• 제목/요약/키워드: Difference Frequency

검색결과 5,611건 처리시간 0.035초

위상차 변화에 따른 초음파 모터의 주파수-속도 특성 (The Frequency-Speed Characteristics of Ultrasonic Motor by the Change of Phase difference)

  • 김동옥;정국영;오금곤;김영동
    • 전력전자학회:학술대회논문집
    • /
    • 전력전자학회 2003년도 춘계전력전자학술대회 논문집(1)
    • /
    • pp.146-149
    • /
    • 2003
  • To control the position, velocity and torque of the ultrasonic motor, a great variety of method are proposed such as the amplitude, phase difference, frequency and so on. In the case of phase difference method, it has some advantages: it can control the direction and velocity of rotation only adjusting the phase difference and it has wide control-band. During the USM driving on adjusting phase difference, its characteristic was transformed by the change of resonance-frequency of stator, which means that the resonance frequency is different according to the phase difference. Consequently, we need to set up the most suitable driving frequency according to each phase difference.

  • PDF

위상차-주파수 다중 파라미터 조절에 의한 초음파 모터 속도 특성 (A Speed Characteristics of the Ultrasonic Motor by the Multi-Parameters adjustment with Phase difference-Frequency)

  • 김동옥;강원창;김성철;오금곤;김영동
    • 전기학회논문지P
    • /
    • 제52권1호
    • /
    • pp.20-27
    • /
    • 2003
  • In this study, we designed and made Ultrasonic motor-digital multi controller(USM-DMC) using FPGA chip, A54SX72A made in Actel Corporation. By the minute, USM-DMC can adjust the frequency, duty ratio, and phase difference parameters of USM by digital input to be each 11bit from PC. Therefore, when we use this controller, it is possible to apply typical three parameters individually as well as multi-parameters simultaneously to control the speed and the torque. What is more, the strongest point is that it can trace frequency based on optimized frequency as compared with the phase difference because we can input optimized resonant frequency while in motoring. And we test the speed of USM with the adjustment of multi-parameters, the phase difference-frequency. As the result of the test, in the case of the multi-parameters of the phase difference and frequency, the speed characteristic is more linear and stable, and wider in the range of control than the single-parameter of the phase difference or the frequency.

The Effects of Whole Body Vibration Exercise on Jump Performance and Quadriceps Muscle Activation in Soccer Player

  • Kim, Je-Ho
    • The Journal of Korean Physical Therapy
    • /
    • 제27권3호
    • /
    • pp.129-134
    • /
    • 2015
  • Purpose: The purpose of this study was to determine the influence of WBV exercise on CMJ and quadriceps muscle activation according to different frequency of vibration in soccer player and also to find effective frequency for leading appropriate treatment reaction. Methods: Thirty three subjects were randomly divided into three groups: the three groups are WBV group using 20 Hz frequency, WBV group using 30 Hz frequency and squat exercise group according to training method. The exercise program was conducted for six weeks. Subjects were measured on CMJ and quadriceps muscle activation. Results: Significant difference in CMJ was observed in the group I, II compared with the group III (p<0.05). Results of post-hoc, showed a significant difference in CMJ in on group I, II compared with the group III, but no a statistically significant difference between group I and II. Significant difference in quadriceps muscle activation was observed in the group I, II compared with the group III (p<0.05, p<0.01). Results of post-hoc, significant difference in quadriceps muscle activation in on group I, II compared with the group III and significant difference between group I and group II. Conclusion: This research intervened WBV for soccer players and compared the differences of CMJ and quadriceps muscle activation; as a result of the effective frequency for improving performance, there is a significant difference in CMJ and quadriceps muscle activation of WBV group with comparison of control group; and it was proved that WBV is effective using 30 Hz frequency for improving quadriceps muscle activation.

