• Title/Summary/Keyword: Sway suppression

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A Study on the Sway Suppression Control of Container Cranes (컨테이너 크레인의 흔들림 억제 제어에 관한 연구)

  • Baek, Woon-Bo
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.21 no.1
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    • pp.109-115
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    • 2012
  • In this paper, we consider the sway suppression control problem for container cranes with load hoisting. The proposed control law improves the positioning accuracy but also the sway suppression through fast stabilization of the under-actuated sway dynamics, which is based on a class of feedback linearizing control incorporated with an additional control including the sway angle and its rate as well as positioning errors and their rates. For the design of the additional control, a variable structure control with the proper sway damping and simple switching action is employed, thus preventing excessive overshoots of the trolley travelljng and effectively suppressing the residual sway of container arrived at the target position. Simulation results are provided to show effectiveness of the proposed controller in the presence of such uncertainties as winds and the variation of payload weights.

A Second Order Sliding Mode Control of Container Cranes with Unknown Payloads and Sway Rates (미지의 부하와 흔들림 각속도를 갖는 컨테이너 크레인의 2차 슬라이딩 모드 제어)

  • Baek, Woon-Bo
    • Journal of Institute of Control, Robotics and Systems
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    • v.21 no.2
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    • pp.145-149
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    • 2015
  • This paper introduces a sway suppression control for container cranes with unknown payloads and sway rates. With no priori knowledge concerning the magnitude of payload mass and sway rate, the proposed control maintains superior sway suppressing and trolley positioning against external disturbances. The proposed scheme combines a second order sliding mode control and an adaptive control to cope with unknown payloads. A second order sliding mode control without feedback of the sway rate is first designed, which is based on a class of feedback linearization methods for stabilization of the under-actuated sway dynamics of the container. Under applicable restrictions of the magnitude of payload inertia and sway rate, a linear regression model is obtained, and an adaptive control with a payload estimator is then designed, which is based on Lyapunov stability methods for the fast attenuation of trolley oscillations in the vicinity of the target position. The asymptotic stability of the overall closed-loop system is assured irrespective of variations of rope length. Simulation are shown in the existence of initial sway and external wind disturbances.

Container Crane Control: Modified Time-Optimal Traveling Followed by Nonlinear Residual Sway Control (컨테이너 기중기의 제어 : 수정된 시간최적주행과 비선형 잔류흔들림 제어)

  • Hong, Keum-Shik
    • Journal of Institute of Control, Robotics and Systems
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    • v.5 no.5
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    • pp.630-639
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    • 1999
  • To achieve fast loading and unloading of containers from a container ship, quick suppression of the remaining sway motion of the container at the end of each trolley stroke is crucial. Due to the pendulum motion of the container and disturbances like sind, residual sway always exists at the end of trolley movement. In this paper, the sway-control problem of a container crane is investigated. A two-stage control is proposed. The first stage is a time optimal controlfor the purpose of fast trolley traveling. The second stage is a nonlinear control for the quick suppression of residual sway, which starts right after the first stage while lowering the container. The nonlinear control is investigated in the perspective of controlling an underatuated mechanical system, which combines partial feedback linearization to account for the known nonlinearities as much as possible, and variable structure control to account for the unmodeled dynamics and disturbances. Simulation and experimental results are provided.

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Anti-Sway Tracking Control of Container Cranes with Friction Compensation (마찰 보상을 갖는 컨테이너 크레인의 흔들림 억제 추종 제어)

  • Baek, Woon-Bo;Shin, Jin-Ho
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.21 no.6
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    • pp.878-884
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    • 2012
  • In this paper, we consider the sway suppression control problem for container cranes with the frictions between the trolley and the rail. If the friction effects in the system can be modelled, there is an improved potential to design controllers that can cancel the effects. The proposed control improves the trolley positioning and sway suppressing against various frictions. The proposed synthesis combines a variable structure control and the adaptive control to cope with various frictions including the unknown constants. First, the variable structure control with the simple switching action is designed, which is based on a class of feedback lineariztion methods for the fast stabilization of the under-actuated sway dynamics of container. Second, the adaptive control with a parameter estimation is designed, which is based on Lyapunov stability methods for suppressing the oscillation of the trolley travelling, especially due to Coulomb friction in the vicinity of the target position. The asymptotic stability of the overall closed-loop system is assured irrespective of variations of rope length. Simulation are shown under initial sway, external wind disturbances, and various frictions.

Payload-Swing Suppression of a Container Crane: Comparison Between Command Shaping Control and Optimal Control

  • Do, Huh-Chang;Shik, Hong-Keum
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.54.2-54
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    • 2001
  • In this paper two control strategies, command shaping control and optimal control, which aim to the reduction of the residual vibrations of the payload in a container crane system are investigated. Both control methods are open loop control. Due to unmodeled dynamics of the plant and disturbances like initial sway and wind, some residual sway always exists at the end of trolley movement. Command inputs are designed to achieve the control objectives including minimal residual vibration and robustness in the presence of unmodeled dynamics. Simulation results of various command inputs are compared in terms of arrival time, residual sway angle, robustness, and maximum sway distance during the traveling. Command shaping method provides a more competent tool than optimal control.

