• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.5
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• pp.845-851
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• 2008

A simple RMRAC (Robust Model Reference Adaptive Control) scheme for the PMSM (Permanent Magnent Synchronous Motor) is proposed in the synchronous frame. A current control of PMSM is the most inner loop of electro-mechanical driving systems and it requires a fast and simple control law to play a foundation role in the control hierarchy. In the proposed synchronous current model, the input signal is composed of a calculated voltage by proposed adaptive laws and real system disturbance. The gains of feed-forward and feedback controllers are estimated by the proposed modified Gradient method respectively, where the system disturbances are assumed as filtered current tracking errors. After the estimation of the system disturbances from the tracking errors, the corresponding voltage is fed forward to control input voltage to compensate for the disturbances. The proposed method is robust against high frequency disturbance and has a fast dynamic response. It also shows a good real-time performance due to it's simplicity of control structure. Through the simulations and real experiments, efficiency of the proposed method is verified.

• Advances in concrete construction
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• v.9 no.6
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• pp.577-588
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• 2020

In this paper, vibration attributes of chiral double-walled carbon nanotubes (CNTs) based on nonlocal elastic shell model have been investigated. The impact of small scale is being perceived by establishing Flügge shell model. The wave propagation is engaged to frame the ruling equations as eigen value system. The influence of nonlocal parameter subjected to different end supports has been overtly examined. A suitable choice of material properties and nonlocal parameter been focused to analyze the vibration characteristics. The new set of inner and outer tubes radii investigated in detail against aspect ratio and length. The dominance of boundary conditions via nonlocal parameter is shown graphically. Whereas for lower aspect ratio the frequencies coincide but as it continues to expand the difference between all respective boundary conditions slightly tend to increase. The results generated furnish the evidence regarding applicability of nonlocal shell model and also verified by earlier published literature.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.6
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• pp.792-797
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• 2010

Microwave oven and household cooker are devices of high voltage producer and high voltage storage batteries respectively for formation of necessary high frequencies at drive. These devices emit much heat energy because they are run at high voltages. Therefore, emitted heat energy becomes a factor that raises temperature of microwave ovens' main frame. In this research, the analysis shows the temperature distribution in microwave oven with the cooling fan drive conditions and the heat energy occurrence conditions. According to the analysis, as the speed of air outpoured in cooling fan increases, and the internal temperature decreases quantitatively. Also the inside temperature distribution was investigated by controlling heat energy emission.

• Conservation Science in Museum
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• v.12
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• pp.77-88
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• 2011

The study investigated conservation and fiber of 66 letters of Sukmyeonghancheob (national treasure No.1629) that the National Cheongju Museum kept. Before treatment, the cover was destroyed and inner paper was stained by water and humidity and destroyed by insects. One volume of King Hyojong was kept at separate frame. The author disassembled book and removed old Baejeobji and inspected paper quality of letter and tested fiber by using C-stain: The author reassembled one volume by including one letter separated after repairing destroyed area of the edge.

• International Journal of Precision Engineering and Manufacturing
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• v.5 no.1
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• pp.36-41
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• 2004

The blanking of thin sheet metal using progressive dies is an important process on production of precision electronic machine parts such as IC leadframe. This paper summarizes the results of simulating the progressive blanking process by means of LS/DYNA. In order to verify the influence of blanking order on the final lead profile and deformed configuration, simulation technique has been proposed and analyzed using a commercial FEM code, LS/DYNA. The results of FE-simulations are in good agreement with the experimental result. After then, to construct rule base in progressive blanking process, FE-simulation has been performed using a simple model. Based on this result rule base is set up and then the blanking order of inner lead is rearranged. Consequently, from the results of FE-simulation using suggested method in this paper, it is possible to predict the shift of lead to manufacture high precision lead frame in progressive blanking process. The proposed method can give more systematic and economically feasible means for designing progressive blanking process.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.703-708
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• 2002