시간영역에서 ISSC TLP의 비선형 응답 특성 (Nonlinear Response Characteristics of the ISSC TLP in Time Domain)

  • 이창호
    • 한국해양공학회지
    • /
    • 제20권5호
    • /
    • pp.30-35
    • /
    • 2006
  • In tire presence of incident waves with different frequencies, there are second order sum and difference frequency wave exciting forces due to the nonlinearity of tire incident waves. Although the magnitude of these nonlinear wave forces are small, they act on TLPs at sum and difference frequencies away from those of the incident waves. So, the second order sum and difference frequency waveexciting forces occurring close to tire natural frequencies of TLPs often give greater contributions to high and law frequency resonant responses. Nonlinear motion responses and tension variations in the time domain are analyzed by solving the motion equations with nonlinear wave exciting forces using tire numerical analysismethod. The numerical results of time domain analysis for the nonlinear wave exciting forces on the ISSC TLP in regular waves are compared with the numerical and experimental ones of frequency domain analysis. The results of this comparison confirmed tire validity of the proposed approach.

주파수 차이 검출기를 이용한 광파의 off-set 주파수 로킹 연구 (A Study on the Lightwave off-set Locking using Frequency Difference Detector)

  • 유강희
    • 한국정보통신학회논문지
    • /
    • 제8권2호
    • /
    • pp.484-493
    • /
    • 2004
  • 본 논문은 초고주파 주파수 차이 검출기를 이용한 광파의 off-set 로킹에 대하여 설계 및 제작 실험 결과를 기술하였다. 두 광파를 비팅하여 중간 주파수인 1.5GHz 주파수 성분을 추출하고 이 값을 다시 1.5GHz 기준 발진기 주파수와 곱하여 차이주파수 성분을 추출한 후 주파수 차이 검출기를 이용하여 주파수 로킹을 시켰다. 상용화된 초고주파 부품을 사용하여 주파수 차이 검출기를 제작하였으며 1.55$\mu\textrm{m}$ 파장의 반도체 레이저의 발생 광파를 입력 광파와 1.5GHz의 주파수 off-set을 유지하면서 로킹이 이루어짐을 확인하였으며 로킹 범위는 320MHz이었다.

발달장애아동의 중증도에 따른 어머니의 요통 빈도 비교 (Comparison of low back pain frequency mother owing to severity of Developmental-children with disability)

  • 임형원
    • 대한물리치료과학회지
    • /
    • 제13권2호
    • /
    • pp.27-36
    • /
    • 2006
  • The purpose of this study would like to analyze statically significant difference for low back-pain frequency of mother after development-disability children. Seven nursery children with disability conducted survey from 122 mothers cared children with disability. Survey data was obtained from April 14. 2006 to May 23. 2006. The results were as follows: According to walking-existence, assistance walking, and disability-degree, low back pain incidence frequency of mothers were statically significant difference, (p<0.05). Low back pain incidence frequency of walker-ability population was 51.4%, but low back pain incidence frequency of walker-disability population was 80.0%. then low back pain incidence frequency of mothers to walking-existence was differed amount. Disabled not statically significant difference to encephalopathy and disability-type1 and disability -type2 (p>0.05). children with disability-degree and assistance walking benchmarked low back pain disability-measure. Low back pain degree not relevancy statically significant. Physical load was statically significant difference between Oswestry's low back pain score and reach effect to child-cared(p<0.05). As development-children with disability of disable degree, Mother appeared to highly low back pain frequency rate and appeared to large reach effect child-cared owing to physical load of low back pain. So hereafter, location and person request to approach with more clinical and objectively. As approach result, it will help to stress solution of children with disability owing to develop to low back pain class and family capable strengthening program and so on.

