An improved adaptive stabilization control scheme for nonlinear systems with unknown gain directions

This article presents a stabilization technique for nonlinear systems with dynamics uncertainties and uncertain control gain functions by applying the fuzzy approximation. Fuzzy logical systems are applied to estimate uncertain nonlinear functions and backstepping together with adaptive control are used to design a controller. The presented controller ensures all closed-loop signals remain bounded in mean squares. Numerical results are used to illustrate the validity of the controller.