Indirect adaptive interval type-2 fuzzy control for nonlinear systems

Abstract

A new indirect adaptive type-2 fuzzy controller for a nonlinear dynamical systems is developed in this paper. The parameters of the Membership Functions (MFs) characterising the linguistic terms in the type-2 fuzzy IF-THEN rules change according to some adaptive laws for the purpose of controlling a plant to track a reference trajectory. A supervisory controller is appended to the type-2 fuzzy controller to force the state to be within the constraint set. Stability of this adaptive scheme is established using Lyapunov stability tools, where we guarantees the global stability of the resulting closed-loop system in the sense that all signals involved are uniformly bounded. The simulation results for an inverted pendulum, show better performances, that is, tracking error and control effort can be made smaller.