• Journal of Sensor Science and Technology
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• v.2 no.1
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• pp.11-17
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• 1993

We have constructed an acceleration sensor which is based on the maximum magnetic induction changes of amorphous wire as a measurand. The frequency bandwith of the constructed sensor depends on the mass of a sensing element. For $Co_{72.5}Si_{12.5}B_{15}$ amorphous wire, the bandwith is DC-700 Hz for $1{\times}10^{-3}kg$ sensing element and DC-200 Hz for $5{\times}10^{-3}kg$. The linearity of the acceleration sensor was less than 1% within the acceleration of 5 g.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2008.04a
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• pp.205-208
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• 2008

This paper propose a advanced technique for exciting and receiving the guided torsional wave to detect flaws in pipe systems. There are some difficulties in selecting and exciting of modes by using the nickel strip attached on pipe systems, such as qualification of residual magnetic field and multi-exciting of the unwanted modes etc. In order to there difficulties we propose the new sensor, so called Crossed-coils sensor. We will prove that it is possible to select the modes to be excited and to find a optimal excitation condition for torsional mode by using the proposed sensor.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.6
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• pp.856-862
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• 2008

This paper propose a advanced technique for exciting and receiving the guided torsional wave to detect flaws in pipe systems. There are some difficulties in selecting and exciting of modes by using the nickel strip attached on pipe systems, such as qualification of residual magnetic field and multi-exciting of the unwanted modes etc. In order to there difficulties we propose the new sensor, so called Crossed-coils sensor. We will prove that it is possible to select the modes to be excited and to find a optimal excitation condition for torsional mode by using the proposed sensor.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.5
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• pp.699-705
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• 2009

This paper is represented to research of driving control for the forklift AGV. The related works that were studied about AGV as heavy equipment used two methods which are magnet-gyro and wire guidance for localization. However, they have weaknesses that are high cost, difficult maintenance according to change of environment. In this paper, we develop localization system through sensor fusion with laser navigation system and encoder, gyro for robustness. Also we design driving controller using fuzzy and proportional control. It considers distance and angle difference between forklift AGV and pallet for engaging work. To analyze performance of the proposed control system, we experiment in same working condition over 10 times. In the results, the average error was presented with 54.16mm between simulation of control navigation and real control navigation. Consequently, experimental result shows that the performance of proposed control system is effective.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.267-270
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• 2002

The accuracy and the dynamic bandwidth are the two most important indices that an inductive position sensor is evaluated with. Eddy currents and magnetic hysteresis affect both of these performance indices. As the modulation frequency of the sensor increases to improve the dynamic bandwidth, the effects of eddy currents and hysteresis also increases, which results in the loss of accuracy. In this paper, a magnetic circuit model of the differential inductive sensor is developed. This model includes the effects of hysteresis and eddy currents. Experimental results confirm the validity of the model. The model predicts that the eddy current effects are not significant below the modulation frequency of 50kHz, as long as the lamination thickness is adequate.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.10a
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• pp.250-254
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• 2001

The resolution of analog sensor is determined by its sensitivity and amplitude of noise. This paper presents modeling of inductive gap sensor base on equivalent magnetic circuit and analysis of sensitivity. We can simulate static characteristic of inductive gap sensor using this model. Computer simulation show that sensor's sensitivity is affected by magnetic flux's leakage and fringing, and that they are affected by shape of sensor probe. Base on this, we designed shape of inductive position sensor probe.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.4
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• pp.72-78
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• 2004

In this paper, a development of an inductive position sensor is described. The sensor is similar to a radial magnetic bearing in that the sensor stator is shaped like a heteropolar magnetic bearing and is driven by a switching amplifier. A demodulation filter extracts the gap information from the switching current ripples. A prototype sensor exhibits the resolution of $0.43\mum$ and the dynamic bandwidth of about 800Hz. The dynamic performance can be improved by increasing the switching frequency. However, the eddy current effects become noticeable at high switching frequency, thus limiting the improvement of the bandwidth.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.249-252
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• 1997

The resolution of analog sensor is determined by its sensitivity and amplitude of noise. This paper presents modeling of inductive gap sensor base on equivalent magnetic circuit and analysis of sensitivity. The model of inductive gap sensor is verified by the experimental results. Then we can simulate static characteristic of inductive gap sensor using this model. Computer simulation show that sensor's sensitivity and linearity are affected by magnetic flux's leakage and fringing, and that they are affected by shape of sensor probe.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.596-599
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• 2000

벡터 제어이론은 교류전동기의 토오크와 자속을 독립적으로 제어할 수 있는 특징이 있으므로 토오크 제어를 주로 하는 견인용 전동기의 제어에 적용하기 위한 연구가 활발히 수행되어 왔다 그러나 선형 유도전동기 구동에는 아직 널리 사용되지 않은 실정이다 벡터 제어이론은 일반적으로 회전자자속 기준제어(Rotor flux oriented control)을 의미하며 이를 구현하기 위한 방법은 자속을 직접 측정 혹은 연산하는 직접제어 방식과 속도를 측정하여 슬립주파수 명령을 제어하는 간접방식으로 분류된다. 최근에는 기존의 회전자자속 기준방식뿐만 아니라 고정자자속(Stator flux oriented) 공극자속(Air gap flux oriented) 기준 방식등이 제안되고 있다. 본연구에서는 자기부상열차의 추진용 선형 유도 전동기의 추진에 가장 적합하다고 생각되는 고정자자속 기준벡터제어 방식과 이를 구현하기 위한 고정자 자속을 추정하는 방법에 대하여 설명한다. 또한 속도제어를 위한 속도 추정방식도 안내코일 등 부장치 없이 전동기 파라미터로 추정할 수 있는 기법에 대하여 논한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.997-999
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• 2008

In this paper, viologen derivative is used as charge transfer material to develop sensors for detecting the organic pollutants which are the main reason of harbor pollution. We fabricated self-assembled monolayers of viologen derivative on gold electrode of QCM and investigated an electrochemical behavior property. We also determined electrochemical sensing property about environmental pollution materials such as bezene, phosphate and surfactant through quantitative and qualitative analysis of charge transfer using intrinsic property of viologen derivative by temperature and concentration change. From the achieved results, we can apply and develope the detecting sensors for harbor pollutants.