• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.786-790
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• 2001

In this paper, we propose an optimum design method for optical pick-up actuators. Using this method, we can design an optimal pick-up actuator having the required tracking/focusing performances. Also, the designed actuator has the small mass, force constant for small size of magnetic circuit and large resistance for reduction of heat generation. Simulation results show that this method can be potentially implemented in all the pick-up actuators.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.190-194
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• 2005

There is a great demand of micro-actuators for mobile information devices such as SFF optical drives and mobile camera phones. However, conventional magnetic coils of electromagnetic motors are a major obstacle for miniaturization because of their complicated structures and large power consumption. In this paper, a linear ultrasonic motor to actuate focusing lens of mobile devices is proposed. The new actuator uses a ring type bimorph piezoelectric material, and $d_{31}$ mode is adopted for applying linear motion. The interaction between inertia force and friction force makes linear motion by high-frequency saw signal input. The saw signal gives steady forces on the one direction by asymmetric inclination property of the signal itself on time domain. A commercial FEM (ANSYS) was used in this investigation for simulating structural analysis, identification of dynamic property, such as resultant displacement and coupled analysis with piezoelectric material. To evaluate the performance of the new design, a prototype was manufactured and experiments were carried out. Experimental results show the actuator motion of 1.52 mm/s at 10 kHz input signal in 5 V.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.12
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• pp.1207-1222
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• 2004

In this paper, the explicit equations on the power consumption and sensitivity ratio of VCM-type actuator for disk drive are proposed. The power consumption and sensitivity ratio is derived in frequency domain. The power consumption during the track following of the actuator can be described well in frequency domain and it can be used to calculate the total power dissipation of the actuator which is needed to compensate the tracking and focusing errors. Also, the sensitivity ratio of an actuator is derived by using the reference servo of a disk drive and will be used to optimally obtain the performances of the actuator. This sensitivity ratio can persuasively explain the basis of the target performances of the actuator in the considerations of the reference servo. The usefulness of the proposed equations for the sensitivity ratio and power consumption of an actuator is shown by a lot of simulations. In the near future, we will verify the simulation results by experiments.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.577-580
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• 2005

This paper reports the high sensitivity actuator for flexible disk. The air stabilized flexible optical disk has very small axial runout. Therefore, It is proper to develop an actuator which has high sensitivity in tracking direction rather than in focusing direction. In order to maximize driving force in radial direction, we present an efficient design of magnetic circuit with simple multi-polarized magnets and auxiliary magnets. Designed magnetic circuit has big force in tracking direction. And we shift 2$^{nd}$ resonance frequency of moving parts Into high frequency band, not causing increase of mass and discord between force and mass centers to secure high sensitivities and sufficient control bandwidth. Finally, experimental results show that designed actuator has superior sensitivity in tracking direction.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.672-675
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• 2006

It is becoming more significant to develop a rotary VCM type actuator for small form factor ODD, as portables are getting more and more popularized nowadays. In this paper, the procedure of development of the actuator which is applicable to compact flash II card and is fit in the specification of BD 1X is explained. This is based on the rotary VCM type actuator, which is good for reducing thickness. Air core solenoid coil is used in order to do focusing mechanism. And the total weight is reduced by using the structure of steel-aluminium-steel triple layer, so, the stiffness is still adequate. Additionally, the tracking coil is moved next to the actuator, so the total length was reduced, then the actuator become applicable to compact flash II card. The force of Magnetic Circuit is improved by using Magnetic Circuit DOE. And flexible mode frequency improved through the DOE of structure part. Modeling was exactly done in consideration of air core solenoid coil and pivot bearing. It is confirmed that the designed model is satisfied with the specification of BD 1X and is applicable to Compact Flash II card.

