다중 센서를 이용한 음향 센서 시스템의 고장 진단

오원근 한국전자통신학회 2016 한국전자통신학회 논문지 Vol.11 No.2

This paper presents a fault detection and data processing algorithm for acoustic sensor systems using the multiple sensor algorithm that has originally developed for the wireless sensor nodes. The multiple sensor algorithm can increase the reliability of the sensor systems by utilizing and comparing the measurements of the multiple sensors. In the acoustic sensor system, the equivalent sound level() is used to detect the faulty sensor. The experiment was conducted to demonstrate the feasibility of the multiple acoustic sensor algorithm, and the results show that the algorithm can detect the faulty sensor and validate the data. 본 논문에서는 음향 센서 시스템에서 다중 센서를 이용한 실시간 고장 진단 및 데이터 처리 알고리즘을 제안하고 실험을 통해 그 타당성을 입증하였다. 다중 센서 알고리즘은 하나의 물리량 계측을 위해 여러 개의 센서를 동시에 사용하는 방식을 사용하며 효율적으로 센서의 고장을 감지하여 신뢰성 있는 데이터를 출력할 수 있는 방법이다. 이를 음향 센서 시스템에 적용하기 위해 등가 소음레벨 Leq를 이용한 실시간 고장 진단 및 오류 데이터 처리 알고리즘을 제안하고, 이를 검증하기 위한 실험 장치와 프로그램을 제작하고 실험하였다. 그 결과 다중 센서 알고리즘은 음향 센서 시스템에도 잘 적용되어 일부 센서의 고장 시에도 정확한 데이터 처리가 가능함을 보였다.

Hopper type WDM을 이용한 단일모드 FBG(Fiber Bragg Grating)음향센서 트랜스듀서 개발연구

김경복(Kyung Bok Kim) 대한전자공학회 2014 전자공학회논문지 Vol.51 No.10

Object Tracking in 3-D Space with Passive Acoustic Sensors using Particle Filter

( Jinseok Lee ),( Shung Han Cho ),( Sangjin Hong ),( Jaechan Lim ),( Seong-jun Oh ) 한국인터넷정보학회 2011 KSII Transactions on Internet and Information Syst Vol.5 No.9

This paper considers the object tracking problem in three dimensional (3-D) space when the azimuth and elevation of the object are available from the passive acoustic sensor. The particle filtering technique can be directly applied to estimate the 3-D object location, but we propose to decompose the 3-D particle filter into the three planes` particle filters, which are individually designed for the 2-D bearings-only tracking problems. 2-D bearing information is derived from the azimuth and elevation of the object to be used for the 2-D particle filter. Two estimates of three planes` particle filters are selected based on the characterization of the acoustic sensor operation in a noisy environment. The Cramer-Rao Lower Bound of the proposed 2-D particle filter-based algorithm is derived and compared against the algorithm that is based on the direct 3-D particle filter.

광섬유 사냑 간섭형 센서에 기반한 링형 탐촉자의 수중 음향 민감도 해석

이연우,권휴상,권일범 한국광학회 2020 한국광학회지 Vol.31 No.1

To measure underwater acoustics using a fiber-optic Sagnac interferometric sensor, the sensitivities of ring-type probes are investigated by theoretical and experimental studies. A ring-type probe was fabricated by packaging a single-mode fiber wound around an acrylate cylinder of diameter 5 cm with epoxy bond. The probes were prepared as A-type, which was packaged with 46.84 m of sensing optical fiber, and B-type, which was packaged with 112.22 m of sensing fiber. The underwater acoustic test was performed at frequencies of 50, 70, and 90 kHz, and over a range of acoustic pressure of 20-100 Pa, to study the sensitivity. A commercial acoustic generator was located 1 m from the acoustic sensor, such as the ring-type probe or a commercial acoustic sensor. From the experimental test, the acoustic sensitivity of the ring-type probe had different values due to acoustic frequencies, unlike the theoretical prediction. Therefore, the experimental sensitivities were averaged for comparison to the theoretical values. These averaged sensitivities are 25.48 × 10 -5 rad/Pa for the A-type probe and 60.79 × 10 -5 rad/Pa for the B-type probe. The correction coefficient of Young’s modulus c was determined to be 0.35.

