In this paper, a designed scheme for the fuzzy controller through width adaptation of universe of discourse is presented. The proposed adaptation law, which results from the direct adaptive approach, is used to appropriately determine the width of output variable. The resulting of membership function in THEN-part will vary from the width adaptation. The main advantage of the proposed method is that the structure of fuzzy controller does not need to be changed while using a common design procedure. We know that it is not easy to characterize the linguistic control rules and its membership function distribution without expert's knowledge; especially, in those cases when the input variables of fuzzy controller are increased. In this study, we first organize a fuzzy controller without any specific experience information about the controlled system. An adaptive law is then used to tune the width of universe of discourse in the THEN-part to appropriately determine each membership function's distribution. Finally, a nonlinear system simulation example is applied to verifying the effectiveness of the proposed fuzzy controller.
