基于动态双向耦合的高速汽车侧风稳定性控制研究

Control of High-Speed Vehicle Crosswind Stability Based on the Dynamic Two-Way Coupled Method

针对高速汽车在侧风环境下的气动稳定性问题,基于大涡模拟(LES)及五自由度车辆模型,建立了汽车空气动力学与汽车动力学的动态双向耦合分析模型.考虑了主动前轮转向的主动控制(AFS)对高速车辆侧风稳定性的影响;采用调整车辆质心位置的方法验证了动态双向耦合模型的鲁棒性.对在某轿车在有、无驾驶员及有、无AFS控制下的运动及流场特性进行了对比分析.研究结果表明:在侧风作用下车辆的侧向速度及横摆角速度对高速车辆的气动稳定性有着重要影响;在无驾驶员条件下,有AFS控制的车辆仍能回到正常行驶路线,而无AFS控制的车辆无法回到正常行驶路线;在有驾驶员条件下,无AFS控制车辆最大侧向位移为1.1m,有AFS控制车辆最大侧向位移0.47m,表明AFS控制有助于提高车辆侧风稳定性.

Aiming at the aerodynamic stability of vehicles with high speed in crosswind environment,a dynamic two-way coupled method was proposed based on large eddy simulation(LES)and 5 degree of freedom model,coupling vehicle aerodynamics and vehicle dynamics.The influence of active front steering(AFS)on the crosswind stability of high-speed vehicle was considered.The robustness of the two-way coupled method was verified by adjusting the center of gravity of the vehicle.The comparison of the vehicle motion and flow characteristics was conducted with or without driver and with or without AFS control.The results show that the lateral velocity and yawing angular velocity have an important influence on the aerodynamic stability of high-speed vehicle under crosswind condition.And without the control of driver the vehicles can return to the normal path with the help of AFS,while the vehicle without AFS can t.The maximum lateral displacement of the vehicle with the driver is 1.1 m without the control of AFS,which is 0.47 m with the AFS.The results show that the AFS can help to improve the vehicle crosswind stability.