• Title, Summary, Keyword: ultrasonic

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APPLICATION OF DIGITAL ULTRASONIC IMAGE CONSTRUCTION SYSTEM FOR THE DETECTION OF CRACKS IN WATER DISTRIBUTION SYSTEM

  • Lee, Hyun-Dong;Kwak, Phill-Jae;Shin, Hyeon-Jae;Jang, You-Hyun
    • Environmental Engineering Research
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    • v.11 no.2
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    • pp.99-105
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    • 2006
  • A digital ultrasonic image construction system was developed for the nondestructive detection of cracks in water distribution pipes. The system consists of PC based ultrasonic testing system and a scanning device. The PC based ultrasonic system has an ultrasonic pulse/receive board for the generation and reception of ultrasonic signals, an analogue to digital conversion board for the digitization of the received ultrasonic signals, and transducers for the ultrasonic sensors. Using this system, the digitized ultrasonic signals were properly constructed in accordance with the position information obtained by scanning device that moves an ultrasonic transducer along the outer surface of pipes. In the construction of the ultrasonic signals, signal processing concepts, such as spatial average and array concept, were considered to enhance the resolution of ultrasonic images of pipe wall. Using the developed system, crack detection experiments were performed in both laboratory and field, which shows promise for crack detection in the water distribution system.

Study on the Development of Multi-Path Ultrasonic Gas Flowmeter (전달 시간차 방식 다회선 초음파 가스 유량계 개발)

  • 황원호;박상국;이치환;장경영
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.1046-1050
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    • 2003
  • In this paper, we describe study on the development or multi-path ultrasonic gas flowmeter using a transit time method. This system includes 5 pairs of ultrasonic transducers. ultrasonic signal processing unit using switch matrix method, computation algorithm of gas flow rate, spool piece type multi-path pipe unit. We have developed enhanced type of main ultrasonic signal processing unit using switch matrix method fer multi-path ultrasonic gas flowmeter. Also, we have developed the new transmitting & receiving method of ultrasonic waves and the new signal processing algorithm for the computation of ultrasonic transit time from received ultrasonic waves. In this study, we have designed more compact signal processing unit compared with the conventional hardware system of multi-path ultrasonic gas flowmeter. We have confirmed its reliability for multi-path ultrasonic gas flowmeter through the laboratory test using calibration system. In the future. we will perform the field test for the developed system in the POSCO gas line.

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Correlation Analysis between Ultrasonic Parameters and Elastic Modulus of Apple

  • Kim, Ghi-Seok;Kim, Ki-Bok;Park, Jeong-Gil;Lee, Sang-Dae;Jung, Hyun-Mo;Kim, Man-Soo
    • Journal of the Korean Society for Nondestructive Testing
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    • v.28 no.3
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    • pp.279-284
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    • 2008
  • The firmness of fruit is one of the most important quality factors and is highly correlated to the elastic modulus. In this study, the ultrasonic transmission method was applied to evaluate the elastic modulus of the apple. In order to transmit and receive the ultrasonic wave through the whole apple, the ultrasonic measurement setup consisted of ultrasonic pulser, two specially fabricated ultrasonic transducers for fruit and digital storage oscilloscope. Ultrasonic parameters such as ultrasonic wave velocity, apparent attenuation, and peak frequencies were analyzed. The elastic modulus of apple was measured by using compression test apparatus. The correlations between ultrasonic parameters and elastic modulus were analyzed. A multiple linear regression model describing the relationship between elastic modulus and ultrasonic parameters was proposed.

Detection of the Ultrasonic Signals due to Partial Discharges in a 154kV Transformer

  • Kweon, Dong-Jin;Chin, Sang-Bum;Kwak, Hee-Ro
    • KIEE International Transactions on Electrophysics and Applications
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    • v.2C no.6
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    • pp.297-303
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    • 2002
  • We have developed an on-line ultrasonic detector to monitor partial discharge in an operating transformer. The ultrasonic sensor has 150[KHz] resonance frequency and contains a pre-amplifier with 60[㏈] gain. The on-line ultrasonic detector has 50~300[KHz] frequency band-pass filter to remove electrical and mechanical noises from the transformer. This detector has an ultrasonic signal discrimination algorithm which discriminates ultrasonic signals due to partial discharge in a transformer. A moving average method of ultrasonic signal number was employed to effectively monitor the increasing trend of the partial discharge. This paper describes an experience of partial discharge detection in a 154[㎸] operating transformer using an ultrasonic detector. With regards to gas analysis in oil, C2H2 gas was produced with a warning level in this transformer We detected ultrasonic signals on the transformer steel wall, and estimated the position of partial discharge. With further inspection, we found carbonized marks due to partial discharge on the supporting bolt which fastens the windings.

Fabrication and Simulation of Displacement Properties of Ultrasonic Generator Handpiece (초음파 절삭기 핸드피스부 제작 및 변위 특성 시뮬레이션)

  • Kim, Seung-Won;Yoo, Ju-Hyun;Lee, Jie-Young
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.31 no.3
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    • pp.152-155
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    • 2018
  • Ultrasonic wave technologies have been widely used in ultrasonic washing machines, ultrasonic surgery, ultrasonic welding machines, ultrasonic sensors, and medical instruments. Ultrasonic surgery can be realized through the cavitation effect of ultrasonic waves. In this study, piezoelectric ceramics were manufactured to achieve the optimum design of a piezoelectric vibrator in a handheld generator for ultrasonic surgery. The best specimen showed the excellent piezoelectric properties of kp=0.624, Qm=1,531, and $d_{33}=356pC/N$. Numerical modeling based on the finite element method was performed to find the resonance frequency, the anti-resonance frequency, and the displacement properties of the handheld ultrasonic generator. Maximum displacement was observed in the six-step piezoelectric vibrator at $6.36{\mu}m$.

