• 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.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.11
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• pp.1873-1880
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• 2003

The sliding wear characteristics of the crane sheave were investigated using a pin on disk rig tester. The experiment was conducted using a high carbon steel wire that was upper material, also carbon steel castings that was disk material. There are various operating conditions in this work. At the room temperature, we carried out the wear test under a grease lubrication and dry condition. The results of wear test showed that an annealed-casted have lower, also the wear curves are linearly increased with increasing of sliding distance. For the specific wear rate of annealed-casted, the wear resistance was increased with decreasing diameter of wire. The wear of a wire and a disk have a different mechanism, the one is the abrasive wear due to fatigue wear under lubrication, another is the adhesion wear under dry condition.

• Tribology and Lubricants
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• v.29 no.3
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• pp.171-179
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• 2013

In this study, hydraulic systems of the rope brake system of an elevator are modeled to evaluate design parameters that consider friction characteristics such as cylinder pressure, piston displacement, and flow rate. Hydraulic systems of the rope brake system are analyzed using the commercial program AMESim. Analysis modeling data are compared with data obtained from experiments, and the analysis modeling results are found to be reliable. The analysis results will be used to design hydraulic systems of the rope brake system of elevators.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.252-255
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• 2014

The elevator rope is easy to oscillate and continue vibrating because the rope structure is flexible and inner damping is small. The vibration of elevator rope is caused by the building vibration excited by external disturbances such as winds and earthquake. This paper is concerned with the experimental verification of the elevator rope vibrations using a small-scale simulator. The elevator rope vibration coupled with the building vibration was modelled using the energy method in the previous study. In this study, the natural frequencies of the elevator rope were computed using the theoretical model and compared to experimental results. Also, the time-responses of the rope vibration during the cage motion were measured by laser sensors and compared to the theoretical predictions. Experimental results are in good agreement with theoretical predictions.

• Proceedings of the Korean Society of Computer Information Conference
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• 2017.07a
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• pp.269-270
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• 2017

본 연구에서는 부력조형물이 정해진 위치에서 사용자가 원하는 자세를 유지할 수 있는 시스템을 연구하였다. 기존의 부력조형물은 로프를 이용한 고정식이었지만 본 기술이 적용된 부력조형물은 로프 없이 스스로 부력에 의한 공중부양과 사용자가 원하는 자세를 취할 수가 있도록 구성하였다. 이러한 시스템은 주로 홍보용으로 널리 사용되며 박람회, 제품 설명회, 지역축제, 예술 등 많은 분야에 적용이 가능하다. 부력조형물이 자세를 유지하기 위하여 드론 기술에 적용되는 IMU 센서를 이용한 방향과 자세정보와 6개의 BLDC 모터에 8인치 프로펠러를 접합시켜 부력조형물이 상하좌우로 이동이 가능하도록 자세 제어장치를 구성하였으며 실험을 통하여 시스템의 검증하였다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2018.07a
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• pp.355-356
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• 2018

본 연구에서는 드론 기술을 응용한 부력조형물의 수평 및 수직 자세제어에 관한 연구를 수행 하였다. 기존의 공중부양 조형물은 헬륨 Gas를 이용한 애드벌룬이 대표적으로 로프를 이용한 단순한 공중부양 조형물이었다. 본 연구에서는 이러한 공중부양 조형물에 로프를 없애고 드론 기술을 응용한 프로펠러로 공중부양 조형물의 자세를 제어하는 방법을 연구하였다. 시스템 구성은 단일 제어기로서의 역할보다 시스템 구성요소로서의 역할이 매우 중요해지므로 조형물의 제어시스템, 다양한 센서등의 연동되어지는 전체의 제어기로 확장시켜 사용되는 퓨전 시스템의 방향으로 구성하였다. 부력조형물의 수평 및 수직제어를 위하여 사용된 센서는 2축의 자이로센서와 3축의 가속도센서를 사용하였다. 프로펠러와 연결된 BLDC모터를 효율적으로 제어하기 위한 알고리즘으로 PI 알고리즘을 이용하였다. 시스템의 성능 향상을 위한 효율적인 동적 작업부하 균등화와 시스템 자원인 CPU와 메모리를 효율적으로 사용하여 고성능 컴퓨팅 시스템의 처리량을 최소화하고, 센싱 및 제어의 수행시간을 최소화하였다. 본 연구에서는 PI 알고리즘을 시스템에 적용하여 응답특성 실험을 행한 결과 시뮬레이션에 의한 응답 결과와 잘 일치하였으며 그 유용성이 검증하였다.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.11a
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• pp.247-252
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• 2009

With the increasing use of tower cranes higher than free standing height, the importance of lateral support is also growing. Since the fall of 43 tower cranes hit by the last typhoon 'Mami' in 2003, regulations and concerns about safety of construction equipment have increased and construction laws regarding lateral support have been strengthened. In Korea, where there are many large-scale apartment housing construction works with the development of new towns, Rope Guying is a more economical construction method than Wall Brace which fixes building structure like building wall and slab. The safety of this Rope Guying is not verified and many construction works are still carried out based on the experience of site managers. There has been no case of construction work where frame and measurements are applied. The objective of this study is to examine the safety of Rope Guying method and ensure the effective implementation of equipment and prevention of disasters.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.4
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• pp.350-355
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• 2007

Pad-eye is connected to crane with sling. When block is lift, pad-eye have a various applied force. Applied force on pad-eye is related to sling angle. Sling angle is decided by various parameters, including pad-eye location, sling length and crane location. Welded joint on pad-eye requires strength design because sling angle changes force on pad-eye. Strength design for welded joint of pad-eye will calculate with general mechanical design and FE analysis. FE analysis would become a useful tool in the analysis of welded joint. A commercial software(ANSYS 10.0) was used in the structural strength analysis for welded joint of pad-eye.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2005.04a
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• pp.534-539
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• 2005

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.205-206
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• 2014