四轮驱动汽车牵引力控制系统控制策略

针对四轮驱动汽车整车动力性和横向稳定性的问题，提出新的目标滑转率计算和修正方法的牵引力控制系统综合控制策略。首先，建立车辆系统各主要部件的数学模型；然后，针对不同工况，利用模糊PID控制技术建立以发动机节气门开度控制、轴间扭矩分配控制和驱动轮制动控制为一体的牵引力控制系统综合控制策略；在车轮目标滑转率的选取方面，提出了最优纵向滑转率查表法，并根据车速以及轮胎侧偏角的大小对目标滑转率进行实时修正；最后，在典型工况下使用MATLAB/Simulink对四轮驱动汽车牵引力控制系统进行离线仿真研究。结果表明：本文所提出的牵引力控制系统控制策略能有效地抑制驱动轮的过度滑转，充分利用路面附着条件，提高汽车纵向驱动稳定性。

Control strategy of traction control system for four-wheel drive vehicle

Aimed at the problem of the vehicle dynamics and lateral stability of four-wheel drive vehicle, the integrated traction control strategy based on a new method of target slip ratio calculation and correction was proposed. First a mathematical model describing the main components of vehicle system was established. In view of different conditions, the traction control system integrated control strategy, which is based on the engine throttle valve control, inter-axis torque distribution control and driving wheel braking-force active control, was built by using fuzzy PID control technology. In the aspect of selection in tire target slip ratio, a lookup method of the optimal longitudinal slip ratio was proposed, and real-time correction of target slip ratio was carried out according to the vehicle velocity and tire slip angle. Finally, research on off-line simulation for four-wheel drive vehicle traction control system in typical conditions was completed by using MATLAB/Simulink software. The results show that the proposed traction control strategy can effectively inhibits the driving wheel from over slipping, fully use the road adhesion conditions and improve the vehicle longitudinal driving stability.