Ocean Engineering 30 (2003) 453–470 www.elsevier.com/locate/oceaneng Dynamics and control of a towed underwater vehicle system, part I: model development B. Buckham a , M. Nahon c,* , M. Seto b , X. Zhao a , C. Lambert a a Mechanical Engineering, University of Victoria, P.O. Box 3055, Victoria, BC, Canada, V8N 6K8 b Defence Research Establishment Atlantic, P.O. Box 1012, Dartmouth, Nova Scotia, Canada, B2Y 3Z c Mechanical Engineering, McGill University, Montreal, Quebec, Canada, H3A 2K6 Abstract Autonomous vehicles are being developed to replace the conventional, manned surface vehicles that tow mine hunting towed platforms. While a wide body of work exists that describes numerical models of towed systems, they usually include relatively simple models of the towed bodies and neglect the dynamics of the towing vehicle. For systems in which the mass of the towing vehicle is comparable to that of the towed vehicle, it becomes important to consider the dynamics of both vehicles. In this work, we describe the development of a numerical model that accurately captures the dynamics of these new mine hunting systems. We use a lumped mass approximation for the towcable and couple this model to non-linear numerical models of an autonomous surface vehicle and an actively controlled towfish. Within the dynamics models of the two vehicles, we include non-linear controllers to allow accurate maneuvering of the towed system.  2002 Elsevier Science Ltd. All rights reserved. Keywords: Lumped mass; Underwater vehicle; Cable dynamics; Numerical simulation 1. Introduction The use of towed cable systems in acoustic surveying, mine hunting, and undersea cable laying applications has precipitated extensive research into the behaviour of marine cables. Because of non-linear cable geometry and the dominance of the non- linear hydrodynamic forces, the solution of the cable dynamics equations in the time * Corresponding author. E-mail address: meyer.nahon@mcgill.ca (M. Nahon). 0029-8018/02/$ - see front matter  2002 Elsevier Science Ltd. All rights reserved. PII:S0029-8018(02)00029-X