Abstract
The paper describes the robust algorithm for nonlinear SISO plants under parametric uncertainties and external disturbances. Unlike other known results it is shown that in the control system only one filter of dimension n is used, where n is a dynamical order of a plant. Calculation derivatives of stabilizing control signals are realized by first order observers. It allows simplifying the analytical calculation of the control system. Algorithm provides compensation of parametric uncertainties and external disturbances with required accuracy. Simulations are illustrated an efficiency of proposed scheme for an unstable nonlinear plant and control of a magnetic levitation system.