转向工况下的汽车制动防抱死控制的仿真研究

Simulation Study on Control Method of Anti-lock Braking System under Steering Condition

分析了汽车制动动力学,建立了转向制动工况下四轮仿真模型。进行了未安装防抱死装置(ABS)的转向制动仿真试验,结果表明车轮在制动过程中抱死且侧滑严重。建立了基于加权的纵向滑移率及其变化率和横向滑移率的Mamdani模糊控制器,并进行了转向制动仿真试验。制动距离和制动时间表明ABS不仅能减少制动距离,而且能够保持制动时的方向稳定性,说明基于模糊逻辑的ABS能够显著提高汽车的制动安全性能。

Based on the analysis of the structure and the dynamics of the vehicle braking system, the model of a four-wheel vehicle under steering condition was established. Simulation was first carried out without ABS controller, and the result shows that the wheels lock, which leads to danger steering. Then a Mamdanifuzzy controller with longitudinal slip ratio and its derivative and lateral slip ratio as the inputs and braking pressure change as output was designed. Braking time, braking distance and lateral slip were studied based on simulation, and the result shows that the ABS is effective in reducing not only the braking distance and braking time but also the lateral sliding, so that the braking safety is ensured. The simulation shows that the fuzzy logic control strategy is effective in improving the braking performances.