基于流入角实时变化的气动性对操纵稳定性的影响

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.

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

In order to study the influence of the position of the wind pressure center line on the vehicle handling stability when the vehicle is affected by the crosswind, by calculating the aerodynamic force under different wind speed and inflow angle in CCM +, the initial relationship curve of aerodynamic force with wind speed, combined speed and inflow angle is obtained. By using the co-simulation technology of MATLAB and acar, the bi-directional coupling model of aerodynamics and vehicle dynamics is built, the distance between the center line of wind pressure and the center of mass is taken as the variable for simulation analysis. The results show that: 1. As the wind pressure center line moves from the front of the mass center to the rear of the mass center, the lateral displacement of the vehicle will decrease in open-loop driving, but if the wind pressure center line is located at the rear of the vehicle for more than a certain distance, the vehicle will shift to the other side under the yaw moment generated by aerodynamic force. 2. In closed-loop driving, when the wind pressure center line passes through the center of mass of the vehicle, the steering wheel still needs a small angle to maintain the straight-line driving due to the existence of lateral force, and the wind pressure center line needs to continue to move backward to ensure the steering wheel''s steady-state return. The research results have reference significance for vehicle modeling development.