• 대한기계학회논문집A
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• 제39권10호
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• pp.995-999
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• 2015

자기유도(inductive) 센서는 원리가 간단하고 경제적이어서 변위, 힘, 압력 등 다양한 물리량 측정에 사용된다. 본 논문에서는 고리 모양의 강판과 코일로 이루어진 간단한 구조의 자기유도 센서를 제안하였다. 센서의 인덕턴스를 자기회로 방법을 이용하여 추정하고 유한요소 해석을 통해 검증하였다. 고리의 고유 진동수를 Castigliano 정리와 등가 질량 방법을 이용하여 추정하고 실험 및 유한요소 해석을 통해 검증하였다. 기계적 진동에 영향을 주지 않도록 센서의 가진 주파수를 결정하였으며, 구동 및 신호처리 회로를 설계하여 센서를 제작하였다. 제작된 자기유도 센서를 유연관 내부의 유체 압력을 비침습적으로 측정하는데 활용하였다. 압력과 센서 출력 간의 관계를 이차식 형태로 표현하면 2% 이내의 정확도로 압력을 측정할 수 있어 압력 센서로서의 가능성을 확인하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제28권4호
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• pp.569-576
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• 2004

In this paper, passive telemetry capacitive humidity sensor system using a RLSE(Recursive Least Square Estimation) technique is proposed. To overcome the problem like power limits and complications that general passive telemetry sensor system including IC chip has, the principle of inductive coupling is applied to model the sensor system. Specially. by applying the forgetting factor we show that the accuracy of its estimation can be improved even in the case of time varying parameter and also the convergence time can be reduced.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.207-211
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• 2004

The performance of an inductive position sensor has approved by previous research papers. In this paper, magnetic circuit model of a ring-type multi-pole insuctive position sensor is described. The magnetic circuit model is required to design in ductive position sensor as well as draw a fault tolerance algorithm. Using the magnetic circuit theory, we derived the relationship between voltage applied and flux density in the normal air-gap. By idealizing the modulation/demodulation processes of signal processing circuit, sensor gain with respect to change of displacement is theoretically calculation using the magnetic circuit model, which validate the theoretical derivation.

• 한국정밀공학회지
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• 제21권4호
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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.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 추계학술대회
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• pp.379-384
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• 2003

Noise is a problem in many electronic circuits and active control system. Arising from spuriously coupled noise from other circuits, it corrupts the signal of interest and introduces an uncertainty into information it contains. In this paper, re have researched noise characteristics of the inductive displacement sensor which has been designed. n first present basic concept and characteristics of magnetic field-coupled noise in the sensor output signal. Then, n are present relation noise and sensor performances. Finally, we concentrate low noise design of a sensor driver and a signal detection circuit.

• 대한기계학회논문집A
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• 제32권3호
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• pp.232-239
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• 2008

The position sensors used in a magnetic bearing system are desirable to provide some degree of fault-tolerance as the rotor position is necessary for the feedback control to overcome the open-loop instability. In this paper, we propose an inductive position sensor that can cope with a partial fault in the sensor. The sensor has multiple poles which can be combined to sense the in-plane motion of the rotor. When a high-frequency voltage signal drives each pole of the sensor, the resulting current in the sensor coil contains information regarding the rotor position. The signal processing circuit of the sensor extracts this position information. In this paper, we used the magnetic circuit model of the sensor that shows the analytical relationship between the sensor output and the rotor motion. The multi-polar structure of the sensor makes it possible to introduce redundancy which can be exploited for fault-tolerant operation. The proposed sensor is applied to a magnetically levitated turbo-molecular vacuum pump. Experimental results validate the fault-tolerance algorithm.

• Journal of Magnetics
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• 제17권3호
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• pp.210-213
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• 2012

To detect the surface and the opposite side cracks on iron specimen under AC and DC magnetic fields, the planar inductive coil sensors were employed. When the induced signals were measured, the planar inductive coil sensor and the magnetic field source were lifted off about 2 mm from the top surface of the specimen. AC magnetic fields and DC magnetic fields were applied to the specimens by single straight Cu coil and NdFeB permanent magnet, respectively. The detected signals at crack positions were good coincidence with those of the simulation results.

• Journal of Welding and Joining
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• 제23권4호
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• pp.66-72
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• 2005

An electromagnetic inductive sensor consisted of one exciter and three separated (triple) detectors has been developed for both tracking the weld seam of a workpiece and controlling the sensor-to-workpiece distance (height) simultaneously. The left and right detectors are used to track the seam, while the fore and the other two detectors allow the sensor to determine the height and the gap width by being coupled their outputs together. A series of experiments with the proposed sensor located above a mild steel plate containing a weld seam of gap are carried out to examine the feasibility of the sensor. The results revealed that the proposed sensor could fairly well track the desired seam and also well control the height to be constant even when the gap width of the seam varied. The gap width can be also determined during the seam tracking by using the sensor outputs. As a consequence, these can provide the developed sensor with substantial improvement for industrial uses with respect to the previous electromagnetic sensors being used for the weld seam tracking.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 추계학술대회 논문집
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• pp.733-734
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• 2010

• 한국컴퓨터정보학회논문지
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• 제16권5호
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• pp.61-71
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• 2011

금속물체의 피로도를 측정하기 위하여 고속으로 진동시키면서 비접촉으로 정밀하게 변위를 측정하는 방법에 대한 연구가 많이 이루어지고 있다. 비접촉 고속 진동 검출센서들은 와류 센서나 레이저 센서들을 주로 사용하고있지만 매우 고가이다. 최근 저가의 유도성 센서를 고속 진동검출에 적용하려는 연구가 이루어지고 있으나 아직은 초보단계이다. 본 연구에서는 저가의 유도성 센서를 이용하여 비접촉으로 고속 진동을 검출하는 새로운 근접 센서모듈 설계방법을 제안하였다. 기존의 유도성 센서모듈들은 검파, 적분, 및 증폭과정을 통하여 변위를 검출하기 때문에 아날로그회로 특성상 잡음에 약하고 적분과정에서 변위 검출속도 저하의 요인이 된다. 제안된 방법은 AD변환기(Analog to Digital converter)를 사용하지 않고 진동 주파수신호를 직접 디지털 신호로 변환하는 새로운 방법으로 아날로그 잡음의 영향을 적게 받으며 고속으로 신호를 처리할 수 있는 장점이 있다. 성능 평가를 위하여 셰이커로 진동 주파수를 30Hz부터 1,100Hz 까지 일정간격으로 금속편을 진동시키면서 제안된 센서 모듈을 이용하여 비접촉으로 진동 신호를 검출하였다. 실험결과 비접촉 근접 거리 5mm 이내에서 진동 주파수 검출범위는 DC에서 1,100Hz까지 측정할 수 있었으며 진동 폭의 해상도는 $20{\mu}m$로 나타났다. 따라서 제안된 유도성 센서모듈은 정밀 비접촉 고속 진동검출 센서로서 충분한 성능을 가지고 있다고 평가된다.