• 대한기계학회논문집A
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• 제29권4호
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• pp.624-631
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• 2005

A note-book PC has become thinner in recent years, which requires the optical disc drives with small height and high memory capacity. Therefore the actuator of optical disc drives must be thinner and have disc tilt compensation function for high density memory. In this paper, the actuator with hybrid type is investigated for 3-axis ultra-slim actuator. A 3-axis ultra-slim actuator is designed by using the modal analysis of the actuator and the electromagnetic analysis of magnetic circuit to achieve dynamic characteristics. Also, magnetic force between tilt magnet and tilt yoke is investigated to and the influence on the DC sensitivity in the focus and track directions.

• 전기학회논문지
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• 제64권12호
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• pp.1703-1708
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• 2015

This paper deals with the position and torque control of a toroidal type rotor which has a magnetic bearing structure. The proposed magnetic bearing structure supports the rotor by the repulsive forces of permanent magnets, and has a two degree of freedom for rotor position when the rotor is rotating. Permanent magnets and coils in the stator allow for a two degree of freedom control of the rotor position and torque generation by reacting with permanent magnets of the rotor. The executed gyro actuator has a number of poles such as five-phase permanent magnet motors and 10 stator coils for the rotor position control. In this study, the verification of the stability of the magnetic bearing was conducted using the equation of motion when the rotor was rotating, and the coil current commutation method for the position control and torque generation was studied. As a result, the feasibility of the proposed structure and control was verified by simulations of Finite Element Method (FEM) and experiments using the executed gyro actuator.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.1000-1003
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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. This newly suggested actuator features DVD-RAM recording, we achieved the high focus & track AC sensitivity and the greatly stabilized system.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권8호
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• pp.381-389
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• 2003

Nowadays, Vacuum Circuit Breaker(VCB) is used in the most medium voltage level because vacuum has environment-friendly characteristics as well as excellent dielectric strength. In order to elevate the breaking performance, the improvement of vacuum interrupters and the driving mechanism should be proceeded. In this paper, the development of a Permanent Magnet Actuator could replace the mechanical spring mechanism which is the driving mechanism of existing VCB. The holding force and opening characteristics of magnetic actuator are analysed with FEM and the result is verified through experiment.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.962-964
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• 2004

The plunger speed of solenoid actuator is affected by mass of plunger, magnetic motive force, inductance, and return spring. These factors are not independent but related with each other according to design characteristics of solenoid actuator. So, it is impossible to change the designed value for the purpose of increasing plunger speed. In this study, we have analyzed the characteristics of high-speed solenoid actuator having a non-magnetic ring which plays a role to concentrate the effective magnetic flux into plunger. For more detailed analysis, we have induced characteristic equations and performed FEM analysis and simulation for dynamic characteristics of plunger, and proved the propriety of these by experiments.

• Journal of Electrical Engineering and Technology
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• 제9권2호
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• pp.471-477
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• 2014

The novel permanent magnetic actuator (PMA) and its optimal design method were proposed in this paper. The proposed PMA is referred to as the separated permanent magnetic actuator (SPMA) and significantly superior in terms of its cost and performance level over a conventional PMA. The proposed optimal design method uses the evolutionary strategy algorithm (ESA), the kriging meta-model (KMM), and the multi-step optimization. The KMM can compensate the slow convergence of the ESA. The proposed multi-step optimization process, which separates the independent variables, can decrease time and increase the reliability for the optimal design result. Briefly, the optimization time and the poor reliability of the optimum are mitigated by the proposed optimization method.

• 한국정밀공학회지
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• 제15권7호
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• pp.98-103
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• 1998

Recently, DVD/CD compatible driver is needed for DVD and CD is widely used as a new optical data restoring device. The optical systems of DVD and CD driver are different because they have different optical feature. If only one objective lens is used, the change of an aperture or a dual focal length of the lens is required. This method, however, increases the number of parts and results in loss of the power of laser light. Hence, we propose a dual lens actuator design that can read DVD and CD respectively. Albeit magnetic spring is important mechanism in the dual lens actuator design, there has not been the systematic approach to design the mechanism in the preceding researches. In this article. the guideway to design magnetic spring is presented by using the qualitative theoretical approach and the finite element analysis.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.780-785
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• 2001

A moving-magnet type pickup actuator is proposed, which has the back-yoke to improve th sensitivity. Through the magnetic path analysis, we can find that the flux density is increased i the air gap by the pole assignment of magnet and the adding of back-yoke can reduce the flu leakage and induce 40％ up of flux density. Experimental results show that the sensitivity i improved in the tracking direction, however, the improvement doesn't occur in the focusing direction. Finally, the compensation performance is tested in HD-DVD system. And it is verifie that the actuator can compensate the disc tilt of ${\pm}$0.7$^{\circ}$.

• 대한기계학회논문집A
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• 제36권5호
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• pp.481-486
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• 2012

본 논문에서는 대변위 구동이 가능한 구동기의 설계를 위해 기존의 전자기력 구동기에 비해 낮은 스프링 상수를 갖는 굴곡형 스프링을 적용하고, 변위가 발생하는 방향으로만 로렌츠힘이 생기도록 굴곡형 스프링의 일부분만 자기장에 노출시키는 구동기를 제안한다. 굴곡형 스프링의 양쪽 부재가 자기장에 노출된 구조(prototype F)와 굴곡형 스프링의 한쪽 부재만을 자기장에 노출시킨 구조(prototype P)를 설계하고, 제작하여 실험한 결과 prototype P 가 굴곡형 스프링의 양쪽 부재를 자기장에 노출시킨 prototype F의 구동성능에 비해 $16.9{\pm}1.2%$의 진폭 증가를 보임을 실험적으로 검증하였다. 제안된 구동기는 제한된 면적 내에서 작은 전류(<50mA)와 작은 자기장(<0.3T)으로 대변위 구동을 가능케 하여 광 스위치 또는 광 단속기 등에 응용이 가능하다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.743-748
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• 2007

This paper describes a lens transmissive type tilting actuator for a projection TV. An electromagnetic analysis and a structural analysis of the tilting actuator system is necessary to design a tilting actuator for a projection TV. The tilting actuator is composed a permanent magnet, coil and yoke as the electromagnetic components and it needs a driving hinge part as the mechanical component. The design of the tilting actuator for the projection TV is performed by the following procedure. Firstly, a magnetic flux density of the tilting actuator system is analyzed by a mathematical theory and an electromagnetic FEM. Secondary, a magnetic circuit method is used to determine tilting force. Thirdly, the structural FEM is carried out with an FE model of a lens-transmissive type tilting actuator and then the prototype of the model is manufactured. The characteristic of the prototype is experimentally observed. Finally, a design for a new hinge configuration is suggested for better performance.