• Title/Summary/Keyword: 횡동요 운동 예측

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A Study on the Prediction of Ship's Roll Motion using Machine Learning-Based Surrogate Model (기계학습기반의 근사모델을 이용한 선박 횡동요 운동특성 예측에 관한 연구)

  • Kim, Young-Rong;Park, Jun-Bum;Moon, Serng-Bae
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2018.05a
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    • pp.41-42
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    • 2018
  • This study is about the prediction of ship's roll motion characteristic which has been used for evaluating ship's seakeeping performance. In order to obtain the ship's roll RAO during voyage, this paper utilized machine learning-based surrogate model. By comparing the prediction result data of surrogate model with test data, we suggest the best approximation technique and data sampling interval of the surrogate model appropriate for predicting the ships' roll motion characteristic.

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A Study on New Mathematical Model of Ship Manoeuvring Motion Taking Coupling Effect of Roll into Consideration (횡동요를 고려한 선박조종운동의 새로운 수학모델에 관한 연구)

  • Sohn, Kyoung-ho;Kim, Yong-min
    • Journal of Navigation and Port Research
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    • v.27 no.5
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    • pp.451-458
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    • 2003
  • A ship with small metacentric height or high speed vessel performs relatively large roll angles in her manoeuvring motion. Roll coupling effect should be taken into consideration for accurate prediction of manoeuvring motion of such a ship. This paper proposes a new mathematical model of ship manoeuvring motion taking coupling effect of roll into consideration. Some kinds of manoeuvring motion are simulated by computer, based upon the proposed model. The simualted results by proposed model here are compared with those by existing model. The proposed model is found to be practical and useful for prediction of manoeuvring motion with roll effect.

Development of Apparatus for Pure Roll-Motion Test of Underwater Vehicles (수중운동체의 순수 횡동요 시험 기구 개발)

  • Kim, Dong-Hwi;Baek, Hyung-Min;Lee, Seung-Keon;Kim, Eun-Soo
    • Journal of Navigation and Port Research
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    • v.45 no.1
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    • pp.16-25
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    • 2021
  • Hydrodynamic coefficients should be accurately estimated to predict the maneuverability of underwater vehicles. Various captive model tests have been performed as part of estimation methods for these coefficients. Estimating hydrodynamic coefficients related to roll motion is important because underwater vehicles are sensitive to changes of roll moment. In this research, a pure roll motion equipment was newly designed to simply estimate hydrodynamic coefficients with respect to roll motion. Roll motion was implemented through a brief mechanical mechanism. The principle of operation, application process, and system identification of the equipment are described. An analysis method of the pure roll test is also suggested. Repeated tests of the newly equipment were carried out to check its reproducibility.

On a Computer Profram to Calculate the Responses of a Ship in Lateral Regular Waves. (활주형 고속정의 횡파중에서의 순항시의 운동성능 계산 프로그램의 개발)

  • J.H.,Hwang;K.P.,Rhee
    • Bulletin of the Society of Naval Architects of Korea
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    • v.17 no.4
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    • pp.39-45
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    • 1980
  • 내항성이 우수한 선형을 개발하기 위해서는 초기설계단계에서 이미 그 배의 해상에서의 거동을 예측할 수 있어야만 한다. 이 보고서에서는 임의의 입사각을 갖는 규칙파중을 항주하는 선박이 겪게 되는 동요중에서 횡동요, 수평동요 그리고 선수동요의 연성운동방정식의 해를 Tassi-Takaki가 수정한 스트립이론을 적용하여 해석하였다. 제15차 ITTC의 내항성 위원회의 보고서에서 발표된 콘테이너선형에 대한 결과와 똑같이 선형에 대해 본 프로그램을 사용하여 계산한 수평동요, 횡동요 그리고 선수동요의 운동응답을 비교하여 보았으며, 상당히 만족스러운 결과를 얻었다.

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Prediction of the Out-of-plane Motion due to the In-plane Excitation (평면내 방향 기진력에 의한 평면밖 방향 운동의 예측)

  • Oh, Il-Geun
    • Journal of Ocean Engineering and Technology
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    • v.7 no.2
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    • pp.141-149
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    • 1993
  • 삼 자유도를 가진 부유물체의 동적 응답을 이론적으로 연구하였다. 평면내 방향 운동모우드에 대한 지배방정식을 선형화한 후, 그들의 조화해를 평명밖 방향 운동모우드의 방정식과 연성시켰다. 그렇게 해서 주어지는 방정식은 시간에 따라 변화하는 계수를 가진 형태로서, 평면밖 방향의 운동만을 보일 것으로 예측되는 부유물체가 평면밖 방향의 운동을 보일 수도 있음을 밝혔다. 동역학적 불안정성과 그 결과로 나타나는 평면밖 방향의 대진폭 운동을 보이고 있다. 본 결과는 주기적으로 동요하는 부유물체가 서로 연성된 운동을 하는 현상으로도 해석할 수 있다.