Fabrication of a High Performance Acoustic Emission (AE) Sensor to Monitor and Diagnose Disturbances in HTS Tapes and Magnet Systems

김주형,송정빈,정영훈,이영진,백종후,김우석,이해근 대한금속·재료학회 2010 METALS AND MATERIALS International Vol.16 No.1

An acoustic emission (AE) technique was introduced as a non-destructive method to monitor sudden deformation caused by local heat concentrations and micro-cracks within superconductors and superconducting magnets. However, the detection of AE signals in a high temperature superconductor (HTS) tape is not easy because of its low signal to noise ratio caused by the noise from boiling liquid cryogen or mechanical vibration from the cryo-cooler. Therefore, high performance piezoelectric ceramics are needed to improve the sensitivity of the AE sensor. The aim of this study was to improve the piezoelectric and dielectric properties to enhance the performance of an AE sensor. This study examined the effects of Nb2O5 addition (0.0 wt.% to 2.0 wt.%)on the properties of high performance piezoelectric ceramics, Pb(Zr0.54 Ti0.46)O3 + 0.2 wt.% Cr2O3, sintered at 1200 ºC for 2 h. The performance was examined with respect to the acoustic emission response of AE sensors manufactured using the specimens with various Nb2O5 contents. Superior sensor performance was obtained for the AE sensors fabricated with the specimens containing 1.0 wt.% to 1.5 wt.% Nb2O5. The performance and characteristics of the AE sensors were in accordance with their piezoelectric and dielectric properties.

Basilar membrane-inspired self-powered acoustic sensor enabled by highly sensitive multi tunable frequency band

Han, Jae Hyun,Kwak, Jun-Hyuk,Joe, Daniel Juhyung,Hong, Seong Kwang,Wang, Hee Seung,Park, Jung Hwan,Hur, Shin,Lee, Keon Jae unknown 2018 Nano energy Vol.53 No.-

<P><B>Abstract</B></P> <P>Herein, we report a self-powered flexible piezoelectric acoustic sensor (f-PAS) inspired by basilar membrane in human cochlear. The f-PAS covered the voice frequency spectrum via the combination of its low quality (Q) factor and multi-resonant frequency tuning, exhibiting four to eight times higher sensitivity than the conventional condenser sensor. Our piezoelectric acoustic sensor with a thin membrane design produced sufficient output voltages by the distinct resonant movement of the Pb[Zr<SUB>0.52</SUB>Ti<SUB>0.48</SUB>]O<SUB>3</SUB> (PZT) membrane under the minute acoustic sound stimuli. Multiple sensor channels were integrated in a single f-PAS chip with a size of 1.5 × 3 cm<SUP>2</SUP>, which acquire multi-tunable piezoelectric signals without any external power. A linear response of the resonance frequency of the curved piezoelectric membrane was theoretically investigated by a finite element method (FEM) calculation. Low Q factors from corresponding channels were achieved by optimal membrane thickness and channel length.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Self-powered flexible piezoelectric acoustic sensor (f-PAS) was inspired by basilar membrane. </LI> <LI> Multi-channel f-PAS provided abundant voice information from speech without external power. </LI> <LI> A linear response in the resonance frequency of the curved PZT membrane was achieved. </LI> <LI> Coverage of the voice frequency range from 100 to 4000 Hz in f-PAS was realized. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Designing a Non-invasive Surface Acoustic Resonator for Ultra-high Sensitive Ethanol Detection for an On-the-spot Health Monitoring System

Peyman Jahanshahi,Qin Wei,Zhang Jie,Erfan Zal Nezhad 한국생물공학회 2018 Biotechnology and Bioprocess Engineering Vol.23 No.4

Surface acoustic wave (SAW) sensors – based on piezoelectric crystal resonators – are extremely sensitive to even very small perturbations in the external atmosphere, because the energy associated with the acoustic waves is confined to the crystal surface. In this study, we present a critical review of the recent researches and developments predominantly used for SAW-based organic vapor sensors, especially ethanol. Besides highlighting their potential to realize real-time ethanol sensing, their drawbacks such as indirect sensing, invasive, time initializing, and low reliability, are properly discussed. The study investigates a proposed YZ-lithium niobate piezoelectric substrate with interdigital transducers patterned on the surface. Design of the resonator plays an important role in improving mass sensitivity, particularly the sensing area. Accordingly, a tin dioxide (SnO2) layer with a specific thickness is generated on the surface of the sensor because of its high affinity to ethanol molecules. To determine the values of sensor configuration without facing the practical problems and the long theoretical calculation time, it is shown that the mass sensitivity of SAW sensors can be calculated by a simple three-dimensional (3-D) finite element analysis (FEA) using a commercial finite-element platform. In design validation step, different concentrations of ethanol are applied to investigate the acoustic wave properties of the sensor. The FEA data are used to obtain the surface and bulk total displacements of the sensor and fast Fourier transform (FFT) on output spectrum. The sensor could develop into highly sensitive and fast responsive structure so that a positive intensity shift of 0.18e-2 RIU is observed when the sensor is exposed to 15 ppm ethanol. It is capable of continuously monitoring the ethanol gas whether as an ultra-high sensitive sensor or switching applications for medical and industrial purposes.

