Dynamic instabilities in magnetically levitated models

Experiments are reported demonstrating divergence and flutter instabilities in an electrodynamic maglev vehicle. The conducting guideway consists of L-shaped aluminum segments attached to a rotating wheel and qualitatively simulates the Japanese full scale guideway at Miyazaki. The model vehicle employed rare earth permanent magnets. Quantitative tests for a coupled yaw-lateral vibration show both divergence and flutter. The divergence leads to two stable equilibrium yaw positions, while the flutter instability leads to limit cycle oscillations coupling yaw and lateral motions in the neighborhood of the drag peak. A theoretical model based on actual magnetic force measurements is shown to predict this dynamic behavior as functions of vehicle speed and geometry.