• 제목/요약/키워드: Dynamic coordinate system

검색결과 212건 처리시간 0.029초

자동 볼 평형장치의 진동 해석 (Vibration Analysis of an Automatic Ball Balancer)

  • 박준민;노대성;정진태
    • 소음진동
    • /
    • 제9권2호
    • /
    • pp.363-370
    • /
    • 1999
  • In this study, we establish a theory for dynamic behaviors of an automatic ball balancer, analyze its dynamic characteristics, and provide its design guide line. Equations of motion are derived by using the polar coordinate system instead of the rectangular coordinate system which was previously used in other researches. After nondimensionalization of the equations, the perturbation method is applied to locate the equilibrium positions and to obtain the linearized equations of motion around the equilibrium positions. The Eigenvalue problem is used to verify the dynamic stability around the equilibrium positions. On the other hand, the time responses are computed from the nonlinear equations of motion by using a time integration method.

  • PDF

다물체 시스템이 이동하는 유연한 케이블의 동역학 해석에 관한 연구 (Dynamic Analysis of a Very Flexible Cable Carrying A Moving Multibody System)

  • 서종휘;정일호;한형석;박태원
    • 한국소음진동공학회논문집
    • /
    • 제14권2호
    • /
    • pp.150-156
    • /
    • 2004
  • In this paper, the dynamic behavior of a very flexible cable due to moving multibody system along its length is presented. The very deformable motion of a cable is presented using absolute nodal coordinate formulation, which is based on the finite element procedures and the general continuum mechanics theory to represent the elastic forces. Formulation for the sliding joint between a very flexible beam and a rigid body is derived. In order to formulate the constraint equations of this joint, a non-generalized coordinate, which has no inertia or forces associated with this coordinate, is used. The modeling of this sliding joint is very important to many mechanical applications such as the ski lifts. cable cars, and pulley systems. A multibody system moves along an elastic cable using this sliding joint. A numerical example is shownusing the developed analysis program for flexible multibody systems that include a large deformable cable.

탄성 시스템에서의 효율적인 좌표분할법 선정에 관한 연구 (Selection of efficient coordinate partitioning methods in flexible multibody systems)

  • 김외조;유완석
    • 대한기계학회논문집A
    • /
    • 제21권8호
    • /
    • pp.1311-1321
    • /
    • 1997
  • In multibody dynamics, differential and algebraic equations which can satisfy both equation of motion and kinematic constraint equation should be solved. To solve these equations, coordinate partitioning method and constraint stabilization method are commonly used. In the coordinate partitioning method, the coordinates are divided into independent and dependent and coordinates. The most typical coordinate partitioning method are LU decomposition, QR decomposition, and SVD (singular value decomposition). The objective of this research is to find an efficient coordinate partitioning method in the dynamic analysis of flexible multibody systems. Comparing two coordinate partitioning methods, i.e. LU and QR decomposition in the flexible multibody systems, a new hybrid coordinate partitioning method is suggested for the flexible multibody analysis.

조류와 파랑 중에서의 TLP의 동적구조응답해석 (A Dynamic structural response analysis of tension leg platforms in current and waves)

  • 이승철;구자삼;하영록;조효제
    • 동력기계공학회지
    • /
    • 제16권1호
    • /
    • pp.65-71
    • /
    • 2012
  • A numerical procedure is described for predicting the dynamic structural responses of tension leg platforms(TLPs) in current and waves. The developed numerical approach is based on a combination of the three dimensional source distribution method and the dynamic structural analysis method, in which the superstructure of the TLPs is assumed to be flexible instead of rigid. The hydrodynamic interactions among TLP members, such as columns and pontoons, and the structural damping are included in the dynamic structural analysis. The equations of motion of a whole structure are formulated using element-fixed coordinate systems which have the origin at the nodes of the each hull element and move parallel to a space-fixed coordinate system. The dynamic structural responses of a TLP were analyzed in the case of including the current or not including the one in waves and the effects of current on the TLP were investigated.

4각 보행 로봇의 정적 걸음새 생성 (Static Gait Generation of Quadruped Walking Robot)

  • 김남웅;신효철;김국원
    • 한국공작기계학회논문집
    • /
    • 제16권6호
    • /
    • pp.217-222
    • /
    • 2007
  • This paper describes a static gait generation process and a mechanical design process of leg mechanisms for quadruped robots. Actually robot walking is realized with the joint motion of leg mechanisms. In order to calculate the time-angle trajectories for each joint of leg mechanisms, we generate end-tip trajectories with time for each leg in the global inertial coordinate system intuitively, followed by coordinate transformations of the trajectories into the local coordinates system fixed in each leg, finally the angle-time trajectories of each joint of leg mechanisms are obtained with inverse kinematics. The stability of the gait generated in this paper was verified by a multi-body dynamic analysis using the commercial software $ADAMS^{(R)}$. Additionally the mechanical specifications such as gear reduction ratio, electrical specifications of motor and electrical power consumption during walking have been confirmed by the multi-body dynamic analysis. Finally we constructed a small quadruped robot and confirmed the gait.

