• International Journal of Naval Architecture and Ocean Engineering
• /
• v.6 no.2
• /
• pp.347-360
• /
• 2014

The auto-berthing of a ship requires excellent control for safe accomplishment. Crabbing, which is the pure sway motion of a ship without surge velocity, can be used for this purpose. Crabbing is induced by a peculiar operation procedure known as the push-pull mode. When a ship is in the push-pull mode, an interacting force is induced by complex turbulent flow around the ship generated by the propellers and side thrusters. In this paper, three degrees of freedom equations of the motions of crabbing are derived. The equations are used to apply the adaptive backstepping control method to the auto-berthing controller of a cruise ship. The controller is capable of handling the system non-linearity and uncertainty of the berthing process. A control allocation algorithm for a ship equipped with two propellers and two side thrusters is also developed, the performance of which is validated by simulation of auto-berthing.

• Journal of Ocean Engineering and Technology
• /
• v.27 no.6
• /
• pp.56-64
• /
• 2013

Crabbing motion is the pure sway motion of a ship without surge velocity. Thus, it can be applied to a berthing operation. Crabbing motion is induced by a peculiar operation method called the push-pull mode. The push-pull mode is induced by using a combination of the main propeller and side thruster. Two propellers generating the same amounts of thrust and rotating in opposite directions produce some yawing moment on a vessel but do not induce longitudinal motion. With the additional operation of side thrusters, the push-pull mode is used to induce a large amount of lateral force. In this paper, three-degree-of-freedom equations of motion such as for the surge, sway, and yaw are constructed for the crabbing motion. Based on these equations of motion, a feedback linearization control method is applied to auto-berthing control for a twin-screw ship with side thrusters. The controller can deal with the nonlinearity of a system, which is present in the berthing maneuver of a twin screw ship. A simulation of the auto-berthing of a ship is performed to validate the performance of the designed controller.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2022.11a
• /
• pp.168-169
• /
• 2022

In this study, we investigates the auto-berthing problem for the underactuated surface vessel in the presence of constraints of dynamic uncertainties, finite time, transmission load, and environmental disturbance. A novel control scheme is proposed by fusing the finite time control technology and the event-triggered input algorithm. In the algorithm, differential homeomorphism coordinate the transformation is used to solve the problem of underactuation. Then, we apply the finite time technology and event triggered to save the time of the berthing vessel and relieve transmission burden between the controller and the vessel respectively. Moreover, a radial basis function network is used to approximate unknown nonlinear functions, and minimum learning parameters are introduced to lessen the computational complexity. A sufficient effort has been made to verify the stability of the closed-loop system based on the Lyapunov stability theory. Finally, simulation results display the effectiveness of the proposed scheme.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2013.06a
• /
• pp.17-20
• /
• 2013

Many researches have been conducted in the field of constructing controllers for ships over 20 years. But still, ship automatic track-keeping controllers has not been designed for ship's automatic berthing as they considered nearly constant ship's speed. This study dealt with this problem to design track-keeping control on ship's model of SAE NURI using nonlinear mathematical expression. By using this control, the ship is auto track-kept in fare-way at reducing speed to anchorage place. The simulation results proved that this control can be adapted in ship's auto berthing in near future.

• Journal of Power System Engineering
• /
• v.14 no.6
• /
• pp.96-101
• /
• 2010

접안을 위해 선박이 안벽으로 접근할 때나, 좁은 항내에서 선박을 조종할 때는 항해 중에서보다 많은 제약이 따른다. 그것은 대형 선박일수도 분 관성력으로 인해 효과적인 제어가 어렵기 때문이다. 그래서 터그보트를 수동적으로 제어하여 선박을 접안시키는 것이 현재로선 가장 일반적이 접안기술이라 할 수 있다. 지능적인 제어기술을 적용하여 자동접안을 시도하려는 연구결과가 보고되고 있으나, 대부분이 auto-pilot 기술에 지나지 않으며 어느 것 하나 안정적인 접안을 위한 접안기술로 볼 수 없다. 이와 같이 터그보트를 이용할 수밖에 없는 현실이라면, 보다 효과적인 터그보트 제어기술을 기반으로 한 접안지원시스템을 개발하는 것이 우선일 것이다. 그래서 본 논문에서는 터그보트의 원격제어를 통해 모선을 효과적이고 안정적으로 접안하는 문제에 대해 고찰하였다. 즉, 터그보트로 조종되는 선박조종시스템에 대한 모델링을 수행하고, 터그보트로부터 발생되는 제어력을 적절히 분배하여 모선을 제어하는 새로운 접안지원시스템을 개발하였다. 시뮬레이션을 통해 제안된 시스템의 유효성을 검증하였다.

• Journal of Navigation and Port Research
• /
• v.34 no.5
• /
• pp.311-317
• /
• 2010

Mobile Harbor(MH) is a new paradigm for maritime transport system introduced in Korea, the target of which is to carry out ship-to-ship cargo operation rapidly and effectively even under a condition of sea state 3. A MH ship is moored alongside a large container vessel anchored at the defined anchorage and also equipped with gantry cranes for handling containers. The MH study concerned includes rapid container handling system, optimum design for floating structure, hybrid berthing & cargo operation system, design for cargo handling crane, etc. This paper is to deal with a conceptual design of a stabilized mooring system and mooring equipment under a condition of ship-to-ship mooring. In this connection, we suggest a positioning control winch system in order to control heave motions of the MH ship which is to add constant brakepower and stabilized function to an auto-tension winch and mooring equipment used currently in large container ships.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.18 no.3
• /
• pp.221-226
• /
• 2012

This research presents an analysis of algorithm for ship track-keeping along a given trajectory. The maneuver of a free running model ship guiding through a simple path are presented. In order to solve the above problem, a desired trajectory is usually determined by GPS points in a pre-fixed place then these points are set in a pre-programmed navigation so that the ship would be automatically tracked. Proportional-Derivative(PD) control which is useful for fast response controllers was used in this program as a course keeping system. A high accuracy GPS receiver was installed on the model ship that could provide positions frequently, the system will compare and give out the remaining distance and heading to the target way-point. The results of ship auto track-keeping experiment will be explained in order to illustrate the adjustment in controlling parameters. These results can be utilized as a preliminary step to carry out the experiment of ship collision avoidance system and automatic berthing in the future.