• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.450-453
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• 1997

An active control for the swing of crane systems is very important for increasing the productivity. This article introduces the control for the position and the swing of a crane using the fuzzy learning method. Because the crane is a multi-variable system, learning is done to control both position and swing of the crane. Also the fuzzy control rules are separately acquired with the loading and unloading situation of the crane for more accurate control. The result of simulations shows that the crane is just controlled for a very large swing angle of 1 radian within nearly one cycle.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.04a
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• pp.30-35
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• 1997

CNC Grinding Center is developed to improve the flexibility of grinding process and to obtain the high machine accuracy in grinding processes. It consists of a built-in type spindle with max. 25,000 rpm, ATC(automatic tool changer) for quick and reliable loading/unloading of tools, a rotary dresser for trueing, dressing, and personal computer based CNC controller, etc. This research concentrates on the machine structure, the evaluation of efficiency, and the machining technology of the developed prototype

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2000.04a
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• pp.101-105
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• 2000

In cold forging die the shrink fitting is generally used to decrease stress and increase die life. In this paper we have studied about the effect of fitting type, When the die insert is splitted into several pieces the maximum stress could be decreased as much as 50~70% The fitting angle could be selected to minimize the maximum stress and the variation of stress on loading and unloading, . In F, E.M result in case 3。 fitting angle the maximum and variation of stress may be minimized.

• Korean Management Science Review
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• v.26 no.1
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• pp.93-112
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• 2009

In this paper, a model is presented to estimate a cycle time for completing an operation in a new type of AS/RS which can handle very heavy loads by separating the mechnisms for vertical and horizontal movements. Considering loading/unloading time between devices, we generalize the previous work, Hu et al. [9], which neglected the transfer time. Through the numerical experiments for various situations, we find that the difference of the cycle times between two models is fairly large and conclude that the transfer time between devices cannot be neglected at all.

• Journal of the Korea Safety Management & Science
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• v.8 no.2
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• pp.39-49
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• 2006

Forklift achieves transportation of freight and continues loading and unloading work repeatedly long for hours in industry spot. Therefore, drivers feel tired make a mistake for wrong operation of vehicle caused by continuous work. These components are resulted in CTDs, some industrial accident. That is the forklift need to ergonomics access. So, in this paper, requirements of forklift user were abstracted using questionnaire, produced important design factor for pedal and lever using QFD(Quality Function Deployment), and then suggested ergonomic considerations for industrial accident prevention.

• Structural Engineering and Mechanics
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• v.35 no.4
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• pp.431-457
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• 2010

This article provides a discussion of the mathematic modeling of connections for designing and qualifying structures, systems, and components subject to monotonic or cyclic loading. To characterize the force-deformation behavior of connections under monotonic loading, a review of the Ramberg-Osgood, Richard-Abbott, and Menegotto-Pinto models is conducted, and it is shown that these nonlinear functions can be mathematically derived by scaling up or down a linear force-deformation function. A generalized four-parameter model for simulating connection behavior is investigated to facilitate nonlinear regression analysis. In order to perform seismic analysis of frameworks, a hysteretic model accounting for loading, unloading, and reloading is described using the established monotonic model. For preliminary analysis, a method is provided to quickly determine the model parameters that fit approximately with the observed data. To reach more accurate values of the parameters, the methods of nonlinear regression analysis are investigated and the modified Levenberg-Marquardt and separable nonlinear least-square algorithms are applied in determining the model parameters. Example case studies illustrate the procedure for the computation through the use of experimental/analytical data taken form the literature. Transformation of connection curves from the three-parameter model to the four-parameter model for structural analysis is conducted based on the modeling of connections subject to fire.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.536-539
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• 2002

In this paper, we developed the automatic optical fiber aligner by image processing and automatic loading system. Optical fiber is indispensable for optical communication systems that transmit large volumes of data at high speed, but super-precision technology in sub-micron units is required for optical axis adjustment, we have developed 6-axis micro stage system for I/O optical fiber arrays, the initial automatic aligning system/software for a input optical array by the image processing technique, fast I/O-synchronous aligning strategy, the automatic loading/unloading system and the automatic UV bonding mechanism. In order to adjust the alignment it used on PC based motion controller, a $10\mu\textrm{mm}$ repeat-detailed drawing of automatic loading system is developed by a primary line up for high detailed drawing. Also, at this researches used the image processing system and algorithm instead of the existing a primary hand-line up. and fiber input array and waveguide chip formed in line by automatic. Therefore, the developed and manufactured optical aligning system in this research fulfills the great role of support industry for major electronics manufacturers, telecommunications companies, universities, government agencies and other research institutions.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.161-161
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• 2000

The clean mobile robot for wafer transfer is AGV that carry each wafer to each equipment. It has wafer handling technology, wafer ID recognition technology, position calibration technology using vision system, and anti-vibration technology. Wafer loading/unloading working accuracy is within ${\pm}$1mm, ${\pm}$3$^{\circ}$. By application of this AGV, we can reduce the manufacturing tack time and bring cost down of equipment.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.650-655
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• 1993

Carbon/epoxy composite(CFRP) coupons previously damaged by low velocity impact were tested under static tensile loading and microscope progress of damage was characterized by ultrasonic C-scan, Scanning Acoustic Microscopy (SAM) and Acoustic Emission(AE) techniques which were based on the application of elastic waves. The degress of impact damage has been correlated with the AE activity during monotonic or loading/unloading tensile testing as well as the result of ultrasonic test. The coupons were subjected to impact velocities ranged from 0.71 to 2.17 m/sec, which introduced the amount of damage rated as 0%, 10%, 30%, and 50% with reference to the total absorbed energy at fracture. Special attention was paid to determine optimal AE parameters to characterize the microscopic fracture process and to predict the residual strength of composite laminates. AE RMS voltage during the early stage of tensile loading was found an effective parameter to quantify the degree of impact damage. It was also found that the Felicity ratio is closely related to the stacking sequence and the residual strength of the CFRP laminates.

• Geomechanics and Engineering
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• v.37 no.4
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• pp.341-358
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• 2024

This paper reports several plane-strain trapdoor tests conducted to investigate the effects of reinforcement on soil arching development under localized surface loading with a loading plate width three times the trapdoor width. An analogical soil composed of aluminum rods with three different diameters was used as the backfill and Kraft paper with two different stiffness values was used as the reinforcement material. Four reinforcement arrangements were investigated: (1) no reinforcement, (2) one low stiffness reinforcement R1, (3) one high stiffness reinforcement R2, and (4) two low stiffness reinforcements R1 with a backfill layer in between. The stiffness of R2 was approximately twice that of R1; therefore, two R1 had approximately the same total stiffness as one R2. Test results indicate that the use of reinforcement minimized soil arching degradation under localized surface loading. Soil arching with reinforcement degraded more at unloading stages as compared to that at loading stages. The use of stiffer reinforcement had the advantages of more effectively minimizing soil arching degradation. As compared to one high stiffness reinforcement layer, two low stiffness reinforcement layers with a backfill layer of certain thickness in between promoted soil arching under localized surface loading. Due to different states of soil arching development with and without reinforcement, an analytical multi-stage soil arching model available in the literature was selected in this study to calculate the average vertical pressures acting on the trapdoor or on the deflected reinforcement section under both the backfill self-weight and localized surface loading.