汽车工程 ›› 2022, Vol. 44 ›› Issue (3): 350-361.doi: 10.19562/j.chinasae.qcgc.2022.03.006

所属专题: 智能网联汽车技术专题-感知&HMI&测评2022年

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基于多传感器融合的紧耦合SLAM系统

蔡英凤1,陆子恒1,李祎承1,陈龙1,王海2()   

  1. 1.江苏大学汽车工程研究院,镇江  212013
    2.江苏大学汽车与交通工程学院,镇江  212013
  • 收稿日期:2021-10-09 修回日期:2021-11-06 出版日期:2022-03-25 发布日期:2022-03-25
  • 通讯作者: 王海 E-mail:wanghai1019@163.com
  • 基金资助:
    国家自然科学基金(61906076);江苏省自然科学基金(BK20190853);中国博士后科学基金特别资助(2020T130258);江苏省重点研发项目(BE2020083-2)

Tightly Coupled SLAM System Based on Multi-Sensor Fusion

Yingfeng Cai1,Ziheng Lu1,Yicheng Li1,Long Chen1,Hai Wang2()   

  1. 1.Institute of Automotive Engineering,Jiangsu University,Zhenjiang  212013
    2.School of Automotive and Traffic Engineering,Jiangsu University,Zhenjiang  212013
  • Received:2021-10-09 Revised:2021-11-06 Online:2022-03-25 Published:2022-03-25
  • Contact: Hai Wang E-mail:wanghai1019@163.com

摘要:

同时建图与定位(SLAM)是自动驾驶功能重要的组成部分,现有算法以激光或视觉惯性里程计为主,未充分利用多模态传感器各自的优势,对特征缺失的场景鲁棒性不足。针对此问题,本文中提出了一种采用激光雷达、摄像头和惯性测量单元(IMU)的多传感器紧耦合SLAM系统。首先它改善了激光雷达点云特征提取和平面拟合的方案,提升了利用点云对视觉特征点深度信息优化的效率和精度。其次提出的紧耦合状态估计框架通过在视觉惯性系统中直接添加激光雷达里程计约束,在不增加算法复杂度的前提下提升了系统的稳定性和精度。最后由粗到精的视觉-激光雷达耦合回环框架进一步降低了系统的长时累计漂移。在开源数据集KITTI上进行大量测试验证的结果表明,与其它常用的算法相比,所提出的算法具有较高的精度和环境适应能力。另外在基于自主搭建的自动驾驶汽车测试平台进行的实车试验还证明本算法可适应长时间大场景的工作环境。

关键词: 自动驾驶, 状态估计, 同时建图与定位, 多传感器融合, 回环检测

Abstract:

Simultaneous localization and mapping (SLAM) is an essential part of autonomous vehicles. Its existing algorithms are mainly based on lidar or visual-inertial odometer, which do not make full use of the respective advantages of multi-mode sensors, leading to insufficient robustness to featureless scenes. In view of these, a multi-sensor tightly coupled SLAM system using lidar, camera and inertial measurement unit is proposed in this paper. Firstly, the system improves the schemes of the feature extraction of lidar point cloud and plane fitting and enhances the efficiency and accuracy of the depth information optimization of visual feature points by using lidar point cloud. Secondly, the tightly coupled state estimation framework proposed directly adds lidar odometer constraints onto visual inertial system, so enhancing the system stability and accuracy without increasing the complexity of algorithm. Finally, the coarse-to-fine visual-lidar coupled loop framework further reduces the long-term cumulative drift of the system. The results of massive tests for validation on the open-source dataset KITTI show that compared with other commonly used algorithms, the proposed algorithm achieves higher accuracy and environmental adaptability. In addition, the real vehicle test on the self-built autonomous vehicle test platform also demonstrates its adaptability to the long-time and large scene environment.

Key words: autonomous vehicles, state estimation, SLAM, multi-sensor-fusion, closed-loop detection