Effects of the guideway's vibrational characteristics on the dynamics of a Maglev vehicle

Abstract

The levitation control system in an electromagnetically levitated vehicle controls the voltage in its winding to maintain the air gap, which is the clearance between the electromagnet and the guideway, within an allowable range of variation, while strongly interacting with the flexible guideway. Thus, the vibrational characteristics of the guideway play an important role in the dynamics of Maglev (magnetically levitated) vehicles that utilise an active electromagnetic suspension system. In this study, the effects of the guideway's vibrational characteristics, such as natural frequency and damping, on the dynamics of the Maglev vehicle UTM-02 are numerically and experimentally analysed. From these analyses, the coupled equations of motion of the simplified vehicle–guideway model with three degrees of freedom are derived. Eigenvalues are calculated and frequency response analysis is also performed, in order to obtain a clear understanding of the dynamic characteristics resulting from the guideway's vibrational characteristics. To verify the numerical results, air gap tests of the urban Maglev vehicle UTM-02 are also carried out. These results lead us to recommend that the natural frequency of the guideway be decreased by increasing mass density rather than by decreasing rigidity, and that its damping ratio be increased in the Maglev vehicle UTM-02 employing a five-state feedback control law as a levitation control law.

Keywords:

• Maglev
• dynamics
• vibration
• air gap

Acknowledgements

This research was supported by a grant from the Maglev Realization Program, funded by the Korean Ministry of Construction & Transportation. The authors would like to thank K.J. Kim, B.K. Kang, J.M Lee, H.G. Kim, J.M. Cho, J.W. Kim, S.T. Kim, J.W. Lee, and M.W. Park, who work for Hyundai-Rotem Company, for their support for the actual vehicle tests, even in the cold of winter.