Multi-robot exploration with AUVs on cliffs and other 3D structures with a predominant orientation

A multi-robot exploration algorithm is presented which is targeted at the exploration of 3D structures which predominantly extend along one orientation - the motivating example is underwater cliffs which are locally 3D but that are more globally seen to extend along a continuous vertical surface. The multi-robot exploration aims to maximise the sampling of the environment, causing much denser scans and especially complete scans than a simple lawn mower pattern, i.e., it contains an element of view-planning. This is done by fitting a local plane to the points in the sensor field of view and aligning the robot to view the local plane directly. The distributed multi-robot exploration algorithm is integrated into a complete system consisting of mapping, localisation, and navigation modules. Using a realistic simulation based on real world data from Monte da Guia in the Azores, the algorithm is experimentally validated.