车轮踏面多目标优化设计研究进展

车轮踏面优化设计是轨道交通系统的基本问题。根据车轮踏面优化模型的建立及其求解方法,车轮踏面优化设计的数值研究方法可以分为两类,即单目标优化设计方法和多目标优化设计方法。在综述轮轨踏面同步设计法、扩展方法、基于轮轨接触曲线的滚动半径差法和基于接触角曲线法等单目标优化方法的基础上,论证了车轮踏面优化是一个多目标优化问题,并给出了建立车轮踏面多目标优化模型的思路。车轮踏面多目标优化需要求解带约束的非凸不可微规划问题,求解精度和效率直接决定优化结果的可靠性和实用性。现有的求解方法包括遗传算法和拟高斯方法。针对现有计算方法存在计算量大、易早熟、收敛慢的缺点,提出求解车轮踏面多目标优化问题的响应面方法。该方法利用多项式响应面逼近目标函数和约束函数,避免了优化过程中由于数值求导带来的迭代振荡问题;同时该方法具有计算量小、收敛快的优点。以降低轮轨磨耗为目的对车轮踏面进行优化的实例表明,响应面方法能有效的优化车轮踏面。最后对车轮踏面这一课题的发展方向进行了展望。

Research Progress of Multi-objective Optimization Design of Wheel Profile

Optimization design of wheel tread is the basic problem of track transportation system.According to the construction and solving methods of wheel tread optimization design model,the numerical methods of wheel tread optimization can be classified to two kinds,namely one-objective and multi-objective optimization design methods.On the basic of reviewing the one-objective optimization design methods like wheel and rail tread synchronous design method,expanding method,RRD method and contact-angle method based on wheel/rail contact curve,this paper demonstrates that the wheel tread optimization is a multi-objective problem and gives some thinking of the model construction of multi-objective model of wheel tread optimization.The multi-objective optimization of wheel tread need to solve a non-convex non-differentiable programming problem with constrains,and its accuracy and efficiency decide the reliability and practicability of optimization results.The exiting methods include method of genetic algorithm and quasi-Gauss method.On drawbacks of exiting method like the large amount of calculation,premature ponvergence easily and slow convergence,this paper introduces an RSM method of multi-objective problem of wheel tread optimization.The approximation to the objective and constrain function using polynomial response surface avoids the iterative oscillation problem of numerical derivative when optimizing.And this method has the advantage of small amount calculation and fast convergence.The example of wheel tread optimization with the objective of decreasing the wheel/rail wear demonstrates RSM method can optimize the wheel tread efficiently.At last development trend of wheel tread optimization is respected.