• 전기학회논문지P
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• 제65권1호
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• pp.57-65
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• 2016

This paper was analyzed the characteristics of piezoelectric inkjet print head using finite element method(FEM). It showed the bending node driving of piezoelectric and relation theory principle consider piezoelectric material characteristics and ink characteristics. From such result we were had the piezoelectric head design and manufacture. It got a this head characteristics through experiment, we confirmed that proper voltage control is possible to through ink drop control experiment of piezoelectric print head. This paper was obtained the suitable ink jetting characteristics that manufacture the control circuit and piezoelectric inkjet print head. This practice product was applied to improvement of PCB electric circuit pattern by etching resist ink that PCB manufactured to complex process over traditional 6 stages can be simpled to 1 stage by inkjet printing technology.

• 대한기계학회논문집A
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• 제26권7호
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• pp.1366-1375
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• 2002

In cold forging of piston-pin for automobile parts, the flow defect appears by the dead metal zone. This appearance evidently happens in products with a thin piercing thickness for the dimension accuracy and the decrease of material loss. The best method that can prevent flow defect is removing dead metal zone. The purpose of this study is to investigate the material flow behavior of forward-backward extruded piston-pin through the relative velocity ratio and the stroke control of upper moving punch & container using the flow control forming technique. The finite element simulations are applied to analyse the flow defect, then the results are compared with the plasticine model material experiments. The model experiment results are in good agreement with the FE simulation ones.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.319-322
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• 1997

In vector control technique, stator currents of an induction motor are transformed to equivalent d-q currents in reference frame consist of d and q axis, each of which is coincide with flux and torque direction respectively. In this paper, the new algorithm is suggested where the stator current through an induction motor torque is monitored by using a vector control method where an additional equipment is not need. The G-programming is used to apply the suggested algorithm in the experiment and this is applied to an actual system to monitor the torque value of an induction motor on real time. To solve the vibration trouble of estimated torque caused from an unbalanced real rotating speed of an induction motor and measured rotating speed by suggesting the reconstructed in a method based on measurement current signal. This produced system testifies an accuracy of an induction motor through the experiment by comparing the reference value of the control method.

• Journal of Mechanical Science and Technology
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• 제14권2호
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• pp.177-187
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• 2000

Dilution is an important factor which influences the properties of clad layer. In this paper the change of dilution during laser cladding and the control of dilution are simulated by a finite element method. The adaptive mesh method is adopted for the time-dependent finite element method computation so that the shape of melt pool can be well represented. The situation of the width control of melt pool is also simulated, which indicates that the dilution can be controlled if the width of melt pool is controlled. Computational results indicate that if a line energy (input energy per unit distance) remains constant the dilution will increase with time, especially at the beginning. Simulation results show that it is possible to control dilution in a certain range if the line energy decreases with time. Experiment of Nd: YAG laser cladding with wire feeding is performed. Experiment results coincide well with the FEM results.

• 소성∙가공
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• 제11권5호
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• pp.430-438
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• 2002

This paper suggests the new technology to control metal flow in orther to change of the cold forging from conventional deep drawing forming. This technology can be summarized the complex forming, which consists of bulk forming and sheet forming, and multi-action forging, which be performed double action press. The proposed technology is applied to hub clutch model which is part of auto-transmission for automobile. The purpose of this study is to investigate the material flow behavior of hub clutch through control the relative velocity ratio and the stroke of mandrel and punch using the flow forming technique. First of all, the finite element simulations are applied to analyse optimal process conditions to prevent flow defect(necking defect etc.) from non-uniform metal flow, then the results are compared with the plasticine model material experiments. The punch load for real material is predict from similarity law. Finally, the model material experiment results are in good agreement with the FE simulation ones.

• 한국공작기계학회논문집
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• 제18권1호
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• pp.22-28
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• 2009

In order to optimize the polishing process, Run to Run control scheme has been applied to the micro mold polishing in this study. Also, to fully understand the effect of parameters on the surface roughness a design of experiment is performed. By linear approximation of main factors such as gap and rotational speed of micro quill, EWMA (Exponential Weighted Moving Average) gradual mode controller is adopted as a optimizing tool. Consequently, the process converged quickly at a target value of surface roughness Ra 10nm and Rmax 50nm, and was hardly affected by unwanted process noises like initial surface quality and wear of magnetic abrasives.

• 한국산학기술학회논문지
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• 제7권2호
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• pp.150-156
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• 2006

전기철도차량의 성능특성을 향상시키기 위한 효과적인 방법중의 하나는 바퀴와 레일사이의 점착성능을 향상시키는 것이다. 점착특성을 연구하기 위해서 실제 차량을 등가 모델링한 점착시스템을 제작하였다. 이 시스템은 다양한 점착 파라미터를 변화시켜 바퀴와 레일사이의 점착력을 바꿀 수 있도록 제작되었다. 이 논문은 공전속도를 제어하는 기능을 추가하여 점착성능을 향상시키는 연구이다.

• Toxicological Research
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• 제12권2호
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• pp.283-288
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• 1996

This study was performed to investigate the effects of chitosan on the lead poisoning in rats. For this experiment, 15 male Sprague-Dawley rats were used. The experimental groups were divided into five: Control (250 mg/kg lead), Group I (250 mg/kg lead+1% chitosan), Group II (250 mg/kg lead+2% chitosan), Group III(250 mg/kg lead+4% chitosan), Group IV (250 mg/kg lead+8% chitosan). The results were as follows; 1. The lead concentration in the liver showed 3.924~10.217 mg/kg in control group, but treated group was inclined to decrease during the experiment period (P<0.05). 2. The lead concentration in the kidney showed 23.268~31.315 mg/kg in control group, but Experimental group showed 3.765~9.725 mg/kg (Group I), 34.60~9.115 mg/kg (Group II), 3.549~8.816 mg /kg (Group III), 3.502~8.532 mg/kg (Group IV) resectively, also, Experimental group was inclined to decrease compared to control group (P

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.994-998
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• 2004

Hybrid method is used to suppress vibration of an automotive roof surface. The hybrid method proposed in this paper is implemented experimentally using both viscoelastic and piezoelectric material. The piezoelectric material is used to control the vibration of automotive structure for lower range of frequencies and the experiment of vibration control using viscoelastic material has been carried out suppress vibrations of high frequency range mark. At first the plate controlled by using hybrid method has been .implemented to verify the performance for suppressing vibration. Then the experiment has been applied to the automotive roof structure.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 추계학술대회논문집; 한국과학기술회관; 6 Nov. 1997
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• pp.154-159
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• 1997

In this paper, we describe the OGY method that convert the motion on a chaotic attractor to attracting time periodic motion by malting only small perturbations of a control parameter. The OGY method is illustrated by application to the control of the chaotic motion in chaotic attractor to happen at the famous Logistic map and Henon map and confirm it by making periodic motion. We apply it the chaotic motion at the behavior of the thin beam under periodic torsional base-excitation, and this chaotic motion is made the periodic motion by numerical experiment in the time evaluation on this chaotic motion. We apply the OGY method with the Jacobian matrix to control the chaotic motion to the periodic motion.