Self-localization of a Mobile Robot Using Global Ultrasonic Sensor System (전역 초음파 센서 시스템을 이용한 이동 로봇의 자기 위치 추정)

  • 이수영;진재호
    • Journal of Institute of Control, Robotics and Systems
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    • v.9 no.2
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    • pp.145-151
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    • 2003
  • A global ultrasonic sensor system for self-localization of a mobile robot is proposed in this paper. The global ultrasonic sensor system consists of three or more ultrasonic transmitters fixed at some positions in the world coordinate and receivers in the moving coordinate of a mobile robot. In this global sensor system it is easy to get state vector of the mobile robot in the world coordinate from the distance information between each ultrasonic transmitter and receiver. An extended kalman filter algorithm is used to process the noisy ultrasonic signal and to estimate the state vector. In case of using several independent ultrasonic transmitters, it is necessary to avoid the cross talk among the ultrasonic waves and to synchronize between each ultrasonic transmitter and receiver. The small sized radio frequency modules are adopted to solve the cross talk and the synchronization problem Computer simulation and experiments are carried out to verify the effectiveness of the proposed ultrasonic sensor system.

Optimal Design of Overlapped Ultrasonic Sensor Ring for High Resolution Obstacle Detection (고분해능 장애물 탐지를 위한 중첩 초음파 센서 링의 최적 설계)

  • Kim, Sung-Bok;Kim, Hyun-Bin
    • Journal of Institute of Control, Robotics and Systems
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    • v.17 no.2
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    • pp.79-87
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    • 2011
  • This paper presents the optimal design of an overlapped ultrasonic sensor ring for high resolution obstacle detection of an autonomous mobile robot. It is assumed that a set of low directivity ultrasonic sensors of the same type are arranged along a circle of nonzero radius at a regular spacing with their beams overlapped. First, taking into account the dead angle region, the entire range of obstacle detection is determined with reference to the center of an overlapped ultrasonic sensor ring. Second, the optimal design index of an overlapped ultrasonic sensor ring is defined as the area closeness of three sensing subzones resulting from beam overlap. Third, the lower and upper bounds on the number of ultrasonic sensors are derived, which can guarantee minimal beam overlap and also avoid excessive beam overlap among adjacent ultrasonic sensors. Fourth, employing a commercial low directivity ultrasonic sensor, an optimal design example of an overlapped ultrasonic sensor ring is given along with the ultrasonic sensor ring prototype mounted on top of a mobile robot. Finally, some experimental results using our prototype ultrasonic sensor ring are given to demonstrate the validity and performance of an optimally overlapped ultrasonic sensor ring for high resolution obstacle detection.

Study on the Optimizing Ultrasonic Cell for Depth Measurement of Crude Oil (원유 깊이 측정을 위한 초전도셀 최적화에 관한 연구)

  • Oh, Kyutae
    • Journal of the Institute of Electronics and Information Engineers
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    • v.54 no.1
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    • pp.152-156
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    • 2017
  • Until now, most of the studies related to the ultrasonic sensor was in the water or the air. This study is for ultrasonic sensor in crude oil. because the ultrasonic cell use high voltage, it can cause an explosion. So, in crude oil, it did not use an ultrasonic sensor. This is the study of the ultrasonic sensor that generates ultrasonic waves while preventing explosion. Through this study, when trasmit ultrasonic in the crude oil, it found the most adaptive diameter, thickness, transmit frequency of ultrasonic cell to measure the depth of the crude oil and sludge. In conclusion, when a 200kHz frequency is generated by applying a voltage of 24V to the ultrasonic cell, the optimum diameter of ultrasonic cell is 26~28mm, the thickness of ultrasonic cell is 9mm.

Lambda shape multiway moving ultrasonic linear motor (람다형 다방향 초음파 선형 모터)

  • Do, Young-Soo;Nam, Hyo-Duk;Kim, Young-Duk
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.263-265
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    • 2007
  • An ultrasonic linear motor using lambda shape vibrators has been designed and fabricated. The multiway ultrasonic motors mainly consist of an lambda shape ultrasonic vibrator which generates elliptical motions in beat. The lambda shape ultrasonic linear motor use longitudinal and bending vibration mode. In order to high precision motion control and multiway moving, piezoceramics were adhered to lambda shape brass elastic material. The finite element method was used to optimize dimension of ultrasonic vibrator and direction of vibratory displacement. As a result of estimating the characteristics of the ultrasonic linear motor, The results have shown that the lambda shape ultrasonic linear motor can be moved multiwav by using the phase control. Close agreement between the FEM results and experimental results obtained for the lambda shape ultrasonic linear motor.

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Design of Ultrasonic Vibration Tool Horn for Micromachining Using FEM (유한요소법을 이용한 초음파 진동 공구혼 설계에 관한 연구)

  • Lee, Bong-Gu;Kim, Kwang-Lae;Kim, Kang-Eun
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.17 no.6
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    • pp.63-70
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    • 2008
  • Conical horn is used in many high frequency ultrasonic horns, to achieve a longitudinal vibration mode across a wide ultrasonic tool horn output surface. Modal analysis is method for designing tuned ultrasonic tool horn and for the prediction natural frequency of ultrasonic tool horn vibration mode. The design of ultrasonic horn is based on prototype estimate obtained by FEM analysis. The FEM simulated ultrasonic tool horn is built and characterized experimentally through laser vibrometer and electrical impedance analysis. In this paper, FEM analysis is developed to predict the natural frequency of ultrasonic tool horn and use of in the optimal design of ultrasonic horn shape.