• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1060-1065
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• 2003

This paper contributes to development of a new chip mounting head system for flip chip. Recently, the LDM(Linear DC Motor) has been widely used, because it has particular merits than the rotary type motors. In this paper, we proposed a macro/micro positioning system for force control of a chip mounting system. In the proposed macro/micro system, the macro actuator provide the system with a gross motion while the micro device yields fine tuned motion to reduce the harmful impact force that occurs between very small sized electronic parts and PCB surface. In order to prove the effectiveness of the proposed macro/micro chip mounting system, we compared the proposed chip mounting head with the conventional chip mounting head equipped with a macro actuator only. A series of experiments were executed under the mounting conditions of various access velocities and PCB stiffness. As a result of this study, a satisfactory voice coil actuator as the micro actuator has been developed, and its performance meet well the specifications desired for the design of the chip mounting head system and show good correspondence between theoretical analysis and experimental results.

• 한국정밀공학회지
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• 제19권12호
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• pp.163-170
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• 2002

The quality of a precision product, in general, relies on the accuracy and precision of its manufacturing and inspection process. In many cases, the level of precision in the manufacturing and inspection system is also dependent on the positioning capability of tool with respect to the work piece in the process. Recently the positioning accuracy level has reached to the level of submicron and long range of motion is required. For example, for 1 GDARM lithography, 20nm accuracy and 300mm stroke needs. This paper refers to the lithography stage especially to fine stage. In this study, for long stroke and high accuracy, the dual servo system is proposed. For the coarse actuator, LDM (Linear DC Motor) is used and for fine one VCM is used. In this study, we propose the new structure of VCM for the fine actuator. It is 3 axis precision positioning stage for an aligner system. After we perform the optimal design of the stage to obtain the maximum force, which is related to the acceleration of the stage to accomplish throughput of product. And we controlled this fine stage with TDC. So we obtained 50nm resolution. So later more works will be done to obtain better accuracy.

• 제어로봇시스템학회논문지
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• 제2권3호
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• pp.181-187
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• 1996

A frictionless positioning device using cone-shaped active magnetic bearings(AMBs) is developed, which is driven by a brushless DC motor equipped with resolver. The cone-shaped AMB feature that the structure is simple and yet the five d.o.f. rotor motion is controlled by four magnet pairs. A linearized dynamic model, which accounts for the relationship between input voltage and output current in the cone-shaped magnet, is developed and the azimuth motion of the frictionless positioning device is modeled as the second order system. The feedback controller is designed by using linear quadratic regulator with integral action optimal control law so that the cone-shaped AMB system is stabilized and the frictionless positioning device gets the zero steady state. It is observed that the linearized dynamic model is adequate and the frictionless positioning device can achieve the tracking accuracy within the sensor resolution.

• 조명전기설비학회논문지
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• 제16권4호
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• pp.64-72
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• 2002

산업의 발달에 따라 선형 직류 모터의 용용이 확대되고 있다. 본 연구에서는 가동차석형 양측식 다분할 여자 LDM의 해석을 연구대상으로 하였다. 본 LDM의 구조에서 가동자는 큰 추력을 얻도록 영구지석 6개를 사용하였으며, 고정자는 철심의 포화를 억제 하도록 다 분할형 권선을 성층하였다. 또한 양측 여자 권선은 지그재그형으로 성 층하여 추력의 리플을 억제하고, 정추력을 발생할 수 있도록 설계하였다. 여기에 다 분할시 영구자석대 권선 폭의 비가 중요하므로 본 연구에서는 똑비를 1 : 1, 1 : 0.84 및 1 : 0.5의 3개 부분으로 나누어 해석하였다. 해석 방법은 복잡한 수치해석의 유한요소법 보다는 퍼미언스 및 자기저항 법을 이용하여 파라며터를 계산하였다. 제작된 실험장 치를 통하여 추력을 측정한 결과는 전 변위에 대해서 정추력이 발생함을 알 수 있었다.