Development of Highly Sensitive and Stable SAW-based Temperature Sensor Array and its Interface Electronics for Realtime Monitoring of Wafer Surface Temperature in Plasma Chamber

Lee Hyunho,Kim Sihyeok,Jung Sangwon,Lee Keekeun 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.4

Temperature sensor array and its associated peripheral interface electronics has been developed for real-time monitoring of the wafer surface temperature at multiple spots on wafer in the plasma chamber. The developed sensor system comprises multiple surface acoustic wave (SAW) temperature sensors and their associated oscillators inside the chamber, and multiplexer, mixer, low pass fi lter, comparator, fi eld-programmable gate array, and PC outside the chamber. The interface electronics were assembled on a single printed circuit board to improve the system performance and facilitate the installation of the system. All the SAW temperature sensors on the wafer surface have the same confi gurations including the same center frequency and the same variations in the resonant frequency with temperature. A multiplexer with several channels was developed to separate the sensor’s signals and then display each sensor signal on PC one by one through a time interval of 0.2 s. The increases in temperature on wafer surface downshifted the resonant frequencies of the SAW temperature sensors. The resultant sensitivity and linearity of the wired temperature sensor system were 24.2 kHz/ ° C and 0.99, respectively. A wireless wafer temperature measurement was also developed by putting antennas on the output port of the multiplexer and the input port of the mixer. A clear and noticeable frequency shifts were observed on PC display depending on diff erent temperatures at the reading distance of 5 m. The evaluated sensitivity and the linearity were almost the same as those obtained by the wired measurement. The developed SAW sensors showed long term stability against energetic UV-C radiation and electromagnetic interference owing to a thin Si 3 N 4 protection layer.

두 개의 Fabry-Perot 광섬유 센서 배열을 이용한 횡방향 음압 감지 특성 연구

이종길 대한공업교육학회 2006 대한공업교육학회지 Vol.31 No.1

본 연구에서는 구조물이 횡방향으로 음압을 받을 경우 이를 감지하기 위하여 Fabry-Perot형 광섬유 배열 센서를 제작하고 실험하였다. 이는 한 개의 광원으로 두 개의 센서가 병렬로 연결되고 센서의 출력신호를 보기 위한 별도의 신호처리기가 필요 없는 구조이다. 횡방향 음압을 임의의 음원 주파수인 100Hz, 200Hz 및 655Hz의 주파수를 무지향성 스피커에 인가하였으며 60cm×60cm×60cm의 격자 구조물에 부착된 두 개의 배열 센서가 잡은 신호를 분석하였다. 시간 영역에서 두 개의 센서 신호는 진폭에 약간의 차이는 있으나 음원 주파수를 잘 감지함을 확인 하였다. 센서가 실제로 양단이 지지된 구조의 배열 센서를 모델링하고 그 해를 실험결과와 비교하였다. 2kHz의 음원을 배열 센서에 인가하였더니 이론 해석과 비교적 잘 일치하는 측정 결과를 얻었다. In this paper, to detect lateral direction sound pressure fiber optic sensor using Fabry-Perot interferometeric sensor array was fabricated and experimented. This parallel sensor array composed of one light source and the light split into each sensor using directional coupler and to see the output signal the array system do not need any digital signal processor. As a lateral direction sound source arbitrary sound frequency of 100Hz, 200Hz, and 655Hz using by nondirectional speaker were applied to the array sensor which installed on 60cm×60cm×60cm latticed structure. The detected signals from the two sensors were analyzed in the time and frequency domains. It was confirmed that the suggested sensor array detected applied sound source well but there were a little amplitude differences in between the sensors. Because the sensor supported simply at both ends theoretical analysis was performed and its solution was suggested. To compare the theoretical and experimental results arbitrary sound frequency of 2kHz was applied to the sensor array. It shows that experimental results was good agreement with theoretical results.

원통형 배열센서 후면 구조물에 의해 발생하는 허위 표적 감소를 위한 음향 배플 연구

서영수(Young Soo Seo),정우진(Woo Jin Jung),김동현(Dong Hyun Kim),김진태(Jin Tae Kim) 한국소음진동공학회 2015 한국소음진동공학회 학술대회논문집 Vol.2015 No.4

Cylindrical array sensor is used to detect the acoustic signal of underwater enemy. This sensor is installed at sonar dome inside. The structure behind the cylindrical array sensor makes a ghost target. To minimize ghost target, acoustic baffle is used. The performance of acoustic baffle is determined according to the acoustic analysis. Finite element method was used to analyze the acoustic field around cylindrical array sensor. The specimens for pulse tube test were made and echo reductions were measured. The effect of echo reduction of the acoustic baffle were discussed.