• Title/Summary/Keyword: Relative Motion

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A Region Depth Estimation Algorithm using Motion Vector from Monocular Video Sequence (단안영상에서 움직임 벡터를 이용한 영역의 깊이추정)

  • 손정만;박영민;윤영우
    • Journal of the Institute of Convergence Signal Processing
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    • v.5 no.2
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    • pp.96-105
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    • 2004
  • The recovering 3D image from 2D requires the depth information for each picture element. The manual creation of those 3D models is time consuming and expensive. The goal in this paper is to estimate the relative depth information of every region from single view image with camera translation. The paper is based on the fact that the motion of every point within image which taken from camera translation depends on the depth. Motion vector using full-search motion estimation is compensated for camera rotation and zooming. We have developed a framework that estimates the average frame depth by analyzing motion vector and then calculates relative depth of region to average frame depth. Simulation results show that the depth of region belongs to a near or far object is consistent accord with relative depth that man recognizes.

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Development of spine motion analyzer (척추운동 분석기의 개발)

  • 김영은;노병현;유진환;안정호
    • Journal of the Korean Society for Precision Engineering
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    • v.14 no.3
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    • pp.137-146
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    • 1997
  • External linkage type spine motion analysis was developed for relative trunk motion respect to the pelvis. A special programs for calculation of the relative angular motion and for graphical display were also developed. The developed device assured its accuracy and conveniency after application to 15 normal vol- unteers. Compare to the normal subjects, 18 patients treated with fixations and decompression surgery showed relatively large coupling motion. Optimal trajectory of the trunk motion derived from mathematical model in flexion and extension matched well with measurement for normal subjects.

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Extraction of Wave Energy Using the Coupled Heaving Motion of a Circular Cylinder and Linear Electric Generator (원기둥과 선형발전기의 연성 수직운동을 이용한 파 에너지 추출)

  • Cho, Il-Hyoung;Kweon, Hyuck-Min
    • Journal of Ocean Engineering and Technology
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    • v.25 no.6
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    • pp.9-16
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    • 2011
  • The feasibility of wave energy extraction from a heaving truncated cylinder and the corresponding response of the linear electric generator (LEG) composed of spring, magnet, and coil has been investigated in the frame of three-dimensional linear potential theory. The heaving motion of a circular cylinder is calculated by means of the matched eigenfunction expansion method. Further, the analytical results are validated by numerical results using the ANSYS AQWA commercial code. By the action of a heaving circular cylinder, the magnet suspended by a spring can slide vertically inside the heaving cylinder. The mechanical power is extracted from the magnet motion relative to the coil/stator which is attached to the cylinder. The coupled ODE of a heaving cylinder and LEG system in waves is derived to obtain the magnet motion relative to a cylinder. To maximize the relative motion of the magnet, both the buoy draft and the LEG system parameters (spring stiffness, damping) should be selected properly for generating the double resonance considering the peak frequency of the target spectrum.

A Method for Reducing the Effect of Disk Radial Runout for a High-Speed Optical Disk Drive (고속 광 디스크 드라이브를 위한 디스크의 편심 보상 방법)

  • Ryoo Jung Rae;Moon Jung-Ho
    • Journal of Institute of Control, Robotics and Systems
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    • v.12 no.2
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    • pp.101-105
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    • 2006
  • Disk radial runout creates a periodic relative motion between the laser beam spot and tracks formed on an optical disk. While only focus control is activated, the periodic relative motion yields sinusoid-like waves in the tracking error signal, where one cycle of the sinusoid-like waves corresponds to one track. The frequency of the sinusoid-like waves varies depending on the disk rotational speed and the amount of the disk radial runout. If the frequency of the tracking error signal in the off-track state is too high due to large radial runout of the disk, it is not a simple matter to begin track-following control stably. It might take a long time to reach a steady state or tracking control might fail to reach a stable steady state in the worst case. This article proposes a simple method for reducing the relative motion caused by the disk radial runout in the off-track state. The relative motion in the off-track state is effectively reduced by a drive input obtained through measurements of the tracking error signal and simple calculations based on the measurements, which helps reduce the transient response time of the track-following control. The validity of the proposed method is verified through an experiment using an optical disk drive.

Derivation and Verification of the Relative Dynamics Equations for Aerial Refueling (공중재급유를 위한 상대운동방정식 유도 및 검증)

  • Jang, Jieun;Lee, Sangjong;Ryu, Hyuk
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.21 no.4
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    • pp.1-10
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    • 2013
  • This paper addresses the derivation of 6-DOF equation of Tanker and Receiver's aircraft for aerial refueling. The new set of nonlinear equations are derived in terms of the relative translational and rotational motion of receiver aircraft respect to the tanker aircraft body frame. Further the wind effect terms due to the tanker's turbulence are included. The derivation of absolute dynamic equation for tanker aircraft written in the inertial frame is calculated from the relative dynamics equations of receiver. The derived relative and absolute equations are implemented the simulation in the same flight conditions to verify the relative motion and compare the trim results by using the MATLAB/SIMULINK program.

