• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1245-1248
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• 2004

This paper presents a new technique to analyze data on the coordinate x, y, z and apply these data to design the motion control to improve the efficiency of the engraving machine so that it can engrave accordingly in 3 dimensions. First, the tool path on the x-y plane is analyzed to be synchronized with the z-axis. The digital data is then sent to the motion control to guide the movement of the engrave point on the x-y plane. Tool path moves along the x-axis with zero degree and different values of the y-axis according to the coordinate of the digital data and the analysis along z-axis to determine the depth for engraving. The depth can be specified from the gray level with the 256 levels of resolution. The data obtained includes the distances on x-axis, y-axis, and z-axis, the acceleration of the engrave point's movement, and the speed of the engrave point's movement. These data is then transfered to the motion control to guide the movement of the engrave point along the z-axis associated with the x-y plane. The results indicate that engraving using this technique is fast and continuous. The specimen obtained looks perfect in 3D view.

• 한국군사과학기술학회지
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• 제21권4호
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• pp.508-519
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• 2018

This paper concerns on stabilization control of a gyro-stabilized 2-axes gimbal system which is mounted on a moving vehicles such as automobiles, armored vehicles, ships, flying vehicles, etc. A target image acquisition system is attached on the inner gimbal, and the gimbal systems are required to retain high stabilization accuracy in the absolute coordinate in order to provide fine target image while vehicle is moving. The stabilization control performance is hardly depended upon disturbance rejection ability of control, and disturbance feedforward compensation is effective because feedforward compensation reduce the amount of disturbance before the disturbance disturbs the systems. This paper suggests an experimental method which can estimate system parameters and disturbance torques by using 3-axes accelerometer mounted on the inner gimbal. Furthermore, a simple disturbance identification method which can be applied to any slanted base conditions has been suggested to identify mass unbalance vector and friction torques of each gimbal simultaneously. By using the estimated parameters, a feedforward compensation has been applied to the gyro-stabilized 2-axes gimbal system. The experimental results showed that the feedforward compensation based on the identification method suggested is effective to improve stabilization performances.

• 대한공간정보학회지
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• 제16권1호
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• pp.3-12
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• 2008

본 연구는 LBS를 위한 비주얼 베이직 Active X 컨트롤을 이용한 무선 인터넷 DGPS 구축이다. 시스템 개발에 사용된 DGPS 보정방법은 웹상의 위치 보정방법과 양방향 통신에 있어 편리성을 고려하여 좌표 보정방법을 사용하였다. 위치정보 출력 모듈은 PictureBox 컨트롤과 bitblt 함수를 이용하여 개발하였다. 서버와 클라이언트 간의 인터넷 DGPS 통신 모듈은 MS Comm 컨트롤, MS Winsock 컨트롤(TCP/IP), MS CommonDialog 컨트롤, MS Sysinfo 컨트롤 구성요소를 사용하여 개발하였으며 구축된 시스템을 웹에 게시하였다. 구축된 시스템을 이용하여 실시간 무선 인터넷 DGPS를 수행한 결과, 서버 시스템 상의 클라이언트 추적, 클라이언트 시스템에서의 항법, 제 3 이용자의 클라이언트 추적이 근 실시간 가능하였다.

• 로봇학회논문지
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• 제11권1호
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• pp.33-40
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• 2016

In this paper, we propose a method for estimating the pose of the camera using a rectangle feature utilized for the visual SLAM. A warped rectangle feature as a quadrilateral in the image by the perspective transformation is reconstructed by the Coupled Line Camera algorithm. In order to fully reconstruct a rectangle in the real world coordinate, the distance between the features and the camera is needed. The distance in the real world coordinate can be measured by using a stereo camera. Using properties of the line camera, the physical size of the rectangle feature can be induced from the distance. The correspondence between the quadrilateral in the image and the rectangle in the real world coordinate can restore the relative pose between the camera and the feature through obtaining the homography. In order to evaluate the performance, we analyzed the result of proposed method with its reference pose in Gazebo robot simulator.