  • PDF

지연시차에 따른 발파진동의 주파수 특성 예측 (Prediction of Principal Frequency of Ground Vibration from Delayed Blasting)

  • 정두성;강추원;고진석;장호민;류복현
    • 터널과지하공간
    • /
    • 제20권2호
    • /
    • pp.112-118
    • /
    • 2010
  • 도심지 발파와 같이 인체나 구조물에 직접적인 영향을 미칠 수 있는 발파 작업 시에는 지반진동의 영향성 평가 작업이 필수적으로 선행되어야 한다. 이로 인해 주파수가 지반진동의 특성에 관하여 미치는 영향과 피해여부를 판단하는 중요한 요소로 인식되고 있다. 주파수의 영향에 대해서 많은 연구가 이뤄지고 있지만, 이러한 연구들은 지반진동의 발생과 전파에 있어서 지연시차에 따른 주파수 특성을 연구한 것은 아니었다. 따라서 본 연구에서는 Langefors의 시차이론에 근거한 단일공 파형에 의한 중첩모델링으로 얻어진 지연시차를 통하여 지반 진동의 간섭에 있어 보강과 상쇄간섭이 반복되는 각각의 지연시차에 따른 주파수의 관계를 고찰하였다.

차체 구조 차이에 따른 충돌 고주파 신호 전달성 연구 (A Study on the Signal Transmissibility of High Frequency Crash Pulse according to the Car Structure Difference)

  • 박동규
    • 한국자동차공학회논문집
    • /
    • 제21권6호
    • /
    • pp.8-15
    • /
    • 2013
  • Wide range frequency pulses occur in a car crash test. Until now, low frequency under 400Hz has been used to determine an airbag deployment criteria. Also, FIS (Front Impact Sensor) has been used to detect the crash pulse in early stage. Nowadays, technology to determine an airbag delpoyment criteria by using a high frequency crash pulse without FIS is being focused on. In this paper, the signal transmissibility of high frequency pulse for two different cars was studied. Also, signal transfer test of high frequency pulse was done by using a high speed ball impact. Signal runtime of the frontal impact is compared with that of the side impact. The signal transmissibility difference due to the car structure difference was discussed and structure change for improving the signal transmissibility was proposed.

차량 부밍소음의 청감 변화 인지를 위한 주파수 역치 (Difference Limen for Just Noticeable Change of Booming Sensation in Frequency)

  • 신성환;이정권
    • 한국소음진동공학회:학술대회논문집
    • /
    • 한국소음진동공학회 2005년도 춘계학술대회논문집
    • /
    • pp.621-624
    • /
    • 2005
  • Among many auditory feelings for the vehicle interior noise, booming is considered as the most important nuisance to the passenger and developer. Because the main source of booming noise is a power train system including engine, in general, it consists of tonal components related to fundamental engine rotation and its harmonics including the firing frequency. Therefore, it is demanded to extract the effective tonal components only by using pitch extraction algorithm based on the place theory enable to find aurally relevant tonal components. However, there is a difference between booming sensation and pitch perception according to frequency change of tonal component. In this study, subjective listening test using a tracking method was performed to find the difference limen for just noticeable change of booming sensation in frequency. 20 Koreans and 10 Japanese were participated in this test and the results obtained from Koreans and Japanese were compared with each other. Finally, 5Hz was determined as the difference limen for just noticeable change of booming sensation in frequency, and by applying this value to booming analysis using pitch concept, it was confirmed that the degree of prediction of booming sensation was improved.

  • PDF

주파수 추적을 위한 직병렬 구조의 새로운 주종 필터뱅크 (A New Master-Slave Filter-Bank with Series-Parallel Structure for Tracking Center Frequency)

  • 윤형식;임재환;이석필;박상희
    • 대한전기학회논문지
    • /
    • 제43권2호
    • /
    • pp.339-345
    • /
    • 1994
  • A new filter-bank is proposed in order to track center frequency of narrow band signal. The two banks are connected in series-parallel. The master filter bank which is made of traditional filter bank detects the center frequency roughly. And the performance for tracking center frequency is greatly improved by the slave filter bank which is based on energy-difference estimator. Computer simulations show that it achieves a good tracking accuracy.

  • PDF