You are here

Automatic Station Keeping of Small Twin Screw Boats

Download pdf | Full Screen View

Date Issued:
2007
Summary:
This work details the development of tools and controllers for station keeping control of twin screw vessels. A fundamental analysis is conducted of the dynamics of twin screw displacement hull vessels and their actuator systems, where the response characteristics and maneuverability are quantified through a series of full scale trials conducted in different environmental conditions while recording the environmental conditions, actuator states, and geodetic and inertial measurements. The data from these maneuvers were repeatable from run to run and thus provide valuable benchmarks for several maneuvers and the measured actuator response provides valuable set points of performance characteristics/limitations for control development. A comprehensive general simulation of small twin screw displacement hull boats is developed as a tool to estimate ship and actuator responses in support of developing and tuning of control systems. The model and computer simulation is capable of modeling a wide range of the surface vessels, including their actuators and environmental conditions. This model proved to be accurate, when compared to the sea trial data, and model estimates have rms velocity errors for the various steady maneuvers of 1.2-4.6% for surge, 12.6-17.9% for sway, and 7.6-20.2% for yaw. A path following station keeping controller is developed that uses Lyapunov stability analysis to determine the path the vessel should follow to effectively eliminate position error. This controller showed good performance for several different environmental conditions. Encouraged by these finding, three additional station keeping control methodologies are developed for twin screw surface ships. All four of these controllers are examined for their robustness to environmental conditions, as well as their sensitivity to sensor precision, sensor update rates, and actuator limitations. All controllers are evaluated in sea state 4 yielding rms position errors from 3.3 to 16.2 m, the rms surge and sway accelerations are under 0.62 m/s , and the engine shifting frequencies are between 0.011 and 0.145 Hz. These four controllers are then tested over a wide range of environmental conditions, sensor precisions and update rates, and actuator response rates. The results from these tests give quantitative data that will aid in selecting the appropriate controller for a specific application, and will assist in selecting appropriate sensors.
Title: Automatic Station Keeping of Small Twin Screw Boats.
41 views
7 downloads
Name(s): VanZwieten, James H.
Driscoll, Frederick R., Thesis advisor
Florida Atlantic University, Degree grantor
College of Engineering and Computer Science
Department of Ocean and Mechanical Engineering
Type of Resource: text
Genre: Electronic Thesis Or Dissertation
Date Created: 2007
Date Issued: 2007
Publisher: Florida Atlantic University
Place of Publication: Boca Raton, Fla.
Physical Form: application/pdf
Extent: 298 p.
Language(s): English
Summary: This work details the development of tools and controllers for station keeping control of twin screw vessels. A fundamental analysis is conducted of the dynamics of twin screw displacement hull vessels and their actuator systems, where the response characteristics and maneuverability are quantified through a series of full scale trials conducted in different environmental conditions while recording the environmental conditions, actuator states, and geodetic and inertial measurements. The data from these maneuvers were repeatable from run to run and thus provide valuable benchmarks for several maneuvers and the measured actuator response provides valuable set points of performance characteristics/limitations for control development. A comprehensive general simulation of small twin screw displacement hull boats is developed as a tool to estimate ship and actuator responses in support of developing and tuning of control systems. The model and computer simulation is capable of modeling a wide range of the surface vessels, including their actuators and environmental conditions. This model proved to be accurate, when compared to the sea trial data, and model estimates have rms velocity errors for the various steady maneuvers of 1.2-4.6% for surge, 12.6-17.9% for sway, and 7.6-20.2% for yaw. A path following station keeping controller is developed that uses Lyapunov stability analysis to determine the path the vessel should follow to effectively eliminate position error. This controller showed good performance for several different environmental conditions. Encouraged by these finding, three additional station keeping control methodologies are developed for twin screw surface ships. All four of these controllers are examined for their robustness to environmental conditions, as well as their sensitivity to sensor precision, sensor update rates, and actuator limitations. All controllers are evaluated in sea state 4 yielding rms position errors from 3.3 to 16.2 m, the rms surge and sway accelerations are under 0.62 m/s , and the engine shifting frequencies are between 0.011 and 0.145 Hz. These four controllers are then tested over a wide range of environmental conditions, sensor precisions and update rates, and actuator response rates. The results from these tests give quantitative data that will aid in selecting the appropriate controller for a specific application, and will assist in selecting appropriate sensors.
Identifier: FA00012579 (IID)
Degree granted: Dissertation (Ph.D.)--Florida Atlantic University, 2007.
Collection: FAU Electronic Theses and Dissertations Collection
Note(s): College of Engineering and Computer Science
Subject(s): Boats and boating--Design
Actuators--Testing
Fracture mechanics
Lyapunov functions
Held by: Florida Atlantic University Libraries
Sublocation: Digital Library
Persistent Link to This Record: http://purl.flvc.org/fau/fd/FA00012579
Use and Reproduction: Copyright © is held by the author with permission granted to Florida Atlantic University to digitize, archive and distribute this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder.
Use and Reproduction: http://rightsstatements.org/vocab/InC/1.0/
Host Institution: FAU
Is Part of Series: Florida Atlantic University Digital Library Collections.