| Superconducting electrodynamic suspension(EDS)train is of good application prospects because it gets rid of the limitation of wheel - rail limitations of conventional wheel/rail vehicles and has the merits of large suspension gap and stability,which is one of the development directions of higher speed rail transit and its maximum test running speed has exceeded 600 km/h.Dynamic performance is closely related to vehicle operation stability and safety,and is the main factor limiting vehicle speed increase.On the one hand,due to the differences in structure and operation mechanism between superconducting EDS train and conventional wheel/rail train,the dynamic modeling and analysis methods of superconducting EDS train need to be further studied.On the other hand,due to the influence of the track structure of the superconducting EDS train and the special vehicle-track electromagnetic relationship,the dynamic performance of the passive suspension train is seriously deteriorated at high speed,and vibration control methods are needed to improve its running safety and stability.Firstly,based on the dynamic circuit theory,the equivalent circuit model between the superconducting magnet and the track coils was established,and the analytical calculation expression of vehicle-track electromagnetic force was derived.The variation characteristics of levitation and guidance force under different speeds and levitation and guidance gap were analyzed.The calculation results show that the levitation and guiding force have strong nonlinear characteristics,and they increase with the increase of running speed.Due to the discrete distribution of track coils,the electromagnetic force on superconducting magnet fluctuates periodically.Secondly,based on the basic structure of superconducting EDS train,a 22 degree-of-freedom vertical dynamics model based on equivalent magnetic spring was established.Through the SIMPACK 3D dynamics model and the electromagnetic force calculation,track irregularity and magnetorheological fluid dampercalculation module in Simulink,the SIMPACK-Simulink co-simulation dynamics model was finally established to realize the simultaneous simulation of dynamics simulation,electromagnetic force calculation and vibration control.The dynamic simulation results of the vehicle under passive suspension show that the nonlinear characteristics of electromagnetic force have a great influence on the dynamic response.With the increase of running speed,the vertical and lateral vibration of the vehicle increases,and the running stability becomes worse.The lateral running stability of the vehicle deteriorates more seriously than that of the vertical.Finally,in order to improve the vehicle running stability,the vibration controller was designed based on the fuzzy PI control principle and applied to the secondary suspension of the vehicle,and the variable universe fuzzy controller was established to optimize the vibration control.The vibration reduction effect was analyzed in time domain and frequency domain,and the results show that the variable universe fuzzy PI control has better vibration control effect and efficiency than the fuzzy PI control.However,the deterioration effect of variable universe fuzzy PI control on the vibration of the bogie is greater than that of fuzzy PI control.In order to further reduce the vibration of the bogie and improve the safety of vehicle operation,a hybrid damping semi-active control model based on skyhook damping and groundhook damping was established,and the maximum damping coefficient and control coefficient were optimized.The simulation results in time domain and frequency domain show that the effect of hybrid damping control on vehicle body vibration reduction is lower than that of variable universe fuzzy PI control.However,hybrid damping control can effectively suppress the vibration of the bogie,solve the problem of vibration deterioration of the bogie under the variable universe fuzzy PI control,and effectively improve running safety and ride comfort of superconducting EDS train. |
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