Dynamic positioning for Autonomous Surface Vehicles

Abstract

This master seeks to prove that it is possible to control a small autonomous surface vehicle with a dynamic positioning controller, using simple controls and thrust algorithm. This should be done without using observers and estimators, only a RTK GNSS receiver. As a step to completing this, remote controlling of the boat and a heading hold controller should also be implemented. This master thesis focuses on implementation and testing of this experimentally at sea. A simple heading hold controller was developed and the dynamic positioning controller from the project thesis Thorbjørnsen (2016) was implemented in the code as well as remote control of the boat. A part of this master thesis was also to reconfigure a sailboat hull provided by Maritime Robotics from having one thruster to having two thrusters able to turn at least ±135 degrees. The boat was reconfigured and launched to sea. First the remote control was tested and it performed well. Secondly the heading hold controller was tuned, tested and it worked as expected. Lastly the dynamic positioning controller was not tested because it was discovered that the GNSS receiver used, was not able to output correct heading of the boat when it was drifting slowly. This master thesis has shown that it is possible to build a boat using cheap components. It is also concluded that the remote control and heading hold controller worked. As for the dynamic positioning controller installing a two antenna GNSS receiver is recommended and then the system is ready to be tuned and tested experimentally.