Underwater confined space mapping by resource‐constrained autonomous vehicle

Abstract

Abstract For marine industrial inspection, archaeology, and geological formation study, the ability to map unknown underwater enclosed and confined spaces is desirable and well suited for robotic vehicles. To date, there are few solutions thoroughly tested in the field designed to perform this specific task, none of which operate autonomously. With a small, low‐cost biomimetic platform known as the U‐CAT, we developed a mapping‐mission software architecture in which the vehicle executes three key sensor‐based reactive stages: entering, exploring, and exiting. Encapsulated in the exploring stage are several state‐defined navigation strategies, called patterns, which were designed and initially tested in simulation. The results of simulation work informed the selection of two patterns that were executed in field trials at a submerged building in Rummu Quarry Lake, Estonia, as part of several full mapping missions. Over the course of these trials, the vehicle was capable of observing the majority (78–97%) of 49.9 explorable square meters within 7 minutes. Based on these results, we demonstrate the capability of a low‐cost and resource‐constrained vehicle to perform confined space mapping under sensor uncertainty. Further, the observations made by the vehicle are shown to be suitable for a target site reconstruction and analysis in postprocessing, which is the intended outcome of this type of mission in practical applications.