파일럿 양광시스템의 자세 유지를 위한 버퍼시스템의 실해역 방향각 제어

Abstract

This paper introduces the results of heading angle control for a buffer system obtained from the sea test of pilot lifting system conducted in Ease Sea in December, 2016. The pilot lifting system (PLS) is for vertical transportation of manganese nodules collected in the buffer system by mining robot from seafloor. PLS consists of buffer system (BS), lifting pump (LP) and lifting riser (LR). In the sequential launching operation of PLS through moon-pool of surface vessel, twoumbilicals are together deployed along LR down to LP and BS, respectively, when the umbilicals are fastened by cable holders fixed with LR in regular intervals. For the sake of safety during the whole time in sea tests (launch, lifting test and retrieval), twist and rotation of PLS should be forbidden good and proper. Otherwise, excessive twist or free rotation of PLS will cause functional damages of umbilicals and irreparable failure of total system in turn. Surface vessel is asked for heading changes in wind, waves and surface current. Twist moments are loaded on PLS by subsea currents. To avoid the twist and rotation of PLS and to secure the safety of umbilicals, the posture keeping of PLS relative to surface vessel is of utmost importance. The two thrusters at port and starboard of BS are for posture control of BS and PLS in turn. In this paper, the heading control of BS was conducted by means of PI controller, when PI Gains were determined t