• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 추계학술대회 논문집
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• pp.315-316
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• 2006

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 춘계학술대회 논문집
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• pp.603-606
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• 2000

This dissertation is concerned with ultra-precision profile measurement of aspheric surfaces using contact probing technique. A contact probe has been designed as a sensing device to obtain measuring resolutions in nanometer regime utilizing a leaf spring mechanism and a capacitive-type sensor. The contact probe is attached on the z-axis during measurement while aspheric objects are supported on an precision xy-stage whose lateral motions are monitored by a set of two orthogonal plane mirror type laser interferometers. Experimental results show that the contact probing technique developed in this investigation is capable of providing a repeatability of 50 nanometers with a $\pm$3$\sigma$ uncertainty of 300 nanometers. Thermal disturbance is found the most significant factor that should be precisely controlled for accurate measurement.

• 한국정밀공학회지
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• 제17권5호
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• pp.124-130
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• 2000

For measuring out the submicron order straightness, a precision measuring device is developed in this paper. The device is constructed with a hydrostatic feed table and a capacitive type sensor which is mounted to the feed table. Straightness is acquired as substracting the motion error of feed table from the measured profile with probe. Motion error of feed table is simultaneously compensated upto 0.120${\mu}{\textrm}{m}$ of linear motion error and 0.20arcsec of angular motion error using the active controlled capillary. Reversal method and strai호t-edge is used fur estimating the measuring accuracy and from the experimental result, it is verified that the device has the measuring accuracy 0.030m. Also, through the practical application on the measurement of ground surface, it is confirmed that the device is very effective to measure the submicron order straightness.

• Tribology and Lubricants
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• 제10권4호
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• pp.27-32
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• 1994

The capacitive type transducers measure the displacement of rotating shaft using the voltage difference which is formed between the sensor plates and rotor so that the measured signal is not affected by the magnetic field generated by the magnetic bearing. In this paper, the capacitive transducers are embedded inside of the magnetic bearing. In order to verify the support characteristics of the capacitance sensor-magnetic bearing system, we experimented and analyzed the magnetic bearing-rotating shaft system up to 12,000 rpm. The magnetic bearing system proposed in this paper, successfully supports the rotating shaft and we can remain the maximum displacement below $5 \mu m$ at 12,000 rpm.

• 산업기술연구
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• 제34권
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• pp.39-43
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• 2014

This paper represents a highly porous MWCNT film electrode with interconnected open pores and demonstrated the possibility of using an MWCNT network film as the top electrode for polyimide capacitive humidity sensors. Polyimide humidity sensors with MWCNT electrodes exhibited about 6 times faster response than equivalent Cr electrode sensors. This result may be due to their percolated pore structures, which make water molecules accessible to all polyimide surfaces. The much faster response times of MWCNT electrode sensors is attributed to the percolated pore network, which allows more water molecules to be accessible to polyimide surfaces.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 추계학술대회 논문집
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• pp.485-489
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• 2004

Cutting force is important to understand cutting process in milling. To measure cutting force, tool dynamometer is widely used but it is hard to apply in workshop condition. Cutting force measurement which doesn't affect cutting process is needed. Using relations between cutting force and spindle displacement, cutting force can be predicted. Cylindrical capacitive sensor was used to measure spindle displacement during cutting. And signals from tool dynamometer collected to compare with spindle displacement. The result shows spindle displacement has a linear relation with cutting force. Using this result, a simple method to predict cutting force could be applied at workshop condition.

• 한국지능시스템학회:학술대회논문집
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• 한국지능시스템학회 2008년도 춘계학술대회 학술발표회 논문집
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• pp.168-173
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• 2008

본 연구는 UKF Algorithm을 이용한 정전용량형 원격RF센서시스템을 개발하였다. 원격 RF센서 시스템이란 wireless, implantable 그리고 batterless을 만족하는 센서 시스템을 의미한다. 기존의 원격 RF센서 시스템은 보편적으로 집적회로 타입을 채택하지만, 그 구조의 복잡성과 전력소모의 제약을 받는다. 이러한 제약을 해결하기 위해 본 연구에서는 R, L 그리고 C만으로 구성되어있는 유도결합원리를 이용한 원격 RF센서 시스템을 제안하였다. 제안된 RF 센서 시스템은 압력 혹은 습도와 같은 환경의 변화를 정전용량 값으로 측정할 수 있으며 센서의 정전 용량 값을 측정하기 위해 비선형시스템의 파라메타추정에 적합한 Unscented Kalman Filter(UKF) 기법을 채택하였다. UKF 기법을 이용하기 위해 제안된 시스템은 페이저법을 사용하여 수학적으로 모델링되었다. 마지막으로, 제안된 UKF 알고리즘을 이용한 원력 RF센서시스템이 잡음환경에서도 정전용량값을 비교적 정확하게 추정가능함을 확인하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.133-134
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• 2006

A cylindrical capacitive displacement sensor (CCS) was developed and applied for monitoring end milling processes. Dynamic characteristics of a spindle-assembly were measured using the CCS and a designed magnetic exciter. The technique to extract the spindle displacement component caused only by cutting from the measured signals using the CCS was proposed in the paper. Using CCS signals and FRF (Frequency Response Function) derived from dynamics of the spindle tool system, dynamic cutting forces are estimated quantitatively.

• 한국컴퓨터정보학회논문지
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• 제20권9호
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• pp.47-53
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• 2015

In this paper, we propose a novel tangible interface system whose system does not use the expensive hardware is introduced. This proposed tangible interface is used on the table top capacitive multi touch-screen. The tangible interface apparatus which is called smart puck has sanguine arduino compatible board. The board has a Cds photo-sensing sensor and the EPP8266 WiFi module. The Cds sensor decodes the photometric PWM signals from the system and sends corresponding information to the system via TCP/IP. The system has a server called MT-Server to communicate with the smart pucks. The tangible interface shows reliable operation with fast response that is compatible to the expensive traditional devices in the market.

• 한국공작기계학회논문집
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• 제16권6호
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• pp.140-145
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• 2007

To improve productivity of a metal cutting process, it is required to monitor machining stability in real time. Since cutting environment is harsh against sensing conditions due to vibration, chip, and cutting fluid, etc., it is necessary to develop a robust and reliable sensing system for the practical application. In this work, a chatter monitoring system was developed and its effectiveness was proved. Spindle displacement caused by cutting was selected as a main monitoring parameter. A cylindrical capacitive displacement sensor was adopted. Chatter frequencies were identified through modal analysis. To quantify chatter vibrations, chatter correlation coefficient was introduced. The identification of the monitoring system showed a good agreement with the result of experiment.