• Journal of Institute of Control, Robotics and Systems
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• v.17 no.4
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• pp.375-381
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• 2011

This paper deals with the improvement of visual path following through velocity variation according to the coordinate of feature points. Visual path follow first teaches driving path by selecting milestone images then follows the route by comparing the milestone image and current image. We follow the visual path following algorithm of Chen and Birchfield [8]. In [8], they use fixed translational and rotational velocity. We propose an algorithm that uses different translational velocity according to the driving condition. Translational velocity is adjusted according to the variation of the coordinate of feature points on image. Experimental results including diverse indoor cases show the feasibility of the proposed algorithm.

• Journal of Korea Game Society
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• v.10 no.6
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• pp.57-65
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• 2010

In this paper, mobility performance indices are proposed which may be used to estimate characteristics of output velocity space in six-degree-of-freedom parallel mechanism. In order for manipulability and condition number to not suffer from lack of the physical meaning due to dimensional inhomogeneity, output space is partitioned into translational velocity space and rotational velocity space, respectively. In each space, mobility ellipsoids corresponding to unit input space are defined and two types of mobility performance in translational velocity spaces indices are derived. Two types of mobility performance in rotational velocity spaces indices are derived.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.8 s.197
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• pp.50-57
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• 2007

In this paper, two types of novel planar Translational Parallel Manipulators (TPMs) by using parallelogram mechanism are conceived. One is made up of two Pa-P (Parallelogram-Prismatic) legs connecting the base to the moving platform. The other consists of two P-Pa legs, which is the kinematic inversion of the former. Since connecting links in a parallelogram mechanism are subject to only tensile/compressive load and all the heavy actuators are mounted at the base, the proposed manipulators can be applied for planar positioning/assembly tasks requiring high stiffness and high speed. The position, velocity, and statics are analyzed, and the design methodology using prescribed workspace and velocity transmission capability is presented. Finally, two types of prototype manipulators have been developed.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.1
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• pp.32-44
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• 2015

In general, a series of ship steering motion is represented by the combination of translational motion and rotational motion of the ship. Especially, special-functioned ships such as large-scale cruises, ships for installing underwater optical cable, and diver ships must be able to reveal only a translational motion without the change of orientation. In this paper, a method to comprise an integrated control system based on the joystick as a command instrument for translational motion control is suggested. In order to realize the translational motion control system, several algorithms are suggested including the velocity command generation, the selection of motional variables, and the generation and tracking of reference inputs for the selected motional variables. A simulation bench is composed to execute simulations for several translational motion commands. At last, the effectiveness of the proposed method is verified by analyzing the simulation results.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.46-48
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• 2004

This paper presents a simple method of rotational and translational motion estimation for digital image stabilization. The scheme first computes the rotation center by taking least squares of selected local velocity vectors, and the rotational angle is found from special subset of motion vectors. And then translational motion can be estimated by the relation among movement of rotation center, rotation angle and translation movement. To show the effectiveness of our approach, the synthetic images are evaluated, resulting in better performance.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.3
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• pp.313-320
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• 1999

The Lane-Curvature Method(LCM) presented in this paper is a new local obstacle avoidance method for indoor mobile robots. The method combines Curvature-Velocith Method(CVM) with a new directional method called the Lane Method. The Lane Method divides the environment into lanes taking the information on obstacles and desired heading of the robot into account ; then it chooses the best lane to follow to optimize travel along a desired heading. A local heading is then calculated for entering and following the best lane, and CVM uses this heading to determine the optimal translational and rotational velocity space methods, LCM yields safe collision-free motion as well as smooth motion taking the dynamics of the robot Xavier, show the efficiency of the proposed method.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.385-386
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• 2007

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.757-761
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• 2008

The aerostat dynamic equation of motion has been built including the tether cable dynamic effects. A numerical program to solve the derived equation of motion has been developed. The dynamic motion of the 32m aerostat has been analyzed under discrete gust and continuous turbulence. The aerostat behaviors under discrete gust which represents a deterministic approach for determining design loads for manned aircraft are solved to verify the effect of aerostat mechanical properties on the aerostat dynamic behavior. Continuous turbulences are simulated for each given altitude, translational mean wind velocity and gust intensity. Dynamic behaviors of the 32m aerostat are simulated for each continuous turbulence conditions. Translational and vertical velocity and pitching behavior and tether reaction force are monitored for each simulation.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.3
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• pp.191-197
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• 2017

In this study, the visualization of the unsteady flow field of a Weis-Fogh-type water turbine was investigated using particle-image velocimetry. The visualization experiments were performed in a parameter range that provided relatively high-efficiency wing conditions, that is, at a wing opening angle ${\alpha}=40^{\circ}$ and at a velocity ratio of the uniform flow to the moving wing U/V = 1.5~2.5. The flow fields at the opening, translational, and closing stages were investigated for each experimental parameter. In the opening stage, the fluid was drawn in between the wing and wall at a velocity that increased with an increase in the opening angle and velocity ratio. In the translational stage, the fluid on the pressure face of the wing moved in the direction of the wing motion, and the boundary layer at the back face of the wing was the thinnest and had a velocity ratio of 2.0. In the closing stage, the fluid between the wing and wall was jetted at a velocity that increased as the opening angle decreased; however, the velocity was independent of the velocity ratio.

• The Journal of the Acoustical Society of Korea
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• v.24 no.1E
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• pp.7-15
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• 2005

This paper addresses issues encountered in measuring the general, 6-degree-of-freedom motion of a human head, A complete mathematical description for measuring the head motion using the six-accelerometer configured bite-bar is suggested, The description shows that the six-axis vibration cannot be completely obtained without the roll, pitch and yaw angular velocity components, A new method of estimating the three orthogonal (roll, pitch and yaw) angular velocities from the six acceleration measurements is introduced. The estimated angular velocities are shown to enable further quantitative error analysis in measuring the translational and angular accelerations at the head. To make this point clear, experimental results are also illustrated in this paper. They show that when the effects of angular velocities are neglected in the head vibration measurement the maximum percentage errors were observed to be more than $3 \%$ for the angular acceleration of the head and to be close to $5 \%$ for its translational acceleration, respectively. It means that the inclusion of all the angular velocity dependent acceleration components gives more accurate measurement of the head vibration.