Smart enhanced performance intervention ROVs control system advancements for marine work-class ROV manipulators

This thesis describes a body of research work focused on the domain of marine robotics and underwater manipulator control systems in particular. Work-class marine ROVs equipped with hydraulic manipulators are widely used in offshore industry for undersea inspection and intervention operations. In standard subsea operations setup, a human pilot employs telemanipulation technology to operate both vehicle and manipulators based on the worksite visual feedback provided by camera and sonar systems. In the emerging marine renewable energy industry, target devices are in motion due to their location in challenging environments of high energy winds, currents, and waves offshore. In such high energy sites, current commercial ROV technology capabilities are not sufficient for inspection, repair, and maintenance operations and utilising a traditional teleoperation approach is likely to fail even with very skilled pilots. This research describes the development of robotic manipulator control systems beyond the state-of-the-art capable of executing tasks in challenging conditions of the dynamic wave/current environment. A particular focus is on automation solutions that can be easily retrofitted to existing off-theshelf underwater manipulator systems on the global fleet of commercial work-class ROVs without any hardware or software modifications. The thesis describes a developed kinematics control engine that allows human pilots to operate ROV manipulators with auto-assist, utilising enhanced manual, semi-automatic, and fully automatic (visual) servo control modes of operation while addressing stationary and moving targets. A developed collision detection and avoidance algorithm for subsea manipulators for safe, reliable, and efficient operations is also described. The control solutions for automated manipulation have been developed, implemented, and verified in simulation, dry laboratory experimental tests, and through subsea trials on a commercial work-class ROV with industry standard hydraulic manipulators. The developed control systems have a potential to reduce the task load, operational time, and costs of subsea inspection and intervention operations and significantly extend the window of operating conditions for marine ROV inspection, repair, and maintenance in the marine renewable energy and other sectors.