• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.375-378
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• 2005

Voice Coil Motor is used linear motion actuator system that require precision positioning control. In order to control precision positioning of voice coil motor, Mathematical model of voice coil motor is needed. Mathematical model is obtained by combining voice coil motor's equation of motion with the equation of circuit and characteristic of voice coil motor. The induced model can predict output displacement according to duty ratio and amplitude. The model is verified by experimental test. Simulated results have tracking errors of less than 10 percent of experimental results.

• Journal of Electrical Engineering and Technology
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• v.10 no.6
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• pp.2288-2296
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• 2015

This paper proposes a novel systematic modeling approach for an integrated single-stage power converter in order to predict its dynamic characteristics. The basic strategy of the proposed modeling is substituting the internal converters with an equivalent current source, and then deriving the dynamic equations under a standalone operation using the state-space averaging technique. The proposed approach provides an intuitive modeling solution and simplified mathematical process with accurate dynamic prediction. The simulation and experimental results by using an integrated boost-flyback converter prototype provide verification consistent with theoretical expectations.

• Journal of the Korean Society for Nondestructive Testing
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• v.24 no.1
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• pp.8-14
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• 2004

Model-based inversion tools for eddy current signals have been developed by combining neural networks and finite element modeling, for quantitative flaw characterization in steam generator tubes. In the present work, interpretation of experimental eddy current signals was carried out in order to validate the developed inversion tools. A database was constructed using the synthetic flaw signals generated by the finite element model. The hybrid neural networks composed of a PNN classifier and BPNN size estimators were trained using the synthetic signals. Experimental eddy current signals were obtained from axisymmetric artificial flaws. Interpretation of flaw signals was conducted by feeding the experimental signals into the neural networks. The interpretation was excellent, which shows that the developed inversion tools would be applicable to the Interpretation of real eddy current signals.

• 한국전산유체공학회:학술대회논문집
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• 2005.04a
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• pp.91-95
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• 2005

A heat dissipation modeling method of EEE parts is developed for thermal design and analysis of an satellite electronic equipment. The power consumption measurement value of each functional breadboard is used for the heat dissipation modeling method. For the purpose of conduction heat transfer modeling of EEE parts, surface heat model using very thin ignorable thermal plates is developed instead of conventional lumped capacity nodes. The thermal plates are projected to the printed circuit board and can be modeled and modified easily by numerically preprocessing programs according to design changes. These modeling methods are applied to the thermal design and analysis of CTU and verified by thermal cycling and vacuum tests.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.2
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• pp.209-217
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• 2003

In this paper, the dynamic system modeling and the state sensitivity analysis of the spin-coater system are proposed for the reduction of the vibration. In the respect of modeling, the spin-coater system is considered to be composed of servomotor, spindle, supporting base and so on. Each component of model is combined and derived to 3 dimensional equations. The combined model is verified by experimental values of actual system in the frequency domain. By direct differentiation of the constraint equations with respect to kinematic design variables, such as eccentricity of spindle, moment of inertia, rotational stiffness and damping of supported base, sensitivity equations are derived to the verified state equations. Sensitivity of design variables could be used for vibration reduction and natural frequency shift in the frequency domain. Finally, dominant design variables are selected from the sensitivity analysis.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.8
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• pp.641-651
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• 2003

In order to assess the reliability of a building energy simulation program (TRNSYS) from the standpoint of user, a set of verification experiment and calculation of cooling load for a test space is carried out. This work is a complement of the previous study that dealt with heating load for the same space. The test space is kept airtight to eliminate the source of uncertainties in modeling. A window-mounted, on/off controlled air-conditioner is used for cooling, whose performance has been established a priori. The calculation encompasses two models for evaluating cooling load in TRNSYS: energy rate control and temperature level control. Comparison of the total cooling loads obtained from different sets of experimental data enables to validate the measurements. The experimental result shows that the latent load is fairly large even in the absence of apparent air change in the space, which needs to be clarified. Each of hourly and daily accumulated sensible loads is compared between the experiment and two calculation models. Despite an inconsistency associated with solar irradiation, both of the models agree favorably with the experiment within a tolerance, illustrating their capability of properly predicting space thermal loads.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.6
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• pp.517-525
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• 2011