• 드라이브 ㆍ 컨트롤
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• 제13권3호
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• pp.24-31
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• 2016

The performance characteristics of a dynamic control system are evaluated according to the transient and steady-state responses. The transient performance is the controllability of the output for the tracking of the reference or the ability to reduce or reject the effects of unwanted disturbances; alternatively, the steady-state performance is represented by the magnitude of the control error at the steady state. As the effects of the two performances on each other are reciprocal, a controller design that shows a zero steady-state error for the ramp input is uncommon because of the challenge regarding the achievement of an acceptable transient response. This paper proposes a PI+double-integral controller for the elimination of the steady-state error for the ramp input while a sound transient performance is maintained. The control-gain design procedure is described by the second-order response for the step input and the response of the error dynamics for the ramp input. The PI+double-integral controller is designed for the first-order transfer function that is derived from a system identification with the open-loop experiment data of the dc-motor. The simple structure of the proposed controller enables the adoption of a low-end microcontroller for the implementation of a real-time control. The experiment results show that the control performance is as effective as that of the simulation analysis for the operating point of linear system; furthermore, the PI+double-integral controller can be conveniently applied to the control system, which is desirable for the improvement of the steady-state error.

• 대한기계학회논문집A
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• 제33권7호
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• pp.629-636
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• 2009

Mechanical stimulation is known to play a vital role on the differentiation of mesenchymal stem cells (MSCs) to pre-osteoblasts. In this research, we developed a tensile cell stimulator, composed of a DC motor-driven actuator and LVDT sensor for measuring linear displacement, to study the effects of tensile stress on osteogenic differentiation of MSCs. First, we demonstrated the reliability of this device by showing the uniform strain field in the silicon substrate. Secondly, we investigated the effects of tensile stretching on osteogenic differentiation. We imposed a pre-set cyclic strain at a fixed frequency on cell monolayer cultured on a flexible silicon substrate while varying its amplitude and duration. 60 min of resting period was allowed between 30 min of cyclic stretching and this cycle is repeated up to 7 days. Under the combined stimulation with osteogenic media and mechanical stretching, the osteogenic markers such as alkaline phosphatase (ALP), osterix, and osteopontin began to get expressed as early as 4 days of stimulation, which is much shorter than what is typically required for osteogenic media induced differentiation. Moreover, different markers were induced at different magnitudes of the applied strains. Lastly, for the case of ALP, we observed the antagonistic effects of osteogenic media when combined with mechanical stretching.

• 한국정보전자통신기술학회논문지
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• 제16권6호
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• pp.400-405
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• 2023

현재 도립진자는 많은 분야에서 연구 중이며 미사일, 로켓, 등의 자세 제어와 2족 보행 로봇 등에 응용되고 있다. 본 연구에서는 256펄스의 로터리 엔코더와 DC 모터를 이용한 회전형 도립진자(Rotary Inverted Pendulum)를 구성하여 회전형 역 진자의 수직 자세 제어를 연구하였다. 비선형 시스템의 경우 복잡한 알고리즘과 제어기가 필요하지만 고전적이며 비교적 간단한 PID(Proportional Integral Derivation)알고리즘을 이용한 제어 방법을 회전형 도립진자 시스템에 적용하였으며 간단하지만 원하는 성능을 높이는 방안을 연구하였다. 본 연구에서 사용된 회전형 도립진자 시스템은 비선형적이고 불안정한 시스템으로 선형화된 모델링에서 마이크로칩 사의 dsPIC30F4013 임베디드 프로세서를 이용한 PID 제어기를 설계 및 구현하였다. 보통 PID 제어기는 하나 혹은 두 가지 이상을 조합하여 설계하며 우수한 제어 성능에 비해 구조가 간단하며 제어 이득 조정이 다른 제어기들에 비해 비교적 쉽다는 장점이 있다. 본 연구에서는 시스템의 물리적 구조를 수학적 방법으로 분석하고 모델링을 통한 회전형 도립진자의 수직 균형을 위한 제어를 실현하였다. 또한 회전형 역 진자를 이용하여 PID 제어기로 제어가 가능한지 시뮬레이션과 실험을 통하여 그 타당성을 검증하였다.