Task-Based Motion Control of an Autonomous Surface Vehicle in a Combined System with a Remotely Operated Vehicle (ASV-ROV)

Marine robotics plays a crucial role in carrying out a wide range of complex underwater missions. In this context, tethered Remotely Operated Vehicles (ROVs) provide several advantages, including efficient data transmission and a reliable physical connection that ensures safety in emergency situations. However, their operational range is inherently limited by the length of the tether. This study investigates the possibility of extending the operational range of ROVs by introducing a novel control strategy that enables cooperative operation with an Autonomous Surface Vehicle (ASV). The proposed ASV–ROV system addresses two primary challenges: the restricted mobility of the ROV and the potential risk of cable entanglement. To mitigate these issues, a new control framework is developed to ensure smooth ROV motion while minimizing conditions that could lead to tether entanglement. The control system allows the ASV to maintain alignment with the ROV and preserve a desired distance, while simultaneously regulating the length of cable deployed in the water. This thesis presents the control design of the ASV motion for a cooperative navigation with the ROV. The work includes the formulation of a novel control strategy that enables the ASV to autonomously track and follow the ROV while avoiding obstacles and adjusting its trajectory to maintain safe and efficient cooperation. The proposed control framework is validated through comprehensive software-in-the-loop simulations that represents offshore wind farm environments. The numerical results demonstrate the effectiveness and robustness of the system in improving cooperative navigation performance, reducing power consumption, and enhancing operational resilience under dynamic marine conditions. Furthermore, the work of this thesis investigates the impact of tether management on the overall stability and energy efficiency of the ASV–ROV system. An analytical assessment of tether dynamics is conducted, supported by experimental validation in a controlled test basin, where precise measurements about underwater tether behavior were collected. Directions for further research and system optimization are also discussed.