Approximation-based adaptive tracking of a class of uncertain nonlinear time-delay systems in nonstrict-feedback form

ABSTRACT

This paper investigates a predefined performance control problem for adaptive tracking of uncertain nonlinear time-delay systems in nonstrict-feedback form. Nonstrict-feedback nonlinearities, time-varying delays and external disturbances are assumed to be unknown. Based on the exponential decaying design functions denoting the preassigned bounds of transient and steady-state tracking errors, some variable separation lemmas are derived to design an approximation-based robust adaptive control scheme in the presence of nonstrict-feedback time-delayed nonlinearities. The proposed control system guarantees that a tracking error remains within a predesigned bound for all t ≥ 0 and converges to a preselected neighbourhood of the origin. Compared with the existing results in the literature, the main contribution of this paper is to provide a solution on the guaranteed performance control in the presence of unknown nonstrict-feedback nonlinearities related to all delayed state variables. Simulation results illustrate the effectiveness of the proposed methodology.

KEYWORDS:

• Nonstrict-feedback
• predefined performance
• adaptive control
• nonlinear systems
• unknown time-varying delays

Additional information

Funding

This research was supported by the MSIP (Ministry of Science, ICT and Future Planning), Korea, under the ITRC (Information Technology Research Center) support programme [grant number IITP-2016-H8501-16-1018] supervised by the IITP (Institute for Information & communications Technology Promotion); the Human Resources Development [grant number 20154030200860] of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Trade, Industry and Energy; Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education [grant number NRF-2016R1D1A1B03931312].

Notes on contributors

Sung Jin Yoo

Sung Jin Yoo received his B.S., M.S., and Ph.D. degrees in Electrical and Electronic Engineering from Yonsei University, Seoul, South Korea, in 2003, 2005, and 2009 respectively. He has been a Post-doctoral researcher in the Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Illinois, from 2009 to 2010. Since 2011, he has been with the School of Electrical and Electronics Engineering, Chung-Ang University, Seoul, South Korea, where he is currently an Associate Professor. His research interests include nonlinear adaptive control, decentralized control, distributed control, fault tolerant control, and neural networks theories, and their applications to robotic, flight, nonlinear time-delay systems, large-scale systems, and multi-agent systems.