• Title/Summary/Keyword: piezoelectric transducer

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Development of a Wireless Piezoelectric Transducer Excitation Technique using laser and optoelectronic devices (레이저 및 광전자소자를 활용한 압전소자의 무선 가진 시스템 개발)

  • Park, Hyun-Jun;Sohn, Hoon;Chung, Joseph;Kwon, Il-Bum;Yun, Chung-Bang
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2009.04a
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    • pp.6-9
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    • 2009
  • 교량, 댐, 터널 등의 대형 구조물 및 항공기 등의 기계 구조물의 경우 그 중요성과 함께 노후화 및 손상의 발생에 의한 구조물의 사고를 미연에 방지하기 위해 효과적인 건전도 평가와 손상 검색에 대한 연구가 최근 급증하고 있으며 특히 압전소자를 활용하여 구조물의 손상을 추정하는 기법들이 많이 개발되고 있다. 또한, 최근에는 압전소자와 계측기 사이를 케이블을 이용하여 연결할 경우 실제 대형 구조물에 설치 시 비효율적인 부분이 많아 무선 기반 계측시스템이 개발되고 있다. 그러나 이러한 무선 계측 시스템의 경우 압전소자의 가진 및 계측되는 데이터의 전송을 위해 별도의 전원공급이 필요하기 때문에 배터리가 포함되도록 구성되며 이럴 경우 그 수명이 제한적이기 때문에 실제 구조물에 활용 시 문제로 제기되고 있다. 이러한 배경에서 본 연구에서는 레이저를 통해 원격지의 압전소자에 무선으로 전원을 공급하여 가진시키는 시스템을 제안하였다. 압전소자를 가진시키고자 하는 임의의 파형으로 레이저를 변조(modulation)시키고 대기 중으로 전송하여, 압전소자와 연결된 광검출기(photodiode)를 통해 전기적 신호로 변환하여 최종적으로 가진시키게 된다. 이러한 시스템을 실내 실험을 통하여 구현하였으며 그 효용성을 살펴보았다.

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Development of a Ultrasonic System for Nano-Surface Reformation Process

  • Kim, Hyunse;Lim, Euisu;Park, Jong-Kweon
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.26 no.4
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    • pp.365-370
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    • 2017
  • In this article, a 20 kHz Titanium (Ti) ultrasonic waveguide system for a nano-surface reformation process was designed and fabricated. First, finite element analysis using ANSYS software was performed to find the optimal dimensions. The obtained anti-resonance frequency for the Ti transducer with the piezoelectric device was 20.0 kHz, which value agreed well with the experiment result of 20.1 kHz (0.5% error). To test the system, chromium molybdenum steel (SCM) 435 was chosen as a test-piece. The result proved that the reformed depth was $36{\mu}m$. In addition, hardness was measured before and after the process. The value was changed from 14 HRC to 21 HRC, which is 50% increasing rate. Finally, the friction coefficient test result showed that the surface coefficient was reduced from 0.14 to 0.10 (28.6% reduction). Based on the results, the Ti ultrasonic equipment is regarded as a useful device for nano-scale surface reformation.

Bond Graph Modeling, Analysis and Control of Dual Stage System (본드그래프를 이용한 듀얼 스테이지 시스템의 모델링, 해석, 및 제어)

  • Wang, Wei-Jun;Han, Chang-Soo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.4
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    • pp.1453-1459
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    • 2012
  • The dual stage manipulator is composed of the voice coil motor (VCM) and piezoelectric ceramics transducer (PZT), which can produce the high precise displacement and express a well dynamic performance. However, inaccurate modeling of the dual stage will exacerbate the positioning accuracy. This paper presents an approach to model the dual stage system by using bond graph theory. And the state space equations can be derived through the bond graph straightforwardly, which can be used in computing simulations. Through designing the compensators for the dual stage system and simulating, the dual stage performs better dynamics characteristic than the single actuator system.

