基于电动助力转向的车道保持性能研究与分析

Study on Lane Keeping Performance with Electric Power Steering System

由于电动助力转向系统在车辆转向中能提供辅助扭矩,考虑集成电动助力转向系统作为车道保持辅助系统的转向执行机构,并推导了EPS在助力转向和主动修舵转向下的力矩方程。在分析了车道保持辅助系统的基础上建立二自由度单轨车辆模型、非线性轮胎模型、单点预瞄驾驶员模型、EPS模型和最优控制器模型。采用某款量产车辆试验得到的EPS控制脉谱图,利用驾驶员模型在回路仿真的方法验证所建立的系统模型,结果显示整合EPS的车道保持辅助系统能有效提高车辆的路径跟踪能力。

With consideration of the characteristics of Electric Power Steering system(EPS), vehicle lane keeping system can make full use of EPS function as steering actuator for lane following assist. A couple of vehicle dynamic equations were derived for two operational modes including steering assistant mode and active steering mode. Meanwhile, vehicle single track handling model, nonlinear tire model, driver model, EPS model and corresponding optimal lane tracking algorithm were built and developed respectively. The lane keeping algorithm with EPS actuator was validated by virtue driver-in-the-loop approach based on the EPS experimental map from a certain type of production vehicle. It has been shown that the lane keeping system with EPS assist can effectively improve the capability of tracking the desired path.