• 한국정밀공학회지
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• 제23권1호
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• pp.129-135
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• 2006

In this study, a two-axis ultra-precision stage driven by piezoelectric elements is presented. The stage has a flexure-type parallel linear guide mechanism consisting of quad-symmetric simple parallel linear springs and quad-symmetric double compound linear springs. While the simple parallel linear springs guide the linear motion of a moving plate in the stage, the double compound linear springs follow the motion of the simple parallel linear spring as well as compensate the parasitic motions caused by the simple parallel linear springs. The linear springs are designed by rectangular beam type flexures that are deformed by bending deflection rather than axial extension, because the axial extension is smaller than the bending deflection at the same force. The designed guide mechanism is analyzed by finite element method(FEM). Then two-axis parallel linear stage is implemented by the linear guide mechanism combined with piezoelectric elements and capacitance type displacement sensors. It is shown that the manufactured ultra-precision stage achieves 3 nm of resolution in x- and y-axis within 30 ${\mu}m$ of operating range.

• 대한기계학회논문집A
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• 제25권11호
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• pp.1863-1872
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• 2001

In this Paper, we suggest the precision stage using a novel non-contact planar actuator that utilizes an interaction between an array type of air-core solenoids and permanent magnets. The former with axes arranged in the mutually orthogonal direction is fixed on the stator and the latter with the same polar direction is attached below the stage. The promising magnetic structure has little uncertainty such as hysteresis loss caused by ferromagnetic material, then it is simple to quantify the magnetic phenomenon. And all the magnetic forces are transmitted through narrow air-gap between the coil and the permanent magnet, therefore the structure can be highly compacted. Furthermore, the stage or plate can be perfectly isolated from the stator without any wire connection, leading to diminish the generating possibility of wear particles due to mechanical contact. Then. it is estimated that the proposed operating principle is very suitable for work requiring high accuracy and cleanness. or general-purpose nano stage. The main issues rebated to the plate driving are discussed here.

• 한국생산제조학회지
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• 제20권6호
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• pp.756-760
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• 2011

This paper proposed an alignment stage driven by piezo actuators for alignment process of a contact-type lithography. Among contact-type lithography processes, an UV-curable nanoimprint process is an unique process to be able to align patterns on upper and lower layers. An alignment stage of the UV-curable nanoimprint process requires nano-level resolution as well as high stiffness to overcome friction force due to contact moving. In this paper, the alignment stage consists of a compliant mechanism using flexure hinges, piezo actuators for high force generation, and capacitive sensors for high-resolution measurement. The compliant mechanism is implemented by four prismatic-prismatic compliant chains for two degree-of-freedom translations. The compliant mechanism is composed of flexure hinges with high stiffness, and it is directly actuated by the piezo actuators which increases the stiffness of the mechanism, also. The performance of the ultra-precision stage is demonstrated by experiments.

• 열처리공학회지
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• 제20권2호
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• pp.65-71
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• 2007

Microstructural changes and hardness variations in STS 304 steel have been investigated during the processes of carbide dispersion (CD) carburization; carburization, austenitization, subzero treatment and tempering. The carbon content of the surface layer increased up to maximum 4.0% after carburization, and the content was homogenized with the value of 2.3% to the $95{\mu}m$ from the surface after austenitization. The carbide appeared during CD carburization process was $Cr_7C_3$ type, which was composed network carbides along the austenite grain boundaries, square type carbides in the interior of the grain and fine nano-sized carbides. The fine nano-sized carbides precipitated at the austenitization stage and possibly subzero treatment stage were coarsened after tempering at $200^{\circ}C$, resulting the hardness decrease. The tempered steel without subzero treatment increased hardness with increasing time due to the continuous precipitation of fine carbides during tempering. The nano-sized carbide appeared square type morphology.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1542-1546
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• 2003

Nanotechnology is an important challenge, for which nanoparticle manipulation plays an important role in the assembly of nano elements. In this study, the dynamic equation of system plant is established by van der Waals force, friction, capillary forces etc. To push nanoparticles, strain gauges are used as sensors to actuate an X-Y stage in an atomic force microscopy system. A strategy of pushing nanoparticles is developed based on sliding mode control. Moreover, afuzzy controller is responsible for compensating tip-particle contact loss according to feedback signals of a laser-detector system. According to position control result, experimental results of gold nanoparticle manipulation are presented.

• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2006년도 추계학술대회 발표 논문집
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• pp.150-153
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• 2006

Micro vibration isolation, typically originated from ground, is always a prime concern for the nano-measurement instruments such as Atomic Force Microscopes. A four mount active vibration isolation system is proposed in this paper. Modeling and control of such a four mount system as analyzed. Combined active-passive isolation principle is used for vibration isolation by mounting the instrument on a passively damped isolation system made of Elastomer along with the active stage in parallel that consists of very soft actuation system, the Voice Coil Motor. The active stage works in combination with the passive stage for working as a very low frequency vibration attenuator.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 추계학술대회
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• pp.180-185
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• 2003

Performance test of servo control system that is used ultra-precision positioning system with single plane X-Y stage is performed by simulation with Matlab. Analyzed for previous control algorithm and adapted for modem control theory, dual servo algorithm is developed by minimum order observer, and stability priority on controller are secured. Through the simulation and experiments on ultra precision positioning, stability and priority on ultra-precision positioning system with single plane X-Y stage and control algorithm are secured by using Matlab with Simulink and ControlDesk made in dSPACE

• 한국공작기계학회논문집
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• 제18권2호
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• pp.228-233
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• 2009

An ultra-precision stage is used in many industrial areas such as precision machine tools or semiconductor apparatus. These stages used to be driven by piezoelectric actuators in order to obtain ultra precision positioning resolution. Piezoelectric actuator can be moved fast in nanometer resolution. However, it has relatively large non-linear characteristics like hysteresis and creep curve. Although several kinds of control techniques have been developed, controller design method is still complicated. In this paper fuzzy control rules are developed intuitively. In order to verify the performance a series of experiments were conducted and the results were compared with those of the PID controller case.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.309-312
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• 2002

Precision stage is essential device for semiconductor equipments, fiber optic assembly systems and micro machines. In this paper, we develop a piezo-electric inchworm type actuator for long stroke ultra precision linear stages, and implement a controller to interface with commercial motion controllers. It provides fast implementation of precise position control system substituting for rotary motor. In the future, using a laser interferometer as a position sensor, we plan to implement a nano meter precision stage.

• Fibers and Polymers
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• 제3권3호
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• pp.113-119
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• 2002

Nanoimprint lithography (NIL) is a nanofabrication method known to be a low cost method of fabricating nanoscale patterns as small as 6 m. This study is focused on understanding physical phenomena in the embossing of nano/micro scale structures with 100 nm minimum feature size. We present the effects of capillary force and width of stamp groove on flow behavior at the embossing stage through numerical experimentation. We also compare our numerical results with previous experimental results and discuss our results.