Direct adaptive fuzzy control for a class of nonlinear systems

The problem of direct adaptive fuzzy control for a class of nonlinear systems with unknown function control gain is studied in this paper. Based on the supervisory control strategy and the approximation capability of the first-type fuzzy systems. A novel design scheme of direct adaptive fuzzy controller is proposed. The adaptive compensation term of the optimal approximation error and an extra dynamic are adopted to minify the influence of modeling error and parameter estimation error. The approach does not require the optimal approximation error being square-integrable or the supremum of the optimal approximation error to be known. 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. Simulation results demonstrate the effectiveness of the approach.