• Journal of Advanced Marine Engineering and Technology
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• 제30권8호
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• pp.877-884
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• 2006

The objective of this study is to investigate the aerodynamic characteristics of a vertical axis wind turbine blade as the basic study of a design of a vertical axis wind turbine. The lift and drag coefficients of the various shape of the vortical axis wind turbine blades are analyzed and compared using the CFD code Fluent. To validate the numerical analysis, the predicted results of the Fluent are compared with those of the Xfoil code and the experimental results. We conclude that the program Fluent can be used to predict the aerodynamics of the wind turbine blade. By comparing the predicted results of the aerodynamic characteristics of the different shape of the blades, an appropriate shape of the blade is suggested to design the vortical axis wind turbine blade.

• Journal of Mechanical Science and Technology
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• 제18권5호
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• pp.753-761
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• 2004

In this paper, an efficient method for generating 5-axis cutting data for a turbine blade is presented. The interference elimination of 5-axis cutting currently is very complicated, and it takes up a lot of time. The proposed method can generate an interference-free tool path, within an allowance range. Generating the cutting data just point to the cutting process and using it to obtain NC data by calculating the feed rate, allows us to maintain the proper feed rate of the 5-axis machine. This paper includes the algorithms for: (1) CL data generation by detecting an interference-free heel angle, (2) finding the optimal tool path interval considering the cusp-height, (3) finding the adaptive feed rate values for each cutter path, and (4) the inverse kinematics depending on the structure of the 5-axis machine, for generating the NC data.

• 한국공작기계학회논문집
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• 제11권3호
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• pp.1-8
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• 2002

This study is continuous with the study I (A Study on the Modeling) and the sample impeller of this study is defined by the modeling process of the exclusive CAD/CAM system developed in the study Ⅰ. And, this study describes a method for the 5-axis machining of impeller blades formed by ruled surface. Therefore, the exclusive CAD/CAM system is the software for modeling md machining of impeller blades. By using the machining method suggested in this study, we could manufacture impeller blades on 5-axis CNC machining center and the machined impeller was very agreeable to the designed impeller. Thus, theories proposed in this study can be very useful for the 5-axis machining of impeller blades.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.635-640
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• 2000

This paper presents the analysis method of the instantaneous screw axis using line geometry in bump and rebound motion of 5-SS multi-link suspensions. Instantaneous screw axis is based on screw motion, and screw motion of zero pitch can be expressed as $Pl{\ddot{u}}cker$ line coordinates of line geometry instead of screw coordinates. In screw coordinates, twist and wrench are described by components of instantaneous screw axis. For instantaneous motion of wheel assembly, the principle of virtual work with twist and wrench is applied to 5-SS multi-link suspension, and it makes 5 linear equations. Therefore, it is possible to find instantaneous screw axis by solving these equations. This analysis by line geometry demands geometric values only, such as the locations of spherical joints in the case of multi-link suspensions.

• 한국기계가공학회지
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• 제8권4호
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• pp.7-13
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• 2009

Five-axis laser cutting has great advantages when it is applied to 3-dimensional machining requiring high cutting quality. For developing 5-axis CNC laser cutting systems, however, many problems such as rotating a laser head or a working table, 5-axis servo-control mechanism, tool path generation and post processing, and collision avoidance between a laser head and a work-piece should be solved. In this paper, we deal with developing a dedicated CAM system based on UG-NX3 for 5-axis laser cutting machine. Two essential modules such as post-processor and cutting motion simulation was developed. The developed system was applied to cutting curve defined on 3-D workpiece in order to show the validity of the proposed methods.

• 한국기계가공학회지
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• 제17권4호
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• pp.47-54
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• 2018

These days, the aerospace industry uses larger machining parts and assembly parts than those in the past. The assembly machines also show the same trend. This study is concerned with the alignment measuring apparatus for the B-axis of a separated multi-axis machine. The alignment measuring apparatus is widely installed for assembly machines in the aircraft assembly process. The alignment measuring apparatus consists of a swivel part and a measuring part. This is a new conceptual idea under patent. All elements of the alignment measuring apparatus are analyzed with the FEM. The analyzed result shows that the alignment measuring apparatus is high in accuracy with stability and steady deformation.

• 한국CDE학회논문집
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• 제13권2호
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• pp.153-161
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• 2008

This paper proposes an efficient algorithm for deriving inverse kinematics equation of 5-axis machine. Because the joint order and direction of 5-axis machine are different for each type of machine, each type of machine needs its own inverse kinematics equation for post-processing of NC data. Also derived inverse kinematics equation may cause problems of indeterminate and inconsistent solution. In order to resolve these problems, we have developed a generic method to derive direct kinematics equation by considering orthogonal joints of 5-axis machines. Using this method, we also have proposed a general algorithm for deriving inverse kinematics equation for various types of 5-axis machines.

• 제어로봇시스템학회논문지
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• 제1권1호
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• pp.58-62
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• 1995

Necessarily, it is required to analyze interfacial mechanism between tire and road for understanding tire wear, vehicle tracking and breaking. Therefore, there have been some efforts to measure 3-axis pressure and 2-axis displacement on tire road interface. But it was so hard to couple precisely measuring sensor and desired point on tire tread pattern block that it was impossible to analyze the mechanism on commercial tire with tread pattern. To overcome such a problem, a on-line measurement system is proposed in this paper. And an automatic control system is designed to test the tire with similar configuration of real vehicle driving.

• 한국CDE학회논문집
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• 제7권4호
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• pp.254-261
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• 2002

Small marine propeller is generally machined by 5-axis machining. This paper suggests a method to create geometric model from point array data and 4-axis machining NC data for propeller. With conventional method, the setting posture should be changed, because propeller has front and back surface of wing. The change of setting posture has a bad influence on precision of propeller. So this paper pro-poses a method to machine propeller by single setup for 4-axis machining. The cutter moves to parallel direction of the XY plane. To determine the cutter orientation efficiently, the' tilting guiding line' is proposed. A proposed algorithm is written in C language and successfully applied to the 5-axis milling machine of industrial field.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 B
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• pp.435-437
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• 1998

In this productive system, it needs to control the each axis motion harmoniously to perform accurately for the manufacturing, transporting and printing. Independent Axis Control usually used for this objection. However, if Independent Axis Control mismatched the parameter of each axis system or in the case of free curve tracking or the case of high speed control, there would be big contour error so that cannot achieve control objection. As a result, there is Contour Control method suggested to supply for this defect. This paper carried modeling of biaxial system and implemented Independent Axis Control & Contouring Control on straight line, circular, and coner path by simulation and experiment. If feedrate increased, contour error growed. In consequence, according to this factor, we introduced contouring controller, so we could find the fact that contour error was reduced more than that of independent axis control about each path.