Loaded on the survey ship - Xiang Yang Hong 03, “Pioneer Ⅰ”, the deep-sea heavy-duty mining vehicle developed by the marine engineering team of Shanghai Jiao Tong University (SJTU) as part of a major platform of China’s Ministry of Education for integrated solutions to major challenges, completed its 1,300-meter deep-sea trial in the Xisha area of the South China Sea from July 25th to August 3rd, 2021. Without any manual controls, “Pioneer Ⅰ” can move in the “S” or “J” shape under the sea based on preset programs. In addition to this mobility, it also has an exceptional operational capability, which is the awareness of its surrounding mining environment.
Figure 2 The deep-sea mining vehicle landing on the sea floorDeep-sea mobility for mining without manual controls
In this undersea trial, the mining vehicle was put down in various locations with 108 meters, 246 meters, 968 meters and 1,305 meters under the sea, where a variety of tests were successfully conducted such as releasing and retrieving the heavy-duty vehicle on the sea, planning undersea pathways and moving, collecting undersea ores and sediment samples, during which a range of key technologies developed for deep-sea heavy-duty equipment were successfully tested, such as the deep-water high-power hydraulics, high-voltage power supply, signal transmission and intelligent control, automatic control of underwater releasing and retrieving attitudes, undersea mobility and mining.
Figure 1 The deep-sea mining vehicle pictured as it was released
With the innovative undersea intelligent mobility technology, the mining vehicle was able to move 1,305 meters under the sea in complicated geological conditions. And with underwater precise positioning information perception and closed-loop feedback control, the mining vehicle could move under the sea as automatic control was initiated by an intelligent control system in real time. Hence, without manual controls, the mining vehicle could move and operate under the sea as per preset pathways of any large curvatures.
In this undersea trial under the Xisha sea, the mining vehicle managed to not only move in the “S” or “J” shape, but zigzag in large curvatures and even make a U turn in minor radius under complicated circumstances, indicating the outstanding intelligent control and undersea operations of the mining vehicle.
SJTU’s innovative solution to releasing and retrieving heavy-duty equipment on the sea
To tackle the challenge of safely releasing and retrieving heavy-duty equipment on the sea, the team developed the automatic control technology for underwater motion attitude control of the mining vehicle, and used the real-time distribution of the push provided by the propeller to maintain a stable angle as the mining vehicle was released and retrieved deep under water for a long period of time and reduce the torsional load of photoelectric composite cables. And the team safely released and retrieved the heavy-duty mining vehicle in the tested waters as the waves rose two meters high and the wind blew at Level 7.
The mining vehicle, which was 5.6 meters long, 2.5 meters wide and 2.0 meters high and weighed 9.0 tons in the air, targeted the undersea polymetallic nodules, and had such operational capabilities for undersea operations as environment awareness, intelligent control and efficient hydraulic collection. The success of this undersea trial marks an important step in developing engineering and intelligent deep-sea heavy-duty mining vehicles.