空气弹簧动态特性拟合及空气悬架变刚度计算分析

Dynamic Characteristics Fitting of Air Springs and Numerical Analysis of Air Suspensions with Variant Stiffness

为深入研究车辆空气悬架的性能,在悬架系统动力学模型的建立和仿真计算过程中,需要考虑空气弹簧的刚度随弹簧载荷和工作高度改变而变化的特点。根据空气弹簧的动态特性试验数据构成一簇有规律曲线的特点,分别以弹簧工作高度和初始载荷为自变量进行两次曲线拟合,用非线性曲线拟合方法代替气体状态方程,得到空气悬架使用条件下空气弹簧的刚度工作曲线方程。在悬架半车离散状态空间模型仿真的每个计算步长开始时,随悬架动挠度的实时状态来确定模型中空气弹簧的刚度计算数值,从而达到对空气悬架进行变刚度仿真分析的目的。采用此方法计算的某客车空气弹簧气压瞬态响应与滚下法悬架固有频率试验时测到的空气弹簧气压曲线更接近,提出的空气弹簧变刚度特性拟合处理和悬架模型变刚度仿真方法有效。

For studying vehicle air suspension more accurately,the variant stiffness of air springs should be considered in the process of building dynamic models of vehicle suspension and simulation of the models.Based on the test data of dynamic characteristics of air spring,the numerical stiffness equations of air springs used in the air suspension of vehicle are obtained by means of nonlinear curve fitting according to the loads and equilibrium heights of air springs.In the beginning of every simulation step of discrete state space model of half vehicle,the value of air spring stiffness is changed and determined according to the dynamic deflection value of the suspension.In comparison with the experimental air spring pressures during the suspension step tests,the pressure difference between calculation and test is reduced greatly,which shows the effectiveness of the proposed method of dynamic characteristics fitting of air spring and nonlinear simulation of suspension models.