An adaptive fuzzy PI control for a class of unknown nonaffine systems

In this work a fuzzy adaptive PI controller is proposed for a class of uncertain nonaffine nonlinear systems. The parameters of the PI controller that can achieve the control objectives are approximated by a set of fuzzy systems. The fuzzy systems´ parameters are adjusted by the gradient descent algorithm. The purpose behind the use of this adaptation algorithm is to minimize the error between the unknown ideal PI controller and the fuzzy PI controller. The stability of the closed-loop system is proven analytically based on Lyapunov approach. A simulation example is presented to illustrate the performance of the proposed scheme.