两子系统在周期切换连接下的振荡行为及其机理

Oscillations and their mechanism of compound system with periodic switches between two subsystems

研究了两非线性系统在周期切换连接下的分岔和混沌行为.通过局部分析,分别给出了两子系统参数空间诸如Fold分岔、Hopf分岔等临界条件,进而考虑两子系统存在不同稳态解时通过周期切换连接下的复合系统的分岔特性,给出了不同的周期振荡行为,并揭示了其相应的产生机理.指出系统轨迹可以由切换点分割成不同的部分,分别受两子系统的控制,而随参数的变化,切换点数目成倍增加,导致系统由倍周期分岔序列进入混沌.同时,在其演化过程中,虽然子系统定性保持不变,但由于切换导致的非光滑性,复合系统不仅仅表现为两子系统动力特性的简单连接,而是会产生各种分岔,导致诸如混沌等复杂振荡行为.

Complicated behaviors of the compound system with periodic switches between two nonlinear systems are investigated in detail. Through the local analysis, the critical conditions such as fold bifurcation and Hopf bifurcation are derived to explore the bifurcations of the compound systems with different stable solutions in the two subsystems. Different types of oscillations of the switched system are observed of which, the mechanism is presented to show that the trajectories of the oscillations can be divided into several parts by the switching points, governed by the two subsystems, respectively. With the variation of the parameters, cascading of doubling increase of the switching points can be obtained, leading to chaos via period-doubling bifurcations. Furthermore, because of the non- smooth characteristics at the switching points, different forms of bifurcations may occur in the compound system, which may result in complicated dynamics such as chaotic oscillations, instead of the simple connections between the trajectories of the two subsystems.