在ADAMS/Car中建立三轴重型载货汽车的虚拟样机模型,包括前后悬架、动力总成、转向系统、稳定杆、制动系、轮胎及车身,同时还考虑了轮胎、悬架弹簧、减振器等部件的非线性。利用Matlab/Simulink建立了基于滑移率的防抱死制动系统ABS模糊控制系统。分别在高附着路面、低附着路面及分离系数路面上进行不同载重下的直线制动仿真,计算汽车制动时的动态特性。并与无ABS的常规制动进行比较。结果表明,本文设计的基于滑移率的ABS模糊控制策略对于重型汽车具有良好的控制效果。使车轮的滑移率控制在最佳滑移率附近,防止了车轮的抱死,在制动距离、制动时间及制动稳定性方面都有较突出的优势。
An anti-lock braking system for a heavy vehicle was simulated based on ADAMS and Matlab/Simulink. A nonlinear heavy vehicle dynamic model was built in ADAMS/Car, including the front and the rear suspension systems, the vehicle body, the engine system, the steering system, the antiroll system, the brake system, and the tire dynamic model. The nonlinear characteristics of the tire, the bushing spring and the damper were considered so as to reveal the dynamic performance of the vehicle accurately. A fuzzy control Anti-lock Braking System (ABS) model based on the wheel slipping rate was built in Matlab/Simulink. Then the straight-line braking simulations were carried on three types of roads with high friction coefficient, low friction coefficient and split friction coefficient under different vehicle loads. In a joint simulation, the braking dynamic responses of the heavy vehicle were compared with the case of a general brake without ABS. It is shown that the ABS fuzzy control based on the slipping rate as designed in this paper performs vel7 well for the heavy vehicle. The wheel slipping ratio could be maintained near the optimal slipping ratio, and each wheel is prevented from locking up. In addition, the braking distance, the braking time, and the braking stability are greatly improved.