Differential Vibrating Accelerometer(DVA) is a small and accurate resonant device to sense the change in natural frequency in presence of acceleration input. Both mathematical modeling for the electromechanical dynamics and experimental investigation on the structural characteristics are necessary for effective designs of precision controller and high Q-factor structure. In this paper, electromechanical modeling of the resonator of DVA, electrode module, and pre-amplifier is presented. The presented method is experimentally verified by measuring the resonance frequency, effective mass, effective stiffness and Q-factor. The direct comparison of the calculated displacement and the actual pre-amplifier of DVA also indicates the effectiveness of this study.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.12
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• pp.1347-1355
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• 2009

This paper demonstrates the validity of spectral element analysis for modeling the high-frequency dynamic behaviors of a beam with a surface-bonded piezoelectric wafer through a laboratory test. In the spectral element analysis, the high-frequency electro-mechanical interaction can be considered properly with relatively low computational cost compared to the finite element analysis. In the verification test, a cantilever beam with a surface-bonded piezoelectric wafer is forced to be in steady-state motion by exerting the harmonic driving voltage signal on the piezoelectric wafer. A laser scanning vibrometer is used to obtain the overall dynamic responses of the structure such as resonance frequencies, the associated mode shapes, and frequency response functions up to 20 kHz. Then, these dynamic responses from the test are compared to those computed by the spectral element analysis. A two-dimensional finite analysis is conducted to obtain the asymptotic solutions for the comparison purpose as well.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.1
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• pp.77-84
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• 2013

Most research on the inkjet printing technology has focused on the development of inkjet head itself, and of process, not on the landing accuracy of the droplets to a target. Thus, this paper presents the modeling and experimental verification on the static landing accuracy and precision of the droplets from the magnetostrictive inkjet head. A simple model based on the angle deviation of a nozzle tip and on a distance to a substrate is considered, assuming that there is no ambient effect. The angle deviation of the nozzle tip is determined by using its digital image with the aid of a pixel calculation program, and the distance to the substrate is set to 1 mm. Three experiments have planned and preformed. The first experiment is to collect the initial data for the landing distribution of the droplets. The second experiment is to collect the repeatability data of the stage used. Then, these data are used to rederive the equation for the final landing position of the droplet. The final experiment is to verify the equation and to show the calibration results. The respective landing accuracy of the droplet after calibration on the x-axis and on y axis has improved from $338.51{\mu}m$ and $-133.63{\mu}m$ to $7.06{\mu}m$ and $13.11{\mu}m$. The respective percent improvement on the x-axis and on y axis reaches about 98 and about 90. The respective landing precision of the droplet after calibration on the x-axis and on y axis has improved from ${\pm}182.6{\mu}m$ and ${\pm}182.88{\mu}m$ to ${\pm}24.64{\mu}m$ and ${\pm}42.76{\mu}m$. The respective percent improvement on the x-axis and on y axis reaches about 87 and about 77.

• Journal of the Korea Society of Computer and Information
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• v.27 no.5
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• pp.101-107
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• 2022

Modeling and simulation is a technique used for operational verification, performance analysis, operational optimization, and prediction of target systems. Discrete Event System Specification (DEVS) of this representative technology defines models with a strict formalism and stratifies the structures between the models. When the atomic DEVS models operate with an intention different the target system, the simulation may lead to erroneous decision-making. However, most DEVS systems have the exclusion of the model test or provision of the manual test, so developers spend a lot of time verifying the atomic models. In this paper, we propose a script-based automated test system for accurate and fast validation of atomic models in Python-based DEVS. The proposed system uses both the existing method of manual testing and the new method of the script-based testing. As Experimental results in our system, the script-based test method was executed within 24 millisecond when the script was executed 10 times consecutively. Thus, the proposed system guarantees a fast verification time of the atomic models in our script-based test and improves the reusability of the test script.