Development of High Resolution Multichannel Seismic Data Acquisition System and its Field Application (다중채널 고분해능 해양탄성파탐사 시스템 개발 및 현장적용)

  • Kim Youngjun;Yeo Eunmin;Kim Chansu;Shin Sungryul
    • 한국지구물리탐사학회:학술대회논문집
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    • 2005.05a
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    • pp.293-298
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    • 2005
  • In this study, we have developed the high resolution multichannel seismic data acquisition system and shallow marine seismic source. It is easy to operate and handle our source system which utilizes piezoelectric transducer of high electrical power. We have manufactured two 4-channel streamers for multi-channel marine seismic survey. In the recording part, we used 24bits and 8 channel high speed A/D board. Therefore, we could achieve the improvement of data quality and the efficiency of data acquisition. We compared the developed system with the conventional system to demonstrate its field applicability.

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Study on Noise Generation Characteristics of Simulated EGR System for Compression Ignition Diesel Engine (압축착화 디젤엔진의 모사 EGR 시스템에 의한 소음 특성 변화 분석)

  • Park, B.;Yoon, S.;Park, S.;Park, J.
    • Journal of ILASS-Korea
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    • v.19 no.4
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    • pp.204-210
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    • 2014
  • Experimental study was conducted to investigate the effect of EGR(exhaust gas recirculation) on engine noise using single cylinder combustion ignition engine. Under constant engine rotary speed of 1200 RPM, 8 mg fuel quantity was injected with 15, 18 and 21% of oxygen ratio and 1400 bar of injection pressure. Using the in-cylinder pressure data acquired by a piezoelectric transducer, the engine performance parameters were calculated. Radiated engine noise measured for 10 seconds was analyzed using spectral characteristics and sound quality metrics such as loudness, sharpness, roughness. From the obtained engine performance parameters and sound quality metrics, effect of oxygen ratio of the premixed air, start of injection timing on frequency characteristic and sound quality metrics were analyzed. Correlation analysis was conducted between MPRR(maximum pressure rise rate), RI(ringing intensity) and sound quality metrics. RI was identified as the most important factor having influence on the sound quality metrics.

Measurement of a Mirror Surface Topography Using 2-frame Phase-shifting Digital Interferometry

  • Jeon, Seok-Hee;Gil, Sang-Keun
    • Journal of the Optical Society of Korea
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    • v.13 no.2
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    • pp.245-250
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    • 2009
  • We propose a digital holographic interference analysis method based on a 2-frame phase-shifting technique for measuring an optical mirror surface. The technique using 2-frame phase-shifting digital interferometry is more efficient than multi-frame phase-shifting techniques because the 2-frame method has the advantage of a reduced number of interferograms, and then takes less time to acquire the wanted topography information from interferograms. In this measurement system, 2-frame phase-shifting digital interferograms are acquired by moving the reference flat mirror surface, which is attached to a piezoelectric transducer, with phase step of 0 or $\pi$/2 in the reference beam path. The measurements are recorded on a CCD detector. The optical interferometry is designed on the basis of polarization characteristics of a polarizing beam splitter. Therefore the noise from outside turbulence can be decreased. The proposed 2-frame algorithm uses the relative phase difference of the neighbor pixels. The experiment has been carried out on an optical mirror which flatness is less than $\lambda$/4. The measurement of the optical mirror surface topography using 2-frame phase-shifting interferometry shows that the peak-to-peak value is calculated to be about $0.1779{\mu}m$, the root-mean-square value is about $0.034{\mu}m$. Thus, the proposed method is expected to be used in nondestructive testing of optical components.

Structural health monitoring using piezoceramic transducers as strain gauges and acoustic emission sensors simultaneously

  • Huo, Linsheng;Li, Xu;Chen, Dongdong;Li, Hongnan
    • Computers and Concrete
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    • v.20 no.5
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    • pp.595-603
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    • 2017
  • Piezoceramic transducers have been widely used in the health monitoring of civil structures. However, in most cases, they are used as sensors either to measure strain or receive stress waves. This paper proposes a method of using piezoelectric transducers as strain gauges and acoustic emission (AE) sensors simultaneously. The signals received by piezoceramic transducers are decomposed into different frequency components for various analysis purposes. The low-frequency signals are used to measure strain, whereas the high-frequency signals are used as acoustic emission signal associated with local damage. The b-value theory is used to process the AE signal in piezoceramic transducers. The proposed method was applied in the bending failure experiments of two reinforced concrete beams to verify its feasibility. The results showed that the extracted low-frequency signals from the piezoceramic transducers had good agreement with that from the strain gauge, and the processed high-frequency signal from piezoceramic transducers as AE could indicate the local damage to concrete. The experimental results verified the feasibly of structural health monitoring using piezoceramic transducers as strain gauges and AE sensors simultaneously, which can advance their application in civil engineering.

