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为了降低车速变化对车辆操纵稳定性的影响,建立了考虑车速变化的动态车辆转向运动模型,分析了描述模型的微分方程组所有系数都是随车速变化而时变的特性,通过变参数动态仿真,定量研究了车速变化对车辆操纵稳定性的影响。研究结果表明:减速时正的纵向车辆惯性力使后轴负荷向前轴转移,导致前轴侧偏刚度变大,后轴侧偏刚度变小,进而使车辆的横摆角速度增益增大,即车辆操纵稳定性变差;初始车速越高,减速度越大,车辆横摆角速度增益增大越快;加速时负的纵向车辆惯性力使前轴负荷向后轴转移,导致前轴侧偏刚度变小,后轴侧偏刚度变大,进而使车辆的横摆角速度增益减小。可见,减小车辆减速度、降低车身质心高度及增大轴距是弱化减速导致车辆操纵稳定性急剧变差的有效方法。
In order to reduce the influence of vehicle speed on vehicle handling stability, a dynamic vehicle steering motion model considering vehicle speed change is established. All the coefficients of the differential equations describing the model are time varying with vehicle speed. Dynamic simulation , A quantitative study of the impact of vehicle speed on vehicle handling stability. The results show that the positive longitudinal vehicle inertia force reduces the load of the rear axle to the front axle during deceleration, resulting in the increased stiffness of the front axle and the reduced side stiffness of the rear axle, which in turn increases the yaw rate gain of the vehicle, that is, Vehicle handling stability becomes worse; the higher the initial speed, the greater the deceleration, the faster the vehicle yaw rate gain increases; the negative longitudinal vehicle inertia force accelerates the front axle load transfer to the rear axle when accelerating, Becomes smaller, and the partial stiffness of the rear axle becomes larger, thereby reducing the yaw rate gain of the vehicle. Obviously, reducing the vehicle deceleration, reducing the body center of mass and increasing the wheelbase is an effective way to weaken and slow down the stability of vehicle handling dramatically worse.