• Title/Summary/Keyword: Roll motion

Search Result 138, Processing Time 0.069 seconds

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
    • /
    • v.20 no.7
    • /
    • pp.701-705
    • /
    • 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
    • /
    • v.44 no.3
    • /
    • pp.267-278
    • /
    • 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.

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
    • /
    • v.19 no.11
    • /
    • pp.1184-1191
    • /
    • 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.

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
    • /
    • v.33 no.2
    • /
    • pp.131-138
    • /
    • 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
    • /
    • v.3 no.1
    • /
    • pp.53-64
    • /
    • 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.

Study on Model Based Control for the Roll Motion of an Underwater Robot (수중로봇의 롤 운동제어를 위한 모델 베이스 제어에 관한연구)

  • Kim, Chi-Hyo;Park, Woo-Kun;Kim, Tae-Sung;Lee, Min-Ki
    • Journal of Navigation and Port Research
    • /
    • v.33 no.5
    • /
    • pp.323-330
    • /
    • 2009
  • We have been developing an underwater robot for harbour construction using a parallel mechanism The robot is attached to the rope of a crane, which curries a large stone into the undersea The robot's yaw and pitch are controlled by hydraulic cylinders but its roll is uncontrollable. We mount propellers in both side of the robot to generate the roll motion This paper studies on the control for the roll motion of a underwater robot. A gyro-sensor is used to measure the angle in a roll motion We develop the dynamic model to describe the robot's roll motion by a second order non-linear system and identify the model parameters by recursive least square and adaptive identifier. PD control, recursive model based control and adaptive model based control are applied with the dynamic model which computes the control input to compensate disturbances. This paper introduces the underwater robot system and presents the simulated and experimental results of the proposed controller.

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
    • /
    • v.45 no.1
    • /
    • pp.16-25
    • /
    • 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.

Roll motion control of flight vehicles using rollerons (롤러론에 의한 비행체 롤 운동 제어)

  • 김병교;김요섭
    • 제어로봇시스템학회:학술대회논문집
    • /
    • /
    • pp.251-255
    • /
    • 1986
  • Some missiles using canards as control device adopt rollerons to reduce roll motion due to aerodynamically induced rolling moment. This paper presents equations of motion of these missiles including the gyroscopic effect of rolleron rotors. Some linearized analysis results and simulation results are shown to coincide, thus some characteristic motions of missiles and rollerons can be seen.

  • PDF

Low Frequency Roll Motion of a Semi-Submersible Moored in Irregular Waves

  • Hong, Yong-Pyo;Choi, Yong-Ho;Lee, Dong-Yeon;Lee, Wang-Keun
    • Journal of Ship and Ocean Technology
    • /
    • v.11 no.3
    • /
    • pp.1-13
    • /
    • 2007
  • A semi-submersible drilling rig is regarded as one of the typical offshore structures operated in the field with moderate environments such as the Gulf of Mexico, Brazil, and West Africa. Its typical roll and pitch natural periods are around 30 seconds, which avoids prevailing regions of the wave energy spectrum, and their responses in waves are quite acceptable for common operation conditions. But large roll and pitch motions can be induced by wave difference frequency energy spectrum if the metacentric heights of a semi-submersible decrease to small values in some loading conditions, and it is because the roll and pitch natural periods increase and approach to the region where the spectral density of the low frequency wave drift moment has significant value. This paper describes the low frequency roll motion of a semi-submersible that are excited by the wave 2nd order difference frequency energy by a series of model experiments. From the model tests with several different initial metacentric heights (GM), it was observed that a semi-submersible can experience large roll motion due to the wave group spectrum.

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
    • /
    • /
    • pp.41-42
    • /
    • 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.

  • PDF