• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.747-752
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• 2008

Fiber-guided sensor system using a generator and a receiver can detect the amplitude of load or pressure. However, this type of sensor can show some difficulties in detecting the location of damages and pressure loadings. To overcome this weakness of this type, the ultrasonic active fiber sensor, which has an integrated ultrasonic generator and sensing part, was developed in this study. By using this sensor system, the location of mechanical loads can be exactly detected. Moreover, the ultrasonic active fiber sensor is more cost-effective than an ultrasonic fiber sensor using two piezoelectric transducers which are used as a generator and a receiver, respectively. Two applications of the ultrasonic active fiber sensor are demonstrated: cure monitoring of lead and measurement of liquid level. Present results showed that the active fiber sensor can be applied for various environmental sensing.

• 한국융합학회논문지
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• 제9권4호
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• pp.137-142
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• 2018

본 연구는 송 수신 초음파 센서를 이용하여 CNG 탱크에서의 정밀한 연료량을 측정하기 위한 기초 연구로써 탱크내부 압력 및 초음파 센서의 접촉면 변경에 따른 수신감도를 분석하였다. 실험은 탱크와 센서의 접촉면을 점, 선, 면의 3가지 타입으로 변경하고 탱크 내부의 압력을 0 bar 부터 5 bar까지 1 bar 간격으로 충전하면서 측정을 진행하였다. 실험결과 탱크내부의 압력이 증가함에 따라 초음파 센서의 수신신호 값이 감소하는 경향을 확인할 수 있었다. 또한 탱크와 센서의 접촉면적이 증가할수록 수신 신호 값은 증가하지만, 노이즈 또한 증가하는 것을 확인 할 수 있었다. 이와 같은 실험 결과 초음파의 투과 특성을 이용하여 탱크내부의 기체 연료량을 측정할 수 있을 것으로 판단되며, 센서의 접촉면 변경을 통해 정밀성을 향상시킬 수 있을 것으로 판단된다.

• 대한기계학회논문집B
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• 제27권9호
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• pp.1229-1237
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• 2003

The production of hydrogen fuel depends basically on the water electrolysis. The ultrasonic effects the decrease of the overpotential in a water electrolysis. A study on the overpotential which activates the hydrogen production is the core to elevate the hydrogen production efficiency on the principle. A pressure sensor system by a new idea is developed and applied. Solutions are 4 kinds of KOH concentration such as 0%, 10%, 20%, and 30%. Two frequency bands of the ultrasonic transducer are 28kHz and 2MHz. The directions of ultrasonic forcing are the vertical direction and the horizontal direction. The temperatures are two states, i.e., no constant and constant. Experiments are carried out sequentially in order in three cases of no ultrasonic forcing, ultrasonic forcing, and ultrasonic discontinution. In results, it is clarified that the ultrasonic effects the decrease of overpotential to elevate the efficiency of hydrogen production.

• 한국생산제조학회지
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• 제19권2호
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• pp.282-287
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• 2010

This paper gives a description of an experimental study of the ultrasonic welding of metals. In ultrasonic metal welding, high frequency vibrations are combined with pressure to join two materials together quickly and securely, without producing significant amount of heat. Ultrasonic metal welder consists of Transducer, Booster, and horn that are designed very accurately to get the natural frequencies and vibration mode. In this study, The horn was designed and analyzed the natural frequency by the modal analysis and harmonic analysis. And using a fiber optic sensor, we measured the amplitude and analyzed the Fast Fourier Transformed result. Using the horn, Ultrasonic metal welding between Cu sheet and Cu sheet of 0.1mm thickness was accomplished under the optimal conditions of static pressure 0.15MPa, vibration amplitude 30% and welding time of 0.28s. This result can be used for ultrasonic metal welding in manufacturing industry.

• 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.

