When carrying out sampling tasks close to the ocean bottom, a ROV keeps station at a fixed position and compensates the tether effects and currents. However, the operation of ROV thrust propellers for station keeping might stir up sediment and cause poor visibility, which forces ROV operators to stop work until the sediment clears. The purpose of this thesis, therefore, is to design and fabricate a seafloor moving platform able to approach steadily to sampling objects without stirring up much sediment. This moving platform must be combined with the second generation NCKU-NSYSU ROV, a sampling manipulator, and a sample storage apparatus. Also, the moving platform requires some capabilities for travel over relatively smooth seafloor. A wheel-driven mobile platform, as a result, is developed, in which the front wheels and rear wheels are respectively driven by two separately provided DC motors. The required power and serial command signals are transmitted to the platform via the second generation NCKU-NSYSU ROV. A four-bar linkage for steering font wheels is designed to work close to the Ackerman condition, and a chain-and-sprocket drive train is used to transfer power to the rear wheels. The motor controllers used for controlling DC motors are constructed based on MSP430 MCU (Micro Controller Unit). The preliminary driving performance of the platform is tested. The testing results indicate that the moving platform can drive steadily and behave as expected.

No description available.

The acquisition of marine survey data is traditionally undertaken from surface vessels including boats and temporary rigs. Translation of these techniques to the nearshore zone is a complex task and requires equipment adaptation and. often the sacrifice of data coverage. The remotely operated vehicle (ROV) offers the potential for overcoming some of the standard nearshore survey Concems, providing remote intervention and data acquisition in areas of restricted access. In situ testing is the most efficient and reliable method of acquiring data with minimal sediment disturbance effects. Research has been undertaken into the viability of nearshore cone penetration testing (CPT) which has shown the T-Bar flow round penetrometer to be a possible solution. Data could be acquired in sediments with undrained shear strengths of up to 300 kPa from a bottom crawling ROV weighing 260 kgf and measuring 1 m in length by 0.6 m in width. The collection of sediment cores may be necessary in areas requiring ground truthing for geophysical or in situ investigations. A pneumatic piston corer has been designed and manufactured and is capable of collecting sediment cores up to 400 mm in length, 38 mm in diameter, in sediment with undrained shear strength of 17 kPa. To ascertain additional sediment characteristics in situ, a resistivity subbottom profiling system has also been designed and tested and allows for discrimination between sediment types ranging in size from gravel to silt. The integration of equipment and testing procedures can be fiirther developed through the use of integrated data management approaches such as geographical information systems (GIS). An offthe- shelf GIS, Arclnfo 8, was used to create a GIS containing typical nearshore data using the Dart estuary as a case study location.

Thesis (Ph. D.)--California Institute of Technology, 2006. / Includes bibliographical references (p. 103-108). Also available online.

Thesis (Ph. D.)--Auburn University, 2008. / Abstract. Includes bibliographical references (p. 165-169).

Thesis (M.S.)--Naval Postgraduate School, 2006. / "December 2006." Includes bibliographical references (p. 137-141). Also available online from the Web site of the Naval Postgraduate School (http://www.nps.edu).

Refineries, the chemical industry, airports etc. have an existing stock of thousands of storage tanks, the majority of which were manufactured in the sixties. Depending on the field of industry they are used in, these tanks contain environmentally harmful fluids such as gasoline or petroleum oil in the petrochemical industry or acids in the chemical industry. Other than in newly constructed tanks, there are few possibilities in preventive leak detection in older tank constructions, as the bottom plate is in direct contact to the ground. Hidden corrosion in this structural element has caused a series of catastrophic petroleum spills in the past. In response to these spills, guidelines which specify how and when to inspect tanks have been established globally to guarantee their structural integrity. To allow the inspection of the tank's bottom plate in particular, using state of the art techniques and equipment, the tanks are taken out of service and prepared for the inspection. This preparation process requires draining, washing, degassing and ventilating the tank which is a very polluting, time consuming and expensive process. A review of existing approaches has shown that automated inspection systems where a crawler carries the inspection probes, while the tank remains filled, can circumvent the need for the preparation process. However, there are some serious limitations to such systems as the crawlers used are in direct contact with the tank's structure, where obstacles inside the tanks present a problem. To make such remotely operated vehicular systems more flexible and reliable, this study investigates the fundamental requirements and replaces the crawler with a remotely operated submersible. The critical review of currently available ROVs showed that it would be difficult to procure such a vehicle and so it was decided to develop a new ROV, where aspects of operational environment (use in different petrochemical fluids), high lateral stability as well as advantageous design with respect to the subsequent controller design have been taken into account. It has been shown that this design strategy led to a vehicle where linear controller design strategies could be applied. An analysis of its suitability for use in different petrochemical fluids is provided by a detailed study of the materials that have been used and the flexibility to adjust its buoyancy which has been built in. The lateral stability of the vehicle which is a prerequisite to performing the desired plate thickness measurement is demonstrated and the reliability and robustness of the control system that was employed is also considered. A final field experiment has shown the reliable interaction of the system components and that the inspection system provides a useful and desirable capability for use under field conditions. Finally, an analysis of the system's performance has also shown its economic viability.

Thesis (M.S. in Applied Science (Operations Research))--Naval Postgraduate School, 2004. / Title from title screen (viewed July 21, 2006). "June 2004." Includes bibliographical references (p. 79-80). Also issued in paper format.

No description available.

Thesis (M.S.)--West Virginia University, 2004. / Title from document title page. Document formatted into pages; contains viii, 83 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 45-46).