Adaptive Type-2 Fuzzy Control of Non-linear Systems

The paper describes the development of two differenttype-2 adaptive fuzzy logic controllers and their use for thecontrol of a non linear system that is characterized by thepresence of bifurcations and parameter uncertainty.Although a type-2 fuzzy logic controller is able to handle the nonlinearities and the uncertainties present in a system, itsrobustness and effectiveness can be increased by the use of anopportune adaptive algorithm. A simulation study was conductedto compare the behavior of adaptive controllers with that ofsimple type-1 and type-2 fuzzy logic controllers. The system to becontrolled, used for the simulation, is a continuous bioreactor forthe treatment of mixed wastes in which a culture of PseudomonasPutida is carried out while phenol and glucose are carbon andenergy sources. From simulations results it can be seen that bothadaptive controllers, but in particular the self tuning controller,have a better performance being able to eliminate oscillationsthat are present with basic fuzzy controllers.