Study On Maglev Interaction Of High-speed Maglev Vehicle

High-speed maglev track traffic technology is one of transrapid track traffic technologies in future development. As far as high-speed maglev vehicle is concerned, maglev interaction is composed of maglev electro-magnetic suspension (EMS) and guidance EMS, which are stable non-holonomic constraints under the active controls. For maglev EMS, the non-holonomic constraints are built by levitation gap and its first and second differential. For guidance EMS, the non-holonomic constraints are built by the difference of left and right guidance gaps and its first and second differential. The difficulty of maglev interaction stability study is that the controllers should have robust stability to non-structural disturbance because the maglev and guidance systems adopt the discrete and independent control strategy. The paper emphases, therefore, the influences of the maglev tracks (i.e., geometry variation, girder's stiffness, etc.) to the stability of maglev interaction and the performance of maglev vehicle.Based the orthogonal model on single-rail and 2-DOF active control strategy, with three basic modules (suspension /guidance unit, elevating frame and carbody with traction gears), the three-vehicle trainset model was established. Due to the error of the existing formula of curve calculation, it is by the new methodology based on spline functions technology instead. And the matching-performances were compared between two following types of transition sections: sine-type and rounded basic-type. Using discrete flex-body modeling method, the multi-hole rail-girder model was established and the coupling mechanisms between the maglev vehicles and bridges was discussed in the following three levels: (1) the influence of the rail-girder's deflection to the stability of maglev interaction; (2) the mechanical-electromagnetic conditions of levitating frame which happens the high-frequency self-excited vibrations; (3) the coupling conditions of vehicle-controller- bridge.Firstly, the contrast of the forces of swing-rod with testing data confirms that the established assembly models are correct. Secondly, the matching performance comparison between the two curve-type shows that when train is running on the velocity-limited canted curve, the sine-type transitional curves should be used; when the train is running on the un-canted curves (such as rail siding, turnouts and small radius curves, etc. ) , the rounded basic-type curves can be used. Finally, based on vehicle-bridge coupling model simulation analysis, the following three conclusions can be obtained: (1) rail-girder should be designed with the min. vertical deflection in order to avoid the un-favorite effect on the stability of MagLev interaction. (2) Because high-speed maglev vehicles with the three-stage vertical suspensions (two mechanical suspensions and one electromagnetic suspension), the self-excited vibration conditions of levitating frame, therefore, is the coupling condition of primary suspension and electro-magnetic suspension. (3) Since the present electronic circuit technology is not developed well, the low-frequency loop-gain of EMS is also impossible to reduce to desired degree. So when levitation gap changes, the natural frequency of the levitating EMS will be disturbed to some extent, which may cause to couple with the mechanical suspension and result in the resonance phenomenon of vehicle-bridge.In the matching performance comparison and vehicle-bridge coupling analysis, the following new viewpoints and methods are used: (1) the orthogonal models on single-rail and 2-DOF active control strategy; (2) the assembly-modeling technology of the parameterized and modularized subsystem; (3) the curve-calculation methodology based on the spline function; (4) Discrete flexible model technology.