• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.25-26
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• 2007

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.320-320
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• 2004

반도체용 노광장비나 검사장비, 초정밀 광학렌즈, 비구면 렌즈 가공 등의 핵심이 되는 것은 초정밀결정기술이다. 서브미크론의 정밀도를 갖는 장비는 한치의 오차도 허용치 야고 계획된 경로대로 정확하게 목표지점에 도달해야 초정밀 가공을 기대 할 수 있다 초정밀 공기정압 스테이지는 저마찰 특성과 높은 운동정밀도, 청정환경유지가 가능하여 반도체 노광장비에서 PDP 나 LCD검사장비, 초정밀가공 가공기 등 다양한 정밀장비에서 활용된다.(중략)

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.667-668
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• 2006

최근 반도체산업과 광산업 분야에서 고정도의 위치제어 및 고출력 구동이 가능한 초음파 리니어 모터에 대한 관심이 증가되고 있다. 저자는 공진시스템으로 지지하는 고출력 초음파 리니어 모터를 제안해왔다. 이 모터 시스템은 주목할만한 동작 안정성과 제어능력을 달성 하였지만 모터의 공진 주파수가 예압, 열등의 외부의 요인에 의해 변하게 될 때, 모터는 공진 시스템에 의한 지지 메커니즘이 고정된 공진 주파수만을 가지게 되어 안정적인 구동을 이루기 어렵게 되었다. 본 연구는 고강성 지지를 위해 한 진동자에 세 지지점을 가지는 새로운 모터를 설계 하여 시스템의 위치제어 능력에 대해 조사 하였다. 고강성을 띄는 세점 지지부는 모터를 확실히 지지 할 수 있지만, 진동 모드에 영향을 미치지 않는다. 20 mm의 지름을 가지는 모터를 이용하여 기계적 최대 출력은 75N, 무부하 최대속도 0.45 m/s를 달성하였다. PID 피드백 제어 시스템을 적용시켜 6 kg의 스테이지를 100 nm의 정도를 가지고 200 mm/s로 위치 제어를 달성하였다.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.981-982
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• 2007

반도체산업과 광산업 분야에서 고정도의 위치제어 및 고출력 구동이 가능한 초음파 리니어 모터 시스템의 개발을 목표로, 최대 출력 75N, 위치제어 정밀도 100nm의 고출력, 고정도 구동 시스템을 제안해 왔다. 본 연구는 nm order의 위치제어와 구동 안정성 향상을 위해 종래 시스템의 지지부 및 제어 시스템을 개선하였다. 개선된 PID 피드백 제어시스템을 구성하여, 6kg의 스테이지를 step 구동을 수행하여 위치 분해능 20nm, 속도 70mm/s로 왕복구동을 수행하여 20nm의 위치제어를 달성하였다.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.10
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• pp.997-1005
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• 2008

Linear motor stage is a useful device in precision engineering field because of its simple power transmission mechanism and accurate positioning. Even though linear motor stage shows fine positioning accuracy along travel axis, geometric dependent errors which relay on machining and assembling accuracy should be addressed to increase total positioning performances. In this paper, we suggests a cost effective yaw error compensation servo-system which is mounted on platform of the stage and nullify travel position dependent yaw error. This paper also provides a method of designing a sliding mode control which is robust to existing friction disturbance and model uncertainties. The reachability condition of slinding mode control for the yaw error compensating servo-system has been established. From some experimental results by using an experimental set-up, the sliding mode control showed its effective in disturbance rejection and its performance was superior to conventional linear controls.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.8 s.197
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• pp.89-96
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• 2007

In this paper, a new air bearing stage with magnetic preload and a linear motor has been developed for the small precision machine systems. The new air bearing stage is unique in the sense that permanent magnets attached bottom of the iron core of table are used not only for preloading air bearings in vertical direction but also for generating thrust force by current of the coil at base. The characteristics of air bearings using porous pads were analyzed with numerical method, and the magnetic circuit model was derived for linear motor for calculating required preload force and thrust force. A prototype of single axis miniature stage with size of $120(W){\times}120(L){\times}50(H)\;mm^3$ was designed and fabricated and examined its performances, vertical stiffness, load capacity, thrust force and positioning resolution.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.3
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• pp.111-119
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• 2006

The ultra-precision stage is demanded for some industrial fields such as semiconductor lithography, ultra-precision machining, and fabrication of nano structure. A new stage was developed for those applications in order to obtain nano meter resolution. This stage consists of symmetric double parallelogram mechanism using flexure hinges. The mechanical properties such as strength of the flexures and deformations along the applied force were analyzed using FEM. The stage is actuated by a piezoelectric actuator and its movement was measured by a ultra-precision linear encoder. In order to improve positioning performance, a PID controller was designed based on the identified second order transfer function. Experimental results showed that this stage could be positioned within below 5 nm resolution irrespective of hysteresis and creep by the controller.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.5 s.182
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• pp.85-92
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• 2006

Recently in the field of precision positioning device, the contact-free stages are gaining focuses with their outstanding performances by eliminating mechanical frictions. This paper presents the driving algorithm for contact-free linear stage based on switched reluctance principle. The proposed driving algorithm has a similar structure of that of switched reluctance motor but this study has its own originality in terms of reducing the normal farces and force ripple at the same time. The simulation and experiment are executed to verify the proposed algorithm.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.9-10
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• 2008

• Journal of the Korean Society for Precision Engineering
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• v.25 no.7
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• pp.39-46
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• 2008

High precision machining technology has become one of the important parts in the development of a precision machine. Such a machine requires high speed on a large workspace as well as high precision positioning. For machining systems having a long stroke with ultra precision, a dual-stage system including a global stage (coarse stage) and a micro stage (fine stage) is designed in this paper. Though linear motors have a long stroke and high precision feed drivers, they have some limitations for submicron positioning. Piezo-actuators with high precision also have severe disadvantage for the travel range, and the stroke is limited to a few microns. In the milling experiments, the positional accuracy has been readily achieved within 0.2 micron over the typical 20 mm stroke, and the path error over 2 micron was reduced within 0.2 micron. Therefore, this technique can be applied to develop high precision positioning and machining in the micro manufacturing and machining system.