An elastomeric bushing is a device used in automotive suspension systems to reduce the load transmitted from the wheel to the frame of the vehicle. A bushing is an elastomeric hollow cylinder which is bonded to a solid steel shaft at its inner surface and a steel sleeve at its outer surface. The relation between the load applied to the shaft or sleeve and the relative deformation of Elastomeric bushing is nonlinear and exhibits features of viscoelasticity. A load-displacement relation fur elastomeric bushing is important fur dynamic numerical simulations. A boundary value problem for the bushing response leads to the load-displacement relation which requires complex calculations and is hence unsuitable. Therefore, by modifying the constitutive equation for a nonlinear viscoelastic incompressible material developed by Lianis, the data fur the elastomeric bushing material was obtained and this data was used to derive the new load-displacement relation fur radial response of the bushing. After the load relaxation function for the bushing is obtained from the step displacement control test, Pipkin-Rogers model was developed. Solutions were allowed for comparison between the results of Modified Lianis model and those of the proposed model. It is shown that the proposed Pipkin-Rogers model is in very good agreement with Modified Lianis model.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.5
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• pp.154-161
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• 1999

An elastomeric bushing is a device used in automotive suspension systems to cushion the force transmitted from the wheel to the frame of the vehicle. A bushing is an elastomeric hollow cylinder which is bonded to a solid metal shaft at its inner surface and a metal sleeve at its outer suface. The relation between the force applied to the shaft or sleeve and their relative deformation is nolinear and exhibits features of viscoelasticity. Numerical solutions of the boundary value problem represent the exact bushing response for use in the method for determining the force relaxation function of the bushing. The new nonlinear viscoelastic bushing model, which is called Pipkin-Rogers model, is proposed and it is shown that the predictions of the proposed force-displacement relation are in very good agreement with the exact results. This new bushing model is thus very suitable for use in multi-body dynamics codes. The success of the present study for axial mode response suggests that the same approach be applied to other modes, such as torsional or radial modes.

• Elastomers and Composites
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• v.38 no.4
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• pp.334-341
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• 2003

A bushing is a device used in automotive suspension systems to reduce the load transmitted from the wheel to the frame of the vehicle. A bushing is a hollow cylinder, which is bonded to a solid steel shaft at its inner surface and a steel sleeve at its outer surface. The relation between the force applied to the shaft and the relative deformation of a bushing is nonlinear and exhibits features of viscoelasticity. A force-displacement relation for bushings is important for multibody dynamics numerical simulations. For the nonlinear viscoelastic axial response, Pipkin-Rogers model, the direct relation of force and displacement, has been derived from Lianis model and the sinusoidal input was used fer Pipkin-Rogers model, and the affection of displacement with frequency change was studied with Pipkin-Rogers model.

• 보존과학연구
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• s.27
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• pp.23-42
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• 2006

This study is about gilt bronze ornament, that is from Deok Cheon-Ri in Gyeong Ju, of conservation treatment process and of scientific analysis. This relic gathered with soil around the relic by Polyurethane foam. While the relic got rid of soil, Took X-rays. As the result, we decided to process reconstruction as condition that the relic was dug up. After the conservation treatment processed, we made a frame to display the relic. Investigated manufacture techniques of the relic after the conservation treatment processed, and thenexecuted scientific analysis of the relic for a chemical experiment. A analysis of the results of components for composition layers using the SEM-EDS can be briefly summarized as below; Firstly, the average contents of outer, inner and body corrosion layer have a Cu-60.9~39.3wt% and analyzed a little impurities material which is Fe-0.5wt%.Secondly, the average contents of body have a Cu-99.7wt% which was using manufactured by pure copper. Thirdly, gold layer have a mercury of 9.5wt% which indicate that layer was manufactured by mercury amalgam gilding technique.

• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.67-69
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• 2007

PMSM (Permanent Magnet Synchronous Motor) current control is a most inner loop of electromechanical driving systems and it plays a foundation role in the hierarchy's control loop of several mechanical machine systems. In this paper, a simple RMRAC control scheme for the PMSM is proposed in the synchronous frame. In the synchronous current model, the input signal is composed of as a calculated voltage by adaptive laws and system disturbances. The gains of feed-forward and feed-back controller are estimated by the proposed e-modification methods respectively, where the disturbances are assumed as filtered current tracking errors. After the estimation of the disturbances from the tracking errors, the corresponding voltage is fed forward to control input to compensate for the disturbances. The proposed method is robust to high frequency disturbances and has a fast dynamic response to time varying reference current trajectory. It also shows a good real-time performance duo to it's simplicity of control structure. Through the simulations considering several cases of external disturbances and experimental results, efficiency of the proposed method is verified