• Title, Summary, Keyword: Roll motion

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Comparison Among Yaw and Roll Motion Controllers for Rollover Prevention (차량 전복 방지를 위한 롤 및 요 운동 제어기의 성능 비교)

  • Yim, Seongjin
    • Journal of Institute of Control, Robotics and Systems
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    • v.20 no.7
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    • pp.701-705
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    • 2014
  • This article presents a comparison among several yaw and roll motion controllers for vehicle rollover prevention. In the previous research, yaw and roll motion controllers can be independently designed for rollover prevention. Following this idea, several yaw and roll motion controllers are designed and compared in terms of rollover prevention. For the yaw motion control, PID, LQR, SMC (Sliding Mode Control) and TDC (Time-Delay Control) are adopted. For the roll motion control, LQR, LQ SOF (Static Output Feedback) control, PID, and SMC are adopted. To compare the performance of each controller, simulation is performed on a vehicle simulation package, CarSim$^{(R)}$. From simulation, TDC and LQ SOF are the best for yaw and roll motion control, respectively.

Experimental Study on the Eddy Making Damping Effect at the Roll Motion of a Rectangular Barge (사각형 바지선의 횡동요 와류 감쇠에 대한 실험적 연구)

  • Jung, Kwang-Hyo;Suh, Sung-Bu;Chun, Ho-Hwan
    • Journal of the Society of Naval Architects of Korea
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    • v.44 no.3
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    • pp.267-278
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    • 2007
  • This experimental study investigated on the eddy making effect on the roll motion of a rectangular barge in a two-dimensional wave tank. The structure was used to simulate a simplified rectangular barge in the beam sea condition. The structure with a draft one half of its height was hinged at the center of gravity and free to roll by waves. The rectangular barge was tested with regular waves with a range of wave periods that are shorter, equal to, and longer than its roll natural period. Particle image velocimetry (PIV) was employed to obtain the velocity field in the vicinity of the structure. The coupled interactions between the incident wave and the barge were demonstrated by examining the vortical flow fields to elucidate the eddy making effect during the roll motion. For incoming wave with a wave period same as the roll natural period, the barge roll motion was reduced by the eddy making damping effect. At the wave period shorter than the roll natural period, the structure roll motion was slightly reduced by the vertical flow around the barge. However, at the wave period longer than the roll natural period, the eddy making effect due to flow separation at structure corners indeed amplifies the roll motion. This indicates that not only can the eddy making effect damp out the roll motion, it can also increase the roll motion.

Study on Roll Motion Characteristics of a Rectangular Floating Structure in Regular Waves (규칙파 중 사각형 부유식 구조물의 횡동요 운동특성에 대한 연구)

  • Kim, Min-Gyu;Jung, Kwang-Hyo;Park, Sung-Boo;Lee, Gang-Nam;Park, Il-Ryong;Suh, Sung-Bu
    • Journal of Ocean Engineering and Technology
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    • v.33 no.2
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    • pp.131-138
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    • 2019
  • This study focused on the roll motion characteristics of a two-dimensional (2D) rectangular floating structure under regular beam sea conditions. An experiment was conducted in a 2D wave tank for a roll free decay test in calm water and the roll motion in a range of regular waves with and without heave motion to investigate the motion response and heave influence on the roll motion. A numerical study was carried out using Reynolds-averaged Navier Stokes (RANS)-based CFD simulations. A grid convergence test was conducted to accurately capture the wave condition on the free surface based on the overset mesh and wave forcing method. It was found in the roll free decay test that the numerical results agreed well with the experimental results for the natural roll period and roll damping coefficient. It was also observed that the heave motion had an impact on the roll motion, and the responses of the heave and roll motion from the CFD simulations were in reasonable agreement with those from the experiment.

Multi-level approach for parametric roll analysis

  • Kim, Tae-Young;Kim, Yong-Hwan
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.3 no.1
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    • pp.53-64
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    • 2011
  • The present study considers multi-level approach for the analysis of parametric roll phenomena. Three kinds of computation method, GM variation, impulse response function (IRF), and Rankine panel method, are applied for the multi-level approach. IRF and Rankine panel method are based on the weakly nonlinear formulation which includes nonlinear Froude-Krylov and restoring forces. In the computation result of parametric roll occurrence test in regular waves, IRF and Rankine panel method show similar tendency. Although the GM variation approach predicts the occurrence of parametric roll at twice roll natural frequency, its frequency criteria shows a little difference. Nonlinear roll motion in bichromatic wave is also considered in this study. To prove the unstable roll motion in bichromatic waves, theoretical and numerical approaches are applied. The occurrence of parametric roll is theoretically examined by introducing the quasi-periodic Mathieu equation. Instability criteria are well predicted from stability analysis in theoretical approach. From the Fourier analysis, it has been verified that difference-frequency effects create the unstable roll motion. The occurrence of unstable roll motion in bichromatic wave is also observed in the experiment.

