基于车辆动力传动和转向系统的换道轨迹优化策略

现有的换道轨迹研究大多是将换道轨迹规划和换道轨迹跟踪进行相对独立的研究，这类轨迹在实施过程中将产生不可避免的误差。为了消除这一误差以及缓解或解决由于不当换道行为引起的交通问题，本文提出一种考虑车辆动力传动和转向系统的换道轨迹优化策略，用以指导或替代驾驶员的换道行为。首先，利用Next Generation Simulation (NGSIM)数据获得换道过程的主要驾驶任务，并用highD数据对其进行验证。其次，基于二自由度车辆模型分析车辆的换道运动特性，构建能够被动力传动系统和转向系统所实现的换道轨迹。结果表明，所提策略可以在保证驾驶安全性的前提下，实现经济、舒适和高效的换道过程。单独考虑经济、舒适和高效的优化策略，能够分别降低35.71%的单位路程燃油消耗，94.58%的前轮转角的角速度以及70%的换道所需时间。这说明所提的换道轨迹优化策略能够从微观角度缓解或解决由不当换道驾驶行为造成的交通问题，并为驾驶辅助系统提供理论依据和方法指导。

Optimization Strategy of Lane-changing Trajectory Based on Vehicle Powertrain and Steering System

Most of the existing researches on lane-changing trajectory are separated for lane-changing trajectory planning and lane-changing trajectory tracking. This kind of trajectory normally produces some errors in the implementation. To eliminate this type of error and alleviate or solve the traffic problems caused by improper lanechanging behavior, this paper proposes a lane-changing trajectory optimization strategy considering vehicle powertrain and steering system. First, the Next Generation Simulation (NGSIM) data is used to obtain the main driving tasks in the lane-changing process, and the highD data is adopted to verify the tasks. Then, the lane-changing motion characteristics of the vehicle are analyzed based on the two- degree- of- freedom vehicle model. The lane- changing trajectory were realized by the powertrain and the steering system. The results show that the proposed strategy can achieve an economic, comfortable, and efficient lane- changing process on the premise of ensuring driving safety. The proposed strategies that consider economy, comfort and efficiency individually can reduce the fuel consumption per unit distance by 35.71%, the angular speed of front wheel angle by 94.58%, and the time required for lane-changing by 70%, respectively. The result indicates that the proposed lane-changing trajectory optimization strategy can alleviate the traffic problems caused by improper lane-changing driving behavior from a micro perspective and provide theoretical basis and methodological guidance for the design of driving assistance system.