• 한국항해항만학회지
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• 제47권2호
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• pp.66-74
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• 2023

With the increase of interest in developing Maritime Autonomous Surface Ships (MASS), an optimal ship route planning is gradually gaining popularity as one of the important subsystems for autonomy of modern marine vessels. In the present paper, an optimal ship route planning model for MASS is proposed using a nonlinear MPC approach together with a nonlinear MMG model. Results drawn from this study demonstrated that the optimization problem for the ship route was successfully solved with satisfaction of the nonlinear dynamics of the ship and all constraints for the state and manipulated variables using the nonlinear MPC approach. Given that a route generation system capable of accounting for nonlinear dynamics of the ship and equality/inequality constraints is essential for achieving fully autonomous navigation at sea, it is expected that this paper will contribute to the field of autonomous vehicles by demonstrating the performance of the proposed optimal ship route planning model.

• International Journal of Computer Science & Network Security
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• 제22권9호
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• pp.183-188
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• 2022

Recently, more and more researches aimed at the development of automated and autonomous ships are appearing in the scientific environment. One of the main reason is the need to solve the problems of safe navigation and reducing accidents due to human factor, as well as the ever-increasing problem associated with the lack of qualified maritime personnel. Development of technologies based on application of artificial intelligence also plays important role, after all for realization of autonomous navigation concept and enhancement of ship automatic maneuvering processes, advancement of maneuvering functions and elaboration of specific algorithms on prevention of close quarter situations and dangerous approach of ships will be required. The purpose of this work is the review of preconditions of occurrence of the autonomous ship navigation conception, overview of introduction stages and prospects for ship remote control based on unmanned technologies, analysis of technical and intellectual decisions of autonomous surface ships, main research tendencies. The research revealed that the technology of autonomous ship navigation requires further development and improvement, especially in terms of the data transmission protocols upgrading, sensors of navigation information and automatic control systems modernization, which allows to perform monitoring of equipment with the aim of improving the functions of control over the autonomous surface ship operation.

• Journal of Ship and Ocean Technology
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• 제7권2호
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• pp.29-39
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• 2003

A Coanda foil is a high-lift generating device exploiting the phenomena that flow separation is delayed if a high-speed jet is applied tangential to the surface as well known to the aerodynamic fields. In the present study, a Coanda foil with a flap is investigated to seek the possibility of marine application. Model experiments are carried out both in a towing tank and cavitation tunnel and surface pressure distributions, forces and moments acting on the foil are measured at the various angle of attacks and flap angles. The results are also compared to the numerical ones to show good agreements. The results of the present study demonstrate the practical applicability of the Coanda foil in the design of ship control surfaces.

• 로봇학회논문지
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• 제17권1호
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• pp.48-57
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• 2022

In this paper, we propose a legged landing platform for the quadcopter taking off and landing in the ship environment. In the ship environment with waves and winds, the aircraft has risks being overturned by contact impact and excessive inclination during landing on the ship. This landing platform has four landing legs under the quadcopter for balancing and shock relief. In order to make the quadcopter balanced on ships, the position of each end effector was controlled by PID control. And shocks have mainly happened when quadcopter contacts the ship's surface as well as legs move fast. Hence, impedance control was used to cope with the shocks. The performance of the landing platform was demonstrated by a simulation and a prototype in three sea states based on a specific size of a ship. During landing and tracking the slope of the ship's surface, oscillations of rotation and translation from the shock were mitigated by the controller. As a result, it was verified that transient response and stability got better by adding impedance control in simulation models and prototype experiments.

• 대한조선학회논문집
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• 제28권2호
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• pp.21-27
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• 1991

이 논문에서는 periodic 균일 knot vector 뿐만아니라 open 균일 knot vector를 사용하여 선체형상을 Bi-cubic B-spline곡면으로 수식화하는 방법을 보인다. B-spline곡면을 형성하기 위한 B-spline control vertex는 기본 함수의 pseudoinverse matrix를 사용하여 결정된다. 주어진 offset과 형성된 선체곡면을 비교한 결과 잘 일치하였다. 곡면의 순정을 검토하기 위하여 Gaussian곡률을 많은 작은 곡면조각에 대해 계산하여 흑백의 농도 차이를 이용하여 도시화하였다.