A Study on the Dynamic Analysis on the Cross Directional Register in Roll-to-roll e-Printing Systems (롤투롤 인쇄전자에서의 횡방향 레지스터 동적 특성 모델링)

  • Kang, Hyun-Kyoo;Ahn, Jin-Hyun;Lee, Chang-Woo;Shin, Kee-Hyun
    • Journal of the Semiconductor & Display Technology
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    • v.9 no.2
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    • pp.61-65
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    • 2010
  • For the adaption of roll-to-roll printing method to the printed electronics, it is mandatory to increase the resolution of register errors. Therefore it is desired to derive the mathematical modeling of register error or to develop controller design. The cross direction register error was derived considering both lateral motion of moving web and transverse position of printing roll. The mathematical modeling was validated and the relationship between the lateral motion and register error was analyzed by numerical simulations in various operating conditions using multi-layer direct gravure printing machine. The results could be used for a design of the CD register in the multi-layer printing and the lateral motion caused by translation.

Experimental Study on Estimation of Roll Damping for Various Midship Sections (중앙 단면 형상에 따른 횡동요 감쇠 추정 실험 연구)

  • Park, Byeongwon;Jung, Dong Woo;Jung, Jaesag;Park, Inbo;Cho, Seok-Kyu;Sung, Hong Gun
    • Journal of Ocean Engineering and Technology
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    • v.33 no.4
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    • pp.322-329
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    • 2019
  • The magnitude of the roll motion of a floating structure depends on the roll damping acting on the body. In other words, the roll damping of a floating structure must be accurately obtained in order to precisely evaluate the roll motion. Various methods are used to evaluate the roll damping of a floating structure, such as the linear potential theory, computational fluid dynamics (CFD), and model tests. However, it is difficult to evaluate the roll motion of a floating structure with appendages such as a bilge keel and riser slot due to the limitation of ignoring the viscous effects in the linear potential theory. Among these methods, a model test based on a free decay test and harmonic excited roll motion (HERM) is known to be the most reliable method to estimate the roll damping of the floating structures. In this study, model tests using free decay and HERM techniques were performed in the Ocean Engineering Basin (OEB) of KRISO with various types of midship sections. The roll damping results were estimated based on post-processing methods using both techniques, and the roll damping results were compared.

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.

Roll Motion Control of a Mover in Bearingless Linear Motor by Using One-sided Active Magnetic Bearings (베어링리스 리니어 모터에서의 편측식 전자기 베어링을 이용한 이동자의 롤 운동 제어)

  • Kim, Woo-Yeon;Lee, Jong-Min;Kim, Seung-Jong
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.19 no.11
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    • pp.1184-1191
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    • 2009
  • A bearingless linear motor(BLLM) which consists of two stators and a common mover is able to levitate and move its mover without any linear bearing or even additive windings. In the previous study, BLLM was actively controlled on the translation and pitch motion, while the roll motion is passively stable. In order to control the roll motion, this paper suggests adding active magnetic bearings(AMBs) at bottom of the mover in BLLM. The AMBs control the roll motion and also partially supports the weight of the mover. In this paper, magnetic forces generated by the AMBs are estimated by using an FEM model. Based on the analysis results, the bias current of the AMBs is determined and a PD controller is designed. Through an experimental levitation test, it was verified that roll motion is well controlled by AMB during levitation.

Roll Motion Analysis of a 3 D.O.F. Planar Car Model using Instantaneous Centers (순간중심을 이용한 평면 3 자유도 자동차 모델의 롤 운동 해석)

  • Lee, Jae-Kil;Shim, Jae-Kyung
    • Transactions of the Korean Society of Automotive Engineers
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    • v.14 no.4
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    • pp.92-98
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    • 2006
  • In this paper, a planar car model with 3 degrees of freedom was analyzed using the concept of the roll center. To avoid ambiguity, force components which require experimental data were excluded. Only kinematic approach was used to find the position and orientation of the vehicle body and the position of the roll center. The roll center was found by the pole with infinitesimal movement and Kennedy-Aronhold theorem. Centrodes, which are the loci of instantaneous centers of planar motion, were constructed with analyzed results to show characteristics of vehicle body motion. To verify the presented analysis method in this paper, the locus of the roll center and the motion of a 3 D.O.F. planar car model were compared with those of the 1 D.O.F. model.

A STUDY OF AERODYNAMIC MODELING FOR UNFOLDING WING MOTION ANALYSIS (전개하는 날개의 공력 모델링 연구)

  • Jung, S.Y.;Yoon, S.J.
    • 한국전산유체공학회:학술대회논문집
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    • pp.245-250
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    • 2008
  • For simulation of a wing unfolding motion for the various aerodynamic conditions, equation governing unfolding motion and moments applying to the unfolding wing were modelled. Aerodynamic roll moment consists of the static roll moment and the damping moment, which were obtained through wind tunnel tests and numerical analyses respectively. Panel method was used to compute the roll damping coefficient with twisted wing, whose deflection angle was equivalent to angle of attack due to the deployment motion. Roll damping coefficient is a function of angle of attack, sideslip angle, and deployment angle but not of angular velocity of deployment. Simulation with aerodynamic damping model gave more similar deployment time compared to wing deployment test results.

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