Resilient Autonomous Exploration and Mapping of Underground Mines using Aerial Robots This paper presents a comprehensive solution to enable resilient autonomous exploration and mapping of underground mines using aerial robots. The described methods and systems address critical challenges related to autonomy, perception and localization in conditions of sensor degradation, exploratory path planning in geometrically complex, large and multibranching environments, alongside reliable robot operation in communicationsdenied settings. To facilitate resilient autonomy in such conditions, a set of novel contributions in multimodal sensor fusion, graphbased path planning, and robot design have been proposed and integrated in micro aerial vehicles which are not subject to the challenging terrain found in such subterranean settings. The capabilities and performance of the proposed solution is fieldverified through a set of reallife autonomous deployments in underground metal mines.

Graphbased Path Planning for Autonomous Robotic Exploration in Subterranean Environments This paper presents a novel strategy for autonomous graphbased exploration path planning in subterranean environments. Attuned to the fact that subterranean settings, such as underground mines, are often largescale networks of narrow tunnellike and multibranched topologies, the proposed planner is structured around a bifurcated localand globalplanner architecture. The local planner employs a rapidlyexploring random graph to reliably and efficiently identify collisionfree paths that optimize an exploration gain within a local subspace. Accounting for the robot endurance limitations and the possibility that the local planner reaches a deadend (e.g. a mine heading), the global planner is engaged when a returntohome path must be derived or when the robot should be repositioned towards an edge of the exploration space. The proposed planner is field evaluated in a collection of deployments inside both active and abandoned underground mines in the U.S. and in Switzerland.