• 대한기계학회논문집A
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• 제32권3호
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• pp.274-279
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• 2008

Roll to roll (R2R) manufacturing process, also known as 'web processing', has been tried for producing electronic devices on a flexible plastic or metal foil. To increase the performance and productivity the R2R process, effective control and on-line supervision for web quality becomes very important. Wrinkle is one of the defects, which is incurred due to compressive stresses. A system for on-line measurement of wrinkle is developed using area scan camera and machine vision laser. The 2D image, obtained by area scan camera, is produced by Gaussian regression method to characterize the wrinkle on a transparent web. The experiment proves that 0.3mm wrinkle height can be measured successfully with 74fps.

• 반도체디스플레이기술학회지
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• 제9권2호
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• pp.103-109
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• 2010

An ink transfer is modeled and experimentally verified using roll-to-roll electric direct gravure printing process. The ink transfer model based on the physical mechanism for the maximum ink transfer rate is proposed, and experimented by the electric printing machine in FDRC for the relations of the maximum ink transfer rates to the printing pressure, the operating speed, the operating tension, the surface roughness of substrates, and the contact angle between substrate and silver ink. The free ink split coefficient and immobilized ink under the maximum ink transfer rate are calculated by the physical parameter in a printing process and contact angle between substrates and ink. Numerical simulations and experimental studies were carried out to verify performances of the proposed ink transfer model. Results showed that the proposed ink transfer model was effective for the prediction of the amount of transferred ink to the substrate in a direct gravure printing systems.

• 대한기계학회논문집A
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• 제36권12호
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• pp.1563-1568
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• 2012

인쇄전자는 RFID 나 유연 디스플레이 등의 전자회로나 소자를 인쇄방식으로 제작하는 공정이다. 특히 롤투롤과 같은 웹 이송방식 프린팅은 얇은 필름형태의 웹(Web)에 그라비아 인쇄나 고속 잉크젯과 같은 방법으로 이송중인 웹 상에 회로를 형성하는 공법이다. 이 공정은 생산단가가 저렴하고 고속생산이 가능하다는 이점이 있다. 다층구조를 가지는 회로나 디바이스를 생산할 때, 층과 층을 얼마나 정확하게 중첩시켜 인쇄하는가 하는 것은 인쇄된 전자회로의 집적도와 성능을 결정짓는 중요한 요소이다. 인쇄전자공법을 상용화하기 위해서 높은 중첩정밀도 구현이 선행되어야 한다. 본 연구에서는 롤투롤 인쇄방식에서 중첩정밀도의 향상을 위한 위치측정 시스템을 제안하고 신뢰성을 확인하였다. 또한 웹이 변형되었을 때의 측정 강인성도 실험적으로 확인하였다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.605-608
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• 2008

The preparation and characteristics of flexible indium tin oxide electrodes grown on polyethylene terephthalate (PET) substrates using a specially designed roll-to-roll sputtering system for use in flexible optoelectronics In spite of low a PET substrate temperature, we can obtain the flexible electrode with a sheet resistance of 47.4 ohm/square and an average optical transmittance of 83.46 % in the green region of 500~550 nm wavelength. Both x-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) analysis results showed that all flexible ITO electrodes grown on the PET substrate were an amorphous structure with a very smooth and featureless surface, regardless of the Ar/$O_2$ flow ratio due to the low substrate temperature, which is maintained by a cooling drum. In addition, the flexible ITO electrode grown on the Ar ion beam treated PET substrates showed more stable mechanical properties than the flexible ITO electrode grown on the wet cleaned PET substrate, due to an increased adhesion between the flexible ITO and the PET substrates.

• 한국항해항만학회지
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• 제33권5호
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• pp.323-330
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• 2009

병렬기구를 이용하여 항만공사를 위한 수중로봇을 개발하였다. 수중으로 큰 피복석을 옮기기 위해 수중로봇은 크레인에 의해 권양된다. 수중로봇의 요오와 피치운동은 유압 실린더에 의해 제어되지만 롤 운동은 제어되지 않는다. 롤 운동을 위해 로봇 양쪽에 프로펠러가 장착되어 제어된다. 본 논문은 수중로봇의 롤 운동제어에 관한 것이다. 롤 운동 각도를 측정하기 위해 자이로 센서가 사용되었다. 로봇의 롤 운동을 2차 비선형 시스템으로 나타내고 반복 리스트 스퀘어 방법과 적응인식 방법으로 동적 모델을 찾았다. 동적 모델로 외란을 보상하기 위한 제어입력을 계산하고 PD 제어, 반복 리스트 스퀘어 모델 베이스 제어, 적응 모델 베이스 제어를 롤 운동제어에 적용했다. 수중로봇의 시스템을 설명하고 제안한 제어기의 시뮬레이션과 실험결과를 보인다.

