윈치시스템의 효율적 운용을 위한 제어시스템 설계에 관한 연구

Abstract

Maritime facilities operating on the sea, including general ships, use side thrust or mooring winch systems when they need to remain stationary at a certain location or to come alongside the pier. Ordinary vessels are waiting for berthing, berthing on the pier, and special purpose maritime facilities for drilling and related work are carried out at a fixed position in order to fine the marine resources. The mooring winch system is a method of controlling the posture and position of the marine vessel by installing a suitable number of winches on the marine vessel fluid and controlling the rope tension applied to the winch drum using the rotational force of the winch. These winch systems are widely used not only for control of maritime flows, but also for transporting ores mined from mines or for moving workers from the entrance to the work site. In the marine field, it is used essentially for towing a ship by a tugboat or for transporting cargo by a crane. One of the control subjects of the winch system, the rope material, is made of metal or fiber. The material and length of the rope directly affect the handling of the winch and the load control of the winch. In the winch system, the rope tension control is used not only as a horizontal movement of the float but also as a method for controlling vertical movement. That is, when the drilling operation is performed in the drill ship, the vertical motion can be appropriately controlled to achieve the stability of the operation. When the length between the winch part and the load part is short, the elastic characteristics due to the rope material can hardly be ignored. However, if the rope length becomes long, the physical characteristics are changed due to the increase and deflection in material characteristics. This should be reflected in the modeling due to the elasticity and damping characteristics, and the deflection phenomenon should be taken into consideration in designing the control system considering the time delay term. Especially for mine work, it can reach several kilometers from winch to final load part. There is a device or guiding roller to prevent twisting in the middle of the rope, but the starting point and the end point are almost linearly connected. In this case, the load must be controlled by a single winch system, so that the long runoff section from the winch to the load should be appropriately represented and the control system should be designed to achieve satisfactory control performance. Further, when the rope of the long section is wound and unwound, the weight of the winch drum is increased or decreased, so that the rotational inertia moment also automatically changes. Kang and Sul (2000), Takeuchi et al. (1996), Milutinovic et al. (2014), have studied on this problem in the past, but there is no consideration of the dynamic characteristics change to the change of the rope length, and the robust controller is designed considering only the uncertainty change of one nominal model. Others Oguchi et al.(1998) also designed the controller to a degree that reflects the uncertainty without considering the problem of the change in the rope length in the winch system with the long rope. Therefore, it is necessary to construct a model that can positively reflect the change of the rope length considering the fact that the movement characteristics of the control object such as the winch system have a considerable influence. In addition, a control system design method that can improve the stability and control performance of the system by actively reflecting such changes in physical characteristics is needed.