基于指数饱和函数的非线性系统自适应模糊控制

Adaptive fuzzy control for nonlinear system based on exponential saturation function

为减小模糊逻辑系统的逼近误差,引入指数饱和函数项对一类未知非线性系统进行间接自适应模糊控制.直接用模糊逻辑系统逼近未知非线性函数,基于广义误差对模糊逻辑系统中的未知参数进行自适应调整,并用指数饱和函数项对逼近误差进行补偿.该方法不但能使跟踪误差收敛到原点的一个小邻域内,而且通过适当减小控制器中设计参数,可使跟踪误差减小.仿真验证了该方法的有效性.

In order to reduce the approximate errors of fuzzy logic systems, an indirect adaptive fuzzy control for a class of unknown nonlinear systems is presented by introducing exponential saturation function term. In this method, fuzzy logic systems are employed to approximate unknown nonlinear functions, the unknown parameters in fuzzy logic systems are adjusted adaptively by generalized error, and the exponential saturation function term is used to compensate the approximation errors. It is proved that the method can not only make the tracking error converge to the small neighborhood of origin, but also reduce the tracking error by increasing the value of designed parameters. Simulation results indicate the effectiveness of this method.