Autonomous underwater vehicles

Autonomous underwater vehicles

ARTICLE IN PRESS Ocean Engineering 36 (2009) 1 Contents lists available at ScienceDirect Ocean Engineering journal homepage: www.elsevier.com/locate...

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ARTICLE IN PRESS Ocean Engineering 36 (2009) 1

Contents lists available at ScienceDirect

Ocean Engineering journal homepage: www.elsevier.com/locate/oceaneng

Preface

Autonomous underwater vehicles

As technology is improving, an increasingly large number of complex missions are designed to be conducted by autonomous robots. To meet the expectations of these missions, we must design robots with a very high degree of autonomy. This special issue presents new advances in research and development of autonomous underwater vehicles. Over the last few decades, ocean research and exploration have made underwater mechanical systems a necessity. Autonomous underwater vehicles provide a new kind of marine platforms that have proven to be an asset in many areas of oceanographic research. The marine environment is an especially challenging environment and new approaches and control designs need to be developed towards improving the navigation capabilities of an autonomous underwater vehicle. This is the focus of the papers presented here. Autonomous underwater vehicles come in a variety of shapes, sizes and means of propulsion. The specifics of the mission determine these features. Although not to the same extent than their wheeled and flying counterparts, prototypes of AUV are nonetheless currently extensively developed around the world. The first set of five papers presents several prototypes and trials conducted in oceanic environment. ISiMI is a small and versatile vehicle discussed in the papers by Jung et al. and Park et al. This vehicle can easily be launched and a series of simulations and ocean trials are exposed to describe the capabilities and performances of the vehicle. ISiMI can be equipped with a camera to serve as a test-bed vehicle for an underwater docking procedure based on vision-guidance developed by the authors. In Alvarez et al. another low-cost, light-weight AUV, FOLAGA is introduced. The main feature of this vehicle is that it combines two modes of actuation. It can realize glider-type motion using buoyancy changes and an internal sliding mass as well as motion of a propulsion-driven AUV. Cooperative motion of AUV is also discussed in that paper. The prototype introduced in Georgiades et al. is an example of amphibious robot combining terrestrial and aquatic locomotion. Propulsion in the water is realized through the actuation of paddles to provide the vehicle the ability to swim underwater. While the aforementioned papers are mostly concerned with guidance and navigation of a vehicle, intervention missions may require from the AUV the capability to execute

0029-8018/$ - see front matter & 2008 Published by Elsevier Ltd. doi:10.1016/j.oceaneng.2008.12.005

manipulating actions. The paper by Marani et al. focuses on a prototype, SAUVIM, designed for intervention missions that require autonomous manipulation. Successful sea trials are presented. The second set of papers focuses exclusively on developing control strategies for AUVs. A critical aspect of underwater navigation focuses on designing controllers that can take into account external uncertainties due to the continuously varying environment. This question is addressed in the papers by Lapierre, Woolsey et al., and Kumar et al. Equally important for an AUV, due to its increasing load of responsibilities, is its efficiency of movement and energy usage. In Chyba et al., optimal geometric control is used to design time and consumption efficient trajectories. The proposed strategies are validated through experiments on a prototype vehicle named ODIN. Two papers of the special issue discuss hydrodynamic optimization of AUV hull form. In Jagadeesh et al., the authors assume that the vehicle operates under deeply submerged condition while in Alvarez et al., the authors assume that the AUV operates near the free surface. Finally, the paper by Petrich et al. proposes a method to incorporate a local flow field model into their AUV navigation algorithm. The guest editor would like to thank very warmly Prof. Cengiz Ertekin, Editor in Chief of Ocean Engineering, for his guidance and assistance with the preparation of this special issue. Through their work and encouragement, the staff made it all possible. Thank you. A special thank you also goes to the authors of the papers presented in this special issue; it was a pleasure to work with each of you and an honor to receive your contributions. The reviewers played a major role to ensure that the high standards of the journal are met. The guest editor sincerely hopes that the readers will find the papers presented in this special issue both interesting and stimulating. December 8, 2008. Monique Chyba University of Hawaii at Manoa, Department of Mathematics, College of Natural Sciences, 2565 McCarthy Mall, Honolulu,HI 96822, USA E-mail address: [email protected]