不同路况下路面附着系数实时估计

为了准确估计不同路况下的路面附着系数,提高汽车行驶的安全性与稳定性,提出了一种在制动工况下基于前后轮轮速和制动力矩估计路面附着系数的方法。首先,考虑汽车前后轴荷转移,在Matlab/Simulink软件中完成建模操作,创建关于双轮车辆制动的动力学模型;其次,将控制目标确定为汽车前轮以及后轮的理想和实际滑移率,建立理想制动力矩滑模控制器,对于汽车滑模控制器存在的抖振现象,通过积分切换面对其进行处理;最后,以前后轮轮速和制动力矩作为输入进行扩张状态观测器的设计,利用这一观测器观测路面附着系数相关值。结果表明,各种路况中的路面附着系数都可以通过上述手段进行准确估计,扩张状态观测器能够抵抗外界干扰,鲁棒性强。将扩张状态观测器用于路面附着系数识别的良好结果可为汽车稳定性控制系统的设计提供参考。

Real-time estimation of road friction coefficient in different road conditions

In order to accurately estimate the road adhesion coefficient under different road conditions and improve the safety and stability of vehicles, a method was proposed to estimate the road adhesion coefficient based on the front and rear wheels speed and braking torque under braking conditions. First, considering the transfer of front and rear axle load, the modelling was completed in Matlab/Simulink software to create a dynamic model of the two-wheel vehicle braking.Secondly, the control target was determined as the ideal and actual slip ratio of the front and rear wheels of the vehicle, and the ideal braking torque sliding mode controller was established. The chattering phenomenon of the sliding mode controller was properly dealt with through the integral switching surface. Finally, the front and rear wheel speed and braking torque were used as input to design the extended state observer, which is used to observe the correlation value of the road adhesion coefficient. The results show that the road adhesion coefficient in all kinds of road conditions can be accurately estimated by the above method, and the extended state observer can resist the external interference and has strong robustness. The successful application of the extended state observer provides the reference for the design of vehicle stability control system.