• Title/Summary/Keyword: Lagrange stability

검색결과 72건 처리시간 0.028초

삼중레이스를 갖는 자동평형장치의 동적 해석 (Dynamic Analysis of an Automatic Ball Balancer with Triple Races)

  • 좌성훈;조은형;손진승;박준민;정진태
    • 대한기계학회논문집A
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    • 제26권4호
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    • pp.764-774
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    • 2002
  • Dynamic behaviors are analyzed for an automatic ball balancer (ABB) with triple races, which is a device to reduce the unbalanced mass of optical disk drives (ODD) such as CD-ROM or DVD drives. The nonlinear equations of motion are derived by using Lagrange's equations with the polar coordinate system. It is shown that the polar coordinate system provides the complete stability analysis while the rectangular coordinate system used in other previous studies has limitations on the stability analysis. For the stability analysis, the equilibrium positions and the linearized perturbation equations are obtained by the perturbation method. Based on the linearized equations, the stability of the system is analyzed around the equilibrium positions; furthermore, to confirm the stability, the time responses for the nonlinear equations of motion are computed by using a time integration method and experimental analyses are performed. Theoretical and experimental results show a superiority of the ABB with triple races.

Control Moment Gyroscope의 상태되먹임 제어기 설계 (State Feedback Controller Design for Control Moment Gyroscope)

  • 김태연;유준
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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    • pp.70-71
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    • 2007
  • This paper presents an application of LQR(Linear Quadratic Regulator) for experimental control moment gyroscope. To be specific, mathematical model is first derived based on the quaternion and Lagrange's equation, state feedback controller using LQR scheme is designed, and to show the stability of the scheme, experimental results are given.

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지능형 디지털 재설계 기법의 안정화 가능성에 대하여 (On the Stabilizability by the Intelligent Digital Redesign)

  • 이호재
    • 한국지능시스템학회:학술대회논문집
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    • 한국퍼지및지능시스템학회 2006년도 추계학술대회 학술발표 논문집 제16권 제2호
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    • pp.7-10
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    • 2006
  • 지능형 디지털 재설계 기법의 중요한 가정은 퍼지 IF-THEN 규칙의 발화도가 샘플링 구간에서 샘플링 순간의 값으로 근사화 된다는 점이다. 본 논문은 퍼지 IF-THEN 규칙 발화도의 근사화 가정을 배제한 경우에 대하여 기존의 지능형 디지털 재설계 기법에 의하여 재설계된 디지털 제어기의 안정화 가능성을 조사한다.

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COCYCLE EQUATIONS VIA COCHAINS AND HYPERSTABILITY OF RELATED FUNCTIONAL EQUATIONS

  • Young Whan Lee
    • Nonlinear Functional Analysis and Applications
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    • 제28권4호
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    • pp.865-876
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    • 2023
  • This paper presents properties of the cocycle equations via cochains on a semigroup. And then we offer hyperstability results of related functional equations using the properties of cocycle equations via cochains. These results generalize hyperstability results of a class of linear functional equation by Maksa and Páles. The obtained results can be applied to obtain hyperstability of various functional equations such as Euler-Lagrange type quadratic equations.

Impact of the Thruster Jet Flow of Ultra-large Container Ships on the Stability of Quay Walls

  • Hwang, Taegeon;Yeom, Gyeong-Seon;Seo, Minjang;Lee, Changmin;Lee, Woo-Dong
    • 한국해양공학회지
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    • 제35권6호
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    • pp.403-413
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    • 2021
  • As the size of ships increases, the size and output power of their thrusters also increase. When a large ship berths or unberths, the jet flow produced from its thruster has an adverse effect on the stability of quay walls. In this study, we conducted a numerical analysis to examine the impact of the thruster jet flow of a 30,000 TEU container ship, which is expected to be built in the near future, on the stability of a quay wall. In the numerical simulation, we used the fluid-structure interaction analysis technique of LS-DYNA, which is calculated by the overlapping capability using an arbitrary Lagrangian Eulerian formulation and Euler-Lagrange coupling algorithm with an explicit finite element method. As the ship approached the quay wall and the vertical position of the thruster approached the mound of the quay wall, the jet flow directly affected the foot-protection blocks and armor stones. The movement and separation of the foot-protection blocks and armor stones were confirmed in the area affected directly by the thruster jet flow of the container ship. Therefore, the thruster jet flows of ultra-large ships must be considered when planning and designing ports. In addition, the stability of existing port structures must be evaluated.

