• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.649-654
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• 2003

This paper is focused on the research of the ultra precision linear motor by using piezo stack actuators. The development of linear motor which can be controlled nano or micro scale is necessary for the precision manufacturing. Self-moving-cell principle is used for the design of linear motor Self-moving-cell linear motor is consisted of three cell structures, and each cell has two shells and one piezo-stack actuator. Each cell can do clamping and moving by two shell structures. The shell structure deformation by piezo stack actuator can move the linear motor by losing the clamping between the shall and guideway. This paper presents the design, manufacturing and test of the motor.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.437-437
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• 2011

수열합성법에 의해 나노와이어를 합성하였다. 수직하고 장경비가 큰 나노와이어는 기존 Zinc nitrate와 HMTA를 각각 같은 몰 농도(0.015 mol/L)로 하고 이때 나노와이어의 밀도 조절 및 수직성장을 돕고 더 길게 자랄 수 있도록 polyethylenimine (PEI)를 포함하였으며, 이때 화학적으로 불안정한 seed layer 보호하기 위하여 증가 된 Ph 농도를 완화하기 위해 nitrate acid 를 포함한 반응 용액 내에서 생성되었다. 합성된 나노와이어는 지그재그 전극과 결합하여 리니어 모터를 통해 일정한 시간 주기로 일정한 압력을 가하여 얻은 압전특성을 관찰하고 분석하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.458-461
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• 1995

A new type of rotational motor which is developed has a resolution smaller than 10 $^{-4}$ radian and can be accessed for full rotational angles. The operation principle of the motor is based on inchworm motion of two belt driving mechanism. Flexure hinge mechanism, which is pertinent to symmetry construction of the motor, is designed to minimze the effort to frame and is analyzed by using finite element method. Depending on input signal amplitude, rotational angle by one cycle is varied form 0.2*10 $^{-4}$ rad to 9.76* $^{-4}$ rad. This shows that it has the capability of getting very small rotational angle by considering radius of rotor and amplitude of input signal.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.11
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• pp.2723-2731
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• 2000

Ultrasonic motors(USM) has been emerging as one type actuators, which possess many advantages such as high torque, low weight, compact size and no magnetic field generation. In spite of these features, there are several problems to be solved, which are temperature rise in case of long term operation, non -linearity, and hysteresis. Among these, hysteresis cause the most serious problem in force/torque control applications. To cope with this paper we propose a new PWM driving method which can be applied to force/torque control applications. To cope with this problem, in this paper we propose a new PWM driving method which can applied to force/torque control of USM. To verify the proposed method, an experimental setup was built and several experiments were performed.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.3
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• pp.152-157
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• 2001

An ultraprecision rotary motor is developed using inchworm motion of two belts actuated by elongation of piezoelectric elements. A symmetric lever mechanism with flexure hinges is designed to connect belts with piezoelectric elements. The lever mechanism is used not only to amplify the elongation of piezoelectric element but also to minimize the numbers of components and the effort for assembly. By experiment, the rotational angle by one cycle is varied from $0.2{\times}10-4 rad to 9.76{\times}10-4$ rad depending on input signal amplitude. Further, the motor has the capability of getting more precise rotational resolution by enlarging the radius of the rotor.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.18 no.2
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• pp.137-143
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• 2009

This paper presents the fabrication of inchworm motor for high precision actuator system of large displacement and high force. The inchworm motor consists of a extend actuator that provides displacement of tool guide and two clamping actuators which provide the holding force. In order to avoid the PZT fracture, design of pre-load housing was conducted by flexure hinge structure, because PZT actuator has low tensile and shear. To design the pre-load housing and optimize the clamping mechanism, the static and dynamic analysis were conducted by finite element method. From these results, a prototype of the inchworm motor was fabricated and dynamic characteristic with respect to the various frequency was tested. The maximum velocity of the inchworm motor was $41.1{\mu}m/s$ at 16Hz.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.1041-1044
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• 2002

Inchworm linear motor is one of the ultra precision position apparatuses and has many kinds of forms and structures according to the conditions of working space and range. In this paper, the Inchworm linear motor consists of three PZTs(Piezo-electric transducer), three columns ma two plates. finite element method was used to determine the type or hinges installed in column of inchworm linear motor DOE(Design of experiment) was used to determine the optimal design condition of a column by comparing the von-mises stresses according to the change of thickness of hinge, round of hinge, height of arm, angle of v-notch, round of v-notch and thickness of column. From the result, round of hinge, height of arm and thickness of hinge were determined a effective design parameters.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.3 s.96
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• pp.154-163
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• 1999