• Journal of Mechanical Science and Technology
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• 제16권5호
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• pp.703-709
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• 2002

In the present paper, approximate coordinate transformations for simulation of turbulent flows with wall deformation, significantly reducing computational cost with little degradation in numerical accuracy, are presented. The Wavier-Stokes equations are coordinate-transformed with an approximation of Tailor-series truncation. The performance is evaluated by performing numerical simulations of a channel flow at Re$\sub$$\tau$/ = 140 with active wall motions of η$\sub$m/$\^$+/ $\leq$5. The approximate transformations provide flow structures as well as turbulence statistics in good agreement with those from a complete transformation [Phys. Fluids 12, 3301 (2000) ] and allow 25-30% savings in the CPU time as compared to the complete one.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.629-632
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• 1999

In this paper, color coordinate system transformation based visual servo controller has been considered. Mobile robot always has a position error and an orientation error resulted from wheel slipping etc.. Even more, the errors have accumulative properties. So feedback from environments is important. In this paper, by using color model faster land mark extraction can be achieved. And the global position and the orientation of mobile robot can be known by only two land marks positions in image coordinate system. Finally, the adoption of visual information in path tracking problem makes visual servo control.

• International Journal of Aeronautical and Space Sciences
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• 제2권1호
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• pp.78-92
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• 2001

In this paper, several dynamic systems are modeled using the time domain finite element method. Galerkins' Weak Principle is used to model the general second-order mechanical system, and is applied to a simple pendulum dynamics. Problems caused by approximating the final momentum are also investigated. Extending the research, some dynamic analysis methods are suggested for the hybrid coordinate systems that have both slew and flexible modes. The proposed methods are based on both Extended Hamilton's Principle and Galerkin's Weak Principle. The matrix wave equation is propagated in space domain, satisfying the geometric/natural boundary conditions. As a result, the flexible motion can be obtained compatible with the applied control input. Numerical example is shown to demonstrate the effectiveness of the proposed modeling methods for the hybrid coordinate systems.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2004년도 추계학술발표회 논문집
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• pp.239-243
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• 2004

Recently various thematic maps and image maps using aerial photograph and satellite imagery are frequently made. The geo-referencing is essential to make image map and topographic map using aerial photograph and satellite imagery. For this geo-referencing, Ground Control Points (GCPs) are needed. In this paper, we used GPS relative positioning to measure GCP ground coordinate and the accuracy of 8cm level was achieved. We made GCP image chips for the efficiency of geo-referencing and carried out the bundle adjustment of aerial photographs using GCP image chips to acquire the GCP photo coordinate with image matching technique. Finally we analyzed the accuracy of bundle adjustment compared to the accuracy of the case in using digital maps to acquire GCP photo coordinate.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1998년도 제13차 학술회의논문집
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• pp.221-225
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• 1998

This paper is to present a method for recognizing an image of a tracking object by processing the image from a camera, whose attitude is controlled in inertial space with inertial co-ordinate system. In order to recognize an object, a pseudo-random M-array is attached on the object and it is observed by the camera which is controlled on inertial coordinate basis by inertial stabilization unit. When the attitude of the camera is changed, the observed image of M-array is transformed by use of affine transformation to the image in inertial coordinate system. Taking the cross-correlation function between the affine-transformed image and the original image, we can recognize the object. As parameters of the attitude of the camera, we used the azimuth angle of camera, which is de-fected by gyroscope of an inertial sensor, and elevation an91e of camera which is calculated from the gravitational acceleration detected by servo accelerometer.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -2
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• pp.591-595
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• 2000

In this paper color coordinate system transformation based visual servo controller has been considered Mobile robot always has a position error and an orientation error resulted from wheel slipping etc.. Even more, the errors have accumulative properties. So feedback from environments is important. In this paper by using color model faster land mark extraction can be achieved. And the global position and the orientation of mobile robot can be known by only two land mark positions in image coordinate system. Finally, the adoption of visual information in path tracking problem makes visual servo control.