Abstract:The chaotic behavior of the system with anharmonic excitation is discussed by using the Melnikov method. In the limit case, the anharmonic excitation is transformed into the harmonic excitation, and the equation of motion is induced into the inverted pendulum equation. The inverted pendulum equation describes the transverse motion of a charged particle in a periodic bending crystal. The results show that the stability of the system is related to the parameters, and the system can be stabilized by adjusting the parameters properly. Even if the system parameters remain unchanged, adjusting the initial state of the system also allows the system to transit from unordered to ordered, or vice versa.