• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.173-173
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• 2000

This paper discusses a observer based discrete-time controller design and presents a modified control structure for dual-stage hard disk drive systems using piezoelectric microactuator(MA). In plant modeling, dynamic coupling between VCM and MA is not considered. Each controller is organized independently and designed using pole placement. Simulation result shows that 4th-order controller achieves about 3kHz servo bandwidth and 0.22msec of 2% settling time.

• Journal of Institute of Convergence Technology
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• v.1 no.2
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• pp.16-24
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• 2011

The angular electrostatic microactuator using skewed electrode array (SEA) scheme was proposed. The moving and fixed electrodes are arranged to make the driving force perpendicular to the rotating moment of arm. By changing the electrode overlap length, the magnitude of electrostatic force and stable displacement will be changed. In order to optimize the design, electrostatic FE analysis were carried out and the empirical force model was established for SEA. Simulation was performed to make the comparison between conventional actuators and SEA. The proposed SEA generates actuating torque 2 times greater than a comb-drive and stable actuator displacement 40% greater than a parallel plate type actuator. The angular electrostatic microactuator using skewed SEA scheme was designed and fabricated using SoG process.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.911-916
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• 2003

Microactuator is frequently used in some optical or electrical applications such as light modulators and spatial scanner devices. When microactuator is implemented, it should be operated at accurate positions proportional to input voltage. Therefore in order to obtain rapid responses and reduced errors, a position control technique is used. In the paper, design procedure for the mems actuator and a typical PID controller is adapted to improve performance of microactuator as well. Also electrostatic force for the torsional microactuator is calculated via well-known Hornbeck's method.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1413-1418
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• 2003

In this study, the topology optimization is applied to the design of a piezoelectric microactuator satisfying the specific mean transduction ratio(MTR). The optimization problem is formulated to minimize the difference between the specified and the current mean transduction ratio. In order to analyze the response of the piezoelectric-structure coupled system, both the structural and the electric potential are considered in the finite element method. The optimization problem is resolved by using Sequential Linear Programming(SLP) and the results of test problems show that the design of a piezoelectric microactuator with specified mean transduction ratio can be obtained.

• Transactions of the Society of Information Storage Systems
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• v.10 no.1
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• pp.14-18
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• 2014

Adhesion between carbon nanotube (CNT) arrays is measured and characterized for number of different contact areas. The CNT arrays are directly grown on an electrostatic microactuator, and they make contact with each other during the growth process. The pull-out force is precisely applied by the microactuator while the contact status is identified by measuring electrical resistance between the CNT arrays. We have designed different contact areas of 1000, 6000, and 8500 ${\mu}m^2$ between the CNT arrays, and the corresponding adhesion increases from 0.9 to 3.7 ${\mu}N$ as the contact area increases.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.2
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• pp.206-213
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• 2004

In this study, the topology optimization is applied to the design of a piezoelectric microactuator satisfying the specific mean transduction ratio(MTR). The optimization problem is formulated to minimize the difference between the specified and the current mean transduction ratio. In order to analyze the response of the piezoelectric-structure coupled system, both the structural and the electric potential are considered in the finite element method. The optimization problem is resolved by using Sequential Linear Programming(SLP) and the results of test problems show that the design of a piezoelectric microactuator with the specified mean transduction ratio can be obtained.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.10 s.175
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• pp.174-185
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• 2005

This paper presents the design, fabrication, and testing results of a dual stage actuator system for a fine positioning of magnetic heads in magnetic disk drives. A novel rotary microactuator which is electrostatically driven and utilized as a secondary actuator was designed. The stator and rotor electrodes in the microactuator was revised to have the optimal shapes and hence produces much higher rotational torque compared with the conventional comb-shape electrodes. The microactuators were successfully fabricated using SoG(silicon on glass) processing technology, which is known as being cost-effective. The fabricated microactuator has the structural thickness of $45{\mu}m$ with the gap width of approximately $3{\mu}m$. The dynamic characteristic of microactuator/slider assembly was investigated, and its natural frequency and DC gain were measured to be 3.4kHz and 32nm/V, respectively. The microactuator/slider assembly was integrated into a HDD model V10 of Samsung Electronics Co. and a dual servo algorithm was tested to explore the tracking performance of dual stage actuator system where the LDV signals instead of magnetic head signals were used. Experimental results indicate that this system achieves the tracking accuracy of 30nm. This value corresponds to a track density of 85,000 track per inch(TPI), which is about 3 times greater than that of current hard disk drives.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.2
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• pp.72-77
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• 2008

In this study, we propose and develop PDMS-based modular actuators. The microactuator which looks like a small insect uses thermal expansion power of the PDMS (polydimethylsiloxane; $sylgar^{(R)}$ 184 silicone elastomer). The PDMS-based microactuator provides a large displacement due to a high thermal expansion coefficient (approximately 310ppm). The microacruator with 1mm length $350{\mu}m$ width is optimized by using a numerical analysis. The shape of the PDMS actuatoris variously designed. They are placed at several positions to find the optimal position that provides a high transformation ratio. The PDMS-based microactuators are fabricated using a conventional micromaching technique. The fabricated microactuator is heated using a hot-plate. The actuator displacement is measured as a function of temperature from $27^{\circ}C$ to $300^{\circ}C$. The experimental results are compared to the simulation result. When heating temperature up to $300^{\circ}C$ is applied to the PDMS actuator, each V-groove-shaped joint is actuated $30{\mu}$ mat $300^{\circ}C$. Anotherdesign of the microactuator has a maximum displacement of about 656mm.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.2
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• pp.153-160
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• 1999

Dual-stage servo system for super-high density HDD has the chances of being composed of the coarse actuator(VCM) for track-seeking control and the fine actuator(microactuator) for-following control in near future. This paper presents the concept design of dual-stage servo system and the track-following control using an electrostatic microactuator for super-high density HDD. The electrostatic microactuator is designed and fabricated by MEMS(micro-electro-mechanical system) process. Both the nonlinear plant(voltage/displacement-to-electrostatic force) and the linear plant(electrostatic force-to-displacement) of the microactuator are established. Inverse function of the nonlinear plant is employed for a feedforward nonlinear compensator design. And feedforward control effect of this compensator is shown by time-domain experiments. A track-following feedback controller is designed using the feedback nonlinear compensator which is derived from the feedforward nonlinear compensator. The track-following control experiment is done to show the control efficiency of the proposed control system. And, excellent track-following control performance(2.21kHz servo-bandwidth, 7.51dB gain margin, $50.98^{\circ}$phase margin) is achieved by the proposed control system.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1994-1996
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• 2002

This paper reports a novel high-speed fluid injection system employing a simple magnetic micoractuator. This magnetic microacutator consists of current carrying copper beams and permanent magnet under the beams. There were many efforts to magnetic microactuator realization using conducting coils [1-2]. Even though many of magnetic microactuators were successfully fabricated and tested, it is true that most them suffer complex fabrication processes and thus higher production costs than electrostatic counterparts. In this research, efforts were concentrated on the microactuator realization that has simple structure, low production cost, and mass production possibility.