基于流入角实时变化的气动性对操纵稳定性的影响

Influence of aerodynamics on handling stability based onreal time change of inflow angle

为研究汽车受侧风影响时风压中心线位置对整车操纵稳定性的影响,在CCM+软件中计算不同风速和不同流入角下的气动力,获得气动力与风速和车速的合速度以及流入角的初始关系曲线。利用MATLAB和Adams/Car联合仿真,搭建空气动力学和车辆动力学的双向耦合模型,以风压中心线与质心的距离为变量进行仿真分析。结果显示,随着风压中心线由质心前方移动到质心后方:在开环仿真工况中,车辆的侧向位移会减小,但是如果风压中心线位于车辆后方超过一定的距离,车辆会在气动力产生的横摆力矩作用下向另外一侧偏移;闭环仿真工况中,当风压中心线穿过车辆质心时,由于侧向力的存在,方向盘依然需要一个很小的转角以维持直线行驶,风压中心线需要继续后移以保证方向盘稳态时的回正。

To study the influence of the position of the wind pressure center line on the handling and stability of the vehicle under the influence of crosswind,the aerodynamic forces under different wind speeds and inflow angles are calculated in CCM+software,and then the initial relationship curves of aerodynamic force with wind speed,vehicle speed and inflow angle are obtained.Using the co-simulation of MATLAB and Adams/Car,a bidirectional coupling model of air aerodynamics and vehicle dynamics is established,and the distance between the wind pressure center line and center of mass is taken as the variable for simulation analysis.The results show that,as the wind pressure center line moves from the front of the mass center to the back of the center,the lateral displacement of the vehicle will be reduced in open loop simulation,however,while the wind pressure center line is located behind the vehicle for more than a certain distance,the vehicle will offset to the other side under the yaw moment generated by aerodynamic force.In closed-loop simulation,while the wind pressure center line passes through the vehicle centroid,due to the existence of lateral force,the steering wheel still need a small angle to maintain straight driving,and the wind pressure center line needs to continue to move backward to ensure the alignment of the steering wheel in steady state.