• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
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• pp.263-266
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• 1996

A method to determine an optimal temperature trajectory that guarantees polymer products having controlled molecular weight distribution and desired values of molecular weight is presented. The coordinate transformation method and the optimal control theory are applied to a batch PMMA polymerization system to calculate the optimal temperature trajectory. Coordinate transformation method converts the original fixed-end-point, free-end-time problem to a free-end-point, fixed-end-time problem. The idea is that by making the reactor temperature track the optimal temperature trajectory one may be able to produce polymer products having the prespecified physical property in a minimum time. The on-line control experiments with the PID control algorithm have been conducted to establish the validity of the scheme proposed in this study. The experimental results show that prespecified polymer product could be obtained with tracking the calculated optimal temperature trajectory.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.963-966
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• 2005

Previous works related to texture coordinate coding of the three-dimensional(3-D) mesh models employed the same predictor as the geometry coder. However, discontinuities in the texture coordinates cause unreasonable prediction. Especially, discontinuities become more serious for the 3-D mesh model with a non-atlas texture image. In this paper, we propose a new coding scheme to remove discontinuities in the texture coordinates by reallocating texture segments according to a coding order. Experiment results show that the proposed coding scheme outperforms the MPEG-4 3DMC standard in terms of compression efficiency. The proposed scheme not only overcome the discontinuity problem by regenerating a texture image, but also improve coding efficiency of texture coordinate compression.

• Journal of international Conference on Electrical Machines and Systems
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• 제3권4호
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• pp.458-464
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• 2014

This paper proposes the rotor position and rotor speed estimation for an interior permanent magnet synchronous machines (IPMSM) using Unscented Kalman Filter (UKF) in alpha-beta coordinate system. Conventional algorithms using UKF are based on the simple observer model of IPMSM in d-q coordinate system. Rotor acceleration is neglected within the sampling step. An expansion of the observer model in an alpha-beta coordinate system with the consideration of the rotor speed variation provides the improved rotor position and speed estimation. The results show good stability concerning the expansion of observer model for the IPMSM.

• 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.

• 대한공간정보학회지
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• 제3권1호
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• pp.37-44
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• 1995

국가기본도 평면직각좌표계는 3계로 나뉘어져 있으므로 이를 자동차 항법용 수치지도의 좌표계로 수정없이 적용하면, 좌표계의 경계지역에서 인접도엽간 경계접합시 문제가 발생한다. 따라서, 자동차 항법용 수치지도 좌표계는 분리된 3계의 평면직각좌표계가 갖는 문제를 해결하기 위해 하나의 통일원 새로운 좌표계가 필요하다. 본 연구에서는 투영법에 있어서는 국가기본도 평면직각좌표계와 같은 휭 메느카토르도법을 사용하고 중앙자오선의 위치 및 증대율을 조정하므로서 새로운 자동차 항법용 수치지도좌표계를 설계하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.528-530
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• 1996

Because of the convenience of variable speed control and proportion of input current and torque, DC servo motor has been used as an actuator. With increasing development speed of robot and factory automation machinery, the actuator of excellent control characteristics is demanded. In this paper, The control characteristics of DC servo motor is tested by Fuzzy control with microprocessor and DC servo motor controller is designed for drive of the cartesian coordinate type robot. The control characteristics experimentation is realized to one axis position, two axes coordinate and circular motion control by experimental equipments.

• 한국데이타베이스학회:학술대회논문집
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• 한국데이타베이스학회 1999년도 춘계공동학술대회: 지식경영과 지식공학
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• pp.347-350
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• 1999

자율무인잠수정은 자율운항을 위해서 자동화된 제어시스템이 필요하다. 제어시스템은 기능적 측면에서 임무계획단계(mission planning level), 임무제어단계(mission control level), 선체제어단계(vehicle control level)로 구분한다. 자율무인잠수정의 효과적인 임무 수행을 위해서는 임무제어단계의 운행 경로 설정과 제어가 중요하다. 자율무인잠수정은 잠수정의 주변환경을 추상화한 후 탐색기법을 이용하여 경로를 설정한다. 이때 검색기법의 효율적 적용을 위해서는 효과적으로 추상화된 탐색모형이 필요하다. 대표적인 탐색모형으로는 3차원 격자절대좌표 모형(3-dimensional grid unit coordinate model)(1)을 들 수 있다. 그러나 이 모형은 불필요한 동작의 반복, 이동 격자에 따른 비일관성과 같은 취약점이 존재한다. 본 연구에서는 이 모형의 취약점을 개선하기 위해서 자율무인잠수정의 위치 기반 상대적 격자좌표 모형(relative grid unit coordinate model based on AUV state)을 제안한다.

• Journal of applied mathematics & informatics
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• 제32권5_6호
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• pp.783-790
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• 2014

Most distance functions, including taxicab distance, are defined on Cartesian plane, and recent studies on distance functions have been mainly focused on Cartesian plane. However, most streets in cities include not only straight lines but also curves. Therefore, there is a significant need for a distance function to be defined on a curvilinear coordinate system. In this paper, we define a new function named polar taxicab distance, using polar coordinates. We prove that this function satisfies the conditions of distance function. We also investigate the geometric properties and classifications of circles in the plane with polar taxicab distance.

• 대한기계학회논문집
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• 제15권2호
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• pp.668-676
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• 1991

Turbulent flows around tube banks and in the diffuser were studied using a non-orthogonal boundary fitted coordinate system and the modified K-.epsilon. turbulence model. In these cases, many problems emerge which stem from the geometrical complexity of the flow domain and the physical complexity of turbulent flow itself. To treat the complex geometry, governing equations were reformulated in a non-orthogonal coordinate system with Cartesian velocity components and discretised by the finite volume method with a non-staggered variable arrangement. The modified K-.epsilon. model of Hanjalic and Launer was applied to solve above two cases under the condition of strong and mild pressure gradient. The results using the modified K-.epsilon. model results in both test cases.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.649-654
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• 2004

A physically simple but mathematically cumbrous problem of rotating heavy chain with one fixed top point is studied. Nonlinear equation of its two-dimensional shapes of relative equilibrium is obtained and solved numerically. A linear case of small displacements is analyzed in terms of Bessel functions. The qualitative and quantitative behavior of the problem is discussed with the help of bifurcation diagram. Dynamics of the two-dimensional model near the equilibrium positions is studied with the help of simulation using the absolute nodal coordinate formulation (ANCF). The equilibriums are found instable, and the reason of instability is explained using a variational principle.