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A Feedback Linearization Control of Container Cranes: Varying Rope Length

  • Park, Hahn;Chwa, Dong-Kyoung;Hong, Keum-Shik
    • International Journal of Control, Automation, and Systems
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    • v.5 no.4
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    • pp.379-387
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    • 2007
  • In this paper, a nonlinear anti-sway controller for container cranes with load hoisting is investigated. The considered container crane involves a planar motion in conjunction with a hoisting motion. The control inputs are two (trolley and hoisting forces), whereas the variables to be controlled are three (trolley position, hoisting rope length, and sway angle). A novel feedback linearization control law provides a simultaneous trolley-position regulation, sway suppression, and load hoisting control. The performance of the closed loop system is shown to be satisfactory in the presence of disturbances at the payload and rope length variations. The advantage of the proposed control law lies in the full incorporation of the nonlinear dynamics by partial feedback linearization. The uniform asymptotic stability of the closed-loop system is assured irrespective of variations of the rope length. Simulation and experimental results are compared and discussed.

The Effect of Fleet-Angle on Sway Motions of a Cargo: Compatibility and Bifurcation Conditions (화물과 트롤리가 만드는 로프각이 화물의 진자운동에 미치는 영향: 적합조건과 분기조건)

  • SHIN JANG-RYONG;GOH SUNG-HEE;HONG KYUNG-TAE;HONG KEUM-SHIK
    • Journal of Ocean Engineering and Technology
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    • v.19 no.2 s.63
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    • pp.60-66
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    • 2005
  • This paper investigates the relationship between the fleet-angle of the hoisting rope and the swaying and pitching angles of a cargo in container cranes. It is found that for a given disturbance, when the fleet-angle is large, the sway Angle becomes smaller, but the pitching angle becomes larger. Therefore, for a quick suppression of a sway motion, it is desirable to have a large fleet-angle. The compatibility and bifurcation conditions, regarding instability, are characterized.

Adaptive Variable Structure Control of Container Cranes with Unknown Payload and Friction (미지의 부하와 마찰을 갖는 컨테이너 크레인의 적응 가변구조제어)

  • Baek, Woon-Bo;Lim, Joong-Seon
    • Journal of Institute of Control, Robotics and Systems
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    • v.20 no.10
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    • pp.1008-1013
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    • 2014
  • This paper introduces an adaptive anti-sway tracking control algorithm for container cranes with unknown payloads and friction between the trolley and the rail. If the friction effects in the system can be modeled, there is an improved potential to design controllers that can cancel these effects. The proposed control improves the sway suppressing and the positioning capabilities of the trolley and hoisting against uncertain payload and friction. The variable structure controls are first designed based on a class of feedback linearization methods for the stabilization of the under-actuated sway dynamics. The adaptation mechanism are then designed with parameter estimation of unknown payload and friction compensation for the trolley and hoisting, based on Lyapunov stability methods for the accurate positioning and fast attenuation of trolley oscillation due to frictions in the vicinity of the target position. The asymptotic stability of the overall closed-loop system is assured irrespective of variations of rope length. Simulations are shown under various frictions and external winds in the case of no priori information of payload mass.

Sway Control of Container Cranes as an Axially Moving Nonlinear String

  • Park, Hahn;Hong, Keum-Shik
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.2474-2479
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    • 2005
  • The control objectives in this paper are to move the gantry of a container crane to its target position and to suppress the transverse vibration of the payload. The crane system is modeled as an axially moving nonlinear string equation, in which control inputs are applied at both ends, through the gantry and the payload. The dynamics of the moving string are derived using Hamilton's principle. The Lyapunov function method is used in deriving a boundary control law, in which the Lyapunov function candidate is introduced from the total mechanical energy of the system. The performance of the proposed control law is compared with other two control algorithms available in the literature. Experimental results are given.

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Nonlinear Control of Residual Say of a Container Crane in the Perspective of Controlling an Underactuated System (불충분한 작동기를 가진 매니퓰레이터의 비선형제어)

  • 김영민;홍금식;이교일
    • 제어로봇시스템학회:학술대회논문집
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    • 1997.10a
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    • pp.249-252
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    • 1997
  • In this paper the sway-control problem of a container crane is investigated in the perspective of controlling an underactuated mechanical system. For fast loading/unloading of containers from the ship, quick suppression of the remaining swing motion of the container at the end of each trolley stroke is crucial. Known nonlinearities are fully incorporated by feedback linearization. Robustness is enhanced by variable structure control. Compared with the linear LQ control, much better performance can be obtained.

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