• The Journal of the Korea Contents Association
• /
• v.8 no.2
• /
• pp.27-32
• /
• 2008

In this paper, we propose an orientation tracking method and a digestion path model based on angular displacement. The proposed method expresses a capsule's orientation as 3-dimension vectors and its rotation angle. Errors in roll, pitch, and yaw representing capsule's orientation information is down to $1.6^{\circ}$. Using the proposed method we can measure a roll which is not Possible to be measured using the magnetic field method. We reduce algorithm complexity lower than a previous methods based on Euler angle.

• Journal of Biomedical Engineering Research
• /
• v.25 no.4
• /
• pp.301-307
• /
• 2004

An inverse dynamic model of lower limbs is presented to calculate joint moments during gait. The model is composed of 4 segments with 3 translational joints and 12 revolute joints. The inverse dynamic method is based on Newton-Euler formalism. Kinematic data are obtained from 3 dimensional trajectories of markers collected by a motion analysis system. External forces applied on the foot are measured synchronously using force plate. The use of developed model makes it possible to calculate joint moments for variation of parameters.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.24 no.4
• /
• pp.408-415
• /
• 2016

The vehicle attitude and sideslip is critical information to control the vehicle to prevent from unintended motion. Many of estimation strategy use bicycle model or IMU integration, but both of them have limits on application. The main purpose of this paper is development of vehicle orientation estimator which is robust to various vehicle state and road shape. The suggested estimator use 3-axis magnetometer, yaw rate sensor and lateral acceleration sensor to estimate three Euler angles of vehicle. The estimator is composed of two individual observers: First, comparing the known magnetic field and gravity with measured value, the TRIAD algorithm calculates optimal rotational matrix when vehicle is in static or quasi-static condition. Next, merging 3-axis magnetometer with inertial sensors, the extended Kalman filter is used to estimate vehicle orientation under dynamic condition. A validation through simulation tools, Carsim and Simulink, is performed and the results show the feasibility of the suggested estimation method.

• Journal of the Korean Society for Precision Engineering
• /
• v.26 no.1
• /
• pp.130-137
• /
• 2009

This paper deals with the comparisons of methodologies to express finite rotations accounting for analysis of the rotor system. Researches have been made to predict a behavior of its rotational motion by introducing Euler angles which turned out to be lack in consistency and exactness of the analysis. To overcome this deficiency a new methodology is applied by using both spherical coordinate and quaternion in the rotor rotation and shows its superiority over choices of the Euler angle in terms of kinetic energy and rotation velocity. It is found through numerical examples that quaternion is a more useful and valid tool to derive the ideal numerical model of the rotor system.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.20 no.6
• /
• pp.778-784
• /
• 2011

This paper presents the study on orientations interpolation of 6-axis articulated robot using quaternion. In this paper, we propose a control algorithm between given two orientations of 6-axis articulated robot by using a quaternion with spherical linear interpolation. In order to study the quaternion interpolation, We created Inverse kinematics program and Interpolation program using LabVIE$^{(R)}$. The rotation angle of each axis were calculated using both euler orientations interpolation program and quaternion orientations interpolation program. The proposed control algorithm is shown to be effective in terms of motor angles and torques when compared to a conventional Euler angle interpolation, by using both LabVIEW$^{(R)}$ and RecurDyn$^{(R)}$.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.13 no.2
• /
• pp.40-46
• /
• 2004

Magnetic bearing has been adopted to support a rotor by electromagnetic force without mechanical contact and lubrication process. The recent growth of magnetic bearing applications in many industrial fields requires more accurate design of bearing-rotor system. Due to external forces and uncertainties of magnetic bearing system the actual performance and stability my be worse than it is designed. This paper describes the governing equations of rotor magnetic bearing systems and/or the designing of robust controller via standard $H_{\infty}$ control problem. The system stability and response characteristics are studied by simulations and verified with experimental results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 1997.04a
• /
• pp.608-614
• /
• 1997

