Fuzzy Adaptive Output Feedback Optimal Control Design for Strict-Feedback Nonlinear Systems
针对一类严格反馈非线性系统，利用模糊逻辑系统逼近未知函数和代价函数，设计状态观测器和前馈控制器，进而开发模糊自适应最优控制器，保证闭环信号有界且输出跟踪参考信号，同时使代价函数最小。
This paper investigates fuzzy adaptive output feedback optimal control problem for a class of strict-feedback nonlinear systems. With the help of fuzzy logic systems approximating the unknown nonlinear functions and cost function, the unmeasured states are estimated by designing fuzzy adaptive state observer. Combining state observer with backstepping design technique, a feedforward controller is designed. Based on the designed feedforward control strategy, the controlled nonlinear system can be converted to an equivalence nonlinear system in affine-form. Finally, a fuzzy adaptive optimal controller with parameters adaptive laws is developed. The whole control scheme consists of a feedforward controller and a feedback optimal controller. It is shown that the proposed output feedback optimal control approach can guarantee that all signals in the closed-loop system are bounded, and the system output can track the reference signal. In addition, the proposed control approach can guarantee cost function is the smallest. Simulation results are given to demonstrate the effectiveness of the proposed control approach.