbances, most of the current reported results on adaptive control of high‐order nonlinear strict‐feedback systems are semi‐globally bounded. In this paper, a novel backstepping‐based adaptive sliding control scheme is proposed, which makes the tracking error converge to zero in spite of the presence of uncertain nonlinearities and disturbances. In particular, under the framework of adaptive control mechanism, the upper bounds of fuzzy approximation errors and external disturbances are properly estimated. Based on the estimation information, an asymptotic adaptive tracking control strategy is constructed, such that the tracking error will be forced to keep sliding along the origin once the bounds are reached. Therefore, the exact tracking control objective is achieved. Simulation example verifies the effectiveness of the proposed scheme.