단일 시추공 전자탐사 자료 해석을 위한 빠른 역산법 (A Fast Inversion Method for Interpreting Single-Hole Electromagnetic Data)

  • 김희준;이정모
    • 지구물리와물리탐사
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    • 제5권4호
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    • pp.316-322
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    • 2002
  • 단일 시추공 환경에서 얻어지는 전자기장을 해석하기 위해 확장 Born 혹은 국소비선형 근사를 이용한 계산시간이 짧고 효율적인 역산법을 만들었다. 매질은 시추공에 관해 축대칭이라 가정하였으며 그 대칭성을 유지하기 위해 수직 자기 쌍극자원을 사용하였다. 역산법의 효율성과 안정성은 적절한 라그랑지계수의 사용에 크게 의존하지만 이는 일반적으로 원하는 수렴성을 달성하기 위해 수작업으로 결정된다. 본 연구에서는 현장 자료를 다루는 역산법의 효율을 향상하기 위해 라그랑지계수의 자동결정법을 개발하였다. 그 역산법의 안정성과 효율성은 이론모델링 자료를 사용하여 검토되었다.

유체유동 회전 외팔 파이프의 동특성 및 안정성 해석 (Dynamic Characteristics and Stability Analysis of a Rotating Cantilever Pipe Conveying Fluid)

  • 김동진;윤한익;손인수
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2007년도 춘계학술대회논문집
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    • pp.1185-1190
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    • 2007
  • In this paper the vibration system is consisted of a rotating cantilever pipe conveying fluid. The equation of motion is derived by using the Lagrange's equation. Also, the equation of motion is derived applying a modeling method that employs hybrid deformation variables. Generally, the system of pipe conveying fluid becomes unstable by flutter. So, we studied about the influences of the rotating angular velocity, mass ratio and the velocity of fluid flow on the stability of a cantilever pipe by the numerical method. The influences 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) always occur in the second mode of the system.

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종동력을 받는 크랙 외팔 보의 안정성 해석 (Stability Analysis of Cracked Cantilever Beam Subjected to Follower Force)

  • 안태수;윤한익;손인수
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2007년도 춘계학술대회논문집
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    • pp.215-218
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    • 2007
  • In this paper a dynamic behavior(natural frequency) of a cracked cantilever beam subjected to follower force is presented. In addition, an analysis of the flutter and buckling instability of a cracked cantilever beam subjected to a follower compressive load is presented. Based on the Euler-Bernouli beam theory, the equation of motion can be constructed by using the Lagrange's equation. The vibration analysis on such cracked beam is conducted to identify the critical follower force for flutter insstability based on the variation of the first two resonant frequencies of the beam. Besides, the effect of the crack's intensity and location on the flutter follower force is studied. The crack section is represented by a local flexibility matrix connecting two undamaged beam segments. The crack is assumed to be in the first mode of fracture and to be always opened during the vibrations.

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자동볼평형장치가 부착된 광디스크 드라이브의 동특성해석 (Dynamic Analysis of an Optical Disk Drive with an Automatic Ball Balancer)

  • 김강성;정진태
    • 대한기계학회논문집A
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    • 제26권12호
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    • pp.2511-2518
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    • 2002
  • Dynamic behaviors and stability of an optical disk drive coupled with an automatic ball balancer (ABB) are analyzed by a theoretical approach. The feeding system is modeled a rigid body with six degree-of-freedom. Using Lagrange's equation, we derive the nonlinear equations of motion for a non -autonomous system with respect to the rectangular coordinate. To investigate the dynamic stability of the system in the neighborhood of the equilibrium positions, the monodromy matrix technique is applied to the perturbed equations. On the other hand, time responses are computed by the Runge -Kutta method. We also investigate the effects of the damping coefficient and the position of ABB on the dynamic behaviors of the system.

크랙을 가진 유체유동 파이프의 안정성 및 동특성 해석 (Stability and Dynamic Behavior of Cracked Pipe Conveying Fluid)

  • 윤한익;손인수;안성진
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 2006년도 정기 학술대회 논문집
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    • pp.703-708
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    • 2006
  • In this paper a dynamic behavior(natural frequency) of a cracked simply supported pipe conveying fluid is presented. In addition, an analysis of the buckling instability of a cracked pipe conveying fluid subjected to a follower compressive load is presented. Based on the Euler-Bernouli beam theory, the equation of motion can be constructed by using the Lagrange's equation. The crack section is represented by a local flexibility matrix connecting two undamaged beam segments. TI1e crack is assumed to be in the first mode of fracture and to be always opened during the vibrations.

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