【摘 要】
:
新一代汽车产业革命方兴未艾,车辆“智能化”已是全球汽车产业发展的战略目标。感知能力及自动驾驶功能覆盖场景的全面度,是衡量智能车辆“智能化”水平的最直接标准。雾天场景换道无论对驾驶员还是智能车辆来说,都是不小的挑战。雾天场景下,智能车辆的感知系统对环境的错误判断会导致危险换道轨迹的产生。因此,本文对雾天场景下的智能车辆换道轨迹规划进行研究。本文的主要研究内容如下:(1)针对智能车辆雾天等级检测问题,
【基金项目】
:
国家自然科学基金面上项目“面向自动驾驶环境的高速公路平曲线路段安全性能评测方法”(项目编号:51978075); 四川省交通运输科技项目“雨雾极端气候条件下交通运行保障技术研究”(项目编号:2019-D-01);
论文部分内容阅读
新一代汽车产业革命方兴未艾,车辆“智能化”已是全球汽车产业发展的战略目标。感知能力及自动驾驶功能覆盖场景的全面度,是衡量智能车辆“智能化”水平的最直接标准。雾天场景换道无论对驾驶员还是智能车辆来说,都是不小的挑战。雾天场景下,智能车辆的感知系统对环境的错误判断会导致危险换道轨迹的产生。因此,本文对雾天场景下的智能车辆换道轨迹规划进行研究。本文的主要研究内容如下:(1)针对智能车辆雾天等级检测问题,建立雾天等级检测模型。根据雾天的影响程度,将雾天等级分为微雾、薄雾、浓雾三种。以HSV色彩空间特征V/S值为检测依据,采用灭点检测方法在图像中设置计算区域,采用时间滤波计算一定时间范围内的特征值。实验采集雾天视频数据,通过统计微雾、浓雾等级图像各3000帧的特征值,确定了模型中的判断阈值。(2)改进暗通道去雾算法,提高雾天图像质量,并基于YOLO-v3目标检测网络训练车辆检测模型。通过快速估计大气光值与细化透射率有效解决了原算法耗时长、去雾后图像出现光晕这两个问题,并通过与5种去雾算法的对比,验证了本算法的优势。实车采集不同雾天等级下的行车视频,制作雾天车辆检测数据集。结合图像去雾算法,提高了雾天车辆检测的有效率。(3)考虑雾天影响及换道时车辆的安全性与乘客舒适度,提出雾天换道轨迹规划算法,并通过换道安全性检测保证车辆换道时的安全性。基于五次多项式,构建满足横向加速度约束、最高车速等约束的候选轨迹簇,结合雾天等级分类,设计了考虑雾天影响的轨迹评价函数,根据雾天等级的不同选择相应的换道轨迹。在浓雾等级下车辆安全性、舒适性最好;微雾等级下,车辆换道效率最佳。建立了考虑雾天影响的安全距离模型,在不同雾天等级条件下进行安全性检测时,车辆模型的安全范围不同。(4)基于模型预测控制(MPC)设计了换道轨迹跟踪控制器。通过Car Sim与MATLAB/Simulink联合仿真,验证雾天换道轨迹规划算法的安全性与可行性。仿真结果显示,建立的安全距离模型提高了换道安全性,规划的轨迹对车辆来说是安全可行的。
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