• Title/Summary/Keyword: 끝단 강체

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Dynamic Stability of a Free-Free Beam with a Tip Rigid Body under a Controlled Pulsating Thrust (끝단 강체를 갖고 맥동 제어추력을 받는 양단 자유보의 동적 안정성)

  • Ryu, Bong-Jo;Lee, Gyu-Seop;Seong, Yun-Gyeong;Choe, Bong-Mun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.1 s.173
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    • pp.232-239
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    • 2000
  • The paper describes the parametric instability of free-free beams subjected to a controlled pulsating follower force. The beam has a tip rigid body not a mass point, and the direction of pulsating follower force is controlled by the direction control sensor. Equations of motion are derived by Hamilton's principle and the instability regions are obtained by finite element formulation. The effects of magnitude, rotary inertia, the distance between free end of the beam and the center of gravity of the rigid body on the instability types and regions are investigated by the change of the constant and periodic part of the follower force.

Optimal Vibration Control of Rigid Plate Elastically Supported at the Edges (끝단이 탄성 지지된 강체판의 최적진동제어)

  • Lee, Seong-Ki;Yun, Shin-Il;Han, Sang-Bo
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.828-833
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    • 2003
  • Rigid plate elastically supported at the edges is modeled and the performance of the optimal vibration control under sinusoidal excitation is tested. The controller based on the linear quadratic regulator with output feedback is designed to control the multi-degree of freedom vibration. Relative weighting parameters are considered as design constraints to determine the limitation of maximum control force and state parameters. Control force calculated by proportional output feedback of the displacement and velocity is used to suppress the vibration induced by the sinusoidal external force. The active vibration control of vibrating plate by the LQR controller is examined through the numerical simulations that show the effectiveness of optimal control scheme on the three degrees of freedom structure.

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A Mathematical Approach for Analysis of Modes in Pickup Actuators (운동방정식에 의한 픽업 액추에이터 모드 분석)

  • Lee, Kyung Taek
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2013.04a
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    • pp.73-78
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    • 2013
  • In this paper, the vibration for a pickup actuator is described by mathematically analyzing its suspension configuration and motion, confined to lateral and torsional directions of suspensions. In order to prove the accuracy of this result, it is compared to a finite element analysis. Also it is shown that modal frequencies can be modified by changing design parameters in mathematical motion expressions.

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A Mathematical Approach for Modal Frequency Analysis in Actuators (운동방정식 유도에 의한 액추에이터 모드 주파수 분석)

  • Lee, Kyung Taek
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.23 no.6
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    • pp.537-545
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    • 2013
  • In this paper, the vibration for actuators having lens module, confined to lateral and torsional directions of suspensions, is described by mathematically analyzing its suspension configuration and motion. In order to prove the accuracy of this result, it is compared to a finite element analysis. Also it is shown that modal frequencies can be modified by changing design parameters in mathematical motion expressions.

Controller Design and Experiment to Levitate a Rotor in an Active Magnetic Bearing System (능동 자기 베어링 시스템의 제어기 설계 및 연구)

  • Chang, Yu;Shim, Sung-Hyo;Yang, Joo-Ho
    • Journal of Power System Engineering
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    • v.6 no.4
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    • pp.73-80
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    • 2002
  • 이 논문은 MIMO 능동 자기 베어링 시스템에 있어서의 병진 및 회전(기울기)운동을 하는 횡축형 강체 로터의 동적 거동을 모델링하고, 로터 양 끝단의 간섭효과를 고려한 제어방법을 제안한다. 제어기는 DSP 보드를 이용하였으며, 설계된 제어기의 타당성을 시뮬레이션 및 실험을 통하여 검증하였다.

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Straight-line Path Error Reduction for the End of a Flexible Beam Deploying from a Rotating Rigid Hub (회전하는 강체허브에서 전개하는 보 끝단의 직선궤적오차 저감)

  • Kim, Byeongjin;Kim, Hyungrae;Chung, Jintai
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.24 no.11
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    • pp.898-906
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    • 2014
  • This paper presents a reduction method for a straight-line path error of a flexible beam deploying from a rotating rigid hub. Previous studies discussed about only vibration phenomena of flexible beams deploying from rotating hubs; however, this study investigates a vibration reduction of a rotating beam with variable length. The equation of motion and associated boundary conditions are derived for a flexible beam deploying from a rotating rigid hub, and then they are transformed to a variational equation. By applying the Galerkin method, the discretized equations are obtained from the variational equation. Based on the discretized equations, the dynamic responses of a rotating/deploying beam are analyzed when the beam end has a straight line motion. A reduction method for the trajectory error is proposed, using the average length of a rotating/deploying beam. It is shown that the proposed method is able to reduce the residual vibration of a rotating/deploying beam.

Robust control of a heave compensation system for offshore cranes considering the time-delay (시간 지연을 고려한 해상 크레인의 상하 동요 보상 시스템의 강인 제어)

  • Seong, Hyung-Seok;Choi, Hyeong-Sik
    • Journal of Advanced Marine Engineering and Technology
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    • v.41 no.1
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    • pp.105-110
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    • 2017
  • This paper introduces a heave compensation system for offshore crane when it subjected to unexpected disturbances such as ocean waves, tidal currents or winds and their external force. The dynamic model consists of a crane which is considered to behave in the same manner as a rigid body, a hydraulic driven winch, an elastic rope and a payload. To keep the payload from moving upwards and downwards, PD(Proportional-Derivative) control was applied by using linearization. In order to achieve a better performance, the sliding mode control and the nonlinear generalized predictive control algorithm was applied according to the time-delay. As a result, the oscillating amplitude of the payload was reduced by the control algorithm. Considering the time-delay involved in the system to be one second, nonlinear generalized predictive controller with a robust controller was a suitable control algorithm for this heave compensation system because it made the position of te payload reach the desired position with the minimum error. This paper presented a control algorithm using the robust control and its simulation results.

A Heave Compensation System for Offshore Crane (해상 크레인의 상하동요 보상 시스템의 능동제어)

  • Seong, Hyung-seok;Choi, Hyeong-sik;Jeong, Seong-hoon;Lee, Sang-ki
    • Journal of Advanced Navigation Technology
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    • v.20 no.3
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    • pp.175-181
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    • 2016
  • This paper introduces a heave compensation system for offshore crane when it gets unexpected disturbances and external force. The dynamic model consists of crane assumed to be the rigid body, hydraulic driven winch, elastic rope and payload. To keep the payload from moving up and down, PD control algorithm is applied. By using the control, the oscillating amplitude of the payload is reduced. Also by using the estimated values involved with time-delay, the relative motion of payload in heave direction is dramatically shortened. This paper shows using the control algorithm with estimated value having time-delay 0.1 second is enough to heave compensation system.