• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.169-174
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• 2006

The outstanding mechanical property of optical fiber and the merits of acoustic emission sensing technique are unified for novel sensor system. The generated ultrasonic wave from piezoelectric generator are propagated along the optical fiber and also sensed. The propagated wave can be influence by external pressure on the optical fiber or environmental circumstance. The optical fiber sensor using ultrasonic wave has advantages compare with existing sensor system. In this study, the sensitivity of the optical fiber sensor is experimentally investigated. As the applications of the optical fiber sensor system using piezoelectric ultrasonic waves, the point load on the optical fiber is measured and the monitoring system for the void fraction of two phase flows is developed. The experimental results show the linear relationship between sensed voltage and void fraction.

• 대한기계학회논문집A
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• 제30권4호
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• pp.364-372
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• 2006

In this paper, we present a finger tip tactile sensor which can detect contact normal force as well as slip. The sensor is made up of two different materials, such as polyvinylidene fluoride (PVDF) known as piezoelectric polymer, and pressure variable resistor ink. In order to detect slip on the surface of the object, two PVDF strips are arranged along the normal direction in the robot finger tip and the thumb tip. The surface electrode of the PVDF strip is fabricated using silk-screening technique with silver paste. Also a thin flexible force sensor is fabricated in the form of a matrix using pressure variable resistor ink in order to sense the static force. The developed tactile sensor is physically flexible and it can be deformed three-dimensionally to any shape so that it can be placed on anywhere on the curved surface. In addition, a tactile sensing system is developed, which includes miniaturized charge amplifier to amplify the small signal from the sensor, and the fast signal processing unit. The sensor system is evaluated experimentally and its effectiveness is validated.

• 전기학회논문지P
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• 제55권1호
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• pp.31-34
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• 2006

A infrared rays sensor or ultrasonic sensor can detect the object at the narrow area, however a pressure sensor can detect man and animal at the wide area. It is necessary to manufacture the sensor by using Pb-free ceramics in the respect of environmental protection. Piezoelectric properties of ceramics added 0.2wt% $La_2O_3\;into\;0.96Bi_{0.5}(Na_{0.84}K_{0.16})_{0.5}+0.04SrTiO_3$ were 0.4 of kp, $31{\times}$10^{-3}Vm/N\;of\;g_{33}$. The output voltage of the pressure sensor is 0.48 V at 20 in$H_2O$. The output voltage of the pressure sensor with driving circuit is 9.8 V, 37 ms width.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 추계학술대회논문집; 한국과학기술회관; 6 Nov. 1997
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• pp.445-450
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• 1997

Optimal design of a piezoelectric smart structure is studied for cabin noise control. A cubic shaped acoustic cavity with a flat plate which covers one side is taken as the problem. The sensor signal is returned to the actuator through a negative gain. The acoustic cavity is modeled using the modal approach which represents the pressure fields in the cavity as a sum of mode shapes of the cavity with unknown coefficients. By using orthogonality of the mode shapes of the cavity, finite element equation for the structure with the influence of the acoustic cavity is derived. The objective function is the average pressure at a certain region, so-called silent zone, in the cavity and the design variables are the locations and sizes of the piezoelectric actuator and sensor. The optimal design is performed at several frequencies and the results show a remarkable noise reduction.

• 한국음향학회지
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• 제34권2호
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• pp.108-116
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• 2015

수중 음향 벡터센서는 음압 뿐 아니라 음파의 진행 방향에 관한 정보를 측정할 수 있는 센서이다. 본 논문에서는 미세 외팔보를 이용한 수중 음향 벡터 센서를 구현하기 위해 음향학적 이론을 바탕으로 음향과 기계 구조물의 상호작용을 이론적으로 정립하고자 하였다. 감응 방식으로 압전 효과를 이용한 두 가지 유니모프(unimorph)형태의 모델을 제시하였으며, 제시된 모델에 대하여 압전 미세 외팔보의 거동을 집중 질량 모델을 통해 음파가 임의의 주파수와 각도를 가지고 미세 외팔보로 입사할 때 나오는 신호의 크기를 구할 수 있는 전달함수를 유도하였다. 또한 이를 바탕으로 매우 얇고 유연한 구조물로 미세 외팔보를 설계하면 매질의 입자 속도에 관한 정보를 직접적으로 측정 가능한 센서로 활용할 수 있다는 것을 확인하였다.

