Key points
- Shanghai Jiao Tong University tested a prototype deep-sea heavy-duty mining vehicle aboard the research vessel Zhang Jian in the South China Sea in April 2021.
- The polymetallic nodule vehicle is 5.6 m long, 2.5 m wide, 2.0 m high, weighs 8.0 tonnes in air and is rated to 3,000 m depth.
- It tracked an S-shaped seabed path with a maximum tracking error of 0.40 m and held heading within 1.4 degrees during deployment and recovery.
In April 2021, a prototype deep-sea heavy-duty operations mining vehicle developed by Shanghai Jiao Tong University’s ocean engineering team, carried aboard the research vessel Zhang Jian, successfully completed seabed intelligent driving and path-tracking trials in the South China Sea. Through a series of tests covering at-sea deployment and recovery, precise underwater positioning, seabed operating path planning and intelligent driving control, the team validated innovative technologies including automatic attitude control during at-sea deployment and recovery and intelligent autonomous driving on the seabed, achieving the intended research objectives.
The deep-sea mining vehicle is designed to work deep-sea polymetallic nodules. It is 5.6 meters long, 2.5 meters wide and 2.0 meters high, weighs 8.0 tonnes in air, and has a design operating depth of 3,000 meters, with capabilities including seabed operating environment perception, intelligent autonomous control and high-efficiency hydraulic ore collection.
To meet the needs of future engineering-scale development of seabed mineral resources, the project team took a forward-looking approach in developing intelligent autonomous driving technology for the mining vehicle, achieving closed-loop feedback control of the vehicle as it travels across the seabed. Based on the planned operating path and precise underwater positioning information, the system controls the vehicle’s heading, displacement, speed and other motion parameters in real time and intelligently, achieving high-precision tracking of large-curvature curved paths on the seabed for the first time. The vehicle’s real-time track closely matched the planned S-shaped target path, with a maximum tracking error of only 0.40 meters, and ROV sonar surveys of the trial site showed the vehicle’s S-shaped track clearly visible on the seabed.
To address the challenge of safely deploying and recovering a heavy-duty operations mining vehicle at sea, the project team proposed an innovative method for automatically controlling the vehicle’s attitude in the water, allocating thruster forces in real time so that the vehicle autonomously and stably holds its heading throughout deployment and recovery. Across the multiple deployment and recovery operations of this sea trial, the vehicle’s maximum heading deviation was less than 1.4 degrees under fast currents, achieving precise control of the vehicle’s motion attitude in the water and ensuring controlled, stable deployment and recovery.
During the trial, the test area reached sea state 4 with severe low-frequency swell under the influence of Surigae, the year’s second super typhoon, creating major challenges for vehicle deployment and recovery, ship positioning, crew operations and vehicle operations. The project team overcame these difficulties and completed all planned trial tasks.
