Adaptive Vibration Control of the Maglev Vehicle-Track Coupled High Frequency Resonance

Due to the flexibility of the steel track, self-excited vibration between the electromagnet and the steel track may occur when the EMS (electromagnetic suspension) urban maglev train is suspending above the track in a standstill. The self-excited vibration (track resonance) produces large amplitude high frequency vibration, decreases the ride comfort of the maglev vehicle, and causes fatigues to track components; therefore, the track resonance must be eliminated in a commercial maglev line. In this paper, taking the full-scale maglev multi-span steel track as the study object, a mathematical model of the track is firstly established, taking the vibration modes of the F-rails and sleepers, as well as the flexible track supports, into consideration. Then, a levitation module, which is the fundamental levitation structure for the levitation bogie, is modeled; together with the track model, a maglev vehicle-track coupled model is established. On this basis, the coupling between the two levitation units in one levitation module is investigated, and the stability of the coupled model is analyzed. To solve the track resonance problem, an adaptive vibration control scheme, which includes an LMS (least mean square) tuned finite impulse response filter in the feedback paths, is discussed. Analyses show that this scheme is capable of cancelling the vibratory components mixed in the feedback paths, thus eliminating the maglev vehicle-track coupled high frequency resonance. The scheme discussed in this paper is easy to be applied in digital maglev controllers.