Off-Shore Robotics : Robust and Optimal Solutions for Autonomous Operation

Abstract

The vast majority of research in the field of robotics has over the last few decades shifted from industrial robots—in the sense of robots mounted in a structured environment such as a factory floor—to robots operating in unstructured and harsh environments. Even though industrial robotics has become a mature research field we believe that there is still room for progress and improvement. In fact, we show this through both theoretical advances and experimental results in this thesis. However, the main focus of most researchers today has shifted towards autonomous robots and robots in unstructured environments, and this is also the main focus of the work presented here.\n\nThis thesis is concerned with the borderline between the mature technology that includes conventional industrial robots and robots operating in unstructured and harsh environments, an area that is still undergoing considerable advances. The oil fields of the future will have to adopt solutions from both mature and evolving technologies—including the borderline between them—and we will use this application to illustrate the practical importance of the theoretical results throughout the thesis. Several tasks to be performed by the robot on the oil fields of the future resemble the tasks performed by industrial robots on the factory floor in thousands of factories around the world today. In this sense we may consider this a mature and robust technology. At the same time the robots will have to work in an unstructured environment with little or no direct human intervention and autonomous operation is required also for non-routine tasks. In this sense, the oil platforms of the future present us with an interesting case study.\n\nWe believe there to be two main issues that need to be addressed before partially or completely robotised oil platforms will see the light of day. The first is concerned with robustness. Robotic solutions will only be applied to tasks where the efficiency, accuracy, repeatability, and robustness surpass those of the human operator performing the same tasks. Remotely located oil platforms, and especially the ones located in sensitive areas such as the Barents Sea, are characterised by strict legislative standards to protect the environment and the wildlife. Any installation involving petrochemicals such as oil and gas will have to show for robust and reliable solutions at every stage of the operation. Thus, any operation involving robots will have to meet very high standards when it comes to robustness and fault tolerance. This imposes great challenges on the oil companies that are to operate in these areas.\n\nThe second issue is concerned with the effectiveness and cost efficiency of the operation. An experienced human operator has an incredible capability to find efficient solutions to both routine tasks and unexpected occurrences. The robotics system should also strive to solve any task in an optimal manner. Effective and cost efficient operation is vital to be able to justify the high investment in research and installation related with robotised oil fields. Thus, for these systems to be interesting for the oil companies the daily operation should not only be more robust compared to human operators, it should also be more cost efficient to guarantee that the investment in expensive robotic equipment pays off.\n\nWhen it comes to remotely located oil fields, effectiveness and robustness are very much related. The main economical risk involved with the operation of oil platforms today is unscheduled shutdowns. Unscheduled shutdowns, as well as planned maintenance shutdowns, should be made as short as possible and if possible avoided. A robust solution with less chance of failure is thus something the oil companies strive for also with the economical gain as a motivation.\n\nThis thesis is divided into four main parts. Part I is concerned with a large class of robotic systems that will play a very important role in the operation of remote