• 한국융합학회논문지
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• 제9권4호
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• pp.161-167
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• 2018

CNG 차량의 경우 압력센서를 이용하여 CNG의 양을 계측하고 있다. 그러나 주변 환경 조건에 따라 정확한 양을 파악하는데 어려움이 있어 운전자에게 불안감을 조성하게 된다. 본 연구는 CNG 연료 시스템에서 CNG의 양을 정밀하게 측정하기 위한 기초 연구로써 CNG 연료량 검출 시스템을 모사하여 측정방법을 제시하고자 한다. 실험은 Type-3의 CNG 탱크에 초음파 센서를 적용한 연료량 검출 모사장치 구현하였다. 그리고 내부의 압력은 압축공기를 이용하여 100 bar 에서 0 bar 까지 5 bar 단위로 저감시키면서 초음파 센서의 수신 신호를 검증하였다. 그 결과 탱크 내 압력이 감소함에 따라 초음파 센서의 출력 신호가 감쇠하는 것을 알 수 있었고, 다소 차이는 있었지만 선형성을 띄고 있는 것을 확인할 수 있었다.

• 마이크로전자및패키징학회지
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• 제14권1호
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• pp.19-26
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• 2007

본 연구의 목적은 CMOS 이미지 센서용 Au 플립칩 범프와 전해 도금된 Au 기판 사이의 초음파 접합의 가능성 연구이다. 초음파 접합 조건을 최적화하기 위해서, 대기압 플라즈마 세정 후 접합 압력과 시간을 달리하여 초음파 접합 후 전단 시험을 실시하였다. 범프의 접합 강도는 접합 압력과 시간 변수에 크게 좌우되었다. Au 플립칩 범프는 상온에서 성공적으로 하부 Au 도금 기판과 접합되었으며, 최적 조건 하에서 접합 강도는 약 73 MPa이었다.

• 한국생산제조학회지
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• 제26권4호
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• pp.425-429
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• 2017

During ultrasonic welding, plastic deformation, elastic hysteresis, and friction generate heat at the contact portions of the two materials to be welded, theoretically analyzing and experimentally measuring the temperature at the welded part are very important for identifying the heat affected zone. However, the welding temperature during ultrasonic welding wherein welding is performed in less than a second is a challenge. We investigated the effects of welding conditions such as welding time, welding pressure, and the ultrasonic vibration amplitude of horns on the temperature of welded surface of a Ni sheet of thickness 0.1 mm. We used a horn with a resonance frequency of 40 kHz and an ultrasonic welder. The temperature was measured using a intrared sensor, and its characteristics were investigated. Experimental results showed that increase in welding time and pressure and ultrasonic vibration amplitude of horns generally caused the increase in surface temperature of the weld.

• 로봇학회논문지
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• 제18권1호
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• pp.53-58
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• 2023

In general, in order to operate an autonomous underwater vehicle (AUV) in an underwater environment, a navigation system such as a Doppler Log (DVL) using a Doppler phenomenon of ultrasonic waves is used for speed and direction estimation. However, most of the ultrasonic sensors in underwater is large for long-distance sensing and the cost is very high. In this study, not only canal neuromast on the fish's lateral lines but also superficial neuromast are studied on the simulation to obtain pressure values for each pressure sensor, and the obtained pressure data is supervised using spherical CNN. To this end, through supervised learning using pressure data obtained from a pressure sensor attached to an underwater vehicle, we can estimate the speed and angle of the underwater vehicle in a quasi-static underwater environment and propose a method for a non-ultrasonic based navigation system.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.400-403
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• 2005

The sonar sensors can be divided into a piezo type and an electrostatic type according to a principle of an operating system. The electrostatic type of a sonar sensor is used for map building in this paper. If we know the characteristics of sonar sensor, we can derive the ultrasonic pressure equation from an acoustics theory. We, therefore, developed Ultrasonic Pressure Probabilistic Model (UPPM) to consider the sound pressure in the probability updating process. In this paper, we found that the quality of the resulting probability map is considerably improved, through combining the UPPM with the grid-based mapping algorithm.