A nonlinear chattering-free sliding mode control method is designed to stabilize fractional chaotic systems with model uncertainties and external disturbances. The main feature of this controller is rapid convergence to equilibrium point, minimize chattering and resistance against uncertainties. The frequency distributed model is used to prove the stability of the controlled system based on direct method of Lyapunov theory. Numerical simulations are presented to illustrate the effectiveness of the method. تفاصيل المقالة