In this paper, an adaptive fuzzy fault-tolerant control approach is proposed for a class of nontriangular structure nonlinear systems, which contain immeasurable states and unknown actuator faults (actuator loss-of-effectiveness and bias fault). It should be noted that if the existing approaches are employed for nontriangular structure nonlinear systems, the algebraic loop problem may occur. In this study, fuzzy logic systems are employed to approximate unknown nonlinear functions, and a fuzzy state observer is designed to estimate immeasurable states. Then, based on the property of performance function and simple barrier Lyapunov function design method, the prescribed output tracking error dynamic performance and the corresponding stability are guaranteed. By using the parameter estimation technique, a new fault compensation strategy is developed to relax the requirement that the efficiency indicator must be known. The stability of the closed-loop system is proved by using the Lyapunov function stability theory. Finally, a simulation example is given to validate the effectiveness of the proposed control strategy.

中文翻译：

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具有误差约束的非三角结构非线性系统的自适应模糊容错控制

在本文中，针对一类包含不可测状态和未知执行器故障（执行器失效和偏置故障）的非三角结构非线性系统，提出了一种自适应模糊容错控制方法。需要注意的是，如果将现有方法用于非三角结构非线性系统，可能会出现代数环问题。在这项研究中，模糊逻辑系统被用来逼近未知的非线性函数，并设计了一个模糊状态观测器来估计不可测状态。然后，基于性能函数的性质和简单的障碍Lyapunov函数设计方法，保证了规定的输出跟踪误差动态性能和相应的稳定性。通过使用参数估计技术，开发了一种新的故障补偿策略，以放宽必须知道效率指标的要求。利用李雅普诺夫函数稳定性理论证明了闭环系统的稳定性。最后，给出了一个仿真例子来验证所提出的控制策略的有效性。