SIRUS: A mobile robot for Floating Production Storage and Offloading (FPSO) ship hull inspection

This paper describes the current development status of a mobile robot designed to inspect the outer surface of large oil ship hulls and floating production storage offloading (FPSO) platforms. These are usually former oil tanker ships, especially adapted to work as an oil offshore platform. Several mechanisms of corrosion are present in such structures, worsen by the abnormal static operation regime of the vessel and other causes. This situation requires a detailed program of inspection, using several non destructive detection (NDT) techniques, operated manually. Here, a robotic crawler designed to perform such inspections is presented. Locomotion over the hull is provided trough a pair or DC-motor propelled magnetic tracks, while the system is controlled by two networked PCs and a set of custom hardware to drive the motors, video cameras, ultrasound (US), inertial platform and other devices. Navigation is provided by a extended Kalman filter sensor fusion formulation, integrating hodometry and inertial sensors. The current version of the prototype is able to perform ultrasound thickness measurements in the dry part of the hull.