The nonlinear system control is a classical problem in control engineering. In this paper, rather than try to get accurate nonlinear dynamics, the nonlinear and uncertain dynamics are viewed as a signal. It can be estimated by an extended state observer, and compensated by a control law. Accordingly, the nonlinear uncertain system is linearized. Based on the linearized system and the key point of the U-model control, a controller can be designed to obtain predetermined closed-loop system dynamics. To get a more satisfactory performance, a compensation signal of the total disturbance estimation (CSTDE) is designed. Based on the CSTDE, a compensation of the total disturbance estimation based extended state observer (CTDESO) and a fast-response active disturbance rejection control (FRADRC) are proposed. Convergence of the CTDESO and the closed-loop stability of the FRADRC are analyzed. Four nonlinear systems are considered to testify the proposed approaches. Numerical results show that, no matter disturbances exist or not, the proposed CTDESO can linearize a nonlinear system better, and the predetermined closed-loop responses can also be achieved more satisfactorily by the FRADRC.

中文翻译：

---

一类非线性不确定系统的快速响应自抗扰控制

非线性系统控制是控制工程中的一个经典问题。在本文中，不是试图获得精确的非线性动力学，而是将非线性和不确定的动力学视为信号。它可以由扩展状态观察者估计，并由控制律补偿。因此，非线性不确定系统被线性化。基于线性化系统和U模型控制的关键点，可以设计控制器以获得预定的闭环系统动力学。为了获得更令人满意的性能，设计了总扰动估计（CSTDE）的补偿信号。基于CSTDE，提出了基于扩展状态观测器的总扰动估计补偿（CTDESO）和快速响应自抗扰控制（FRADRC）。分析了 CTDESO 的收敛性和 FRADRC 的闭环稳定性。考虑四个非线性系统来验证所提出的方法。数值结果表明，无论是否存在扰动，所提出的CTDESO都能更好地线性化非线性系统，并且FRADRC也能更令人满意地实现预定的闭环响应。