• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.378.2-378
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• 2002

This paper deals with a moving coil type linear motor for fast access of the miniature ODD. This slim-line motor is composed of the mover supported by guide mechanism, the coil wound into it, and the yoke attached to the permanent magnet for stator. The driving force is generated by the PM of the stator and the current in the coil of the mover. Magnetic circuit analysis and Finite Element Method are applied to estimate force at air gap. (omitted)

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.388.2-388
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• 2002

An equivalent electroacoustic circuit approach of estimating the sound absorption coefficient for parallel perforated plate system is proposed. The proposed approach is validated by comparing the calculated absorption coefficients of a parallel single layer perforated plate system with the values measured by the two-microphone impedance tube method for various porosity and cavity depth. (omitted)

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.328.2-328
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• 2002

General modeling of a resonant shunting damper has been made Iron piezoelectric sensor/actuator equation. It is found that an additional damping, which is augmented to a system, is generated by the shunt damping effect The transfer function of the tuned electrical absorber is derived for both series and parallel shunt circuit. The governing equations and associated boundary conditions are derived using Hamilton's Principle. The shunt voltage equation is also derived from the charge generated in PZT due to beam vibration. The frequency response function of the obtained mathematical model is compared with that of the tuned eledtrical absorber and experimental work. The vibration amplitude is reduced about 15 dB at targeted second mode frequency.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.397.1-397
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• 2002

For high density optical storage, there should be a high NA objective lens and a shorter wavelength laser diode. To secure the disc tilt margin related to the coma aberration, moreover, it's difficult to apply the tilt compensation mechanism into the portable PC. In this paper, we proposed the 3-axis asymmetry pickup actuator with high efficiency symmetric magnetic circuit, which consisted of the top cover type inner yoke for high magnetic flux density, the coil stack unit for the 3-axis independent operation and vertically polarized magnets. (omitted)

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.8
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• pp.757-765
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• 2007

Enhanced PSPICE circuit model for vented-box loudspeaker system with lumped parameters was proposed to more accurately simulate real vented-box loudspeaker system. Frequency dependent parameters were used to model voice coil inductor. Acoustic pressure response curves and electrical impedance curves were simulated and investigated by PSPICE circuit model according to circuit parameters' variations. Finally, it was used to identify faults detection in woofers manufactured by unskilled persons.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.342-345
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• 2004

We design a new actuator in order to achieve 3-axes motion for high performance optical device. The actuator makes it possible to control the tilting motion by using moving magnet and PCB-coil, which have benefits in terms of prices and manufacturing. To predict the features of actuator, especially the effect of moving magnet, finite element method and electro-magnetic analysis are used From comparing simulated data with experimental results, we verified the accuracy of the simulation and the superiority of the present actuator.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1992.10a
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• pp.141-146
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• 1992

본 연구에서는 먼저 낙하 충격을 받는 전자 제품을 수학적인 모델링을 행하 므로서 낙하 충격시 제품이 받게되는 충격력을 정량화하였고, 전자 제품내 많은 부품들의 낙하충격에 대한 동특성해석의 일환으로 핵심 부품인 PCB(printed circuit board)를 해석하였다. PCB 해석을 위하여 유한요소법을 사용하였고, PCB에 작용하는 half-sine pulse의 속도 변화에 다른 가속도 응 답 및 최대 충격가속도, 주기의 변화에 다른 PCB의 가속도 응답을 해석하였 다. 제시된 해석 기법은 낙하충격에 대비한 적절한 electric component의 layout및 최적의 PCB 취부조건등의 결정을 가능케 함으로써, 설계단계에서 낙하 충격을 고려한 PCB설계가 될 수 있도록 그 활용 방안을 제시하였고 반복된 낙하충격 실험을 줄일 수 있으므로 경비 절감 및 개발 소요기간도 절감할 수 있다.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.6
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• pp.455-462
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• 2004

This paper is concerned with the implementation of the active vibration suppression controller using analog circuit and microprocessor. The target active vibration controller is the positive position feedback(PPF) controller since it provides a simple algorithm suitable for both analog circuit and digital controllers. In this study, the analog PPF controller is realized using an operational amplifier and the digital PPF controller is realized using a low-cost micro-controller. The circuit diagrams are explained in detail. We then discuss the advantages and disadvantages of both methods from the view of practical implementation. Experimental results show that both implementation methods can be effectively used for the active vibration control but need to be chosen based on the mission objective.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.2 s.95
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• pp.156-160
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• 2005

We design a new actuator of 3-axis motion for high performance optical devices. The actuator makes it possible to control the tilting motion by using moving magnet and PCB-coil, which have benefits in price and manufacturing. To predict the characteristics of the actuator, especially the effect of moving magnet, finite element method and electro-magnetic analysis were used. By comparing simulation data with experimental results, we verified the accuracy of the simulation and the superiority of the present.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.78-81
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• 2002

Printed Circuit Boards for satellite are composed of multi-layered copper plate and glass epoxy. Each copper layer have the complicated and different pattern to operate correctly for its mission. Especially. copper layer give effect on the PCB stiffness seriously. But It can make more complicate to predict the exact stiffness of PCB. In KOMPSAT-2 program, too many type of PCB are used for each electronic unit, and they have different type of pattern of copper layer. Solar array regulator has two type of PCB and it will be considered for this study. In this study. we calculate the PCB board stiffness of KOMPSAT-2 SAR unit considering the concept of simplified representative volume element. It will be correlated with the test results under KOMPSAT-2 vibration environmental condition to increase the reliability of this study.