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Low‐complexity adaptive tracking control of MIMO nonlinear systems with unknown control directions
Author(s) -
Zhang JinXi,
Yang GuangHong
Publication year - 2019
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.4486
Subject(s) - backstepping , control theory (sociology) , robustness (evolution) , multiplicative function , bounded function , nonlinear system , adaptive control , tracking error , computer science , iterative learning control , constraint (computer aided design) , robust control , mimo , control (management) , mathematics , artificial intelligence , mathematical analysis , computer network , biochemistry , chemistry , physics , geometry , channel (broadcasting) , quantum mechanics , gene
Summary This paper is concerned with the tracking control problem for a class of multiple‐input–multiple‐output systems with unmatched disturbances and the unknown additive and multiplicative nonlinearities. The objective is to provide a low‐complexity control solution in the sense that (i) approximating structures are not involved, despite unknown nonlinearities and (ii) iterative calculations of command derivatives are avoided in the backstepping design. A robust adaptive control strategy is proposed to fulfill the task. In the control design, a new‐type adaptive law is first developed to update Nussbaum gains to handle control direction uncertainties, while ensuring Nussbaum gains bounded. Then, the potential robustness of error constraint techniques is exploited to counteract the effects of unknown nonlinearities and disturbances and achieve predefined transient and steady‐state tracking performance. Finally, simulation results are given to illustrate the above theoretical findings.