含不匹配扰动非严格反馈系统的输出反馈补偿控制

针对一类非严格反馈非线性系统,系统中包含不确定函数和未知外部扰动,提出一种带不匹配扰动补偿的输出反馈模糊控制器.采用模糊逻辑系统逼近未知的非线性函数,同时构造模糊状态观测器观测系统未知状态.考虑观测器和控制器会受到外部扰动和模糊逼近误差构成的不匹配总扰动信号影响,采用改进的扰动观测器对不匹配扰动进行估计和补偿,使扰动观测误差能够在有限时间内平缓地收敛到任意小的范围,消除不匹配扰动信号对模糊观测器设计的影响.同时在控制器设计中进行扰动的精确补偿,提高系统的抗扰动性.通过Lyapunov函数证明了闭环系统所有信号都是有界的.最后,通过数值仿真进一步验证了所提出方法的有效性.

Output feedback compensation control for non-strict feedback system with mismatching disturbance

An output feedback fuzzy controller with mismatched disturbance compensation is designed for a class of non-strict feedback nonlinear systems, which contain uncertain nonlinear functions and unknown external disturbances. Considering observer and controller are affected by the mismatched total disturbance signal composed of external disturbance and fuzzy approximation error, improved disturbance observation is designed to estimate and compensate the mismatched disturbance. Through the improved disturbance observer, the disturbance observation error can gently converge to an small range in finite time, and the influence of mismatched disturbance signal on the design of fuzzy state observer can be eliminated. Fuzzy logic system is used to approximate the unknown nonlinear function, and the fuzzy state observer is constructed to observe the unknown state of the system At the same time, the accurate compensation of disturbance is carried out in the controller design to improve the robustness of the system. Through the Lyapunov theory, it is proved that all the signals in the closed-loop system are bounded. Finally, the effectiveness of the proposed method is further verified by numerical simulation.