• Journal of Power System Engineering
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• v.18 no.3
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• pp.36-41
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• 2014

The structure of a variable liquid column oscillator(a VLCO) is analogous to that of the tuned liquid column damper used to suppress oscillatory motion in large structures like tall buildings and cargo ships. The VLCO is a system absorbing high kinetic energy of accelerated motions of the multiple floating bodies in the effect of air springs occurred by installation of inner air chambers. Thus, VLCO can improve the efficiency of energy than wave energy converters of the activating object type made in Pelamis Company. In this research, the experiment was performed in two models of same draft. The one is that weights were filled, and the other is that water was filled. The numerical results were estimated by assuming that do not exist internal flow, and the results were compared with the results of experiments.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.9
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• pp.106-110
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• 2002

A need fer stable and comfortable cabins in the high-speed passenger ships has increased. For active control of the motion of the ship cabin, a few control algorithms have been applied to the three dimensional real models in the vibration basin. Experimental results show that the feedforward neural network with a linear feedback controller is one of the promising control algorithms for this active control.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.774-781
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• 2006

This paper presents a study on the analytical prediction of vibration transmission from helical gears to the bearing. The proposed method is based on the application of the three dimensional helical gear behaviors and complete description of shaft by the spectral method. Helical gear system used in this paper consists of the driving element, helical gears, shafts, bearings, couplings and load element. In order to describe all translation and rotation motion of helical gears twelve degree of freedom equations of motion by the transmission error excitation are derived. Using these equations, transfer matrix for the helical gear is derived. For the detail behavior of shaft motion, the $12{\times}12$ transfer matrix for the shaft is derived. Transfer matrix for the bearing, coupling, driving element, and load is also derived. Application of the boundary conditions in the assembled transfer matrix produces the forces and displacements in each element of the helical gear system. The effect of the proposed method is shown by numerical example.

• Journal of Ocean Engineering and Technology
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• v.2 no.2
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• pp.27-36
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• 1988

For the purposes of drilling oil field and extracting oil deep water in more rough weather, the size of drilling rigs must be estimated. In this paper, the three dimensional source distribution method is used and we assume 10 deg. heeling and trimming condition of the drilling rig(SR-192). Also, the effects of the hydrodynamic forces which include the drift forces for field method, and the motion responses are studied with changing the incident wave direction in the assumed inclining condition. The theory and numerical codes used in this thesis appeared to be very useful for the preliminary design of drilling rigs.

• 한국전산유체공학회:학술대회논문집
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• 1999.05a
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• pp.66-72
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• 1999

A numerical simulation method has been under development for solving turbulent flows around a ship model in maneuvering motion using the Reynolds Averaged Navier-Stokes equations. The method used second-order finite differences, collocated grids, pressure-Poisson equation and four-stage Runge-Kutta scheme as key components of the solution method. A modified Baldwin-Lomax model is used for the turbulence closure. This paper presents a preliminary result of the computational study on turbulent flows past a ship model in drift motion. Calculations are carried out for a Series 60 $C_B=0.6$ ship model, for which detailed experimental data are available. The results of the present calculations are compared with the experimental data for hydrodynamic forces acting on the model as well as velocity distributions at longitudinal sections. Only fair agreements has been achieved. The computational results show the complex asymmetrical shear flow patterns including three-dimensional separations followed by formation of bilge vortices both in bow and stern regions.

• Journal of the Society of Naval Architects of Korea
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• v.45 no.3
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• pp.229-237
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• 2008

For predicting the motion and structural responses of tension leg platforms(TLPs) in regular waves, a numerical scheme is introduced. The numerical approach in this paper is based on a combination of the three dimensional source distribution method and the finite element method. The hydrodynamic interactions among TLP members, such as columns and pontoons, are included in the motion and structural response analysis. The drag forces on the submerged slender members, which are proportional to the square of relative velocity, are newly included in order to estimate the responses of members with better accuracy. Comparisons with other's results verifies the works in this paper.

• Structural Engineering and Mechanics
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• v.38 no.2
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• pp.195-210
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• 2011

Bernoulli-Euler beam theory is used to develop an exact dynamic stiffness matrix for the flexural-torsional coupled motion of a three-dimensional, axially loaded, thin-walled beam of doubly asymmetric cross-section. This is achieved through solution of the differential equations governing the motion of the beam including warping stiffness. The uniform distribution of mass in the member is also accounted for exactly, thus necessitating the solution of a transcendental eigenvalue problem. This is accomplished using the Wittrick-Williams algorithm. Finally, examples are given to confirm the accuracy of the theory presented, together with an assessment of the effects of axial load and loading eccentricity.

• Journal of Information Display
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• v.12 no.1
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• pp.43-46
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• 2011

A three-dimensional windshield display (3D-WSD) can present driving information at the same depth as the objects in the outside scene. Herein, a super-multiview 3D-WSD is proposed because the super-multiview display technique provides smooth motion parallax. Motion parallax is the only physiological cue for perceiving the depth of a 3D image displayed at a far distance, which cannot be perceived by vergence and binocular parallax. A prototype system with 36 views was constructed, and the discontinuity of motion parallax and accuracy of depth perception were evaluated.

• Journal of Biomedical Engineering Research
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• v.15 no.3
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• pp.289-294
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• 1994

A new type of electrogoniometer to measure the three dimensional motion of the human knee joint was developed. This instrument is composed of six potentiometers: four arranged for two universal joints, one for pin joint, and one for axial rotation measurement. The voltage change in six potentiometers were collected through A/D converter for acquisition, storage and analysis. With a developed instrument, gait analysis was performed. Compared to earlier developed triaxial type goniometer, new instrument shows its convenience in application and accuracy in measurement.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.5 s.170
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• pp.95-102
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• 2005

The coordination of locomotion and manipulation has been the typical and main issue for a mobile manipulator. This is particularly because the solution for the control parameters is redundant and the accuracies of controlling the each joints are different. This paper presents a motion planning method for which the mobile base locomotion is less precise than the manipulator control. In such a case, it is appropriate to move the mobile base to discrete poses and then to move the manipulator to track a prescribed path of the end effector, while the base is stationary. It uses a variant of the conventional manipulability measure that is developed for the trajectory control of the end effector of the mobile manipulator along an arbitrary path in the three dimensional space. The proposed method was implemented on the simulation and the experiments of a mobile manipulator and showed its effectiveness.