Motion Capture of the Human Body Using Multiple Depth Sensors

  • Kim, Yejin;Baek, Seongmin;Bae, Byung-Chull
    • ETRI Journal
    • /
    • 제39권2호
    • /
    • pp.181-190
    • /
    • 2017
  • The movements of the human body are difficult to capture owing to the complexity of the three-dimensional skeleton model and occlusion problems. In this paper, we propose a motion capture system that tracks dynamic human motions in real time. Without using external markers, the proposed system adopts multiple depth sensors (Microsoft Kinect) to overcome the occlusion and body rotation problems. To combine the joint data retrieved from the multiple sensors, our calibration process samples a point cloud from depth images and unifies the coordinate systems in point clouds into a single coordinate system via the iterative closest point method. Using noisy skeletal data from sensors, a posture reconstruction method is introduced to estimate the optimal joint positions for consistent motion generation. Based on the high tracking accuracy of the proposed system, we demonstrate that our system is applicable to various motion-based training programs in dance and Taekwondo.

전역좌표계에 근거한 부분구조합성법과 국부좌표계에 근거한 부분구조합성법의 비교 (Comparison of Substructure Synthesis Methods based on Global and Local Coordinates)

  • 곽문규;나성수;배병찬
    • 한국소음진동공학회논문집
    • /
    • 제16권7호
    • /
    • pp.712-719
    • /
    • 2006
  • This paper is concerned with the comparison of substructure synthesis methods based on global and local coordinates. The substructure synthesis methods based on the global coordinates were first proposed for the dynamic analysis of complex structure and the substructure synthesis method based on the local coordinates was proposed to solve the dynamic problem of tree-like structure. However, the conceptual difference between two methods in solving the dynamic problem has never been explained. In this paper, a structure consisting of two beams is considered to show the conceptual difference of two methods. The dynamic formulation shows the characteristics and differences of two methods explicitly. The procedure for choosing proper substructure modes in each method is also explained in detail. In addition, the advantage of the substructure synthesis method based on the local coordinate system is discussed based on the numerical example. Numerical examples show how two methods are applied to the addressed problem.

다중 모드/물리 좌표 합성법을 이용한 대형선박엔진의 동적 모델링 (Vibration Analysis for a Huge Marine Engine using a Multiple Mode/Physical Coordinate Synthesis Method)

  • 김재실;이재환;박원호;박형호
    • 한국산업경영시스템학회:학술대회논문집
    • /
    • 한국산업경영시스템학회 2002년도 춘계학술대회
    • /
    • pp.445-454
    • /
    • 2002
  • This article explains the theory of multiple mode/physical coordinate synthesis method in order to analyze the dynamic characteristics for an huge marine engine. The theory leads to make a simulation code. The natural frequencies obtained from the simulation code is compared to those from a commercial analysis software, ANSYS. The simulation code is well reviewed.

  • PDF

로보트 운동에 대한 공간 좌표 제어 (Cartesian Coordinate Control of Robot Motion)

  • 노영식;우광방
    • 대한전기학회논문지
    • /
    • 제35권5호
    • /
    • pp.177-184
    • /
    • 1986
  • An effective cartesian coordinate model is presented to control a robot motion along a prescribed timebased hand trajectory in cartesian coordinates and to provide an adaptive feedback design approach utilizing self-tuning control methods without requiring a detailed mathematical description of the system dynamics. Assuming that each of the hybrid variable set of velocities and forces at the cartesian coordinate level is mutually independent, the dynamic model for the cartesian coordinate control is reduced to first-order SISO models for each degree of freedom of robot hand, including a term to represent all unmodeled effects, by which the number of parameters to be identified is minimized. The self-tuners are designde to minimize a chosen performance criterion, and the computed control forces are resolved into applied joint torques by the Jacobian matrix. The robustness of the model and controller is demonstrated by comparing with the other catesian coordinate controllers.

  • PDF

Nozzle Swing Angle Measurement Involving Weighted Uncertainty of Feature Points Based on Rotation Parameters

  • Liang Wei;Ju Huo;Chen Cai
    • Current Optics and Photonics
    • /
    • 제8권3호
    • /
    • pp.300-306
    • /
    • 2024
  • To solve the nozzle swing angle non-contact measurement problem, we present a nozzle pose estimation algorithm involving weighted measurement uncertainty based on rotation parameters. Firstly, the instantaneous axis of the rocket nozzle is constructed and used to model the pivot point and the nozzle coordinate system. Then, the rotation matrix and translation vector are parameterized by Cayley-Gibbs-Rodriguez parameters, and the novel object space collinearity error equation involving weighted measurement uncertainty of feature points is constructed. The nozzle pose is obtained at this step by the Gröbner basis method. Finally, the swing angle is calculated based on the conversion relationship between the nozzle static coordinate system and the nozzle dynamic coordinate system. Experimental results prove the high accuracy and robustness of the proposed method. In the space of 1.5 m × 1.5 m × 1.5 m, the maximum angle error of nozzle swing is 0.103°.