非线性耦合统一混沌系统的同步

研究非线性耦合的两个统一混沌系统的同步问题．首先利用线性时变系统的稳定性理论，推出当两个统一混沌系统的误差系统渐近稳定时，耦合函数的参数选择范围，从而得出两个统一混沌系统全局渐近同步的充分条件．然后基于Routh-Hurwitz稳定性判别方法，同样得出了混沌系统同步的一个充分条件．通过数值仿真发现，根据第1种方法选择的参数能使混沌系统全局渐近同步；而依据第2种方法选择的参数，即使误差系统系数矩阵的瞬间特征值具有负实部，也会出现混沌同步失去的情况，从而表明了该分析方法的有效性．

Nonlinearly Coupled Synchronization of Unified Chaotic Systems

The issue of the synchronization of two nonlinearly coupled unified chaotic systems is dealt with. A sufficient condition for synchronization is attained by using the criterion of the stability of time-varying systems. In addition, another sufficient condition for synchronization is obtained when the stability criterion of Routh-Hurwitz is employed. Compared with the two kinds of results, the synchronization state is stable by the first criterion when the range of the parameters in a vector coupling function is given. Unfortunately, the synchronization is sometimes loss when using the second criterion. Moreover, the analytic method is tested in coupled unified system, and the numerical results show the effectiveness of the theoretical analysis.