Adaptive Fuzzy Control for a Class of Nonlinear Systems with Unknown Dead-Zone

The problem of adaptive fuzzy control is studied for a class of SISO nonlinear systems with unknown dead-zone and unknown function control gain in this paper. Based on the principle of sliding mode control and the property of Nussbaum function, a design scheme of adaptive fuzzy controller is proposed. By introducing characteristic function for the dead-zone model in the systems, a simplified dead-zone model is developed. The approach removes the condition of the equal slope with defined region. The adaptive compensation for the approximation error is employed to minimize the influence of modeling errors and parameter estimation errors. By theoretical analysis, the closed-loop control system is proved to be semi-globally uniformly ultimately bounded. Simulation results demonstrate the effectiveness of the approach.