Loop closure detection is an effective strategy to reduce the pose drift of lidar-inertial simultaneous localization and mapping(SLAM),and the accuracy and speed of loop closure detection are key factors for its application in SLAM.Based on this,a lidar-inertial SLAM algorithm based on triangle bag of words loop closure detection is proposed.Firstly,a triangle descriptors are generated by the LinK3D features of the laser point clouds,and a triangle word bag is constructed by using the triangle descriptors to achieve real-time position recognition and six-degree-of-freedom loop pose estimation.Secondly,LinK3D features can also be used for frame to frame point cloud registration,combined with inertial measurement unit(IMU)pre-integration to achieve accurate and robust interframe pose estimation.The experimental results on the KITTI dataset show that compared with the current advanced LIO-SAM algorithm,the proposed SLAM algorithm has a more robust interframe pose estimation,the average root mean square error of the output trajectory is reduced by 29.79%,and the average time required for each loop constraint is reduced by 93.53%.The field experimental results show that compared with LIO-SAM,the proposed algorithm reduces the average time required for each loop constraint by 85.15%,and the root mean square error of the absolute trajectory error in outdoor long-distance experiments is reduced by 84.36%.
simultaneous localization and mappingloop closure detectionbag of wordspoint cloud registration