• Title/Summary/Keyword: 반공진주파수

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The Utilization of Frequency Response Characteristic for the Detection of Change of Backlash Magnitude (백래시 크기 변화 감지를 위한 주파수응답특성의 활용)

  • Baek, Joo-Hyun
    • Journal of the Korea Society for Simulation
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    • v.24 no.3
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    • pp.45-54
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    • 2015
  • This paper presents the influence of backlash can be greatly increased on the frequency response characteristic which is presented as the angular velocity of a motor to the motor input voltage, if the motor input voltage is adequately reduced. And, this paper verifies theoretically, analytically and experimentally the availability on the method of detecting the change of backlash magnitude by investigating on the change of the anti-resonance and resonance frequencies in the frequency response characteristic due to the change of backlash magnitude. The amount of change of anti-resonance frequency is more useful that of resonance frequency when detecting the change of backlash magnitude, because the change of anti-resonance frequency can be measured more stable. This paper also shows the sharp change of resonance frequency can be investigated when the motor input voltage is enough reduced. The work will be useful for the further research on the backlash estimation method of a servo system with a gear reducer.

Estimation of Characteristics Change on Transverse Mode PZT Vibrator Under Space Environment (우주환경하에서 횡진동 모드 PZT진동자의 특성변화 예측)

  • Lee, Sang Hoon;Moon, Guee Won;Yoo, Seong Yeon;Kim, Jung Soon;Kim, Moo Joon
    • The Journal of the Acoustical Society of Korea
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    • v.31 no.8
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    • pp.514-522
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    • 2012
  • The temperature dependence of the characteristics in a PZT-5 piezoelectric ceramic vibrator with the transverse mode was investigated in the range of $-100^{\circ}C$ to $90^{\circ}C$ using a thermal vacuum chamber to utilize the vibrator in aerospace industries. As the results, at room temperature, the resonant and anti-resonant frequencies had the minimum value, whereas, the dielectric constant increased linearly from about 2500 to 7500 in the given temperature range. The mechanical loss decreased linearly from 0.08 to 0.03. Through the regression analysis, the temperature dependence functions of the characteristics were derived to linear and square regression functions. Applying the functions, the input admittance characteristics of the piezoelectric vibrator were calculated, and the results showed good agreement with measured ones. It can be confirmed that this method is useful to estimate the characteristics change of the piezoelectric vibrator caused by the temperature change under the space environment.

A New Modeling Methodology of TFBAR (박막공진기에 대한 새로운 모델링 기법)

  • 김종수;구명권;육종관
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.15 no.1
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    • pp.103-109
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    • 2004
  • In this paper, a new modeling methodology of thin film bulk acoustic resonator(TFBAR) is presented and the formulations of each lumped element in the model are also introduced. The new model is based upon the Mason model that is a reasonable model to explain the physical characteristics of unit TFBAR. After simplifying the modified Mason model with an additional dielectric loss term, the new model similar to Modified Butterworth-Van Dyke(MBVD) model is complete. The proposed model has three optimization variables which is half of the MBVD model. As a result, the curve fittings for the measured data are much faster and more accurate than any other conventional models. Moreover, it is very useful to design the bandpass filters or voltage controlled oscillators due to the design parameters, such as resonant and anti-resonant frequency, which can reflect the intentions of designer in the model.

A Study on the PZT Application for Spacecraft Components (압전진동자의 우주부품 활용에 관한 연구)

  • Lee, Sang-Hoon;Hwang, Kwon-Tae;Cho, Hyokjin;Seo, Hee-Jun;Moon, Guee-Won
    • Aerospace Engineering and Technology
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    • v.12 no.1
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    • pp.32-39
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    • 2013
  • All spacecraft components shall be checked for compatibility with vacuum using CVCM and TML in advance. CVCM and TML of the PZT-5 piezoelectric vibrator has to be less than 0.1% and 1.0% respectively. Also, it has less than $500ng/cm^2/hr$ of TQCM for vacuum bake-out test using high temperature and high vacuum. Thus, the piezoelectric vibrator may be employed in the vacuum environments. Finally, it can be confirmed that the characteristics change of the piezoelectric vibrator is less than 1% under vacuum environments. Also, the temperature dependency of the characteristics in the PZT-5 piezoelectric vibrator with the lateral mode was investigated in the range of $-100^{\circ}C$ to $90^{\circ}C$ using the thermal vacuum chamber to utilize the vibrator to the aerospace industries. As the results, at room temperature, the resonant and anti-resonant frequencies had the minimum value, whereas, the dielectric constant increased linearly from about 2500 to 7500 in the given temperature range. The mechanical loss decreased linearly from 0.08 to 0.03.

Development of Highly Efficient Underwater Loudspeaker for Attracting and Threatening Fish (어류의 유집과 구집용 수중 스피커 개발에 관한 연구)

  • Kim Chun-Duck;Lee Chai-Bong
    • The Journal of the Acoustical Society of Korea
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    • v.25 no.1
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    • pp.7-13
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    • 2006
  • Fisheries policy change from catching to farming requires more intensive consideration for aquaculture industry. The oceanic farm is a desirable cost effective aquaculture method. However. in odor to gather fish in the oceanic farm, eating sound or any attracting sound should be radiated through underwater loudspeaker. In this Paper, it has been found in literature that the frequency range responding to fish is about 16Hz to 13kHz but sensitive frequency range is about 150Hz to 2kHz and sound pressure level is about 100dB to 150dB reference $1{\mu}Pa$. Therefore, frequency range and output sound level of designed underwater loudspeaker has been specified as 150Hz to 3kHz and 100dB to 145dB reference $1{\mu}bar$. respectively To verify the stability and the endurance to the pressure of 40m water depth, manufactured underwater loudspeaker was examined before sea trial in manufactured water pressure tank which gives a maximum of 10 atmospheric Pressure. We experimented on acoustic characteristic with manufactured underwater loudspeaker under water depth of 10m.

Fabrication of GHz-Band FBAR with AIN Film on Mo/SiO2/Si(100) Using MOCVD (Mo/SiO2/Si(100)기판 위에 MOCVD법으로 성장시킨 AIN박막이용 GHz대역의 FBAR제작에 관한 연구)

  • Yang, Chung-Mo;Kim, Seong-Kweon;Cha, Jae-Sang;Park, Ku-Man
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.20 no.4
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    • pp.7-11
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    • 2006
  • In this paper, it is reported that film-bulk-acoustic resonator with high c-axis oriented AIN film on $Mo/SiO_2/Si(100)$ using metal-organic-chemical-vapor deposition was fabricated. The resonant frequency and anti-resonant frequency of the fabricated resonator were observed with 3.189[GHz] and 3.224[GHz], respectively. The quality factor and the effective electromechanical coupling coefficient(${k_{eff}}^2$) were measured with 24.7 and 2.65[%], respectively. The conditions of AIN deposition were substrate temperature of $950[^{\circ}C]$, pressure of 20Torr, and V-III ratio of 25000. A high c-axis oriented AIN film with $4{\times}10^{-5}[\Omega{cm}]$ resistivity of Mo bottom electrode and $4[^{\circ}]$ of AIN(0002) full-width at half-maximum(FWHM) on $Mo/SiO_2/Si(100)$ was grown successfully. The FWHM value of deposited AIN film is useful for the RF band pass filter specification for GHz-band wireless local area network.