An ocean going autonomous underwater vehicle "URASHIMA" equipped with a fuel cell

The underwater platform which has enough ability to cruise globally and freely in vast deep sea will allow us to make the survey of entire oceans. We aim to develop an underwater platform which travels and surveys across entire oceans for the research into the global change, ocean-trench earthquake, and biodiversity and so on. We have developed the first prototype underwater platform or the long-range cruising autonomous underwater vehicle (LCAUV) named Urashima since 1998. The vehicle powered by a polymer electrolyte fuel cell system marked the world record of cruising distance of 317 kilometers in 2005. The vehicle has the following specifications: length; 10 m, weight; 10 tons, maximum depth ratings; 3500 m, maximum cruising speed; 3.2 knots, and endurance; 60 hours. This large vehicle has large user payload of a few hundreds kilograms. In 2007, we started research and development of the elemental technologies which will be utilizes for development of the second generation LCAUV to achieve cruising range of over 3000 kilometers. The technologies under research and development are power sources, navigation methods, communication methods, vehicle controllers, materials for body, and advanced sensors for highly resolution survey. The fuel cell and secondary battery hybrid system is had to improve at energy efficiency to generate electricity as possible for long time running with limited energy. A high accuracy inertial navigation system and an underwater positioning system being covered area of over 1000 km are under development. A synthesized aperture sonar is also under development.

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Sizing and Dynamic Modeling of a Power System for the MUN Explorer Autonomous Underwater Vehicle Using a Fuel Cell and Batteries

Journal of Energy ◽

10.1155/2019/4531497 ◽

2019 ◽

Vol 2019 ◽

pp. 1-17 ◽

Cited By ~ 3

Author(s):

Mohamed M. Albarghot ◽

M. Tariq Iqbal ◽

Kevin Pope ◽

Luc Rolland

Keyword(s):

Fuel Cell ◽

Power System ◽

Autonomous Underwater Vehicle ◽

Underwater Vehicle ◽

Hydrogen Gas ◽

System Capacity ◽

Li Ion Batteries ◽

Li Ion ◽

Battery Bank ◽

Bank System

The combination of a fuel cell and batteries has promising potential for powering autonomous vehicles. The MUN Explorer Autonomous Underwater Vehicle (AUV) is built to do mapping-type missions of seabeds as well as survey missions. These missions require a great deal of power to reach underwater depths (i.e., 3000 meters). The MUN Explorer uses 11 rechargeable Lithium-ion (Li-ion) batteries as the main power source with a total capacity of 14.6 kWh to 17.952 kWh, and the vehicle can run for 10 hours. The drawbacks of operating the existing power system of the MUN Explorer, which was done by the researcher at the Holyrood management facility, include mobilization costs, logistics and transport, and facility access, all of which should be taken into consideration. Recharging the batteries for at least 8 hours is also very challenging and time consuming. To overcome these challenges and run the MUN Explorer for a long time, it is essential to integrate a fuel cell into an existing power system (i.e., battery bank). The integration of the fuel cell not only will increase the system power, but will also reduce the number of batteries needed as suggested by HOMER software. In this paper, an integrated fuel cell is designed to be added into the MUN Explorer AUV along with a battery bank system to increase its power system. The system sizing is performed using HOMER software. The results from HOMER software show that a 1-kW fuel cell and 8 Li-ion batteries can increase the power system capacity to 68 kWh. The dynamic model is then built in MATLAB/Simulink environment to provide a better understanding of the system behavior. The 1-kW fuel cell is connected to a DC/DC Boost Converter to increase the output voltage from 24 V to 48 V as required by the battery and DC motor. A hydrogen gas tank is also included in the model. The advantage of installing the hydrogen and oxygen tanks beside the batteries is that it helps the buoyancy force in underwater depths. The design of this system is based on MUN Explorer data sheets and system dynamic simulation results.

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