Cooperative Mutual 3D Laser Mapping and Localization

A 3D laser scanner is built by adding a rotating mirror to a conventional 2D scanner. The scanners are deployed on four robots to build full 3D representations of an indoor environment. An original representation mechanism referred to as occupancy lists, rather than standard 2D free space grids, is used to maintain the 3D map. Localization is done by extracting horizontal sub-ceiling cross-sections. Taking cross-sections from near the ceiling in this way results in more reliable and time invariant maps. Experimental results show inter-robot sightings and the sharing of map data aid mapping by improving the reliability of localization. Mapping with four robots reduced the average position error from 0.35 m for single robot operation to 0.1 m when cooperating.