• 한국항행학회논문지
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• 제22권6호
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• pp.507-513
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• 2018

자율운항선박은 인간의 개입을 최소화하고, 선박에게 주어진 임무를 안전하게 수행하기 위해 운항에 필요한 다양한 정보를 자동으로 수집 관리하며, 선박이 스스로 판단하여 정해진 목적지까지 부분 또는 전체 항로를 자율적으로 운항하거나, 필요시 부분적으로 원격관제에 의해 운항을 가능하게 하는 선박운항기술을 말한다. 이러한 선박의 안전운항을 위해 선박에 탑재된 다양한 항해 통신장비 및 엔진, 기관 등의 각종 센서로 부터 신호를 수집 및 관리하기 위해서는 공통플랫폼 기술이 필요하다. 이 논문에서 제안하는 공통플랫폼은 스마트 선박 구현의 핵심으로 육상과 선박 간의 위성통신 또는 지상파 통신으로 연결된 통신 환경에서 실시간으로 원활한 정보 교환을 통해 육상의 관제국에서 모니터링과 원격관제를 지원하여 해상의 안전한 선박 운항을 가능하게 한다.

• 한국군사과학기술학회지
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• 제21권1호
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• pp.103-114
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• 2018

The operational concept of control systems on surface combatants has been changed from individual control for each system to integrated control for all systems due to computing technology development and crew reduction policy of navy. The purpose of this study is to identify current status of control technology, to analyze user requirement and to develop an architecture to support the conceptual change of ship control. An architecture, which integrates several control and monitoring systems on naval surface combatant, is proposed. The proposed architecture is focused on sharing network and computing resources related to user command, and reducing systems complexity. The architecture can be adopted to next surface combatants in Korean navy.

• 한국군사과학기술학회지
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• 제14권3호
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• pp.380-387
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• 2011

In this paper, we considered the authoritative representation of Command and Fire Control System(CFCS) for the surface ship that was the engineering level model to develop system specifications and to analyze operational concepts on the concept design phase and to analyze military requirements, effectiveness and performance for the system. The engineering level model of CFCS can be used in simulation independently of the surface ship's type, and also it takes reuse, interoperability, and extension into consideration. The detailed sub-models, internal and external data interface, data flow among each sub-model, sensor and weapon models about the engineering level model of CFCS was defined. It was verified via engineering level simulations according to the V&V process.

• 해양환경안전학회지
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• 제25권3호
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• pp.306-312
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• 2019

This paper investigates to design a controller for maritime autonomous surface ship (MASS) by means of adaptive super-twisting algorithm (ASTA). A input-out feedback linearization method is considered for multi-input multi-output (MIMO) system. Sliding Mode Controller (SMC) is suitable for MASS subject to ocean environments due to its robustness against parameter uncertainties and disturbances. However, conventional SMC has inherent disadvantages so-called, chattering phenomenon, which resulted from the high frequency of switching terms. Chattering may cause harmful failure of actuators such as propeller and rudder of ships. The main contribution of this work is to address an appropriate controller for MASS, simultaneously controls surge and yaw motion in severe step inputs. Proposed control mechanism well provides convergence bewildered by external disturbances in the middle of steady-state responses as well as chattering attenuation. Also, the adaptive algorithm is contributed to reducing non-overestimated value of control gains. Control inputs of surge and yaw motion are displayed by smoother curves without excessive control activities of actuators. Finally, no overshoot can be seen in transient responses.

• Journal of Hydrospace Technology
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• 제1권1호
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• pp.41-56
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• 1995

Flew control devices, such as flow liners, are frequently introduced in a cavitation tunnel in order to reduce the tunnel blockage effect, when a three-dimensional wake distribution is simulated using a complete ship model or a dummy model. In order to estimate the tunnel wall effect and to evaluate the effect of flow liners on the simulated wake distribution, a surface panel method is adopted for the calculation of the flow around a ship model and flow liners installed in a rectangular test section off cavitation tunnel. Calculation results on the Sydney Express ship model show that the tunnel wall effect on the hull surface pressure distribution is negligible for less than 5% blockage and can be appreciable for more than 20% blockage. The flow liners accelerate the flow near the afterbody of the ship model, so that the pressure gradient there becomes more favorable and accordingly the boundary layer thickness would be reduced. Since the resulting wake distribution is assumed to resemble the full scale wake, flow liners can also be used to simulate an estimated full scale wake without modifying the ship model. Boundary taper calculation should be incorporated in order to correlate the calculated wake distribution with the measured one.