Journal of Systems Engineering and Electronics ›› 2025, Vol. 36 ›› Issue (1): 269-279.doi: 10.23919/JSEE.2024.000130

• CONTROL THEORY AND APPLICATION • Previous Articles    

Observed-based adaptive neural tracking control for nonlinear systems with unknown control directions and input delay

Yuxuan DENG(), Qingling WANG()   

  • Received:2023-11-07 Accepted:2024-07-28 Online:2025-02-18 Published:2025-03-18
  • Contact: Qingling WANG E-mail:yuxuandeng@seu.edu.cn;csuwql@gmail.com
  • About author:
    DENG Yuxuan was born in 1999. She received her B.S. degree from the College of Intelligent Systems Science and Engineering, Harbin Engineering University in 2022. She is currently working toward her M.S. degree in the School of Automation, Southeast University. Her research interests include time-delay system, and adaptive neural network. E-mail: yuxuandeng@seu.edu.cn

    WANG Qingling was born in 1982. He received his B.S. and M.S. degrees from Central South University, Changsha, China, in 2007 and 2010, respectively, and Ph.D. degree in control science and engineering from Harbin Institute of Technology, Harbin, China, in 2014. He was a visiting student with Australia National University, Canberra, Australian Capital Territory, Australia, from 2012 to 2014, and was a visiting scholar at Technical University of Berlin, Germany, in 2016. He is currently a professor with the School of Automation, Southeast University, Nanjing, China. His current research interests include distributed optimization, constrained control, adaptive control, and cooperative control of multi-agent systems. E-mail: csuwql@gmail.com
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (62373102), the Jiangsu Natural Science Foundation (BK20221455), and the Anhui Provincial Key Research and Development Project (2022i01020013).

Abstract:

Enhancing the stability and performance of practical control systems in the presence of nonlinearity, time delay, and uncertainty remains a significant challenge. Particularly, a class of strict-feedback nonlinear uncertain systems characterized by unknown control directions and time-varying input delay lacks comprehensive solutions. In this paper, we propose an observer-based adaptive tracking controller to address this gap. Neural networks are utilized to handle uncertainty, and a unique coordinate transformation is employed to untangle the coupling between input delay and unknown control directions. Subsequently, a new auxiliary signal counters the impact of time-varying input delay, while a Nussbaum function is introduced to solve the problem of unknown control directions. The leverage of an advanced dynamic surface control technique avoids the “complexity explosion” and reduces boundary layer errors. Synthesizing these techniques ensures that all the closed-loop signals are semi-globally uniformly ultimately bounded (SGUUB), and the tracking error converges to a small region around the origin by selecting suitable parameters. Simulation examples are provided to demonstrate the feasibility of the proposed approach.

Key words: adaptive neural network, dynamic surface control, unknown control direction, input delay