Automatic Position Control of a 300,000-Ton Ship Ocean Mining Systems

Abstract

Extensive computer simulation and performance analysis and assessment have been carried out for the dynamic positioning control of a large, commercial ocean mining ship / pipe system, and selective results are presented. It is tentatively concluded that automatic position control, with a manual override option, of a 300,000-ton ship with 18 thrusters of 4500 hp and an 18,000 ft long lift pipe system would be feasible for commercial operations of a preliminary mining system in the Pacific Ocean. The preliminary system employs a self-propelled miner. For the feasibility study, we have performed the following: the thruster power estimate, a subsequent selection of an azimuthing ship thruster system configuration, steady-state and dynamic motion of the ship-pipe system, track-keeping, turning and station-keeping control, design of an automatic control system, and nonlinear control simulation during mining operations and selective contingency situations. For the development of commercial systems, the small-size, test-mining system does not provide all the design data. It is much larger, and subsequently, requires development of more sophisticated technology and engineering capabilities. The present method of analysis and simulation can be applied to many other mining system analyses, and to the position keeping control of deepsea drilling systems, and deepsea piplaying.