Adaptive synchronization of novel hyperchaotic Lorenz system via passive control

In this paper, the adaptive synchronization of novel hyperchaotic Lorenz systems is investigated based on passive control. By introducing three output variables, the passive controllers are designed to achieve global and asymptotical synchronization between the two novel hyperchaotic Lorenz systems without calculating the bound of the state of the system, which is very difficult to obtain. In addition, the update laws of the parameters are given and the sufficient condition is derived as well. Finally, numerical simulations are provided to illustrate the effectiveness of the proposed control scheme.