In July of 1997, a cooperative research program was begun between the Autonomous Undersea Systems Institute and the Institute for Marine Technology Problems (IMTP), Russian Academy of Sciences, Far Eastern Branch, in Vladivostok. In January of 1998, The Office of Naval Research NICOP program funded a joint proposal to evaluate the technologies required for a solar-powered AUV. One of the products of this program was the development, fabrication and testing of a solar AUV engineering prototype (figure 1). The 90 kg. vehicle is 1.7 meters in length, 0.7 meter wide with a pressure case diameter of 24 meters. It has two Solarex (MSX30L) 30 watt solar panels and 32 NiCd cells in a four battery (8 cells in series) configuration. The onboard computer system controls all vehicle functions and records engineering data. This prototype system has undergone at sea testing near Vladivostok, Russia. 48 runs were executed during 22 working days with the objective of defining performance of the vehicle and verifying it's ability to function as a moving platform for long endurance measurements in the ocean. The calculated motion characteristics of the vehicle were compared with calculated ones. Also the properties of vehicle behavior in conditions unique to the SAUV such as sea keeping during drifting or moving on the surface were considered. On the whole, the test results are very positive. These test results will be discussed. A second vehicle was fabricated at AUSI. This platform is a near duplicate of the IMTP vehicle but contains only a solar energy system. This testbed has been used for at sea testing to determine the effect of wave action on the amount of solar energy collected by the vehicle during recharging. This energy system has been in continual use at AUSI for 9 months without failure. An energy system testbed (EST) which duplicates the onboard energy system of the SAUV has been fabricated at AUSI in order to investigate alternative energy management strategies. Its solar arrays routinely charge the duplicate battery storage system. System electronics then discharge the batteries during evening hours or when solar energy is not available. The results of these and other similar experiments as well as the at-sea testing accomplished to date have begun to validate initial beliefs of the inherent reliability of this autonomous system. Testing continues to further verify system reliability. The testing of the solar-powered AUV developed in these programs, as well as the development tools such as the energy systems testbed, will be discussed in this paper.
