• 전자공학회논문지CI
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• 제43권6호
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• pp.71-82
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• 2006

3D 그래픽에서는 실시간 애니메이션을 위하여 이동, 회전, 스케일링 변환 노드로 구성되는 키프레임 애니메이션이 널리 이용되고 있다. 본 논문에서는 VRML 기반의 3D 애니메이션 상에서 CoordIndex 노드 내에 꼭지점 좌표를 이용한 기하학적 워터마킹 기법과 PositionInterpolator 노드 내에 키 값을 이용한 보간기 워터마킹 기법을 제안한다. 실험 결과로부터 제안한 방법이 각종 기하학적 공격 및 타임라인 공격에 대한 강인성 및 비가시성을 가짐을 확인하였다.

• 한국통신학회논문지
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• 제32권3C호
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• pp.287-296
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• 2007

3D 키프레임 애니메이션은 실시간 애니메이션을 위하여 3D 그래픽스에서 널리 사용되고 있다. 이 방법은 전체 프레임들 중 중요 프레임들 내에 애니메이트되는 키값들을 등록한 후, 등록된 키값들을 이용하여 이외의 프레임들을 보간기에 의하여 생성한다 본 논문에서는 위치 보간기를 이용한 3B 키프레임 애니메이션 워터마킹 기법을 제안한다. 제안한 방법에서는 계층적인 구조 상에서 부분 모델로 이루어진 변환 노드들을 임의로 선택한 후, 선택된 변환 노드 내의 위치 보간기의 키값에 워터마크를 삽입한다. 실험결과로부터 제안한 방법이 기하학적 및 타임라인 공격에 대하여 견고성을 가짐을 확인하였다.

• 대한기계학회논문집A
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• 제26권9호
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• pp.1888-1896
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• 2002

This study presents a new type of CNC interpolator that is capable of generating cutter paths for ball-end milling of NURBS surfaces. The proposed surface interpolator comprises real-time algorithms for cutter contact (CC) path scheduling and CC path interpolator. Especially in this study, a new interpolator module to regulate cutting forces is developed. This propose algorithm utilizes variable-feedrate commands along the CC path according to the curvature of machined surfaces during the interpolation process. Additionally, it proposes an OpenGL graphic library for computer graphics and animation of interpolated tool-position display. The proposed interpolator is evaluated and compared with the existing method based on constant feedrates through computer simulations.

• 한국정밀공학회지
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• 제16권4호통권97호
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• pp.129-137
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• 1999

A parametric curve interpolator has been proposed for machining curves instead of a linear interpolator in which curves are approximated by a set of line segment. The parametric curve interpolator is superior to linear interpolator in machining time and contour error and generate exact position commands directly from curve equations. In this paper, a new toolpath generation method is proposed based on the parametric curve interpolator. This method retains all the benefits of parametric curve interpolator and can bound the scallop height within a specified value. By interpolating curves and surfaces directly from the mathematical equations, the amount of data from CAD/CAM system to CNC controller can be significantly reduced. The proposed method was implemented on a CNC controller and was confirmed to give a better result than the other existing method.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 춘계학술대회 논문집
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• pp.1032-1035
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• 2000

Increasing demands on precision machining with computerized numerical control (CNC) machines have necessitated that the tool to move not only position error as small as possible, but also with smoothly varying feedrates in space. This paper presents a new high precision interpolation algorithm for 3-dimensional (3D) Non-Uniform Rational B-Spline (NURBS) curve in the reference-pulse CNC technique. Based on the minimum path error strategy, real-time NURBS interpolator was developed in software and this was implemented with a PC-NC milling machine. The several experimental results have shown that the proposed NURBS interpolator is useful for the high precision machining of complex shapes. It is expected that this algorithm can be applied to the CNC machines for the machining of 3D free-form surfaces.

• Journal of Mechanical Science and Technology
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• 제17권3호
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• pp.336-342
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• 2003

Increasing demand on precision machining using computerized numerical control (CNC) machines have necessitated that the tool move not only with the smallest possible position error but also with smoothly varying feedrates in 3-dimensional (3D) space. This paper presents the simultaneous 3D machining process investigated using a retrofitted PC-NC milling machine. To achieve the simultaneous 3-axis motions, a new precision interpolation algorithm for 3D Non Uniform Rational B-Spline (NURBS) curve is proposed. With this accurate and efficient algorithm for the generation of complex 3D shapes, a real-time NURBS interpolator was developed using a PC and the simultaneous 3D machining was accomplished satisfactorily.

• 한국정밀공학회지
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• 제17권12호
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• pp.115-120
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• 2000

Increasing demands on precision machining of free-form surface have necessitated that the tool to move not only position error as small as possible, but also with smoothly varying feedrates. This paper presents new algorithm for high precision 3D(3-dimensional) NURBS(Non-Uniform Rational B-Spline) interpolation in the reference-pulse technique. Based o the minimum path error strategy, interpolation algorithm was designed to follow the NURBS curve. Using this algorithm a real-time 3D NURBS interpolator was developed in software. The algorithm implemented in a PC showed promising results in interpolation error and speed performance. It is expected that this can be applied to the CNC systems for the high precision machining of complex shapes.

• 한국정밀공학회지
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• 제19권5호
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• pp.89-94
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• 2002

Increasing demands on precision machining using CNC machines have necessitated that the tool to move with a position error as small as possible in 3-dimensional (3D) space. This paper presents the simultaneous 3D machining with a retrofitted PC-NC milling machine. To achieve the simultaneous 3-axis motions, a new precision interpolation algorithm for 3D Non-Uniform Rational B-Spline(NURBS) curve is used. With this accurate and efficient algorithm for the generation of complex. 3D shapes, a real-time NURBS interpolator was developed using a PC and the simultaneous 3D machining is accomplished.

• 한국정밀공학회지
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• 제21권4호
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• pp.64-71
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• 2004

The growing need for higher precision and productivity in manufacturing industry has lead to an increased interest in computer numerical control (CNC) systems. It is well known fact that the cross-coupling controller (CCC) is an effective method for contouring applications. In this paper, a multi-axis contour error controller (CEC) based on a contour error vector using parametric curve interpolator is introduced. The contour error vector is a vector from the actual tool position to the nearest point on the desired path. The contour error vector is the closest error model to the contour error. The simulation results show that the CEC is more accurate than the conventional CCC for a biaxial motion system. In addition, the experimental results on 3-axis motion system show that the CEC is simply applied to 3-axis motions and contouring accuracy is significantly improved.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.121.1-121
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• 2002

Calculation unit and peripheral units that are used to make the position controller are embedded to one chip FPGA. $\textbullet$ Feed-forward PID controller and interpolator in the calculation unit mitigate frequent context switching. $\textbullet$ The peripheral units reduce the size of the joints position control board. $\textbullet$ Because the calculation unit is designed with pipeline structure, it has the advantages to apply to the multi joints.