REN Xianhao, LIU Lihong, WEI Dingbang, XIA Jianxin
In order to select an appropriate deep-sea polymetallic nodule collection method, a technical evaluation system was established based on five criteria, including green, economy, reliability, intelligence and safety (GERIS). Then, as for three kinds of collection methods, including collection with a rotary raking system, or a hydraulic collection system, and a robotic arm collection system, the weights of 22 engineering indicators were determined by adopting the Analytic Hierarchy Process (AHP), and also a quantitative comparison was made among those three typical methods. It is found that collection by a rotary raking system presents better performance in terms of collection efficiency, operation stability and safety, with a comprehensive score of 80.1, while the hydraulic collection system is characterized by simple structure and high efficiency, but is not environment-friendly and intelligent, with a score of 76.3. The robotic arm collection system shows some sort of potential in intelligent development, but is limited by its low efficiency and high mechanical complexity, with the lowest score of 70.2. Overall, the collection by a rotary raking system is more feasible in current engineering applications, and the hydraulic collection system may be banned to use due to strict environmental protection regulations, while the robotic arm collection system still has developmental potential for precise collection in high-value areas in the future.