• Journal of Biosystems Engineering
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• 제21권2호
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• pp.182-190
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• 1996

A macerating technique which can apply to the mechanical production system of the agricultural by-product was developed to increase the utilization of agricultural waste and solve the shortage problem in the forage supply for the livestock production. The macerating method is to shred the agricultural by-product by the two rolls which rotate at different speeds each other. The testing macerator was built and the optimum operating conditions are suggested. Results of this research are as follows: 1. The increase of the base roll speed and speed ratio between two rolls shows the better shredding index but decrease the drying rate. The optimum conditions of the base roll speed and the speed ratio between two rolls for the rice straw are 1200 rpm and 1.7-2.0 respectively. 2. The macerated alfalfa was dried to the 15%(w.b.) within 3 hrs in a field at speed ratio of rolls, 2:1 and base roll speed, 1800rpm. 3. The milled surface and straight knurled surface for the macerating roll have same effect on the drying rate of material. Both rolls have self-cleaning functions during operation.

• 한국공작기계학회논문집
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• 제13권4호
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• pp.44-55
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• 2004

In order to meet the requirement for higher thickness accuracy in tandem cold rolling processes, it is strongly necessary to have good performance in control units. To meet this requirement, this paper suggested an output regulating control system with a roll-eccentricity estimator for each rolling stand of tandem cold mills. Considering entry thickness variation and roll eccentricity simultaneously as the major disturbances, a synthesis of multivariable control systems was presented based on H$\infty$ control theory, which could reflect the knowledge of input direction and spectrum of disturbance signals on design. Then, to effectively reject roll eccentricity, a weight function having some poles on the imaginary axis was introduced. This lead to a non-standard H$\infty$ control problem, and the design procedures for solving this problem were analytically presented. The effectiveness of the proposed control method was evaluated through computer simulations and compared to that of the conventional linear quardratic control and feedforward control methods for roll eccentricity.

• 한국생산제조학회지
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• 제26권3호
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• pp.306-312
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• 2017

Press rolls are constantly exposed to physical and heat stresses on their surface and are prone to crack, bruise, and spall if the accumulated stress goes beyond the critical point. Such surface phenomenon can cause them to lose their functionality and eventually lead to a halted production line. Eddy current testing can be considered a useful method to investigate the surface of the roll. The method involves the application of a high intensity magnetic field onto the surface of the roll, and thereby finding any early stage of possible defects. When the method was applied for roll inspection, the cross section of the sensor was regulated as per the overall testing speed. A smaller cross sectional area implied a better resolution but a longer testing time. In this paper, a convenient method to increase both overall system resolution and inspection speed of eddy current roll inspection is suggested by using a devised array sensor structure.

• Transactions on Electrical and Electronic Materials
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• 제17권3호
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• pp.178-181
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• 2016

In this study a coating experiment was performed to fabricate blue light cut films, which represent a 390~430 nm cut off rate of more than 40% and a transmittance rate of more than 90%, using a roll-to-roll nano micro coating system. The study also analyzed the characteristics of the blue light cut films. Thus, the hardness, which is more than 3H, is ensured through fabricating films using a Sol-Gel process that will determine the proper hardness level. Also, the experiment shows excellent results by cutting blue light through a mixing blue light powder.

• 제어로봇시스템학회논문지
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• 제20권8호
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• pp.828-834
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• 2014

This paper presents a comparison among three types of approaches to an ARC (Active Roll Control) with an AARB(Active Anti-Roll Bar) for a vehicle system. Lateral acceleration and road profile are considered as disturbance. The ARC is designed with an LQ SOF (Linear Quadratic Static Output Feedback) control, $H_{\infty}$ control and SMC (Sliding Mode Control). These approaches are compared in terms of rollover prevention and ride comfort. For comparison, Bode plot analysis based on linear model and frequency response analysis based on CarSim simulation are performed.