考虑坡度影响的车辆行驶动力学建模与仿真

考虑横向坡度、纵向坡度与合成坡度道路特征参数对车辆动力学与轮胎垂直载荷变化的影响，基于15自由度车辆动力学模型，建立横向坡度、纵向坡度与合成坡度车辆动力学与轮胎垂直载荷变化模型，联立转向系、制动系、动力传动系、车轮与悬架模型，构建整车行驶动力学仿真模型，并在不同横向、纵向、合成坡度以及车速下进行仿真分析比较。结果表明：横摆角速度受纵向坡度的变化影响很小，但随横向与合成坡度的增大而逐渐减小，且在相同坡度下，随着车速的增大，波动幅度增大，峰值增大；前轮侧偏角受纵向与合成坡度的变化影响很小，但随横向坡度的增大而增大；侧倾角速度随横向与合成坡度的增大而先减小后增大，且在相同纵向坡度下，随车速的增大，波动幅度增大，峰值增大。

Modeling and simulating the vehicle riding dynamics considering gradient effects

Considering road characteristic parameters such as lateral gradient, longitudinal gradient and synthetic gradient, and based on 15 degrees of freedom (DOF) vehicle dynamics model, the authors develop the vehicle dynamics model, tire vertical load variation model and whole vehicle riding dynamics simulation model combined with steering system, braking system, power train system, wheel and suspension models. The situations are compared under different lateral, longitudinal, synthetic gradient and vehicle speed. The simulation results show that yaw rate maintains invariably to longitudinal gradient variation, but decreases gradually with the increase of lateral and synthetic gradient. The margin of fluctuation and peak value increase with the increase of vehicle speed under the same gradient; front wheel sideslip angle maintains invariably to longitudinal and synthetic gradient variation, yet increases with the increase of lateral gradient; the roll rate decreases and then increases with the increase of lateral and synthetic gradient, and the margin of fluctuation and peak value increase with the vehicle speed increase under the same longitudinal gradient.