Design and analysis of type-2 fuzzy PI controller

Studies have shown that PID controllers can be realized by type-1 (conventional) fuzzy logic systems (FLSs). However, the input-output mapping of such fuzzy PID controllers is fixed. The control performance will, therefore, vary if the system parameters are uncertain. Type-2 fuzzy sets offer the possibility of representing higher level of uncertainty then type-1 and hence let us model and minimize the effect of uncertainties. This paper aims at developing an Interval type-2 FLS whose inputs are error (e) and change in error (ce) of a feedback control system to control a plant whose parameters are uncertain. Authors proposed a detailed discussion on design of interval type-2 fuzzy PI controller. We used Fuzzy type-2 PI Controller to control 1^st order system and 2^nd order system with different standard reference inputs. Comparison of results of conventional PI controller, type-1 PI controller and type-2 PI fuzzy controller are presented and discussed. The simulation results verify the proposed type- 2 fuzzy PI Controller is superior to its type- 1 counterpart.