Robust Sliding Mode ControlUsing Fuzzy Controller

In this paper, a fuzzy sliding mode controller is designed for a nonlinear control system. Instead of fuzzifying the error and the error change, we fuzzify the sliding surface. Sliding surface is formed from error and error change, i. e. we are converting a two variable problem into a single variable problem. Now, the basis of rules formation is the sliding surface and the output is deduced by the proper organization of inference. This fuzzy sliding mode controller is based on Variable Structure Control (VSC) theory that introduces the boundary layer in the switching surface and also the control law is continuously approximated in this layer which guarantees the stability and robustness. By using Lyapunovs theory, we ensure the stability of this controller.