• Smart Structures and Systems
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• v.14 no.2
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• pp.71-83
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• 2014

The purpose of this paper is to investigate the flexible structure of parabolic shell using photostrictive actuators. The analysis is made to know its dynamic behavior and light-induced control forces for coupled parabolic shell. The effects of an actuator location as well as membrane and bending components under the control action have been analyzed considering the approximate spherical model. The parabolic membrane shell accuracy is being mathematically approximated and validated comparing the light induced control forces using approximate equivalent spherical shell model. The parabolic shell with kapton smart material and photostrictive actuators has been used to formulate the governing equation in the transverse direction. The Kirchhoff-Love assumptions are used to obtain the governing equation of shell with actuator. The mechanical membrane forces and bending moments for parabolic thin shell with actuator is used to analyze the dynamic effect. The results show that membrane control action is much more significant than bending control action. Photostrictive actuators oriented along circumferential direction (actuator-2) can give better control effect than actuators placed along longitudinal direction (actuator-1). The slight difference is observed between spherical and parabolic shell for a surface with focal length to the diameter ratio of 1.00 or more than unity. Space applications often have the shape of parabolical shells or shell of revolution, due to their required focusing, aiming, or reflecting performance. The present approach is focused that photostrictive actuators can effectively control the vibration of parabolical membrane shell. Also, the actuator's location plays an important role in defining the control force.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.3
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• pp.214-225
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• 2023

Piezoelectric actuators, which utilize piezoelectric crystals or ceramics, are commonly used in precision positioning applications, offering high-speed response and precise control. However, the use of low-performance ceramics and expensive single crystals is limiting their versatile use in the actuator market, necessitating the development of both high-performance and cost-effective piezoelectric materials capable of delivering higher forces and displacements. The use of textured Pb (lead)-based piezoelectric ceramics formed by so-called templated grain growth method has been identified as a promising strategy to address the performance and cost issue. This review article provides insights into recent advances in texturing Pb-based piezoelectric ceramics for improved performance in actuation applications. We discussed the relevant issues in detail focusing on current challenges and emerging trends in the textured piezoelectric ceramics for their reliability and performance in actuator applications. We discussed in detail focusing on current challenges and emerging trends of textured piezoelectric ceramics for their reliability and performance in actuator applications. In conclusion, the article provides an outlook on the future direction of textured piezoelectric ceramics in actuator applications, highlighting the potential for further success in this field.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.6 s.99
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• pp.660-666
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• 2005

Recently, the need for subminiature storage systems has increased with the diversification of portable devices. An actuator for small optical disk drives has to satisfy performance requirements such as higher access speed, lower power consumption, and smaller size. In this paper, we proposed the miniaturized rotary type VCM actuator that had an effective focusing mechanism and secured sufficient bandwidth for small form factor (SFF) optical disk drive (ODD). Initial model was designed by electromagnetic (EM) and structural analyses. Such a model was improved using design of experiments (DOE) procedure based on a Blu-ray disk (BD) 1x specifications.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.813-819
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• 2006

The state of the art for the design of swing ann actuators for optical disc drives is to obtain the high efficient dynamic characteristics, especially for the small size for the mobile information devices, It is affected by the need of consumers who wants the portable digital storage devices maintaining highly functional and removable characteristics of the optical disk drive (ODD). As a necessary consequence, the need of the small form factor (SFF) storage device has been considered as an important part in the information storage technology. In this paper. we suggest a new conceptual miniaturized swing arm type actuator that has high efficient dynamic characteristics as well as satisfies the sensitivity and the heat emission requirements for the SFF-ODD. It also uses a tracking electromagnetic (EM) circuit for a focusing motion. Due to the size constraint, the thermal problem of optical head arises; therefore, we design an efficiently heat emitted structure for the actuator.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.684-687
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• 2002

In optical disk drive(ODD), pickup actuator, which comprises a key part of an optical disk drive equipment. must be thin. compact, and high sensitive. Low tilt is also an important requirement for the actuator, since optical disks are to high density. This tilt occurs from around the axis parallel to the tangential and radial direction of the disk. The main reason of the moment is the coupling effect between focus driving system and tracking driving system. This paper analyzed tut quantity due to focusing and tracking force through coupled fields analysts with electromagnetic analysis and structural analysis.