This article proposes a high-order disturbance observer (HODO) and dynamic surface control (DSC) technique-based adaptive fuzzy control scheme for nonlinear systems subjected to input saturation and external time-varying disturbances. First, based on a Sigmoid function, the saturation input is tackled by utilizing a well-defined nonlinear smooth function. Furthermore, HODO and fuzzy logic systems are used to estimate the external disturbances and to handle the lumped unknown functions, respectively. Then, by using the backstepping method and DSC technique, a HODO-based adaptive fuzzy tracking control scheme is proposed for nonlinear systems with saturation nonlinearity, uncertainties, and external disturbances. The Lyapunov analysis method is used to prove that all signals in the entire system are semiglobally uniformly ultimately bounded (SGUUB). In addition, the tracking error converges to a compact set with a tunable error bound determined by some design parameters. Finally, a numerical simulation of two-stage chemical reactor shows the effectiveness of the developed tracking control strategy.

中文翻译：

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具有输入饱和和外部干扰的非线性系统的模糊鲁棒约束控制


本文提出了一种基于高阶扰动观测器（HODO）和动态表面控制（DSC）技术的自适应模糊控制方案，用于承受输入饱和和外部时变扰动的非线性系统。首先，基于 Sigmoid 函数，利用定义明确的非线性平滑函数来处理饱和输入。此外，HODO 和模糊逻辑系统分别用于估计外部干扰和处理集总未知函数。然后，利用反步法和DSC技术，针对具有饱和非线性、不确定性和外部干扰的非线性系统，提出了一种基于HODO的自适应模糊跟踪控制方案。利用李亚普诺夫分析方法证明整个系统中的所有信号都是半全局一致最终有界（SGUUB）的。此外，跟踪误差收敛到一个紧凑集，其可调误差范围由一些设计参数确定。最后，两级化学反应器的数值模拟显示了所开发的跟踪控制策略的有效性。