Development of a Real-time 3D Intraoral Scanner Based on Fringe-Projection Technique (프린지 투영법을 이용한 실시간 3D 구강 내 스캐너의 개발)

  • Ullah, Furqan;Lee, Gunn-Soo;Park, Kang
    • Korean Journal of Computational Design and Engineering
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    • v.17 no.3
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    • pp.156-163
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    • 2012
  • Real-time three-dimensional shape measurement is becoming increasingly important in various fields, including medical sciences, high-technology industry, and microscale measurements. However, there are not so many 3D profile tools specially designed for specifically narrow space, for example, to scan the tooth shape of a human jaw. In this paper, a real-time 3D intraoral scanner is proposed for the measurement of tooth profile in the mouth cavity. The proposed system comprises a laser diode beam, a micro charge-coupled device, a graticule, a piezoelectric transducer, a set of optical lenses, and a polhemus device sensor. The phase-shifting technique is used along with an accurate calibration method for the measurement of the tooth profile. Experimental and theoretical inspection of the phase-to-coordinate relation is presented. In addition, a nonlinear system model is developed for collimating illumination that gives the more accurate mathematical representation of the system, thus improves the shape measurement accuracy. Experiment results are presented to verify the feasibility and performance of the developed system. The experimental results indicate that overall measurement error accuracy can be controlled within 0.4 mm with a variability of ${\pm}0.01$.

Full Bridge Resonant Inverter Using Asymmetrical Control with Resonant-frequency Tracking for Ultrasonic Cleaning Applications

  • Jittakort, Jirapong;Sangswang, Anawach;Naetiladdanon, Sumate;Koompai, Chayant;Chudjuarjeen, Saichol
    • Journal of Power Electronics
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    • v.17 no.5
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    • pp.1150-1159
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    • 2017
  • Flexibility in the power control of ultrasonic transducers has remained a challenge for cleaning applications. This paper introduces a modification of the existing piezoelectric ceramic transducer (PCT) circuit to increase the range of operation through its impedance characteristics. The output power is controlled using the asymmetrical voltage-cancellation (AVC) method. Together with a phase-locked loop control, the switching frequency of the inverter is automatically adjusted to maintain a lagging phase angle under load-parameter variations during the cleaning process. With the proposed modification, the region of the zero-voltage switching (ZVS) operation is extended, which results in a wider range of output power control. A hardware prototype is constructed and the control algorithm is implemented using an STM32F4 microcontroller. Simulation and experimental results are provided to verify the proposed method for a 50-W PCT. The operating frequency and output power ranges under study are 37 - 41 kHz and 15.8 - 50 W, respectively.

Fabrication and Electrical Properties of Piezoceramics PZT-Polymer 1-3-0 Type Composite (압전세라믹 PZT-고분자 1-3-0형 복합압전체의 제조 및 전기적 특성)

  • Shon, Mu-Hun;Choi, Hun-Il;Sa, Gong-Geon
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.48 no.4
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    • pp.241-246
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    • 1999
  • In this study, the piezoelectric ceramics PZT powders were synthesized by Wet-Dry combination method. And the flexible 1-3-0 type composites were favricated with piezoceramic PZT and Eccogel polymer matrix embedded 3rd phase. Dielectric constant of 1-3-0 type composites was lower than that of single phase PZT ceramics. Thickness mode coupling factor $k_t$ which was comparable with single phase PZT ceramics, and Mechanical Quality factor $Q_m$ were about 0.65 and 6 respectively. These composites are considered as a good candidates for broad-band type transducer applications. The acoustic impedance for 1-3-0 type composites was lower than that of single phase PZT ceramics. Therefore, these composites would be better used for hydrophone applications.

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