A robot for offshore pipeline inspection

Abstract

The robot presented in this paper was designed to find damages to the external sheath of offshore pipelines. The pipeline section subject to inspection is known as “riser” and connects the pipe running on the seabed to the production facility at the platform or “floating production, storage and offloading” ship (FPSO). When compared to the current tools used to perform this work, the main advantage of this robot is to be able to execute the inspection without umbilical cable or operator assistance. The vehicle, called Autonomous Underwater Riser Inspection robot (AURI), uses the pipeline for guidance. A closed feedback loop control system is used to maintain constant speed during the mission. Several sensors provides multiple return conditions for safe operation, such as maximum depth, maximum time or maximum distance. The robot is suited to carry different inspection devices (payloads). The payload for the first prototype consists of four cameras which provide 100% coverage of the external pipe surface. All robot vessels were designed to support up to 100 Bar of pressure, allowing the vehicle to reach a maximum depth of one thousand meters. This paper presents the general concepts of the robot as well as results from the tests in a pool, including some hydrodynamic parameters of the vehicle.