• Title/Summary/Keyword: Angular Velocity

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피치제어형 풍력발전시스템의 속도제어 (Speed Control of a Wind Turbine System Based on Pitch Control)

  • 임종환;허종철
    • 제어로봇시스템학회논문지
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    • 제7권2호
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    • pp.109-116
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    • 2001
  • The paper presents a speed control algorithm for a full pitch-controlled wind turbine system. Torque of a blade generated by wind energy is a nonlinear function of wind speed, angular velocity, and pitch angle of the blade. The design of the controller, in general, is performed by linearizing the torque in the vicinity of the operating point assuming the angular velocity of the blade is constant. For speed control, however the angular velocity is on longer a constant, so that linearization of the torque in terms of wind speed and pitch angle is impossible. In this study, a reference pitch model is derived in terms of a wind speed, angular velocity, and pitch angle, which makes it possible to design a controller without linearizing the nonlinear torque model of the blade. This paper also suggests a method of designing a hydraulic control system for changing the pitch angle of the blade.

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단을 가진 수평축의 비틀림진동 측정에 관한 연구 (A Study on the Torsional Vibration Measurement of the Horizontal Shaft with Disks)

  • 박일수;안찬우;김중완
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1997년도 춘계학술대회 논문집
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    • pp.3-8
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    • 1997
  • This parer was presented for the experimental results of torsional vibrations of the horizontal rotating shaft with three disks. The torsional vibrations meter used is a laser system for non-contact measurement of torsional angular vibration velocity and torsional angular vibration displacement. The distance between the disks war changed; the one that had 76mm of disk distance war called basic model, and another that had 106mm of disk distance wide model, and other that had 46mm of disk distance narrow model. In each model, outer diameter of disk was 40mm. And 45mm, or 50mm was also used to extend the effective range of frequencies. The angula vibration displacement and the angular vibration velocity in its torsional vibration were measured to obtain the stable and the unstable regions.

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유체유동 회전 외팔 파이프의 안정성 해석 (Stability Analysis of a Rotating Cantilever Pipe Conveying Fluid)

  • 손인수;윤한익;김동진
    • 한국소음진동공학회논문집
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    • 제17권8호
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    • pp.701-707
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    • 2007
  • In this paper the vibration system is composed of a rotating cantilever pipe conveying fluid. The equation of motion is derived by using the Lagrange's equation. Generally, the system of pipe conveying fluid becomes unstable by flutter. Therefore, the influence of the rotating angular velocity, mass ratio and the velocity of fluid flow on the stability of a cantilever pipe by the numerical method are studied. The influence of mass ratio, the velocity of fluid, the angular velocity of a cantilever pipe and the coupling of these factors on the stability of a cantilever pipe are analytically clarified. The critical fluid velocity ($u_{cr}$) is proportional to the angular velocity of the cantilever pipe. In this paper Flutter(instability) is always occurred in the second mode of the system.

자동볼평형장치의 밸런싱 성능에 대한 중력과 속도파형의 영향 (Gravity and Angular Velocity Profile Effects on the Balancing Performance of an Automatic Ball Balancer)

  • 정진태;정두한
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2003년도 추계학술대회논문집
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    • pp.418-423
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    • 2003
  • The balancing performance of an automatic ball balancer (ABB) in the vertical or horizontal position is studied in this paper. Considering the effects of gravity and angular velocity profiles, a physical model for an ABB installed on the Jeffcott rotor is adopted. The non-linear equations of motion for the rotor with ABB are derived by using Lagrange's equation. Based on derived equations, dynamic responses for the rotor are computed by using the generalized-u method. From the computed responses, the effects of gravity and angular velocity profiles on the balancing performance are investigated. It is found that the rotor with ABB can be balanced regardless of the gravity effect. It is also shown that a smooth velocity profile yields relatively smaller vibration amplitude than a non-smooth velocity profile.

