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Adaptive robust dynamic surface control for uncertain strict‐feedback nonlinear systems using fuzzy logic systems
Author(s) -
Chen Sanyan,
Wang Yuchao,
Shi Wenrui,
Wu Hansheng
Publication year - 2021
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.2253
Subject(s) - control theory (sociology) , backstepping , fuzzy logic , nonlinear system , controller (irrigation) , mathematics , upper and lower bounds , robust control , fuzzy control system , filter (signal processing) , adaptive control , computer science , control (management) , artificial intelligence , agronomy , computer vision , mathematical analysis , physics , quantum mechanics , biology
In this paper, an adaptive robust stabilization problem is dealt with for a class of uncertain strict‐feedback nonlinear systems in the presence of unknown structure uncertainties, external disturbances, and unknown time‐varying virtual control coefficients. It is not required to know the upper bounds of external disturbances, as well as the upper and lower bounds of unknown time‐varying virtual control coefficients. The controller is designed by adopting backstepping. In addition, to avoid suffering from the problem of ‘explosion of terms’, a dynamic surface control approach is employed by introducing the first‐order low‐pass filter. Furthermore, at every step of the backstepping design procedure, fuzzy logic systems are used to approximate the unknown structure uncertainties. In particular, the norms of weight matrices and the upper bounds of approximation errors of fuzzy logic systems are supposed to be unknown. It is also shown that the proposed controller can guarantee the uniform boundedness of uncertain strict‐feedback nonlinear systems. Finally, the simulation for a single‐link manipulator actuated by a brush DC motor is carried out to illustrate the validity of the proposed controller.