%0 Journal Article
%T Reconstruction of Riser Profiles by an Underwater Robot Using Inertial Navigation
%A Luciano Luporini Menegaldo
%A Stefano Panzieri
%A Cassiano Neves
%J Journal of Robotics
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/638394
%X This paper proposes a kinematic model and an inertial localization system architecture for a riser inspecting robot. The robot scrolls outside the catenary riser, used for underwater petroleum exploration, and is designed to perform several nondestructive tests. It can also be used to reconstruct the riser profile. Here, a realistic simulation model of robot kinematics and its environment is proposed, using different sources of data: oil platform characteristics, riser static configuration, sea currents and waves, vortex-induced vibrations, and instrumentation model. A dynamic finite element model of the riser generates a nominal riser profile. When the robot kinematic model virtually scrolls the simulated riser profile, a robot kinematic pattern is calculated. This pattern feeds error models of a strapdown inertial measurement unit (IMU) and of a depth sensor. A Kalman filter fuses the simulated accelerometers data with simulated external measurements. Along the riser vertical part, the estimated localization error between the simulated nominal and Kalman filter reconstructed robot paths was about 2£żm. When the robot model approaches the seabed it assumes a more horizontal trajectory and the localization error increases significantly. 1. Introduction One of the key elements of deep-water petroleum exploration is the production riser. Risers are the ducts that transport petroleum, water or gases from the exploitation well up to the production platform. Either rigid or flexible types of risers may be used in the oil field. Both types are submitted to a broad spectrum of failure causes [1]: mechanical loads, aging, corrosion, erosion, temperature effects, installation or fabrication nonconformities, and so forth. Therefore, the availability of inspection tools to assess riser integrity status in situ is highly desirable. Such procedures are performed mainly by visual inspection with remotely operated vehicles (ROVs) [2] or autonomous underwater vehicles (AUVs) [3]. In some cases, sensors are installed directly on fixed points of the riser surface to measure strain and riser motion [4]. Other types of nondestructive testing (NDT) techniques can be used, such as magnetic, radiographic, or ultrasound methods [5]. In these cases, however, the operational constraints for using human operators are a major problem. A few papers address robotic devices specifically designed for underwater riser inspection. Psarros and his collaborators [6] proposed a robot that moves along the riser by using a mechanism composed of two parts. One part stays attached to the riser
%U http://www.hindawi.com/journals/jr/2012/638394/