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제연구역 방화문의 각속도 변화와 폐쇄 조건 분석 (A Study on the Conditions of Injection Pressurization in the Smoke-Control Zone II. Analysis of the Conditions for Closing Force of Fire Door with Variation of Angular Velocity)

  • 이창욱;김홍진;최영기;염문천;유홍선
    • 한국화재소방학회논문지
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    • 제27권2호
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    • pp.6-10
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    • 2013
  • 본 연구는 풍도, 부속실, 거실 그리고 계단실로 구성된 구조물의 제연설비 성능에 관한 연구를 수행하고 급기 가압실의 안전성을 구현하기 위한 실험 자료를 구축하고자 하는데 목적이 있다. 이를 위해서 부속실 가압 및 차압 조절 설비와 방화문의 개폐력 측정 장치를 제작하였다. 본 주제는 부속실의 가압을 위한 설계유량과 폐쇄시 차압이 동일한 경우 방화문의 크기와 닫히는 각속도 증가에 따라서 폐쇄력을 분석하였다. 실험 결과 방화문의 크기와 닫히는 각속도가 증가 할수록 폐쇄력이 증가하였으며, 일정 각속도 이상으로 증가할 경우 폐쇄력이 일정하게 유지되는 임계각속도가 존재하는 것을 확인하였다.

각속도 측정시스템을 이용한 특발성 파킨슨병 환자와 정상인의 빠른 손놀림 동작의 비교 (Comparison of Movement of Rapid Alternating Movements of Hands in Idiopathic Parkinson's Disease Patients and Normal Subjects using Angular Velocity Measurement System)

  • 김지원;권유리;엄광문;전재훈;이정한;이정환;권도영;고성범;박병규
    • 전기학회논문지
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    • 제59권3호
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    • pp.674-677
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    • 2010
  • The purpose of this study was to analyze bradykinesia of forearm movement in patients with Parkinson's disease (PD) as compared to those of normal subjects. A gyrosensor was selected for the measurement of forearm movement, because it can provide angular velocity signal which is free from the gravitational artifact and also because it can be conveniently used during clinical test of bradykinesia. Forty PD patients (age: $65.7\pm11.1$ yrs, H&Y stage:$2.3\pm0.5$), 14 age-matched elderly subjects ($65\pm3.9$ yrs) and 17 healthy young subjects ($24\pm2.1$ yrs) participated in this study. Angular velocity during forearm movement of pronation/supination was measured in both arms. Suggested quantitative measures of bradykinesia were root-mean-squared (RMS) angular velocity, RMS angle, peak power and total power which were derived from the angular velocity. ANOVA showed that all measures were significantly different among three groups (p<0.001). Subsequent post-hoc test revealed that all measures in PD patients were significantly smaller than in healthy elderly and healthy young subjects (p<0.05). This results suggest that PD patients can be differentiated from normal subjects using suggested measures.

무인 달착륙선의 동력하강단계에서 자세각속도 영향에 따른 최적화 착륙궤적 분석 (Analysis of Optimal Landing Trajectory in Attitude Angular Velocity Influence at Powered Descent Phase of Robotic Lunar Lander)

  • 박재익;류동영
    • 한국항공우주학회지
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    • 제46권5호
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    • pp.402-409
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    • 2018
  • 이 논문에서는 무인 달착륙 임무를 위해 고려하고 있는 달착륙 시나리오를 제안하고 제안된 시나리오를 기반으로 동력하강단계에서의 최적화 착륙궤적을 구현한다. 동력하강단계에서 달착륙선의 자세 변화는 사용 연료량뿐만 아니라 영상기반 항법의 센서 운용에도 영향을 주므로 자세 변화가 급격하게 이루어지지 않도록 자세각속도를 최적제어 가격함수에 포함하고 이때 자세각속도의 영향을 조절하는 가중치가 최적화 착륙궤적에 미치는 영향을 분석한다. 분석된 결과를 바탕으로 연료 사용을 최소화하고 안정된 자세 변화를 갖도록 최적화 착륙궤적을 설계할 수 있는 적절한 가중치를 제시한다.

