| dc.description.abstract | Remote control and monitoring of marine operations is in many cases desirable, due to distance, harsh environment, and dangers related to human life, and safety. Marine control systems in interaction with remote control give an accurate and reliable operation, where the aim is e.g. motion control, signal processing, maintenance, and installation. The system can perform its mission with a certain level of involvement from the operator, located remotely.
The topic of this thesis is remote control and monitoring of two marine vehicles performing path following operations. The marine vehicles are the remotely operated vehicle Neptunus, a low-cost underwater vehicle, and Cybership Enterprise I (CSEI), a model-scale vessel in Marine Cybernetics laboratory (MC lab) at NTNU.
Mathematical models for both vessels are established, based on Fossen s robot-like vectorial model. For Neptunus, system identification is performed, and the parameters are found using full scale towing tests, software simulations and expressions from the literature. For CSEI, these parameters have been calculated in previous works, and are only briefly presented.
Simulation models for Neptunus and CSEI are set up, and a set of benchmark tests are conducted for validation. A comparing study against an estimated model of Neptunus is performed. Simulations revealed that the estimation model are in compliance with the identified model obtained in this thesis.
Path following algorithms working in the horizontal plane (surge, sway, and yaw) for Neptunus and CSEI are developed and tested. The control systems vary in complexity and performance related to their control objectives. In all the control systems, integral action to account for current is implemented. Neptunus is underactuated, and CSEI is made underactuated by disabling the bow thruster, and mapping the Voith Schnei- der propellers to a rudder-propeller system. This is done using the first order Nomoto model of the yaw dynamics. Simulations rendered satisfying and stable behavior for the two vehicles. However, for more advanced motion control systems, full and accurate state feedback is needed for optimal performance, together with a robust mathematical model of the system.
Neptunus is not lab-functional. Thus, CSEI is working as test platform. For testing of the performance, hardware in the loop (HIL) is conducted. Successful HIL opened for model-scale testing in the MC lab. The establishment of a interface that allowed communication between CSEI and a tablet opened for remote control and monitoring. The tablet is used to tune controller gains online and to investigate the control objective real time. | |
