• Title/Summary/Keyword: Anti-Rolling Pendulum

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Rolling Reduction of Floating body by Anti-Rolling Pendulum (안티롤링 추를 이용한 부유체의 롤링 저감)

  • Park, Sok-Chu;Park, Kyung-Il;Yi, Geum-Joo
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2016.05a
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    • pp.106-107
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    • 2016
  • Rolling motion of floating body might upset the body, make crews and passengers exhausted and/or apply forces to the structure to cause damage. Therefore for almost ships bilge keels are equipped, in special case fin stabilizer or gyroscope may be installed. This paper suggests the Anti-rolling pendulum to reduce roll motion to act the similar role with anti-rolling tank. The device suggested has more effective than the anti-rolling tank with 1/6 volume of the tank.

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Reducing Ship Rolling with a Anti-Rolling Pendulum (안티롤링 진자를 이용한 부유체의 횡동요 저감)

  • Park, Sok-Chu;Yi, Geum-Joo;Park, Kyung-Il
    • Journal of Navigation and Port Research
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    • v.40 no.6
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    • pp.361-368
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    • 2016
  • A ship's rolling motion can make crew and passengers sick and/or apply forces to the structure that cause damage.. Therefore bilge keels are equipped in most ships for anti-rolling. In special cases, anti-rolling tanks (ARTs), fin stabilizers, or gyroscopes can be installed. However, ARTs require a large area to install, and fin stabilizers and gyroscopes are costly to install and expensive to operate. This paper suggests a Anti-rolling pendulum (ARP) to reduce roll motion. ARPs acts like ARTs. However, the ARP has a circular shaped guidance arc instead of the string or wire of a simple pendulum. The device suggested has about 1/ 8 the weight and 1/ 6 the volume of a ART and is more effective. This study derives the nonlinear and linear differential equations of system motion.

A Sea-Trial Test of a Pendulum-type Mass Driving Anti-Rolling System for Small Ships (소형 선박용 진자식 횡동요 저감장치의 실선시험)

  • 문석준;박찬일;정종안;김병인;윤현규
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2004.05a
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    • pp.438-441
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    • 2004
  • Reduction of a ship's rolling is the most important performance requirement for improving the safety of the crew on board and preventing damage to cargos as well as improving the comfort of the ride. A mass driving anti-rolling system (MD-ARS) might be one candidate of several systems against the ship's rolling. In this paper, a sea-trial test on a pendulum-type MD-ARS passively operated is carried out in Suyoung, Busan. After the system is installed on the cabin of the small leisure boat, a series of test is conducted before and after operating the system. Through the test, it is confirmed that the roll rate of the ship is pretty well reduced by the system.

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A Study on Viscous Damping System of a Ship with Anti-Rolling Pendulum (안티롤링 진자를 장치한 선박의 점성감쇠계 해석에 대한 연구)

  • Park, Sok-Chu;Jang, Kwang-Ho;Yi, Geum-Joo
    • Journal of Navigation and Port Research
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    • v.41 no.6
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    • pp.365-372
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    • 2017
  • The rolling motion of a floating body makes crews and passengers exhausted and/or applies forces to the structure to cause damage; it might even upset the body. Therefore, almost all ships are equipped with bilge keels for anti-rolling; in special cases, an anti-rolling tank(ART) or fin stabilizer or gyroscope could be installed. But an ART requires a large capacity to install it, and a fin stabilizer and gyroscope need great costs to install and also many expenses to operate. The authors suggest the use of an anti-rolling pendulum(ARP), and they showed that the ARP is effective to reduce rolling by experiments and via a Runge-Kutta analysis. This paper introduces the linearized 2 degrees of freedom with a viscous damping system for a ship equipped with ARP; it also shows the validation of the linearized analysis for the ship's roll motion. The paper proposes an optimum ARP on the basis of the justified model. The case of the 7.7kg model with ship 20g ARP of a mass ratio of 0.26%, is the most effective for reducing roll motion. The paper shows the ARPs with various mass ratios are effective for reducing the roll motion of a ship by free decaying roll experiments.

Design of a Pendulum-type Anti-rolling System for USSV and Verification Based on Roll Damping Coefficient (무인반잠수정의 진자식 횡동요 저감 장치 설계 및 감쇠계수 기반 검증)

  • Jin, Woo-Seok;Kim, Yong-Ho;Jung, Jun-Ho;Lee, Kwangkook;Kim, Dong-Hun
    • Journal of the Society of Naval Architects of Korea
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    • v.56 no.6
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    • pp.550-558
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    • 2019
  • The roll motion of a general vessel, which is more influenced by resonance as compared to other motions, adversely affects the passenger and hull. Therefore, reducing the roll motion through an anti-rolling system is critical, and most ships use various devices such as anti-rolling tanks, bilge keels, and fin stabilizers to accomplish this. In this study, a simplified model is developed for the application of an anti-rolling device for unmanned semi-submersible vessels. The applied anti-rolling device is installed on the stern and stem of a ship using a pair of servo motors with added weight, and the motor is controlled through the Arduino. The moment of the motor is designed and implemented based on a mathematical model such that it is calculated through the restoring force according to the heel angle of the ship. The performance of the proposed system was verified by utilizing the roll damping coefficient calculated by the free-roll decay test and logarithmic decrement method and was validated by a towing tank test. The system is expected to be used for unmanned vessels to perform sustainable missions.