Gyroscope Free 관성 측정 장치를 이용한Attitude Heading Reference System 설계 (Design of Attitude Heading Reference System using Gyroscope Free Inertial Measurement Unit)

  • 손재훈;이상윤;김효석;황동환
    • Journal of Positioning, Navigation, and Timing
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    • 제13권3호
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    • pp.237-244
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    • 2024
  • An Attitude and Heading Reference System (AHRS) provides the attitude of a vehicle with a constant velocity using an Inertial Measurement Unit (IMU) and a magnetometer. In this case, in order to avoid the disadvantage of a gyroscope, an AHRS using a Gyro-Free IMU (GF-IMU) that is composed of only accelerometers may be considered instead of the gyroscopes. In this paper, a design method of an AHRS using a GF-IMU is proposed. The proposed AHRS consists of roll and pitch calculation, yaw calculation, angular acceleration and angular velocity calculation, attitude calculation, and a Kalman filter. In particular, since the angular velocity cannot be measured from a gyroscope, the angular acceleration is obtained from the accelerometer output, and the angular velocity is calculated by integrating it. In order to show the usefulness of the proposed method, a performance evaluation was carried out. The performance evaluation results show that the attitude estimation performance of the proposed AHRS is similar to that of the conventional AHRS.

골프 드라이버 스윙 시 임팩트 전·후 신체 균형성이 클럽헤드의 속도와 각도에 미치는 영향 (Effect of Balance before and after Impact on the Velocity and Angle of Golf Club during Driver Swing)

  • 류지선;김태삼
    • 한국운동역학회지
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    • 제21권4호
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    • pp.411-420
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    • 2011
  • The purpose of this investigation was to determine whether correlations exist between balance and impact velocity, angular position, and maximum velocity of a club during drive swing. Twelve skilled golfers were recruited in this study. They were asked to perform ten swing trials and two trials were selected for analysis. Balance parameters were calculated via the force platform while kinematic variables were determined by using the Qualisys system. The results of the present study demonstrated that the average of COP velocity was faster in the medio-lateral direction rather than the anterio-posterior direction. Also, left foot's COP velocity and free torque were greater than the right foot's before impact. The range of the right foot's COP in the anterio-posterior direction before impact were correlated with the club velocity and angular position at impact. There was a negative correlation between the left foot's COP velocity before the impact and the velocity at impact. Additionally, the range and RMS of the left foot's free torque affected on the club angular position at impact and the maximum velocity at release, respectively. Finally, a negative correlation existed between the range of the right foot's free torque after the impact and club's maximum velocity at release.

시간적으로 변하는 각속도를 가지는 실린더 내부의 비균질 유체의 스핀업 (Spin-up for stratified fluid in a cylinder with time-dependent rotation rate)

  • 김경섭;현재민
    • 유체기계공업학회:학술대회논문집
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    • 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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    • pp.323-326
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    • 2006
  • Numerical solutions for spin-up problem of a thermally stratified fluid in a cylinder with an insulating sidewall and time-dependent rotation rate are presented. Detailed results are given for aspect ratio of O(1), fixed Ekman number $10-^{4}$, Rossby number 0.05 and Prandtl number O(1). Angular velocity of a cylinder wall changes with following formula, $\Omega_f=\Omega_i+\Delta\Omega[1-\exp(-t/t_c)]$. Here, this $t_c$, value, which is very significant in present study, represents that how fast/slow the angular velocity of the cylinder wall reaches final angular velocity. The normalized azimuthal velocity and meridional flow plots for several tc value which cover ranges of the stratification parameter S(1 ~ 10) are presented. The role of viscous-diffusion and Coriolis term in present study is examined by diagnostic analysis of the azimuthal velocity equation.

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