Design of a sliding mode controller based on fuzzy logic

On the basis of fuzzy logic, a sliding mode control is developed for a class of nonlinear systems. To eliminate the chattering in sliding mode control, a fixed boundary layer around the switch surface is used. Within the boundary layer, since the fuzzy logic control is applied, the chattering phenomenon, which is inherent in a sliding mode control, is avoided by smoothing the switch signal. Outside the boundary, the sliding mode control is applied to driving the system states into the boundary layer. The control method is verified by designing a controller for a nonlinear time-varying system using the proposed method and the simulation results demonstrate the efficiency of the method.