Table of Contents
ISRN Oceanography
Volume 2013, Article ID 219545, 8 pages
http://dx.doi.org/10.5402/2013/219545
Research Article

Nomoto Indices for Constant-Depth Zigzag Manoeuvres of an Autonomous Underwater Vehicle

1Department of Marine Industries, Faculty of Marine Science and Technology, Science and Research Branch, Islamic Azad University, Tehran 1477893855, Iran
2National Research Council Canada, Institute for Ocean Technology, P.O. Box 12093, St. John's, NL, Canada A1B 3T5

Received 3 October 2012; Accepted 11 November 2012

Academic Editors: M. Lipinski and J. L. Zhou

Copyright © 2013 Farhood Azarsina and Christopher D. Williams. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A two-dimensional simulation code is used to study the characteristics of constant-depth zigzag manoeuvres of the axisymmetric autonomous underwater vehicle (AUV) MUN Explorer. Sea trials data for several manoeuvres with the AUV have been reported during the past four years; however, to obtain a more complete understanding of the vehicle's hydrodynamics, additional towing tank tests and computer simulation were performed. The present work, based on the towing tank test results and sea-trials data, utilizes computer simulations to predict the performance of the MUN Explorer AUV during horizontal zigzag manoeuvres. Next, the Nomoto indices for this AUV during constant-depth zigzag manoeuvres are estimated using the simulation results, and, then, Nomoto's first-order model for the rate of turn of the vehicle during horizontal zigzag manoeuvres in response to a square-wave input for the rudder deflection angle is analytically solved. The paper investigates the validity of the simplified yaw equation to predict a zigzag manoeuvre. Results of this research are a first step to understand the details of zigzag manoeuvres of an AUV such as duration of the first execute, yaw-checking ability, and duration of the overshoot.