| Urban vehicles are between high-speed EMUs and urban rail vehicles,and have the characteristics of high running speed,large start-stop acceleration,and strong passenger carrying capacity.With the development of our country’s intercity railways and the improvement of train running speed,it is necessary to use appropriate methods to study the dynamic performance of urban vehicles,and to optimize the relevant parameters of the bogie suspension.A large number of tests show that with the acceleration of the train’s running speed,the various dynamic performance indicators of the train tend to deteriorate,which is mainly manifested in the intensification of the meandering motion of the vehicle,and the increase in the related indicators such as operation safety and running stability.Therefore,based on the Pareto theory,the sensitivity analysis of the parameters of the suspension system is carried out,and the parameters of the suspension system obtained by the sensitivity analysis are used as the optimization variables to build the optimization model and complete the optimization of the vehicle dynamic performance,which is the focus of this paper.The work done in this paper is summarized as follows:(1)The original car mechanics simulation model was established.Under the UM multi-body dynamics analysis software environment,the dynamic model of the urban railway A-type car was established,and the typical dynamic indicators such as derailment coefficient,wheel load reduction rate,lateral force of wheel and axle,vertical Sperling index,and lateral Sperling index were simulated and calculated.(2)Sensitivity analysis was carried out on the design variables of the primary suspension and the secondary suspension.Based on the Pareto sensitivity analysis method,the system parameters of the primary suspension and the secondary suspension were used as the sensitivity analysis variables,and the dynamic performance index were used as the sensitivity analysis target,the contribution rate of each suspension system parameter to the typical dynamic index under five different radius is analyzed,and the reasonable design variables of the suspension system were selected according to the contribution rate.(3)The sensitivity analysis was carried out on the structural design parameters of the air spring.Based on the Pareto sensitivity analysis method,the structural design parameters of the air spring were used as the sensitivity analysis variables,and vertical Sperling index,and lateral Sperling index were used as the sensitivity analysis targets.The contribution rate of structural design parameters of air spring to vertical and lateral Sperling index was analyzed under five different velocities,and reasonable optimization design parameters of air spring were selected according to the contribution rate.(4)Pareto optimization was carried out on the parameters of the suspension system of the urban railway A-type car.Based on the Isight multi-objective optimization software platform,a multi-objective optimization model of the vehicle dynamic performance of the urban railway A-type car was built.The design variables include primary suspension parameters,secondary suspension parameters and air spring parameters,etc.The optimization objectives include typical indicators such as derailment coefficient,wheel load reduction rate,lateral force of wheel axle,vertical and lateral Sperling index,etc.With the help of surrogate model and genetic algorithm,the Pareto optimal solution set of multi-objective optimization is obtained,and the optimal primary suspension parameters,secondary suspension parameters and air spring parameters with multiple objectives balanced are obtained. |
