Guidance Laws for Autonomous Underwater Vehicles

About 70% of the surface of the Earth is covered by oceans, and the ocean space represents a vast chamber of natural resources. In order to explore and utilize these resources, humankind depends on developing and employing underwater vehicles, not least unmanned underwater vehicles (UUVs). Today, UUVs encompass remotely operated vehicles (ROVs) and autonomous underwater vehicles (AUVs). The first ROVs were built in the 1950s, put into commercial use in the 1980s, and are mostly used today by the offshore oil and gas industry to carry out inspection and intervention operations at subsea installations (Antonelli et al. 2008). These vehicles are teleoperated by connection to a surface vessel through an umbilical cable that provides them with power and telemetry. In particular, the dependence on a tether represents a considerable challenge for ROV deepwater operations (Whitcomb 2000). On the other hand, AUVs are free-swimming vehicles that rely on their own energy supply. The first AUVs were built in the 1970s, put into commercial use in the 1990s, and today are mostly used for scientific, commercial, and military mapping and survey tasks (Blidberg 2001). Developed in cooperation between Kongsberg Maritime and the Norwegian Defence Research Establishment, the HUGIN series represents the most commercially successful AUV series on the world market today (Hagen et al. 2003). HUGIN vehicles have been employed for commercial applications since 1997 and for military applications since 2001. The workhorse HUGIN 3000 has an impressive 60 hours endurance at 4 knots speed with payload sensors running. Currently, the main challenges for AUVs encompass endurance, navigation, communication, and autonomy issues. Traditionally, ROVs and AUVs have been assigned different tasks due to different strengths and weaknesses, see Fig. 1. In the future, hybrid ROV/AUV designs are expected to bridge the gap between these two main UUV types, utilizing the best of both worlds (Wernli 2000). Regarding motion control research for UUVs, Craven et al. (1998) give an overview of modern control approaches with an emphasis on artificial intelligence techniques; Roberts & Sutton (2006) treat guidance, navigation, and control issues for unmanned marine vehicles with an emphasis on underwater vehicles; while Antonelli et al. (2008) present a state-of-theart survey of control-related aspects for underwater robotic systems. O pe n A cc es s D at ab as e w w w .in te ch w eb .o rg