A closed-loop, position-controlled, electrohydraulic manipulator system has been developed to provide an autonomous inspection capability for sub-sea structures. The arm comprises three main degrees-of-freedom each microprocessor controlled within a hierarchical computer system. The control algorithms permit local motion control resulting in smooth position changes based on a time-optimal acceleration strategy. OvVerall motion demands, coordinate transformations, etc., being performed by a higher level microprocessor. To conduct an inspection task, the arm system will be deployed by an ROV near a subsea tubular pipe joint, and be capable of locating a cylindrical pipe and establishing its position and orientations with respect to the arm datum coordinate system. This operation is repeated for other pipes and the pipe intersections computed. Subsequently the arm can perform an autonomous tracking operation along this defined trajectory, so as to clean a weld and then deploy NDT sensing equipment.
Development of a manipulator for automated inspection of subsea structures
Entwicklung eines Manipulators fuer eine automatisierte Inspektion von Unterwasserbaustrukturen
1984
5 Seiten, 6 Bilder
Conference paper
English