Kim Hyoung Oh, Yoo Sung Jin
School of Electrical and Electronics Engineering, Chung-Ang University, 84 Heukseok-Ro, Dongjak-Gu, Seoul 156-756, South Korea.
School of Electrical and Electronics Engineering, Chung-Ang University, 84 Heukseok-Ro, Dongjak-Gu, Seoul 156-756, South Korea.
ISA Trans. 2017 Sep;70:419-431. doi: 10.1016/j.isatra.2017.07.017. Epub 2017 Jul 27.
This paper presents a delay-independent nonlinear disturbance observer (NDO) design methodology for adaptive tracking of uncertain pure-feedback nonlinear systems in the presence of unknown time delays and unmatched external disturbances. Compared with all existing NDO-based control results for uncertain lower-triangular nonlinear systems where unknown time delays have been not considered, the main contribution of this paper is to develop a delay-independent design strategy to construct an NDO-based adaptive tracking scheme in the presence of unknown time-delayed nonlinearities and non-affine nonlinearities unmatched in the control input. The proposed delay-independent scheme is constructed by employing the appropriate Lyapunov-Krasovskii functionals and the same function approximators for the NDO and the controller. It is shown that all the signals of the closed-loop system are semi-globally uniformly ultimately bounded and the tracking error converges to an adjustable neighborhood of the origin.
本文提出了一种与延迟无关的非线性干扰观测器（NDO）设计方法，用于在存在未知时间延迟和不匹配外部干扰的情况下，对不确定纯反馈非线性系统进行自适应跟踪。与所有现有的针对未考虑未知时间延迟的不确定下三角非线性系统的基于NDO的控制结果相比，本文的主要贡献在于开发了一种与延迟无关的设计策略，以构建一种在存在未知时滞非线性和控制输入中不匹配的非仿射非线性情况下基于NDO的自适应跟踪方案。所提出的与延迟无关的方案是通过为NDO和控制器采用适当的Lyapunov-Krasovskii泛函和相同的函数逼近器来构建的。结果表明，闭环系统的所有信号都是半全局一致最终有界的，并且跟踪误差收敛到原点的一个可调邻域。
