Open AccessAdaptive quantised control of uncertain non‐linear systems with state constraints and time‐varying delays
Author(s) -
Xia Xiaonan,
Kang Guanpeng,
Zhang Tianping,
Fang Yu
Publication year - 2020
Publication title -
iet control theory and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.059
H-Index - 108
eISSN - 1751-8652
pISSN - 1751-8644
DOI - 10.1049/iet-cta.2019.0769
Subject(s) - control theory (sociology) , controller (irrigation) , adaptive control , state (computer science) , mathematics , logarithm , focus (optics) , lyapunov function , computer science , control (management) , nonlinear system , algorithm , artificial intelligence , mathematical analysis , physics , optics , quantum mechanics , agronomy , biology
This study proposes an adaptive quantised fuzzy control strategy for a class of non‐linear systems with time‐varying delay, state constraints, and input unmodelled dynamics. Design difficulties focus on the fact that the input‐quantised actuator possesses both unknown control gain and non‐linear input unmodelled dynamics, and all the states are required to satisfy state constraints. To remove these obstacles, integral barrier Lyapunov functions combined with Nussbaum functions are designed to deal with the unknown control gains and state constraints, and a quantised controller combined with the normalised signal is developed to tackle the quantised input and input unmodelled dynamics. To avoid the chattering and reduce the quantisation error in a wide scope of the control volume, a novel logarithmic uniform hysteresis quantiser is employed, which has both advantages of the existing uniform quantiser and hysteresis quantiser. Two simulation examples of practical control systems are conducted to demonstrate the effectiveness of the proposed control protocol.