Full-order and reduced-order observer-based synchronization for chaotic systems with unknown disturbances and parameters

The Letter deals with the problem of synchronization of chaotic dynamic system with unknown disturbances and parameters based on observer. First, under some assumptions for drive system, a kind of full-order observer-based synchronization method is summarized. The response system is a robust adaptive full-order observer with adaptation laws for the unknown disturbances and parameters. Second, under the same assumptions, a reduced-order observer-based response system which can synchronize part states of drive system is developed. By choosing a special reduced-order gain matrix, the reduced-order observer-based response system is able to eliminate the influence of the unknown disturbances and parameters directly, so it is unnecessary for one to design the adaptation laws of them. Finally, some numerical simulations for Lorenz chaotic system are design and the simulation results are analyzed in detail. (C) 2007 Published by Elsevier B.V.