Vibration reduction for a new-type maglev vehicle with mid-mounted suspension under levitation failure

Levitation failure occasionally occurs when a maglev vehicle runs on a track. At the moment of levitation failure, the levitation module falls and hits the track, and there is a violent impact on the maglev vehicle-bridge coupled system. In this paper, the response of the maglev vehicle-bridge coupled system at the moment of and after levitation failure is analyzed, and three methods of reducing the vibration are proposed. First, a dynamics model of the maglev vehicle-bridge coupled system, which considers the control system, five flexible bridges, and track irregularity, is established, and the correctness of the model is verified using test data. The system response for different failure cases is then analyzed. Finally, the three methods of reducing vibration under levitation failure are proposed, and their effectiveness is evaluated. The results show that the failure position and speed barely affect the response, whereas the maximum impact forces due to levitation failure reduced by 13%, 63%, and 50% by adopting the three methods, namely connecting the first and third coils in series, coupling the ends of the levitation module vertically, and adopting two sets of anti-roll devices, respectively. When the latter two schemes are combined, the maximum impact force reduced from 133 kN(without vibration-reduction measures) to 9 kN, and the vibration-reduction measure is also effective for failures of the levitation units at the ends of the vehicle.