• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.132.4-132
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• 2001

Field robot represented by excavator can be applied for various kinds of working in manufacturing, construction, agriculture etc. because of the flexibility of its multi-joint mechanism and the high power of hydraulic actuators. In general, the dynamics of field robot have strong coupling, various kinds of non-linearity, and time varying parameters according to working conditions. Therefore, it is very difficult to describe the system well, and design controller systematically based on its model. This paper established the mathematical model of field robot driven by electro-hydraulic servomechanism and constructed the adaptive control system robust to external load variations. The proposed control system for the field robot was evaluated by the computer simulation, and the performance results of trajectory tracking were compared with that of PID control system.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.292-292
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• 2004

There are many difficulties to get the scattered field generated by obstacle which has arbitrary shape or irregular surface impedance by using analytic solution or numerical methods. In this study, we propose experimental method of acoustic scattering holography that can predict the far-field scattered field based on nearfield measurements. First of all, we express scattered field using K-H integral equation and compare the differences of which green's function we use. Also we consider analytic solution of scattered field by infinite cylinder to analysis for the errors due to apply cylinderical holography. So the errors which caused by holography due to frequency (ka) and microphone spacing are also analyzed by numerical simulation.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.601-604
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• 2001

The insulation materials of cables used for underground power transmission requires a higher insulating capability. and the most popular method to examine the cable is partial discharge test due to applying variation voltage. In the thesis. air void. silicone oil. of which may possibly exist real cables. are simulated by Electra 2D program. Also the relations between calculated field strength and the void defect type in the cable joint materails. In the modeling. electic field inner to the cable joint material composed by XLPE and EPDM is modeling simulated. We obtained the electric field distribution in void due to two conditions.

• 한국전기전자재료학회논문지
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• 제16권10호
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• pp.952-957
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• 2003

The purpose of this paper is analyses about in 12kV/50kA vacuum interrupter with an axial magnetic field type electrode system through the studies of electromagnetic phenomena. Vacuum interrupter is important in electric safety part. In this paper, we performed analysis of electric field, magnetic field, current density in AMF electrode using the Maxwell 3D simulation. The current distribution and magnetic field in simple models are analyzed to verify its efficiency and accuracy. In addition the validity of FEM is confirmed by performing the analyses of distribution in current density and magnetic flux density.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.430-433
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• 1996

In This paper, we design the developed path generation method which is named that CBPM(Continuous path generation method Based artificial Potential field) that is able to be used in the obstacles environment. This CBPM is designed so that it puts together two obstacle avoidance algorithm-the continuous path generation method and the artificial potential field method. Here, the continuous path generation method generate the safety path using continuous path curvature. But, this method has demerits when used in obstacles environment in which are closely located. Another method which is named the artificial potential field method generates the path with the artificial potential field in the obstacles environment. But, APFM has local minima in certain places and unnecessarily calculates the path in which obstacles are not located. So, the developed path generation method, CBPM, is suggested and performances in many different obstacles environments are shown by using computer simulation.

• 한국소음진동공학회논문집
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• 제17권1호
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• pp.3-9
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• 2007

In this paper, a numerical case study is carried out on the hydroelastic vibration of rectangular plate with various fluid field. It is assumed that the tank wall is clamped along the plate edges. The VMM(virtual mass method) of Nastran is used for the simulation of fluid domain and calculating natural frequency of fluid-coupled structure. In this paper, natural frequencies are calculated and compared for rectangular plates with various fluid field such as infinite fluid and finite fluid, length change of finite fluid field and various fluid contacting conditions.

• Journal of Mechanical Science and Technology
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• 제19권8호
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• pp.1611-1620
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• 2005

This paper shows the use of wavelet transformation combined with inverse acoustics to reconstruct the surface velocity of a noise source. This approach uses the boundary element analysis based on the measured sound pressure at a set of field points, the Helmholtz integral equations and wavelet transformation for reconstructing the normal surface velocity field. The reconstructed field can be diverged due to the small measurement errors in the case of nearfield acoustic holography (NAH) using an inverse boundary element method. In order to avoid this instability in the inverse problem, the reconstruction process should include some form of regularization for enhancing the resolution of source images. The usual method of regularization has been the truncation of wave vectors associated with small singular values, although the order of an optimal truncation is difficult to determine. In this paper, a wavelet transformation is applied to reduce the computation time for inverse acoustics and to enhance the reconstructed vibration field. The computational speed-up is achieved, with solution time being reduced to $14.5\%$.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.30-32
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• 2005

In this paper, voltage control strategy for maximum torque operation of stator flux-oriented induction machine drive in the field-weakening region is proposed. In a conventional stator flux-oriented (SFO) induction machine drive system of the maximum torque capability cannot be obtained. The field-weakening method is used to vary the stator-flux reference in proportion to the inverse of the rotor speed. The proposed algorithm, based on the voltage control strategy, ensures the maximum torque operation over the field-weakening region. The proposed algorithm, voltage control strategy for maximum torque operation of capability, which is insensitive to the variation of machine parameters In the field-weakening region. The proposed algorithm is verified by simulation.

• Bulletin of the Korean Chemical Society
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• 제28권5호
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• pp.767-771
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• 2007

By adopting a time-resolved optical emission spectrometry, we have investigated the effects of transverse magnetic field on C2 and CN molecules produced by laser ablation of a graphite target in nitrogen atmosphere. We found that the spectroscopic temperatures of both species, obtained via simulation of the optical emission spectra, as well as their emission intensities from the electronically excited states increased significantly in the presence of a magnetic field. The cyclotron radii and frequencies for electrons and ions were estimated to explain the increase in the number of collisions in the laser-produced carbon plasma plume under a magnetic field.

• 한국전자파학회논문지
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• 제28권11호
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• pp.916-919
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• 2017

본 논문에서는 모바일 기기용 소형 금속 캔으로부터 발생하는 전자기장의 누설 경로를 시뮬레이션을 통해 확인하고, IC-stripline 방법을 이용하여 전기장 및 자기장에 대한 근접장 결합(coupling) 현상을 분석하였다. 금속 캔의 윗면 개구부에 의한 전자기장 누설은 주로 자기장이 우세하고, 측면을 통한 누설은 전기장이 우세함을 확인하였다.