Robust fuzzy PID controller for discrete-time uncertain nonlinear systems

This paper presents a design method of robust fuzzy PID controller for discrete-time uncertain nonlinear systems. The Takagi-Sugeno fuzzy model with parameter uncertainties is employed to describe discrete-time uncertain nonlinear system with bounded uncertainties. A robust pole placement called pole coloring is used to control each local model. Controller parameters are determined through cost function minimization by an optimization procedure. Closed-loop system´s poles are chosen according to desired performance. The global controller is obtained by local control inference. Finally, two examples are treated to illustrate the effectiveness of the proposed design method.