Sensitivity Analysis Of High-speed EMU Parameters And Parameter Optimization

Bogie technology fundamentally restricts the EMU speed increase and decides the operation quality and reliability. The dynamics performance of bogie is determined by the structure parameters and suspension parameters, after the determination of structure parameters, the suspension parameters determine the EMU dynamics performance, so the core of bogie design is the Optimization of suspension parameters.In the optimization design of the EMU, will find some parameters on the EMU dynamics performance are sensitive, influence on the dynamic index is large, but some parameters are not sensitive. If the design parameters can be divided into sensitive design parameter and not sensitive design parameters, when doing the dynamics performance optimization design, we can specifically design for sensitive parameter optimization, ignore the not sensitive parameters, which will greatly improve the EMU efficiency of optimized design and avoid the optimization error convergence may result in design. In addition, parameter sensitivity analysis is the design requirements of the robust optimization system.Based on orthogonal experiments of sensitivity analysis method, the sensitivity analysis of suspension parameters for dynamic performance of a high-speed EMU is made by establishing orthogonal table with combinatorial theory. Furthermore, the influence degree of suspension parameters on the dynamic performance of railway vehicle is quantitatively determined. The results show that the most sensitive parameters for safety performance are the longitudinal stiffness of primary suspension and the damping of yaw damper. When the suspension parameters change±15%, the variation of safety performance range from5%to7%. The most influence on the lateral ride comfort is the lateral stiffness of secondary suspension and the damping of lateral damper. The greatest impact on the vertical ride comfort is the vertical stiffness of secondary suspension and the damping of vertical damper. When the parameters change in the vicinity of the reference point±15%. ride index variation is about1%.To improve the dynamic performance of the EMU is a multi-parameter, multi-objective, multi-constraint and nonlinear optimization problem. A suitable optimization method can effectively improve the dynamic performance of the EMU. This paper presents an improved niche genetic algorithm to optimize the EMU with the dynamic performance of the new wheel tread and three repairing tread as the objective function. Experimental results indicate that the optimized critical velocity of EMU with new wheel tread is575km/h, compared to before optimization speed is increased by26%and the speed of three repairing wheel tread increased by6%. Optimization of the EMU can not only improve the critical velocity, but also ensure safety performance and ride comfort, realize the reasonable matching between the suspension parameters. Finally, the robust design concept is applied to the optimization of vehicle design, the optimized dynamic performance not only is optimal, and parameters on the performance of the lowest sensitivity.