Autonomous Docking for Marine Vessels Using a Lidar and Proximity Sensors.
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- Institutt for marin teknikk 
This thesis reviews the development of an autonomous docking feature for a marine vessel in a small-scale, sheltered, environment. Proximity sensors are added to aid the autonomous exploration by detecting obstacles outside the lidars scan-plane, an assessment of different thrust allocations to emulate leisure boats are addressed. The Cyber Ship Saucer, a model-scale vessel built for testing in the Marine Cybernetics Laboratory at NTNU, have been serving the platform for testing the docking scheme. The model and the lab, together with autonomous systems, optimal thrust allocation, sensors and SLAM is presented as a background for the experimental work performed in this thesis. In addition to the fixed thrusters, four new configurations which considering rotation, emulating a leisure boat, have been studied. The ''constrained control allocation for azimuth thruster'' were applied to find an optimal solution for each of the modes. The online visualization process has been altered such that obstacles detected by the proximity sensors become apparent for the operator, along with the heading of the vessel. Through modifying the existing system, influencing both the path planning strategy and operator interaction, autonomous docking and take-off arose. Simulations, and later experiments, verified the autonomous docking by utilizing the proximity sensors using a fixed thruster configuration. Through the user interface, the user is able to select a spot and then inputting the desired heading there. The results are presented, and discussed, in a separate chapter. The electronic attachment contains, among other, photos and videos from the experimental trials.