Synchronization of two different chaotic systems with unknown parameters

In this Letter, a general method is proposed for the synchronization between two different chaotic systems with unknown parameters. This approach is based on the invariance principle of differential equations, and employs a combination of feedback control and adaptive control. With this method one can achieve synchronization between almost all chaotic systems, e.g., Lorenz system, Chen system, Liu system, Rössler system, Chua's system, etc. Although the models used in the research are the systems with unknown parameters, the method is also applicable to the systems with known parameters. Numerical simulations results are presented to demonstrate the effectiveness of the method.