• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.8
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• pp.669-675
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• 2003

Transducer for ultrasonic linear motor with symmetric and anti- symmetric modes was studied. The ultrasonic linear motor consists of two Langevin type piezoelectric vibrators that cross at right angles with each other in tip. In order to excite symmetric and anti-symmetric modes, the transducer must have a phase shift of 90 degree in space and time. As a result, the tip of transducer moves on an elliptical motion. In this paper, the finite element analysis was used to optimize dimension and displacement of the transducer.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1996.03a
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• pp.79-84
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• 1996

This paper presents a new approach to the design of adaptive control system using DSPs(TMS320C31) for robotic manipulators to achieve trajectory tracking by the joint angles. Digital signal processors are used in implementing real time adaptive control algorithms to provide an enhanced motion control for robotic manipulators. In the proposed control scheme, adaptation laws are derived from the improved Lyapunov second stability analysis method based on the adaptive model reference control theory. The adaptive controller consists of an adaptive feedforward controller, feedback controller, and PID type time-varying auxillary control elements. The proposed adaptive control scheme is simple in structure, fast in computation, and suitable for implementation of real-time control. Moreover, this scheme does not require an accurate dynamic modeling, nor values of manipulator parameters and payload. Performance of the adaptive controller is illustrated by simulation and experimental results for a SCARA robot.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.5 no.4
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• pp.26-37
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• 1996

This paper presents a new approach to the design of adaptive control system using DSPs(TMS320C30) for robotic manipulators to achieve trajectory tracking by the joint angles Digital signal processors are used in implementing real time adaptive control algorithms to provide an enhanced motion control for robotic manipulators. In the proposed control scheme adaptation laws are derived from the improved Lyapunov second stability analysis method based on the adaptive model reference control theory. The adaptive controller consists of an adaptive feedforward controller. feedback controller. and PID type time-varying auxiliary control elements. The proposed adaptive control scheme is simple in structure, fast in computation, and suitable for implementation of real-time control. Moreover, this scheme does not require a an accurate dynamic modeling, nor values of manipulator parameters and payload. Performance of the adaptive controller is illustrated by simulation and experimental results for a SCARA robot.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.5
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• pp.82-88
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• 2008

Conventional aspherical lens polishing methods by the small tool polishing use aspherical profile and the trajectory of the polishing tool is also controlled. In this paper, new full contact polishing mechanism is suggested to polish aspherical glass lens mold by both airbag polishing tool and eccentric motion. Full contact concept by airbag polishing tool and no position control make the easy polishing setup and do not need aspherical design profile. An aspherical lens polishing machine was made for this study and a verification experiment was performed for surface roughness improvements.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.4
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• pp.330-336
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• 2005

An intelligent control method is proposed for control of rigid robot manipulators which achieves exponential tracking of repetitive robot trajectory under uncertain operating conditions such as parameter uncertainty and unknown deterministic disturbance. In the learning controller, exponentially stable learning algorithms are combined with stabilizing computed error feedforward and feedback inputs. It is shown that all the error signals in the learning system are bounded and the repetitive robot motion converges to the desired one exponentially fast with guaranteed convergence rate. An engineering workstation based control system is built to verify the effectiveness of the proposed control scheme.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.29B no.10
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• pp.27-36
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• 1992

This paper proposes a numerical method of motion planning for manipulators using Foruier series. For a redundant manipulator, we predetermine the trajectories of redundant joints in terms of the Nth partial sum of the fourier series. then the optimal coefficients of the fourier series are searched by the Powell's method. For a nonredundant or redundant manipulator, CS02T-continuous smooth joint trajectory for a point-to-point task can be obtained while considering the frequency response. We apply the proposed method to the 3-link planar manipulator and the PUMA 560 manipulator. To show the validity of the proposed method, we analyze solutions by the Fast Fourier Transform (FFT). Also, several features are discussed to obtain an optimal solution.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07b
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• pp.883-885
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• 2005

비디오 데이터에서 의미적 인식을 위해 활용되는 요소 중 하나가 객체에 대한 움직임 정보로 이는 비디오 데이터에 대한 색인과 내용 기반 검색을 수행하는데 중요한 역할을 한다. 본 논문에서는 효율적인 객체기반 비디오 검색과 비디오의 움직임 해석을 위한 시공간 관계 표현 방법을 제시한다. 비디오의 객체표현 방법은 Polygon-based Bounding Volume의 3차원 Mesh 모델을 생성한 후 이를 이용하여 비디오 내 개체의 구조적 내용을 저차원적 속성과 움직임에 대한 기본 구조로 활용하였다. 또한, 움직임 객체에 대해 시공간적 특성과 시각적 특성을 동시에 고려하여 표현되도록 하였다. 각 Vertex는 시각적 특징 중 일부분이고, 비디오 내 개체의 공간적 특성과 개체의 움직임은 Volume Trajectory로 모델링되고, 개체와 개체간의 시공간적 관계를 표현하기 위한 Operation을 정의한다.

• International Journal of Aeronautical and Space Sciences
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• v.3 no.1
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• pp.39-49
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• 2002

This paper presents a robust tracker design method that is specific to the trajectories of target aircraft. This method assumes that representative trajectories of the target aircraft are available. The exact trajectories known to the tracker enables the incorporation of the exact data in the tracker design instead of the measurement data. An estimator is designed to have acceptable performance in tracking a finite number of different target trajectories with a capability to trade off the mean and maximum errors between the exact trajectories and the estimated or predicted trajectories. Constant estimator gains that minimize the cost functions related to the estimation or prediction error are computed off-line from an iterative algorithm. This tracker design method is applied to the longitudinal motion tracking of target aircraft.

• The KIPS Transactions:PartA
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• v.9A no.1
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• pp.99-104
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• 2002

The goal of this paper is to generalize the concept of Bezier curves and surfaces defined on the vector space $R_n$ to Lie groups, which is a new generation method of curves (called Bezier curves) on Lie groups. The defined Bezier curves and surfaces are alsways smooth because of the properties of Lie groups. We apply this method to smooth motion interpolation or smooth trajectory generation for moving rigid body in space.

• Journal of Advanced Marine Engineering and Technology
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• v.18 no.4
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• pp.25-32
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• 1994

This paper presents a robust impedance controller design to coordinate a robot manipulator under system uncertainties while regulating external forces. By an impedance approach, the relationship between the motion and external forces is defined. Due to the system uncertainties, two kind of sliding mode control schemes based on the impedance approach are derived to ensure that the manipulator end-effector follows a desired trajectory and the force applied to end effector is regulated according to a target impendance. A stability condition is shown according to a sliding condition. To evaluate the devised control scheme, a numerical example is shown.