Inspection of Undersea Oil and Gas Pipelines by New Variable Thrust Vector Underwater Robotic Platform

This paper presents a special underwater robot for subsea pipelines inspection which is used to transport extracted oil and gas from oil platforms to onshore facilities. Due to the high pressure in the deep sea and the long pipelines, it is impossible to inspection by divers. Therefore underwater robot can be used to solve this problem. This paper investigate a hovering type of underwater vehicle including four thruster with variable thrust vector, which it is able to simultaneous control of six degrees of freedom. Therefore, high flexibility is an advantage of this underwater robot. Using two perpendicular servomotors for each thruster, we prepare independent and time variable orientation for each thruster. This paper investigates a trajectory controller for this hovering type autonomous underwater vehicle to meet the demands of in-water pipeline inspection.