• 한국ITS학회 논문지
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• 제12권2호
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• pp.45-51
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• 2013

본 논문에서 호흡 기반의 운전자 졸음 감지 센서 시스템에 대해 언급하였다. 센서 시스템은 운전자의 복부 부분 안전벨트에 장착된 PZT 압력센서와 개인용 컴퓨터로 구성됐다. PZT 압력센서는 호흡 시 운전자 복부의 움직임에 의해 압력센서에 가해지는 압력의 변화를 측정하기 위해 사용되었고 운전자의 졸음을 감지하기 위한 신호처리는 Labview를 사용하여 개발됐다. 30세 남자 운전자를 상대로 운전자 졸음 감지 관련 실험들이 수행되어 졌다. 운전자가 각성상태일때 호흡의 크기는 졸음상태일 때보다 컸으며 반대로 호흡 주파수는 낮았다. 이런 실험을 바탕으로 제작된 졸음 감지 센서 시스템은 운전자의 졸음을 성공적으로 실시간 감지할 수 있었다.

• 한국해양공학회지
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• 제23권6호
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• pp.17-22
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• 2009

This study presents an investigation of the characteristics of piezoelectric sensors whose main utilization is to measure impact pressure. The piezoelectric sensors were tested from several points of view. Their characteristics were investigated for repeatability, the effect of the diameter, temperature effect, water purity, flush mounting, and AC and DC coupling. Out of these, it was revealed that the temperature effect is very significant. The characteristics of the AC and DC coupling are also very important in understanding the time history of the impact pressure.

• 한국산업정보학회논문지
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• 제14권5호
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• pp.149-154
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• 2009

사람들의 평균 수명이 늘어남으로써 건강에 대한 관심도가 매우 높아지고 있다. 그에 따라 사람들은 자신의 몸 상태를 체크하며 주기적으로 자신의 건강상태를 확인하기 위해 정기검진을 받는다. 그러나 평소 자신의 맥박이나 혈압의 체크를 통하여 건강관리 및 질병예방이 가능하다. 따라서 본 논문에서는 간편하게 얻을 수 있으면서도 기본적이고 유용한 정보를 많이 가지고 있는 맥박신호를 혈액량에 따라 투과율의 변화를 측정할 수 있는 광센서를 이용한 방법과 압전 센서를 사용하여 손목의 요골동맥의 압력을 측정하여 맥박을 측정할 수 있는 휴대용 맥박측정 시스템을 구현하였으며 두 방법으로 제작된 시스템을 비교연구 하였다.

• 센서학회지
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• 제8권3호
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• pp.211-218
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• 1999

This paper describes the application of a coupled finite element-boundary element method (FE-BEM) to obtain the steady-state response of a piezoelectric transducer. The particular structure considered is a PZT4 disc-typed projector. The projector is three-dimensionally simulated to transduce applied electric charge on axial surfaces of the piezoelectric disc to acoustic pressure in air or in water. The directivity pattern of the acoustic field formed from the projected sound pressure is also simulated. And the displacement of the disc caused by the externally applied electric charge is shown in temporal motion. The coupled FE-BE method is described in detail.

• 센서학회지
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• 제20권5호
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• pp.322-328
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• 2011

There are many ways to detect the heart rate non-invasively such as ECG, PPG, strain gauge, and pressure sensor. In this paper, the pulse wave measurement system using bipolar biased head on mode of the Hall sensor is proposed for measuring the radial artery pulse. TMS320F2812 was used to implement the proposed system and a portable wireless network(zig-bee) was used to show the experimental result. It was confirmed from experiment that the performance of the implemented system was more stable and faster than PPG sensor or piezoelectric film pressure sensor.