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Prediction of Ship Roll Motion using Machine Learning-based Surrogate Model (기계학습기반의 근사모델을 이용한 선박 횡동요 운동 예측)

  • Kim, Young-Rong;Park, Jun-Bum;Moon, Serng-Bae
    • Journal of Navigation and Port Research
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    • v.42 no.6
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    • pp.395-405
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    • 2018
  • Seakeeping safety module in Korean e-Navigation system is one of the ship remote monitoring services that is employed to ensure the safety of ships by monitoring the ship's real time performance and providing a warning in advance when the abnormal conditions are encountered in seakeeping performance. In general, seakeeping performance has been evaluated by simulating ship motion analysis under specific conditions for its design. However, due to restriction of computation time, it is not realistic to perform simulations to evaluate seakeeping performance under real-time operation conditions. This study aims to introduce a reasonable and faster method to predict a ship's roll motion which is one of the factors used to evaluate a ship's seakeeping performance by using a machine learning-based surrogate model. Through the application of various learning techniques and sampling conditions on training data, it was observed that the difference of roll motion between a given surrogate model and motion analysis was within 1%. Therefore, it can be concluded that this method can be useful to evaluate the seakeeping performance of a ship in real-time operation.

Statistical Analysis of Random Ship Rolling Using Equivalent Linearization Method (등가선형화방법을 이용한 선체의 불규칙 횡동요 운동의 통계적 해석)

  • Dong-Soo Kim;Won-Kyoung Lee
    • Journal of the Society of Naval Architects of Korea
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    • v.30 no.4
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    • pp.39-45
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    • 1993
  • In order to analyze the rolling motion of a ship in random beam waves we have used the equivalent linearization method. The quadratic nonlinear damping, the cubic and quintic nonlinear restoring moments were added to a single degree of freedom linear equation of roll motion. The irregular excitation moment was assumed to be the Gaussian white noise. The statistical characteristic of the response by the equivalent linearization method was compared with the simulation result.

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ESTIMATION OF ROLL COEFFICIENT OF UNDERWATER VEHICLE USING A CALCULATION OF HYDRODYNAMIC FORCES (동유체력 계산을 이용한 수중운동체의 횡동요 계수 변화 예측)

  • Kim, T.W.;Kang, T.J.;Park, W.G.;Jung, C.M.
    • Journal of computational fluids engineering
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    • v.20 no.2
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    • pp.81-87
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    • 2015
  • For Underwater vehicles, Unwanted roll excursions are inevitable as they are caused by induced propeller torque, disturbances, and banking motion during turns. To estimate the manoeuvring performance of underwater vehicle, it is necessary to obtain the roll coefficient of body. This paper was covered estimation of roll coefficient of underwater vehicle using STAR-CCM+, commercial CFD(Computational Fluid Dynamics) code. The RANS equations for incompressible fluid flows was solved numerically by using a finite volume method. An MRF(Moving Reference Frame) Method was Also adopted for rotations of body. For the validation, the flow around a DARPA SUBOFF bare hull model was simulated and good agreement with experiments was obtained. And Pure roll coefficients were calculated and campared with the experimental data which were presented by Seoul National University. Finally, an underwater vehicle model with propeller was simulated and analyzed for estimation of roll coefficient variation caused by induced propeller torque.

Application of Equivalent Nonlinear Method to Nonlinear Rolling Motoion of Ships (등가 비선형화법 적용에 의한 선박의 비선형 횡동요 계산)

  • Kwon, Sun-Hong
    • Journal of Ocean Engineering and Technology
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    • v.7 no.1
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    • pp.92-98
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    • 1993
  • 불규칙 해상에서 선박의 큰 횡요각의 예측이 중요한 과제로 대두 되고 있다. 본 논문에서는 추계적 해석에 의한 이의 예측 방법을 제시한다. 즉, 주어진 비선형 횡요 운동 방정식으로 부터 배의 횡요각과 각속도의 확률 밀도 함수를 구하는 방법으로 평균화 법과 등가 비선형화 법을 적용하였고 각종 계수들의 값의 변화에 따른 예측 결과를 다른 논문에서 제시한 simulation 결과와 비교하였다.

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