• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.5
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• pp.379-384
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• 2014

This article describes the dynamic behaviors of a rubber tired gantry crane(RTGC) under typical load conditions which are used in the design of gantry cranes. In order to investigate the dynamic characteristics of an RTGC, we developed a finite element crane model for its huge structure. The finite element model was validated with the modal test results, e.g., natural frequencies and normal modes. And other components of RTGC were converted into detailed 3D CAD models and finally transformed to rigid body models in a dynamic simulation program ADAMS. The load conditions considered in this paper were a normal operating condition(OP1) and container hanging condition with no external loads. As a result, we could find there was large influence of crane's vibration owing to its structural stiffness and deformation. And the vibration of crane could made the movements of RTGC, which occurs crash or malfunction of crane works.

• Journal of Power System Engineering
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• v.15 no.5
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• pp.91-96
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• 2011

The handling ability of containers at the terminal strongly depends on the performance of the cargo handling system such as RTGC(Rubber Tired Gantry Crane) and RMGC(Rail Mounted Gantry Crane). This paper introduces a guide line measurement system on the operating condition, in which two camera are installed to detect the guide line. Because the line tracking is the basic technique for control system design of RTGC, it is necessary to develop a useful and reliable measurement system. If the displacement and angle of the RTGC relative to a guide line as the trajectory to follow is obtained, the position of RTGC is automatically calculated. Therefore, in this paper, a camera-based measurement system is introduced. The proposed measurement system is robust against light fluctuation and cracks of the guide line. This system consists of two camera and a PC which are installed at the lower side of the RTGC. Two edges of the guide line are detected from an input image taken by the cameras in the moving state, and these positions are determined in a Hough parameter space by using the Hough transformation method. From the experimental results, the accuracy and usefulness of the proposed system is evaluated by comparing other instruments.

• Journal of Navigation and Port Research
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• v.34 no.6
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• pp.479-485
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• 2010

To handle container effectively is one of the most important factors in a port because working time is linked soon into cost. Since the middle of 1990s, RMGC(Rail-Mounted Gantry Crane) and RTGC(Rubber-Tired Gantry Crane) have been developed and widely used to operate containers in the yard. The RTGC is more difficult than RMGC in the automatic control system design. Although, the RTGC is largely advantaged to free driving environment, it has some considerable disadvantages in the system operating. In general, the problems are due to tire slip and lack of tire pressure etc. Therefore, a desirable research result has not been shown in this time. So, in this paper, we propose a new approach to design tracking control system for the RTGC in which the mathematical modeling is included. From the simulation results, the control performance of the designed control systems is evaluated.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.9
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• pp.892-896
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• 2011

This paper describes a camera-based position measurement system for automatic tracking control of a rubber Tired Gantry Crane (RTGC). An automatic tracking control of RTGC depends on the ability to measure its displacement and angle from a guide line that the RTGC has to follow. The measurement system proposed in this paper is composed of a camera and a PC that are mounted on the right upper between front and rear tires of the RTGC's side. The measurement accuracy of the system is affected by disturbances such as cracks and stains of the guide line, shadows, and halation from the light fluctuation. To overcome the disturbances, both side edges of the guide line are detected as two straight lines from an input image taken by the camera, and parameters of the straight lines are determined by using Hough transform. The displacement and angle of the RTGC from the guide line can be obtained from these parameters with the robustness against the disturbances. From the experiments with the disturbances, we found the accurate displacement and the angle from the guide line that have the standard deviations of 0.95 pixels and 0.22 degrees, respectively.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2010.04a
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• pp.280-281
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• 2010

컨테이너의 효율적인 이송은 작업 시간이 곧 비용으로 연결되는 항만에서 가장 중요한 요소이다. 따라서 1990년대 중반부터 세계항만은 RMGC(Rail-Mounted Gantry Crane), RTGC(Rubber-Tired Gantry Crane)등의 크레인이 개발되어 야드에서 컨테이너를 적재하는데 널리 이용되어 오고 있으며, 특히 최근에는 CCD카메라, 각종 센서 둥을 이용하여 트랜스퍼 크레인의 무인화를 위해 수많은 연구가 진행되었고 실용화 된 많은 기술들이 현장에서 사용되고 있으나, 여전히 많은 부분이 연구를 필요로 한다. 특히 RTGC의 경우 RMGC에 비해 무인 자동화 연구개발은 미비한 수준이다. 따라서 본 논문에서 RTGC의 무인자동화 작업을 위한 가장 기초라고 볼 수 있는 수학적 모델링을 기반으로한 고정밀도 주행제어기를 설계하고자 한다.

• Journal of Power System Engineering
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• v.15 no.1
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• pp.72-77
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• 2011

The handling ability of containers at the terminal strongly depends on the performance of the cargo handling system such as RTGC(Rubber Tired Gantry Crane). This paper introduces a new guide line position measurement method using a camera for the RTGC which plays a important role in the harbor area. Because the line tracking is the basic technique for control system design of RTGC, it is necessary to develop a useful and reliable measurement system. If the displacement and angle of the RTGC relative to a guide line as trajectory to follow is obtained, the position of RTGC is calculated. Therefore, in this paper, a camera-based measurement system is introduced. The proposed measurement system is robust against light fluctuation and cracks of the guideline. This system consists of a camera and a PC which are installed at the lower side of the RTGC. Two edges of the guide line are detected from an input image taken by the camera, and these positions are determined in a Hough parameter space by using the Hough transformation method. From the experimental results, high accurate standard deviations were found as 0.98 pixel of the displacement and 0.24 degree of the angle, including robustness against lighting fluctuation and cracks of the guide line also.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.12
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• pp.1212-1219
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• 2010

The most important thing in the container terminal is to handle the cargo effectively in the limited time. To achieve this object, many strategies have been introduced and applied to. If we consider the technical trends and environment of the automated container terminal, it is necessary that the systems for cargo handling are equipped with more intelligent control technologies. To cope with this tendency, from the middle of the 1990's, the automated RMGC (Rail-Mounted Gantry Crane) and RTGC (Rubber-Tired Gantry Crane) have been developed and widely used to handle containers in the yards. Recently, in these cranes, the many equipments like CCD cameras and sensors are mounted to cope with the automated terminal environment. If we want to obtain more efficient handling performance, the modelling, tracking control, anti-sway system design, skew motion suppressing and complicated motion control problems must be considered in the control system design and application process. Considering these problems, in this paper, the system modelling with the tire slip and a tracking control approach are proposed. Especially, we design the tracking control system based on the 2DOF servosystem design approach to cope with undesirable disturbance input. The experiment results show the desirable performance and usefulness of the designed control system.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2010.04a
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• pp.276-277
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• 2010

This paper deals with energy storage system for saving the energy of RTGC(rubber tired gantry crane). Advantage and disadvantage of battery, super-capacitor, and flywheel as an energy storage system were surveyed. Even if a flywheel energy storage system includes some problems such as manufacturing technique and high price, it is surveyed with a promising energy storage system In addition, RTGCs using battery or flywheel as the energy storage system were quantitatively presented through a survey of literatures. It was found that the both RTGC with those systems can reduced the waste of energy.