An Indirect Decoupled Adaptive Fuzzy Sliding-Mode Control through width adaptation

Abstract

In this paper, A decoupled fuzzy sliding-mode control design scheme through width adaptation for a class of fourth-order nonlinear systems is presented. Each subsystem, which is decoupled into two second-order systems in this paper, is classified to main and sub controlled purpose. Each sliding surface is constructed though state variable of the decoupled subsystem. and, we define main and sub target condition for these sliding surfaces. We made intermediate variable which are interconnected both surface conditions from the sub sliding surface condition. The proposed adaptation law, which results from the indirect adaptive approach, is used to appropriately determine the width of the unknown system variables which is changed main target condition for including intermediate variable. And the result of the membership functions in the THEN part will vary with the width adaptation. An adaptive law is then used to tune the width in the THEN part to appropriately determine each membership function's distribution. In this study, the main advantage of the proposed method not only maintain, when it is not easy to characterize the linguistic control rules and its membership function distribution without expert knowledge, that the structure of fuzzy controller dose not need to be changed while using a common design procedure, but also reduce computing time considerably. Finally, a nonlinear system simulation example is applied to verify the effectiveness of the proposed Adaptive fuzzy-sliding mode controller.