In this paper, an ultra precision positioning system has been developed using dual servo loop control. For positioning system having long distance with ultra precision , the combination of global stage and micro stage was required. A servo motor based ball screw is used as a global stage and the piezo actuator as a micro stage. For the improvement of positional precision, the digital Chebyshev filter is implemented in the developed to dual servo system. Therefore, the positional repeatability has been achieved within ${\pm}$ 10 mm, and this technique can be applied to develop precision semiconductor equipments such as lithography steppers and probers.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.295-295
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• 2007

기계적 에너지를 전기적 에너지로 변화하는 에너지 변환소자인 압전 세라믹스는 액츄에이터, 변압기, 초음파모터, 초음파 소자 및 각종 센서로 응용되고 있으며, 그 응용분야는 크게 증가하고 있다. 최근 이러한 에너지 변화 소자는 앞으로 도래하는 ubiquitous, 무선 모바일 시대의 휴대용 전자제품, robotics, 항공우주, 자동차, 의료, 건축, MEMS 분야 등의 대체 에너지원으로 응용하기 위한 연구가 진행되고 있다. 특히 인간의 동작 등과 같은 일상적인 동작으로 필요한 전력을 얻을 수 있고, 세라믹 소자를 이용하기 때문에 전자노이즈가 발생되지 않을 뿐 아니라 반영구적으로 사용할 수가 있어서, 기존 이차전지, 연료전지를 대체 또는 보완 할 수 있는 방안도 검토되고 있다. PZT계 세라믹스는 높은 유전상수와 압전특성으로 전자세라믹스분야에서 가장 널리 사용되어지고 있지만 $1200^{\circ}C$이상의 높은 소결온도 때문에 $1000^{\circ}C$ 부근에서 급격히 휘발되는 PbO로 인한 환경오염과 기본조성의 변화로 인한 압전 특성의 저하가 문제시되고 있다. 또한, 적층 세라믹스의 제작 시 구조적 특성상 내부 전극이 도포된 상태에서 동시 소결이 필요한데, 융점이 낮은 Ag전극 대신 값비싼 Pd나 Pt가 다량 함유된 Ag/Pd, Ag/Pt 전극이 사용되고 있어 경제적인 문제가 발생하게 된다. 따라서 순수 Ag 전극을 사용하거나, Ag의 비율이 높은 내부 전극을 사용하기 위해서는 $950^{\circ}C$ 이하에서 소결되는 압전 세라믹스를 개발 하는 것이 필요하다. 따라서 본 연구에서는 압전특성이 우수한 $(Pb_{1-x}Cd_x)\;[(Ni_{1/3}/Nb_{2/3})_{0.25}Zr_{0.35}Ti_{0.4}]O_3$계의 조성을 설계하여, 소결온도를 낮추기 위해서 2단계 하소법을 이용하였다. 분말을 ball milling을 통해 24시간 동안 혼합하였다. 혼합된 분말은 $800^{\circ}C$에서 2시간 동안 하소하였다. 하소한 분말을 72시간 동안 ball milling 하여 최종 분말을 얻었다. 최종 분말에 PVB를 첨가하여 ${\Phi}21$ disk 형태로 성형한 후, $800{\sim}950^{\circ}C$ 소결을 하였다. 최종 분말 및 소결된 시편을 XRD분석을 통하여 상을 확인하였고, SEM을 이용하여 미세조직을 관찰하였다. 전기적 특성을 확인하기 위하여 두께 1mm로 연마한 시편에 Ag 전극을 도포하여 열처리한 후, 분극 처리하였다. 압전특성은 $d_{33}$ 미터로 측정하였고, impedance analyzer를 이용하여 주파수 및 impedance 특성을 측정하였다. 그 결과 $900^{\circ}C$에서 우수한 압전 특성 및 전기적 특성을 확보 할 수 있었다.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.345-348
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• 1989

A small linear incremental device, which is called a microworm, is introduced, and this paper explains working principle, design considerations and theoritcal force analysis of the microworm. A fluid control microvalve and a piezoelectric motor as an application of the microworm are explored for feasibility.