Effects of mechanical interfaces on magnetic levitation systems and analysis of self-excited vibration mechanisms in coupled systems

Magnetic levitation is a non-self-stabilizing system that requires high control performance. The system's stability is affected by the mechanical interface between the levitation object and the loading device, with self-excited vibration generated in the operation process. This paper proposes to consider the mechanical behavior of the contact interface in the magnetic levitation system. Since electromagnetic and control systems are mechanically equivalent, the coupled electric-magnetic-mechanical model is established by adopting the lumped mechanical modeling method. Furthermore, the effect of the contact clearance on the mechanical behavior of the system is analyzed using the Routh-Hurwitz theory. The research results show that with the decrease in the contact clearance, the vibration frequency increases. When the vibration frequency exceeds the critical value, a continuous vibration phenomenon occurs in the system under the joint action of feedback and energy mechanisms. Finally, the effect of interface parameters on the vibration characteristics is analyzed using the fourth-order Runge-kutta numerical method. The analyses show that the interface contact leads to combination frequency and frequency multiplication components in the coupled system.