• 연구논문집
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• s.28
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• pp.89-100
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• 1998

This paper deals with the design and analysis of a beating cam. The beating device of a high speed rapier loom, weaving fabric by completion of warp-weft patterns, is driven by double cam type on the same axis. As the double cam, coupled with two cams, performs the mutual conjugate motion, the double cam must be very preciously designed for smooth. For the shape design of a double cam, an instant velocity center method is proposed. This method can determine the cam profile from the contact conditions of the cam and roller follower and the velocity relationships at the instant velocity center. And the practical applicability was verified by developing “DISKCAM of a CAD program. As the results in this paper, the shapes of two cams, which are in the conjugate motion, are designed by instant velocity center method. We applied 8-order polynominals for the beating as displace¬ment curves for shape determination of double cams. The data of displacement, velocity, and acceleration of beating cam can be used adjust in accurate operation and to develope an advanced beating device.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1398-1401
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• 2004

This paper proposes a new approach for the shape design of the rotating outer-ring type epicycloid plate gear by using instant velocity center. First, this method defines the instant velocity centers for rotating outer-ring type epicycloid plate gear and calculates the contact angles and the contact points by using the geometric relationships and the kinematic properties of the reducer. Second, it generates the full shape of the cycloidal plate gear. Finally, the paper develops CAD-program for construction of the design automation using the proposed method. This CAD-program is developed to have the functions of the friendly user interface and the simulation of the real operation for the cycloid reducer.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.389-390
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• 2006

The cycloidal reducer is one of the velocity controlling equipments in machinery. It has advantages of the higher reduction ratio, the higher accuracy, the easier adjustment of the transmission ratio and the smaller workspace than any other kinds of the reducers. This paper proposes a simple and exact approach for the lobe profile design of the two teeth difference cycloidal plate gear, which is different from the standard cycloidal reducer, by means of the principle of the instant velocity center in the general contact mechanism and the homogeneous coordinate transformation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.916-919
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• 2002

Cam mechanism is one of the common devices used in lots of automatic machinery. This paper introduces to an inverse cam mechanism. The inverse cam mechanism has a reverse structure as compared with common cam mechanism. For shape design of the inverse cam the approach used in this paper is an instant velocity center method that find the contact point between cam and roller at any contact time. And a computer program is developed for shape design and simulation by visual $C^{++}$ language. As the results, this paper presents two examples for the shape design of the inverse cam mechanism in order to prove the accuracy of the design procedures.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.523-526
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• 2000

This paper performs the motion analysis for a disk cam and a follower mechanism using a circular arc method, a coordinate transformation method and an instant velocity method in order to find a contact point between the cam and the follower. Based on the proposed method, the displacement and the velocity are calculated by using the geometric relationships of the cam mechanism. Also, the acceleration is determined on using the central difference method. As the results, this paper presents the original curve and the analyzed curve for the motion analysis of the disk cam for an example.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.772-777
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• 2000

Cam mechanisms are used commonly in many automatic machinery. Disk cam mechanisms has 4 different types according to the different types of followers. The motion characteristics of the cam mechanisms depend on the shape of the cam and the type of the follower. This paper performs the motion analysis for a disk cam and follower mechanism using a circular arc method and a coordinate transformation method in order to find a contact point of the cam and follower. The velocity is calculated by using the instant velocity concept. Also, the acceleration is determined on using the central difference method. As the results, this paper presents the original curve and the analyzed curve for the motion analysis of the disk cam for an example.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.6
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• pp.871-883
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• 1997

Kinetodynamics of a cam driving slider mechanism consists of kinematic analysis and force analysis. The kinematic analysis is to determine the kinematic characteristics of a cam driving mechanism and a slider mechanism. The force analysis is to determine the joint forces of links, the contact forces of the cam and follower, and the driving torque of a main shaft. This paper proposes a close loop method and a tangent substitution method to formulate the relationships of kinematic chains and to calculate the displacement, velocity and acceleration of the cam driving slider mechanism. Also, and instant velocity center method is proposed to determine the cam shape from the geometric relationships of the cam and the roller follower. For dynamic analysis, the contact force and the driving torque of the cam driving slider mechanism are calculated from the required sliding forces, sliding motion and weight of the slider.

• Journal of Ocean Engineering and Technology
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• v.12 no.1
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• pp.113-119
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• 1998

An experimental study was carried out in a three-dimensional cubic cavity driven by 2-dimensional plane Poiseuille flow for three kinds of Reynolds number, $10^4$, 3 $\times$ $10^4$ and 5 $\times$ $10^4$ based on the cavity width and cavity inlet mean flow velcoity. Instant simultaneous velocity vectors at whole field were measured by 2-D PIV system. Laser based illumination and two-frame grey-level cross correlation algorithm are adopted. Severe unsteady flow fluctuation within the cavity are remarkable at above Re = 3 $\times$ $10^4$ Reynolds numbers and sheared mixing layer phenomena are also found at the region where inlet driving Poiseuille flow is collided with the clock-wise rotating main primary vortex at upper center area. Instant velocity profiles reveal that deformed forced vortex formation is observed throughout the separate two areas.

• Korean Journal of Applied Biomechanics
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• v.13 no.3
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• pp.1-14
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• 2003

This study was conducted to investigate the principles and motions for increasing the jumping height of Fosbury Flop. The subjects were three male jumpers who were former Korean national team players. Their jumping motions were analyzed using the DLT method of three-dimensional cinematography. The conclusions were as follows. 1. The horizontal velocity of approach run and decreasing of this velocity during the take off phase were increased as the jumping height was increased. Therefore, in order to increase the jumping height, the horizontal velocity of approachrun should be increased and decreased properly during the take-off phase. The average height of the analyzed Dials was 2.15m. The average horizontal velocity of approachrun was 7.49m/s and decreased to 4.16m/s at the instance of take-off. 2. The vertical velocity of the center of gravity was increased as the ascending height of the center of gravity during the take-off phase was increased. Therefore, the center of gravity at the instant of touch down should be lowered. This could be possible by increasing the length of the last stride and the backward lean angle of the body. The average length of the last stride was 111.1% of the standing height, the average height of the center of gravity was 46.6% of the standing height and the average backward lean angle of the body was 40.3 degrees.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1231-1232
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• 2010