Design of a robust observer and its applications for third order systems with disturbances

This paper presents a novel robust observer for third order minimum-phase dynamical systems with matched disturbances. By using the implicit observer techniques and the VSS theory, the robust observer is constructed for systems with arbitrarily relative degrees. The disturbance is also estimated by VSS theory. The estimated state and the disturbance are applied in a controller to place a desired pole and to cancel the disturbance of the closed-loop systems. Finally, examples and simulation results are presented to show the effectiveness of the algorithms.