The development and experimental testing of the DUKW-Ling amphibious vehicle was performed during the first phase of an autonomous amphibious vehicle system development project. The DUKW-Ling is a 1/7th scale model of a cargo transport concept vehicle. The vehicle was tested in the three regions it is required to operate: land, sea and the surf zone region. Vehicle characteristics such as turning radii, yaw rate and velocities were found for different motor inputs on land and water. Also, because a vehicle navigating the surf zone is a new area of research that lacks experimental data the vehicle was tested in the breaking waves of the surf zone and its motion characteristics were found, as well as the drivetrain forces required to perform this transition. Maneuvering tests provided data that was used to estimate a model for future autonomous control efforts for both land and water navigation. / by Joseph G. Marquardt. / Thesis (M.S.C.S.)--Florida Atlantic University, 2012. / Includes bibliography.

Thesis (M.S. in Applied Physics)--Naval Postgraduate School, June 2005. / Thesis Advisor(s): Richard Harkins, Ravi Vaidyanathan. Includes bibliographical references (p.87-88). Also available online.

The Small Robot Initiative at the Naval Postgraduate School (NPS) has spent several years in development based on the Foster Miller lemmings platform. This platform, in conjunction with a commercial off-the-shelf (COTS) control architecture, is capable of autonomous, land based waypoint navigation, self orientation, and rudimentary obstacle avoidance. It can receive waypoint information, manual control input, and transmit video and audio information back to a control station via 802.11 wireless communication. The introduction of the WHEGS design, developed at Case Western Reserve University, and a modified version of the COTS control system will provide a platform with greater speed, mobility and versatility. This thesis developed a prototype WHEGS vehicle and integrated the control system with improvements in the navigation routine through the addition of a dead reckoning sensor and calculation function. Although the mechanical design proved to be highly inefficient and unable to propel itself, the control system was successful, allowing integration with a more robust mechanical design from Case Western Reserve University. Follow on development and research will lighten the body through the use of carbon fiber and test the robots ability to maneuver effectively in the surf-zone.

The DUCKW-Ling is an 8.3 foot long, amphibious water plane area twin hull (SWATH) concept vehicle which is propelled by a pair of crawler tracks on land and dual propellers when water-borne. In its operational zone, the vehicle's dynamics change dramatically as it transitions from being completely water-borne and buoyancy supported to being completely land-borne and track supported. In the water environment, a cascaded, first-order sliding mode controller was used to control the surge and heading of the vehicle, and was capable of having a faster response when compared to using a proportional controller. Additionally, field trials of the DUKW-Ling show the capability of the vehicle to navigate and track predetermined waypoints in both terrestrial and aquatic terrains. In the transitional zone, the electric motor current from the tracks was used as the feedback mechanism to adequately actuate the propellers and tracks in the system as the dynamics of the vehicle change. / by Josâe L. Alvarez. / Thesis (M.S.C.S.)--Florida Atlantic University, 2013. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.