Analysis of Relative Bow Displacements of a Ship in Regula Waves (선박(船舶)의 규칙파중(規則波中)에서의 상대선수변위(相對船首變位)의 해석(解析))

  • D.H.,Bai;Hyo-Chul,Kim;S.H.,Kang;K.P.,Rhee
    • Bulletin of the Society of Naval Architects of Korea
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    • v.19 no.4
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    • pp.53-59
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    • 1982
  • Relative bow-motions of a ship in wave are investigated by using linear theory. The relative displacement is assumed to be composed of incident wave elevation, motion response, dynamic swell-up and ship wave elevation. Radiation problem is solved by distributing sources on the hull surface and wave elevation in a uniform stream is obtained by integrating Havelock's function with centerplane source distributions. Relative displacements for I.T.T.C. S7-175 model are calculated. Dynamic swell-ups make the relative displacement larger except small heading angles. Amplitudes of relative motion on weather-side are generally larger than those on lee-side. Ship wave elevations in a uniform stream also give considerable contributions and our calculations are verified to be reasonable in comparison with experimental results.

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An Unstructured 3-D Chimera Technique for Overlapped Bodies inRelative Motion (3차원 비정렬 중첩격자계를 이용한 서로 겹쳐진 물체들 간의 상대운동 해석기법에 관한 연구)

  • 안상준;권오준;정문승
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.34 no.8
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    • pp.1-7
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    • 2006
  • In the present study, A 3-D chimera technique for overlapped bodies in relative motion is studied using unstructured meshes. If all node points of a mesh element at solid boundary are in another body, this element is excluded from computational domain. For computation of unsteady flow, non-active cells have proper variables using interpolation and extrapolation. These variables are used in next time step. The motion of a launching trajectory ejected from a wing and the motion of deploying fins of a trajectory which have not been simulated are computed to conform practicality of this technique.

Method for Collision Avoidance Motion Coordination of Multiple Mobile Robots Using Central Observation (다중 이동 로봇의 중앙 감시에 의한 충돌 회피 동작조정 방법)

  • Ko Nak Yong;Seo Dong-Jin
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.52 no.4
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    • pp.223-232
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    • 2003
  • This paper presents a new method driving multiple robots to their goal position without collision. Each robot adjusts its motion based on the information on the goal location, velocity, and position of the robot and the velocity and position of the .other robots. To consider the movement of the robots in a work area, we adopt the concept of avoidability measure. The avoidability measure figures the degree of how easily a robot can avoid other robots considering the following factors: the distance from the robot to the other robots, velocity of the robot and the other robots. To implement the concept in moving robot avoidance, relative distance between the robots is derived. Our method combines the relative distance with an artificial potential field method. The proposed method is simulated for several cases. The results show that the proposed method steers robots to open space anticipating the approach of other robots. In contrast, the usual potential field method sometimes fails preventing collision or causes hasty motion, because it initiates avoidance motion later than the proposed method. The proposed method can be used to move robots in a robot soccer team to their appropriate position without collision as fast as possible.

SHORT-TERM COMPARISON OF SEVERAL SOLUTIONS OF ELLIPTIC RELATIVE MOTION (타원 상대운동 여러 궤도 해의 단주기 비교)

  • Jo, Jung-Hyun;Lee, Woo-Kyoung;Baek, Jeong-Ho;Choe, Nam-Mi
    • Journal of Astronomy and Space Sciences
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    • v.24 no.4
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    • pp.315-326
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    • 2007
  • Recently introduced, several explicit solutions of relative motion between neighboring elliptic satellite orbits are reviewed. The performance of these solutions is compared with an analytic solution of the general linearized equation of motion. The inversion solution by the Hill-Clohessy-Wiltshire equations is used to produce the initial condition of numerical results. Despite the difference of the reference orbit, the relative motion with the relatively small eccentricity shows the similar results on elliptic case and circular case. In case of the 'chief' satellite with the relatively large eccentricity, HCW equation with the circular reference orbit has relatively larger error than other elliptic equation of motion does.

Development of an Efficient Vehicle Dynamics Model Using Massless Link of a Suspension (현가장치 무질량 링크를 이용한 효율적인 차량동역학 모델 개발)

  • Jung Hongkyu;Kim Sangsup
    • Transactions of the Korean Society of Automotive Engineers
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    • v.13 no.1
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    • pp.99-108
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    • 2005
  • This paper represents an efficient modeling method of a suspension system for the vehicle dynamic simulation. The suspension links are modeled as composite joints. The motion of wheel is defined as relative one degree of freedom motion with respect to car body. The unique relative kinematic constraint formulation between the car body and wheel enables to derive equations of motion in terms of wheel vertical motion. Thus, vehicle model has ten degrees of freedom. By using velocity transformation method, the equations of motion of the vehicle is systematically derived without kinematic constraints. Various vehicle simulation such as J-turn, slowly increasing steer, sinusoidal sweep steer and bump run has been performed to verify the validity of the suggested vehicle model.