Sliding-Mode Adaptive Observer Approach to Chaotic Synchronization

Extensions of sliding-mode adaptive observer are presented for state reconstruction of nonlinear systems with uncertainty having unknown bounds. The observer uses nonlinear gains that are smoothened versions of classical sliding-mode gains and they are continuously updated to guarantee a globally stable observation error. This observer is applied to Chua’s circuit in a chaotic synchronization scheme. A generalization to known waveform type disturbances and measurement uncertainties is pointed out. [S0022-0434(00)02304-2]