• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.610-613
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• 2003

Ensuring technical ability is essential in the construction industry to increase competitiveness in the global market. A new paradigm is coming up in academic education system to cultivate the competent engineers. The major objective of this research is to suggest a positive learning pattern In order to overcome the limitations of the passive learning style. A case study, technical upgrading with a tower crane, us explained in terms of active learning process, results, and evaluation of students' performance.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.2
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• pp.83-89
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• 2008

This paper presents the dynamic analysis and input shaping control of a positioning stage. Vibration characteristics of the positioning stage are affected not only by the structural dynamics but also by the servo actuators that consist of the mechanism; driving motor and controller. This paper proposes an integrated dynamic model to accommodate both the structural dynamics and the servo actuators. Theoretical modal analysis with a commercial finite element code is carried out to investigate the dynamic characteristics of the experimental positioning stage. Experiments are performed to validate the theoretical modal analysis and estimate the equivalent stiffness due to the servo actuators. This paper deals with an input shaping scheme to suppress vibration of the positioning stage. Input shapers are systematically implemented for the positioning stage in consideration of its dynamics. The effects of servo control gain are also investigated. The experiments show that input shaping effectively removes residual vibrations and then improves the performance of positioning stage.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.4
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• pp.808-814
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• 2007

In this paper, the measurement system of crane moving range is concerned with range recognition technology using phase and magnitude of radio wave. By the proposed technology, we design the radio transmitter and receiver and realize the measurement system, and save the data in disk that is earned from 900Mhz RF signal, middle frequency 450khz of analog signal. As a result of RF measurement, we got 9.3 dBm of RF output and 96 dBc@10khz of phase noise. Range information is earned the data through digital signal processing of IF signal. For the estimation of range measured, we analyze the difference between real range and measurement range, and also suggest the method to remove the measurement error using average processing and amplitude properties. A result is 0.12 and 0.00422 deviation in l0mn-30m and within 5m respectively, and then 2.4E-04 deviation in 4m by using compensation of level characteristics lately.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.11
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• pp.1022-1032
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• 2000

We propose a sliding mode controller tracking the states of a time-varying reference model. The reference model generates the desired trajectories of the states, and the sliding mode controller regulates robustly the errors between the desired states and the measured states. We apply this controller to the overhead crane. Its reference model generates the trajectories of the damped-out swing angle and the swing angular velocity to suppress the swinging motion caused by the acceleration and the deceleration of crane transportation. Also, this model generates the desired trajectories of the position and velocity of the crane. The crane model is identified from the experimental data using an orthogonal function. Kalman filtering is applied to estimate the crane states. The designed controller is simulated on a computer and is tested through a 2-ton industrial overhead crane using the vector-controlled servo motor system. It is verified that, from the simulated and experimental results, the sliding mode controller tracking a time-varying reference model works well.

• Journal of the Korean Society of Industry Convergence
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• v.22 no.6
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• pp.757-765
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• 2019

In manufacturing An offshore plant is a structure that produces resources buried in the seabed. It can be classified into fixed, floating, and hybrid methods depending on the installation method. In particular, the Lattice boom type crane is typically used because it is used for a long time in the sea and moves to other seas, which is less affected by wind. In this study, the crane was designed by using three-step optimization design in the early stage of the design of Lattice boom crane for offshore plant. Finite element analysis was performed to verify the safety factor, deflection, buckling coefficient and fatigue life of the designed crane and the results were verified.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.6_2
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• pp.937-946
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• 2021

The floating crane is used to lift the heavyweight on the ocean. The floating crane has a winch system for lifting the heavyweight and the system is controlled by the winch control system. The heavyweight is lifted safely by control of the winch control system. Before the make the control system and controller, there are many restricted conditions to test and validate at design and development steps. In order to solve the problems, commonly use the HILS (Hardware-In-the-Loop-Simulation). HILS is the method of test and validation for the hardware control system. It can be composed of the control system in hardware with surrounding environments which is a virtual model. In this study, we developed the winch system model for HILS of the 150t winch control system in a floating crane. Through this simulation and winch model, it can be applied to HILS for the winch control system.

• Journal of Korea Foundry Society
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• v.41 no.1
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• pp.16-25
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• 2021

The development of technology to prevent environmental pollutants and reduce energy consumption has already become a very significant issue not only for the foundry industry but also for society as a whole. In this paper, we introduce a new dust collector developed for low energy consumption and high performance compared to a roof top dust collector. The roof top dust collector which is using widely in the domestic foundry plant has a low performance about the dust suction ability in spite of high energy consumption because it is installed in a high place to collect the whole dust from all processes in foundry. A dust collector away from dust sources inevitably has low energy efficiency. The development of an efficient collector for foundry is very difficult because the position of the dust source continues to change from the melting process to the pouring process. New dust collector is installed on the ladle transfer equipment such as cranes, hoists, and monorails to effectively respond to moving dust sources. The movable device, attached close to the source of dust, provides high performance even with low energy consumption. The new dust collector is expected to be an environment-friendly device that can be applied to the foundry.

• Journal of Practical Engineering Education
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• v.16 no.4
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• pp.529-540
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• 2024

In industrial sites, experiential virtual training contents are partially used to replace high-risk and high-cost training, and virtual training contents development is also becoming active along with the increasing demand for non-face-to-face industries. Existing studies mainly focused on quantitative research through surveys, and only measured the change in users' learning commitment. This study attempted to investigate the effect of the combination of theoretical education and virtual training on the improvement of actual job performance in a dual vocational training environment by conducting an experimental study. This study studied whether the combination of theoretical education and virtual training can improve the performance of vocational training in dual vocational training (comparative work and learning) in which companies and schools participate. The results of pre- and post-evaluation of vocational training using traditional vocational training and virtual training contents were compared with 24 vocational training trainees. As a result of the study, it was demonstrated that the outcome of virtual training education was higher than that of traditional vocational training, and the combination of virtual reality-based education was more effective in theoretical education. This study suggests that the virtual training content presents a new paradigm for industrial safety education, and through the interview results of trainees, it was confirmed that virtual training can lead to a change in attitude toward safety beyond just knowledge transfer. This contributes to the prevention of safety accidents in industrial sites and provides important implications for improving the quality of vocational training.

• The Journal of Korean Institute for Practical Engineering Education
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• v.4 no.1
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• pp.80-85
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• 2012

The importance of warehouse is increasing since the role of warehouse in modern industry is changing from concept of storage to concept of circulation which facilitates purchasing, production, storage and distribution activities by induction of information system. In this study, a program is developed using C# for evaluating efficiency of automated storage and retrieval system(AS/RS). A simulation work is done for eight operating schemes under the combination of three conditions, which are storing method, the shape of automatic warehouse and the sequence of command performs, and the moving distance of stacker crane is calculated using the same gateway data. Using this program, the optimal operating scheme can be proposed based on the analyzed results of simulation. This progrm shows the effectiveness and applicability through the simulation work and can be utilized for courses which are related to factory facilities.