Direct adaptive sliding mode control with nonlinearly parameterized fuzzy approximators

A new scheme of a direct adaptive fuzzy controller for a class of nonlinear systems with unknown function control gain is proposed in this paper. The design is based on the principle of sliding mode control and the approximation capability of the second type fuzzy systems. The approach is able to avoid the requirement of the upper bound of the first time derivative of the control gain, which is assumed to know a priori in some of the existing adaptive fuzzy/neural network control schemes. By theoretical analysis, the closed-loop control system is proven to be globally stable in the sense that all signals involved are bounded, with tracking error converging to zero. The simulation results are given to demonstrate the effectiveness of the approach.