2차원 압축성 오일러 방정식을 지배 방정식으로 하여 음향학적 문제를 직접 수치 계산하였다. Roe의 개략적인 리만해(Approximate Riemann Solver)에 의거하여 대류항을 구성하였고 높은 정확도를 유지하기 위해 Vanleer의 MUSCL 방법을 사용하여 공간을 이산화하였다. 시간 적분으로는 2차의 Runge-Kutta 방법을 사용하였다. Resonance tube 내의 음향학적 문제 해석을 위해 최근까지 제시된 음향 경계 조건들을 비교하였고 각 경계 조건들이 갖는 물리적 의미를 고찰하였다. 이들을 통하여 압력파의 물리적인 행태를 모사하였고 실험과 비교하였다. 계산결과들을 통하여 사용된 방법은 전형적인 압축성 유동 해석 문제 뿐만 아니라 선형, 비선형의 음향학적 문제들을 적절한 경계 조건과 결합하여 해석할 수 있음을 알 수 있었고 resonance tube와 같은 공학적으로 실제적인 문제들에 대한 응용이 기대된다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2003.11c
• /
• pp.1383-1386
• /
• 2003

최근 공간 데이터베이스의 선택률 추정 문제에 대한 관심이 증가하면서, 데이터분포의 편중, 중복 계산, 메모리 공간 최소화등의 문제를 고려한 다양한 기법들이 제안되고 있다. 그러나 이들 기법들 간의 성능 분석을 통한 비교평가는 이루어지지 않고 있다. 따라서, 이 논문에서는 공간 영역 객체의 범위질의에 관한 선택률 추정 기법인 Min-Skew, 웨이블릿, 누적밀도, 오일러 히스토그램을 비교 분석한다. 즉, 실제 데이터셋을 기반으로 여러 형태의 질의에 대한 성능 비교를 통해 각 기법들을 비교 평가한다. 이 연구 결과는 새로운 기법 도출에 이용될 수 있다.

• Proceedings of the Korean Information Science Society Conference
• /
• 2007.10b
• /
• pp.194-197
• /
• 2007

본 논문에서는 모바일용 3차원 그래픽 라이팅 엔진을 위한 부동소수점 멱승기클 제안한다. 3D 그래픽의 라이팅 과정은 연산량이 많고, 복잡하기 때문에 각 연산 유닛들이 저비용으로 빠르게 연산을 수행해야 한다. 본 논문에서 제안한 멱승기는 처리율을 높이기 위해 파이프라인 구조를 사용하였으며, $10^{-4}$의 정확도를 만족한다. 전체 구조는 5 stage로 구성되며, 크게 로그연산기와 지수연산기로 이루어져 있다. 일반적으로 로그연산기는 정확도를 높이기 위하여 큰 롬 테이블을 사용하는데, 이는 많은 면적을 차지하게 된다. 이러한 롬 테이블 면적 문제를 해결하기 위하여 Newton method을 사용하여 롬 테이블의 사이즈를 줄였다. 또한 오일러 상수를 밑으로 하는 지수연산기도 입력 비트의 크기를 줄이고, 테이블의 개수를 늘림으로써 롬 테이블의 크기를 줄였다. 지수연산의 밑은 부동소수점 포맷으로 [0, 1]의 범위를 가지며, 승은 정수 포맷으로 [0, 128]의 범위를 갖는다. Magnachip $0.18{\mu}m$ 공정에서 100Mhz의 동작주파수를 만족하였으며, 약 16k gates을 차지한다.

• Geophysics and Geophysical Exploration
• /
• v.15 no.3
• /
• pp.136-143
• /
• 2012

In this case study, we present the various and consistent processing techniques for the reasonable interpretation of aeromagnetic data. In the processing stage, we especially focused on the three major respects. First, in the low latitude area, severe artifacts are occurred as a result of reduction to the pole technique. To overcome this problem, variable alternative methods were investigated. From the comparison of each technique, we concluded that energy balancing method gives more fruitful result. Second, because of limited a priori information, it is nearly impossible to employ detailed geological survey due to wide and thick spreading of soils in the survey area. So we especially investigated the new techniques such as extracting slope, curvature and aspect information mainly used in GIS field as well as conventional methods. Finally, by using the Euler deconvolution, we extracted the depth information on the magnetic anomalous body. From the synthetic analysis between depth information and previous discussed results, the detailed future survey area was proposed. We think that a series of processing techniques discussed in this study may perform an important role in the domestic and abroad resource development project as a useful guideline.