CCTEG Beijing Tianma Intelligent Control Technology Co., Ltd.

即时定位与建图 （SLAM）技术应用于煤矿井下无人机自主定位时，由于采用特征点构建地图，易出现退化问题，导致定位不准确，且因其以机体作为参考坐标系，无法实现全局定位。针对该问题，提出了一种基于全局点云地图的煤矿井下无人机定位方法。以Fast−LIO2算法作为激光SLAM算法，获得无人机位姿估计；采用迭代最近邻算法，对获取的激光雷达实时点云和全局点云地图进行两步匹配，实现无人机位姿校正；针对因点云数量过多导致点云匹配速度无法保证定位实时性的问题，设计了基于时间的位姿输出策略，提高了无人机位姿数据输出频率。在1 000 m煤矿井下巷道中测试无人机定位方法的SLAM精度和位姿校正效果，结果表明：在长距离巷道环境中，Fast−LIO2算法的定位累计误差小于1 m，在600 m以上范围内小于0.3 m，明显小于LOAM−Livox算法和LIO−Livox算法；Fast−LIO2算法输出的位姿估计经校正算法校正后，飞行路径全部位于全局点云地图中，验证了位姿校正算法有效；单次SLAM算法运行耗时14.83 ms，单次位姿校正耗时883 ms，位姿数据输出频率为10 Hz，满足无人机定位实时性要求。

When simultaneous localization and mapping (SLAM) technology is applied to autonomous positioning of unmanned aerial vehicles in coal mines, the use of feature points to construct maps can easily lead to degradation issues, resulting in inaccurate positioning. Moreover, due to its use of the body as a reference coordinate system, global positioning cannot be achieved. In order to solve the problems, a positioning method for underground unmanned aerial vehicles (UAV) in coal mines based on global point cloud map is proposed. The method uses Fast-LIO2 algorithm as the lidar SLAM algorithm to obtain UAV position and attitude estimation. An iterative nearest-neighbor algorithm is used for two-step matching of the acquired real-time lidar point cloud and the global point cloud map to achieve UAV position and attitude correction. To address the issue of point cloud matching speed not ensuring real-time positioning due to the excessive number of point clouds, a time-based position and attitude output strategy is designed to increase the frequency of outputting UAV position and attitude data. The SLAM precision and position and attitude correction effect of the UAV positioning method are tested in a 1 000 m underground coal mine roadway. The results show that in long-distance roadway environments, the cumulative positioning error of the Fast-LIO2 algorithm is less than 1 m, and is less than 0.3 m in the range of 600 m or more, which is significantly smaller than the cumulative positioning errors of LOAM-Livox algorithm and LIO-Livox algorithm. The position and attitude estimation output by the Fast-LIO2 algorithm has been corrected by the correction algorithm, and all flight paths are located in the global point cloud map, verifying the effectiveness of the position and attitude correction algorithm. The time consumption of single SLAM algorithm operation is 14.83 ms, the one of single position and attitude correction is 883 ms, and the output frequency of position and attitude data is 10 Hz, meeting the real-time requirements of UAV positioning.

北京市科学技术委员会科技成果转移转化项目（Z171100002317029）；山东省重大科技创新工程项目（2020CXGC01150102）；天地科技股份有限公司科技创新创业资金专项项目（2022-2-TD-QN011）；北京天玛智控科技股份有限公司科技项目 (2022TM027-C1)。

高海跃，王凯，王保兵，等. 基于全局点云地图的煤矿井下无人机定位方法[J]. 工矿自动化，2023，49(8)：81-87, 133.

GAO Haiyue, WANG Kai, WANG Baobing, et al. Positioning method for underground unmanned aerial vehicles in coal mines based on global point cloud map[J]. Journal of Mine Automation，2023，49(8)：81-87, 133.