• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.224-229
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• 1997

This paper compares the control techniques for position control experiments of a fixible robot moving in a vertical plane. The flexible manipulator is modeled as an Euler-beroulli beam. Elastic deformantion is representedusing the assumed model method. A comparison function which satisfies all geometric and natural boundary conditions of a cantilever beam with an end mass is used as an assumed mode shape. Lagrange's equation is utilized for the development of a discretized model. Control schemes are developed using PID control,pole placement control and discrete Linear Quadratic Regulater(LQQ). The effectiveness of the developed control schems are compared using computer simulation in view of practical experiment. The simulation results show that PID control is very effective in practical implementation.

• Journal of Korean Association for Spatial Structures
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• v.13 no.3
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• pp.65-72
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• 2013

Long span arch structure is composed of arch as relatively flexible structure and column as relatively rigid structure. In this study, the characteristic of dynamic response is analyzed according to the natural frequency ratio between arch and columns. The result of analysis for arch as relatively vertical vibration mode is dominant, the influence of columns mainly appears at relatively high frequency band according to increase of 1st mode frequency in column. However, the dynamic characteristic of arch structure is expected to vary with not only frequency ratio but interaction between vibration modes of arch and columns.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.161-165
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• 2001

Recently, mega-float offshore structure is studied as one of the effective utilization of the ocean space. And mega-float structure are now being considered for various applications such as floating airports, offshore cities and so on. This mega-float structure is relatively flexible compared with real floating structures like large ships. when we estimate dynamic responses of these structures in waves, the elastic deformation is important, because vertical dimension is small compared with horizontal. The analysis of the dynamic response as it receives regular wave is studied. The finite element method is used in the analysis of structural section of this model. And the analysis is carried out using the boundary element method in the fluid division. In order to know the characteristics of the dynamic response of the mega-float structures, effects of wavelength, water depth, and wave direction on dynamic response of the floating structure are studied by use of numerical calculation.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.09a
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• pp.415-422
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• 2001

In this paper, the experimental study was carried out in order to compare the mechanical characteristics of multi-layer elastomeric isolation hearings where the reinforceing elements steel plates case and fiber-reinforcement case. Fiber-reinforced isolater which has the same dimension as the steel reinforced isolator had shown better efficiency in effective damping than NRB. The compression test has shown the corresponding results with the theoretical vertical stiffness in the case of flexible reinforcement. The fiber-reinforced isolator will be significantly lighter and could lead to a much less labor intensive manufacturing process.

• Proceedings of the KSEEG Conference
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• 2001.05a
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• pp.66-70
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• 2001

Recently, mega-float offshore structure is studied as one of the effective utilization of the ocean space. And mega-structure are now being considered for various applications such as floating airports, offshore cities and so on. This mega-float structure is relatively flexible compared with real floating structures like large ships. when we estimate dynamic responses of these structures in waves, the elastic deformation is important, because vertical dimension is small compared with horizontal. The analysis of the dynamic response as it receives regular wave is studied. The finite element method is used in the analysis of structural section of this model. And the analysis is carried out using the boundary element method in the fluid division. In order to know the characteristics of the dynamic response of the mega-float structures, effects of wavelength, water depth, and wave direction on dynamic response of the floating structure are studied by use of numerical calculation.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.1
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• pp.19-25
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• 1998

Remote fault diagnosis and maintenance system using general telecommunication network is necessary for an effective fault diagnosis and higher productivity of NC machine tools. In order to monitor machine tool condition and diagnose alarm states due to electrical and mechanical faults, a remote data communication system for monitoring of NC machine fault diagnosis and status is developed. The developed system consists of (1) remote communication module among NC's and host PC using PSTN. (2) 8 channels analog data sensing module, (3) digital I/O module for control or NC machine, (4) communication module between NC machine and remote data communication system via RS-232C, and (5) software man-machine interface. Diagnostic monitoring results generated through a successive type inference engine are displayed in user-friendly graphics. The validity and reliability of the developed system is verified to be a powerful commercial version on a vertical machining center through a series of experiments.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2000.02a
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• pp.115-118
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• 2000

The superconducting magnet supporting post of the KSTAR system is a flexible structure that absorbs thermal shrink of the superconducting magnet and also a rigid structure that supports the weight of the magnet and dynamic loads. In this work, a structural analyses for the post under the loads were performed. As a result, it turns out that the post would be safe when it is exposed to the loads, such as magnet weight, thermal contraction, and plasma vertical disruption load. And, Buckling and modal analysis results of the post are presented.

• Journal of KSNVE
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• v.7 no.2
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• pp.261-272
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• 1997

Recently washing machines are to be in lower vibration and lower sound because of better environment. Vibration problems in washing machines occur in both washing mode and spinning mode, but vibration in spinning mode becomes main problem because of its high rotating speed and continuity. Vibration while spinning is mainly due to rigid body motion of total washing system which includes suspending rods, washing bath, spinning bath, and gear sets. In this study, some researches were done in order to analyze the rigid body motion of washing system and flexible vibration of spinning bath. A basic mathematical model was established, and the effect of position of salt water and shape change of salt water case were considered. And the effect of lengths of suspending rods, attaching angles, vertical and horizontal position, stiffness of spring on the change of vibration were also considered. To identify the effect of salt water on vibration, some measurements were done. When salt water was positioned at upper part, the effect was most and this coincides with the tendency of simulation.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.399-402
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• 2005

We have studied the Pixel Isolated Phase Separated Composite Organic Film (PI-PSCOF). The PI-PSCOF can be made by the anisotropic phase separation between Ferroelectric Liquid Crystals and Pre-polymer materials by irradiating the UV with optimizing its intensity and time. In the technology, the FLC molecules are isolated in pixels where FLCs are surrounded by the inter-pixel vertical polymer walls and the horizontal polymer films on the upper substrate. The good merits of this technology are fast response time, and good mechanical and thermal stability against external high pressure and temperature. We will compare the results obtained from FLC, PSCOF, and PI-PSCOF modes by using the electro-optic measurement and x-ray scattering, and mechanical method. We believe that the PI-PSCOF technology can be a best candidate for future Flexible Display Applications.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.687-691
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• 2005

We demonstrated stability-enhanced liquid crystal (LC) displays using pixel-iosolated LC mode in which LC molecules are isolated in pixel by horizontal polymer layer and vertical polymer wall. The device shows good electro-optic properties with external pressure and bending due to the polymer structures. The polymer wall acts as supporting structure from mechanical pressure and maintains the cell gap from bending. Moreover, the polymer layer acts as adhesive for tight attachment of two substrates. We presented various methods to produce the polymer structures by using anisotropic phase separation from LC and polymer composites or patterned micro-structures.