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Adaptive controller of nonlinear systems with unknown control directions and unknown input powers
Author(s) -
Guo Tiantian,
Liu Yungang,
Man Yongchao
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.5213
Subject(s) - parameterized complexity , control theory (sociology) , controller (irrigation) , nonlinear system , computer science , bounded function , set (abstract data type) , scheme (mathematics) , adaptive control , control (management) , class (philosophy) , nonlinear control , control engineering , mathematics , engineering , algorithm , artificial intelligence , physics , quantum mechanics , agronomy , biology , mathematical analysis , programming language
Summary This article is devoted to global adaptive stabilization for a class of uncertain nonlinear systems. Notably, the systems under investigation admit unknown control directions and unknown input powers, and particularly the latter, which are a new type of system uncertainties, largely challenge the feasibility of continuous feedbacks. This spurs us to pursue a switching adaptive feedback which is actual a discontinuous one with high feedback capability. To solve the control problem, a parameterized controller in a specified form is first introduced, which can globally stabilize the system once the design parameter involved belongs to a certain set. However, the controller cannot directly be implemented since the set depends heavily on the unknown input powers. To make the parameterized controller implementable, a new switching strategy is delicately proposed, which can instantly update the parameters of the controller to compensate the serious system uncertainties. It turns out that the parameterized controller with switching updating mechanism guarantees that all the signals of the closed‐loop system are globally bounded and ultimately converge to zero. Simulation examples demonstrate the effectiveness of the proposed design scheme.