the instrumentation system. Although use of a CCDE as an underwater power system is being studied in many parts of the world, this Japanese attempt is said to be the first successful effort to achieve sustained long-hour and long-distance diving.
Continuous four-hour diving
On August 21, the R-one Robot" successfully went through a continuous four-hour autonomous diving test over a distance of some 20 km in the Pacific Ocean about 30 km off the coast of Tanabe City, Wakayama Prefecture. During the test, the vehicle also measured such oceanic environmental factors as pH, water temperature, dissolved oxygen and salt concentration. The robot exactly passed through six preassigned points which were at different depths. Its maximum diving depth was 150 meters.
During the recent tests, the "R-one Robot" dived nine times for a cumulative duration of some ten hours, during which time it demonstrated its ability to stay submerged while covering a distance of 120 km. Its stable motions also endorsed its usefulness as a platform for long-distance continuous subsea observation.
Measurements of environmental factors
The measurements under the thermocline at a depth of 150 meters revealed two predominant swirl phenomena extending horizontally approximately 100 and 1,000 meters. This discovery was achieved by the depth keeping ability of extremely high accuracy (within plus or minus 20 cm of depth targets). These measurements may be of great benefit to research on the water mass structure in the vicinity of the seasonal thermocline. Water mass structure is closely related to El Nino and other oceanic phenomena.
The conventional measuring method is to lower an instrument from an observation ship at intervals of several kilometers. By contrast, measurements conducted with this robot are accomplished at a space resolution higher by three figures, at intervals of only several meters. Moreover, depth is maintained to an accuracy of several tens of centimeters.
Summary of features of "R-one Robot"
This robot has the significant feature of being able to autonomously dive without remote control from the mother ship, measure underwater environmental factors, and survey the ocean bed for 24 hours. The CCDE system mounted in this robot removes
