Premium
Two‐stage stability control for strict‐feedback systems with input delays and input nonlinear uncertainties
Author(s) -
Yan Shuai,
Sun Weichao,
Fei Zhongyang
Publication year - 2018
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.4224
Subject(s) - control theory (sociology) , backstepping , nonlinear system , controller (irrigation) , compensation (psychology) , computer science , bounded function , stability (learning theory) , constant (computer programming) , scheme (mathematics) , nonlinear control , control (management) , mathematics , adaptive control , psychology , mathematical analysis , physics , quantum mechanics , artificial intelligence , machine learning , psychoanalysis , agronomy , biology , programming language
Summary In this paper, a two‐stage control procedure is proposed for stabilization of a class of strict‐feedback systems with unknown constant time delays and nonlinear uncertainties in the input. A nominal controller is first designed to compensate input time delays without considering input nonlinear uncertainties. Extended from backstepping algorithm, input delay compensation is realized by means of predicted states that are computed through integration of cascaded system dynamics, making the nominal closed‐loop system asymptotically stable. Based on the nominal controller presented for the input delay system, a multi‐timescale system is subsequently developed to estimate the unknown input nonlinearity and make the estimate approach the nominal control input as fast as possible. It is proved that the proposed control scheme can make states of the strict‐feedback systems converge to zero and all the signals of the closed‐loop systems are guaranteed to be bounded in the presence of input time delays and nonlinear uncertainties. Simulation verification is carried out to illuminate the effectiveness of the proposed control approach.