Optimization Of Suspension Parameters Of New Narrow-rail Straddle Monorail Vehicle

Straddle-type monorail vehicles have the advantages of small turning radius,strong climbing ability,low noise and high utilization of urban space.In recent years,they have attracted widespread attention in China.For the new narrow-rail straddle monorail vehicle,this paper analyzes the overall design,running and guiding mechanism of the straddle monorail vehicle and the topological relationship of the vehicle in detail,and uses the multi-body dynamics software UM to establish the new narrow-rail straddle monorail vehicle dynamic simulation model.With reference to the establishment method of relevant dynamic performance evaluation indicators in GB5599-2019,combined with the structural characteristics of the straddle monorail vehicle,the dynamic performance evaluation indicators suitable for straddle monorail vehicles are proposed to study the effect of vehicle suspension parameters on the dynamic performance of the new narrow-rail straddle monorail vehicle,and the sensitivity of vehicle dynamics performance to various suspension parameters is analyzed.The niche multiobjective genetic algorithm is used to optimize the suspension parameters of the new narrowrail straddle monorail vehicle.Finally,based on the new straddle monorail vehicle-track beam coupling dynamics model,the effects of bridge deflection-span ratio and support stiffness on vehicle dynamics are studied.The main conclusions obtained from the above research are as follows:1.By analyzing the influence of 11 vehicle suspension parameters such as air spring stiffness,anti-roll torsion bar stiffness,vertical shock absorber damping and lateral shock absorber damping on the dynamic performance indicators,as well as the sensitivity of vehicle dynamics to each parameter,The results show that: air spring stiffness,vertical shock absorber damping,lateral shock absorber damping,driving wheel vertical stiffness and driving wheel cornering stiffness have more significant effects on the dynamic performance of the vehicle system.2.The evaluation function is established with the stability index of the new narrow-gauge straddle monorail vehicle,the roll angle of the car body and the roll angle of the running wheel as the objective function,The niche multi-objective genetic algorithm is used to optimize the air spring stiffness,vertical shock absorber damping,lateral shock absorber damping,running wheel vertical stiffness and running wheel cornering stiffness.The results show that the parameters optimized by genetic algorithm can make the dynamic performance of the new narrow-rail straddle monorail vehicle achieve better.3.A new narrow-rail straddle monorail train-trackbeam dynamics coupling model is established,and the influence of bridge deflection-span ratio and support stiffness on vehicle dynamics performance is studied.The results show that when the deflection-span ratio of the trackbeam is less than 1/6000,the vertical stability index of straddle monorail vehicles can achieve better results;the stiffness of the bridge support has a significant impact on the vertical stability index of the vehicle.With the increase of the support stiffness,the vertical stability index of the vehicle shows an improvement trend.Therefore,the vertical stiffness of the new narrow-rail straddle trackbeam support is recommended to be greater than 40MN/m.