Entwicklung und Aufbau eines aktiven Trimmsystems für autonome Unterwasserfahrzeuge [article]

Tino Schmidt, Heinz Lehr, Technische Universität Berlin, Technische Universität Berlin
The increasing demand of underwater vehicles for deep sea applications like ROVs and AUVs can be attributed to the growing request of resources by mankind. With an increasing diving depth, the density of the sea water increases due to the hydrostatic pressure of the water column. At the same time, the increasing pressure leads to a decrease in volume of the vehicle materials. This especially needs to be considered with recent AUVs since they are flooded and the ambient pressure effects every
more » ... re effects every single component. Altogether, the buoyancy force of the vehicle increases, whereas the weight remains almost constant. As a consequence, the buoyancy trim changes with the diving depth. This dissertation describes the development of an active trim system which can be used in the deep sea to trim both buoyancy and position of the AUV PreToS. It consists of two oil-pumped systems which are identical in construction. One oil-pumped system is located in the fore, and the other one in the aft of the PreToS. Through the use of different applications, both buoyancy force and pitch angle of the AUV can be changed. To change the volume of the system, and therefore the generated buoyancy force, the hydraulic fluid can be shifted between pressure hull and flexible container. During this process, the mass of the system remains constant and the displaced volume varies. The displacement of the hydraulic fluid can be accredited to a high pressure pump and to a high pressure valve, adapted to deep sea conditions. Besides, the monitoring of the fluid movement with two newly-developed pressure tolerant sensors was successful using the low rate sensor and liquid level sensor. Single components deployed in the trim system underwent a suitability test for deep sea usage in the pressure tank of the Department of Electromechanical and Optical Systems of the Technical University Berlin. After successfully establishing a prototype of an active trim system, experiments in a steel frame in the Baltic Sea and the Atlantic Ocean were carried out. Afterwa [...]
doi:10.14279/depositonce-4374 fatcat:cmoityhrifdmhdfndcyszzp674