COLREGS compliant Collision Avoidance System for a Wave and Solar Powered USV
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Autonomous ships are the future of modern maritime traffic, but in order to operate in the vicinity of other vessels, Autonomous Surface Vehicles (ASV) must be equipped with a collision avoidance system (CAS). This system must adhere to the rules-of-the-road, the International Regulations for Preventing Collisions at Sea (COLREGS). In this thesis a navigation and collision avoidance system was implemented to a wave- and solar driven Unmanned Surface Vehicle (USV), namely AutoNaut. The COLREGS compliant collision avoidance system has been further developed and its performance has been validated through various simulations in the LSTS software toolchain. The main scenarios designed to test the CAS and the COLREGS compliance were: head-on, crossing and overtaking.From these situations single and multiple obstacle avoidance scenarios were created, to see how the system behaves in a complex situation.A hardware design was made where the CAS combined with hardware-sensor implementation formed the navigation and collision avoidance level of AutoNaut. The CAS performed quite well in the simulated scenarios, and the avoidance maneuvers complies with the COLREGs requirements. However, more tuning is required and environmental forces needs to be taken into account for a more realistic and optimal simulation. Full-scale testing of the USV and the systems were conducted, and the autopilot and the subsystem interactions were tested. The USV was able to operate, but the autopilot needs more tuning. Several attempts were made to test the collision avoidance, however they were not completed due to hardware limitations and the difficulties of obtaining obstacle vessels.