• Journal of Ocean Engineering and Technology
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• v.19 no.1 s.62
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• pp.87-94
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• 2005

This paper investigates the constant-level luffing and time optimal control of jib cranes. The constant-level luffing, which is the sustainment of the load at a constant height during luffing, is achieved by analyzing the kinematic relationship between the angular displacement of a boom and that of the main hoist motor of a jib crane. Under the assumption that the main body of the crane does not rotate, the equations of motion of the boom are derived using Newton's Second Law. The dynamic equations for the crane system are highly nonlinear; therefore, they are linearized under the small angular motion of the load to apply linear control theory. This paper investigates the time optimal control from the perspective of no-sway at a target point. A stepped velocity pattern is used to design the moving path of the jib crane. Simulation results demonstrate the effectiveness of the time optimal control, in terms of anti-sway motion of the load, while luffing the crane.

• Journal of the Korean Society of Safety
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• v.28 no.3
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• pp.11-17
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• 2013

Forensic Engineering is the area covering the investigation of products, structures that fail to perform or do not function as intended, causing personal injury or damage to property. To investigate the mobile crane's overturn accident in terms of the forensic engineering, in this study, we identified the accident mobile crane's position and posture before accident by the analysis of the trace resulted by the contact between the outrigger and the ground, and the accident remodeling has been performed using CATIA modeling program in the basis of the accident mobile crane's position and posture information. The accident analysis has been performed by comparing this accident remodeling and the crane's specification, the table of the allowance load about the boom's length and the working radius. Through these studies, the safety accident that may occur in mobile crane can be minimized by performing specialized and systematic investigation of the accident cause in terms of the forensic engineering.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.10a
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• pp.87-94
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• 2006

In this study we carried out to analyze the effect of wind load on the structural stability of a container crane according to the change of the boom shape using wind tunnel test and provided a container crane designer with data which can be used in a wind resistance design of a container crane assuming that a wind load at 75m/s wind velocity is applied on a container crane. Data acquisition conditions for this experiment were established in accordance with the similarity. The scale of a container crane dimension, wind velocity and time were chosen as 1/200, 1/13.3 and 1/15. And this experiment was implemented in an Eiffel type atmospheric boundary-layer wind tunnel with $11.52m^2$ cross-section area. Each directional drag and overturning moment coefficients were investigated and uplift forces at each supporting point due to the wind load were analyzed.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.06b
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• pp.339-344
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• 2006

The productivity for container hand1ing in container ship is a important role in container terminal, and it is mainly depended on the productivity of gantry crane. From the failure of gantry crane, the crane will be stopped until the repair of the failure. During the repair, the loading and/or discharging for container ship is suspended, and the productivities of the container ship and the yard is just hold. Thus, the prevention maintenance is importance to make a keep the steady state condition for all equipments in container terminal. In this paper, we deal with a optimal determination method of prevention maintenance interval for gantry crane systems. For verification, we will make a productivity of gantry crane and adapt to total container handling in each ship by simulation.

• Journal of Power System Engineering
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• v.2 no.1
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• pp.73-79
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• 1998

In practical fields, the sway of crane systems leads to extra stress to the crane structure during the transporting operation and it is in close connection with its life. Usually, when we operate the cranes with high speed and manual control, the sway motion is irreducible. In this paper, a new type of crane system is proposed to avoid the irreducible sway of the crane systems. The proposed system is composed of mechanical arm with function of anti-sway based on conventional line system. By the anti-sway arm, we can realize to prevent the sway of the container box but cannot avoid the oscillation for the overall body of the crane. So, a controller design method to solve the above stated problem must be considered. The problem is solved by adopting the velocity pattern control methods of trapezoidal and curve types and its effectiveness is proved through experimental results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.838-841
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• 2005

This study was carried out to analyze the effect of wind load on the structural stability of a 50ton articulation type container crane using wind tunnel test and provide a container crane designer with data which can be used in a wind resistance design of an articulation type container crane assuming that a wind load 75m/s wind velocity is applied in an articulation type container crane. Data acquisition conditions for this experiment were established in accordance with the similarity. The scale of an articulation type container crane dimension, wind velocity and time were chosen as 1/200, 1/13.3 and 1/15. And this experiment was implemented in an Eiffel type atmospheric boundary layer wind tunnel with $11.52m^2$ cross-section area. Each directional drag and overturning moment coefficients were investigated and uplift forces at each supporting point due to the wind load were analyzed.

• Safety and Health at Work
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• v.6 no.4
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• pp.279-288
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• 2015

Background: In this study, the measurement of job stress of electric overhead traveling crane operators and quantification of the effects of operator and workplace characteristics on job stress were assessed. Methods: Job stress was measured on five subscales: employee empowerment, role overload, role ambiguity, rule violation, and job hazard. The characteristics of the operators that were studied were age, experience, body weight, and body height. The workplace characteristics considered were hours of exposure, cabin type, cabin feature, and crane height. The proposed methodology included administration of a questionnaire survey to 76 electric overhead traveling crane operators followed by analysis using analysis of variance and a classification and regression tree. Results: The key findings were: (1) the five subscales can be used to measure job stress; (2) employee empowerment was the most significant factor followed by the role overload; (3) workplace characteristics contributed more towards job stress than operator's characteristics; and (4) of the workplace characteristics, crane height was the major contributor. Conclusion: The issues related to crane height and cabin feature can be fixed by providing engineering or foolproof solutions than relying on interventions related to the demographic factors.

• Wind and Structures
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• v.32 no.5
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• pp.405-421
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• 2021

To gain insight into the wind-induced safety concerns associated with attached tower cranes during the construction of super-tall buildings, a 606 m level frame-core tube super-tall building is selected to investigate the wind-induced vibration response and fragility of an outer-attached tower crane at all stages of construction. The wind velocity time history samples are artificially generated and used to perform dynamic response analyses of the crane to observe the effects of wind velocity and wind direction under its working and non-working resting state. The adverse effects of the relative displacement response at different connection supports are also identified. The wind-resistant fragility curves of the crane are obtained by introducing the concept of incremental dynamic analysis. The results from the investigation indicate that a large relative displacement between the supports can substantially amplify the response of the crane at high levels. Such an effect becomes more serious when the lifting arm is perpendicular to the plane of the connection supports. The flexibility of super-tall buildings should be considered in the design of outer-attached tower cranes, especially for anchorage systems. Fragility analysis can be used to specify the maximum appropriate height of the tower crane for each performance level.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.131.6-131
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• 2001

During the operation of crane system in container yard, it is necessary to control the crane trolley position and loop length so that the swing of the hanging container is minimized. Recently an automatic control system with high speed and rapid transportation is required. Therefore, we designed a controller to control the stacking crane system.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.292-297
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• 1990

An anti-swing controller for an overhead crane in the stop position is designed. The developed anti-swing controller improves on the poor damping characteristics of overhead crane by feeding back the crane acceleration as a function of swing angular speed. The experimental results show that this crane using the proposed controller yields small stop position error and rapid damping response characteristics.