• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.2
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• pp.299-306
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• 2016

In this paper, a method of shape prediction of an endoscope handling robot that can imitate a surgeon's behavior using a sensor network is suggested. Unit sensors, which are composed of a 3-axis magnetometer and 3-axis accelerometer pair comprise the network through CAN bus communication. Each unit of the sensor is used to detect the angle of the points in the longitudinal direction of the robot, which is made from a flexible tube. The signals received from the sensor network were filtered using a low pass Butterworth filter. Here, a Butterworth filter was designed for noise removal. Finally, the Euler angles were extracted from the signals, in which the noise was filtered by the low path Butterworth filter. Using this Euler angle, the position of each sensor on the sensor network is estimated. The robot body was assumed to consist of links and joints. The position of each sensor can be assumed to be attached to the center of each link. The position of each link was determined using the Euler angle and kinematics equation. The interpolation was carried out between the positions of the sensors to be able to connect each point smoothly and obtain the final posture of the endoscope in operation. The experimental results showed that the shape of the colonoscope can be visualized using the Euler angles evaluated from the sensor network suggested and the shape of serial link estimated from the kinematics chain model.

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.5
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• pp.683-690
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• 1985

본 논문에는 Euler매개변수를 회전좌표계로 사용하여 구속된 3차원 기계시스템의 역동학력 해 을 수행한 연구결과가 수록되었다. 해석을 위해 문제에 등장하는 비선형 Holonomic구속조건식 들과 운동방정식들을 Cartesian일반좌표계을 사용하여 표시하였으며, 일반좌표계를 구성하는 각 강체의 좌표계로는 변위를 나타내기 위한 3개의 좌표와 회전을 나타내기 위한 4개의 Euler매 개변수가 사용되었다. 구속조건식들과 미분방정식 형태의 운동방정식들을 결합하여 시스템 전 체의 운동방정식을 유도하기 위해 Lagrange승수 기법을 사용하였다. 각 강체의 주어진 시간에 서의 위치, 속도, 가속도는 기구학적 해석(kinematic analysis)을 통해 얻어지고, 이 자료들을 전 체운동방정식에 대입하여 Lagrnage승수의 값을 계산하여 6개의 자유도를 가진 로봇 기구를 원 하는대로 운전하는에 필요한 각 관절의 토오크를 계산하였으며, 계산결과가 정확하다는 사실이 입증되었다. 연구결과 Euler매개변수를 회전좌표로 사용할 경우 특이 경우(singular case)가 발 생하지 않으며, 이 방법은 역동력학 해석용 다목적 전산프로그램 개발에 광범위하게 응용될 수 있음이 밝혀졌다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.21 no.5
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• pp.475-482
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• 2008

This paper indicates that the use of Euler angles lacks in its consistency and exactness of analysis when it was applied to incorporate the rotational equation of motion for rotor systems by previous researcher. Kinetic energy and angular velocity are different from case to case depending on the way of choosing Euler angles and thus only the linear system has been investigated even though the rotor system has a very nonlinear behavior. A new methodology is applied by using both spherical coordinate and quaternion in the rotor rotation to overcome weaknesses of Euler angles and shows its superiority It is found through numerical examples that the use of quaternion will be a more useful and valid tool to derive the numerical model of the rotor system.

• Journal of Biomedical Engineering Research
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• v.22 no.5
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• pp.459-468
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• 2001

The Average Coordinate Referenee System (ACRS) method is developed to reduce experimental errors in human locomotion analysis. Experimentally measured kinematic data is used to conduct analysis in human modeling, and the model accuracy is directly related to the accuracy of the data. However. the accuracy is questionable due to skin movement. deformation of skeletal structure while in motion and limitations of commercial motion analysis system . In this study. the ACRS method is applied to an optically-tracked segment marker system. although it can be applied to many of the others as well. In the ACRS method, each marker can be treated independently. as the origin of a local coordinate system for its body segment. Errors, inherent in the experimental process. result in different values for the recovered Euler angles at each origin. By employing knowledge of an initial, calibrated segment reference frame, the Euler angles at each marker location can be averaged. minimizing the effect of the skin extension and rotation. Using the developed ACRS methodology the error is reduced when compared to the general Euler angle method commonly applied in motion analysis. If there is no error exist in the experimental gait data. the separation and Penetration distance of the femoraltibial joint using absolute coordinate system is supposed to be zero during one gait cycle. The separation and Penetration distance was ranged up to 18 mm using general Euler angle method and 12 mm using the developed ACRS.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.2
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• pp.183-189
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• 2010

This paper deals with the comparison of analysis methodologies by applying both Euler angle and quaternion to observe the kinematical behavior of the universal joint system used as an automotive drive-shaft. At first, conventional approaches are applied to predict a kinematical behavior by introducing only Euler angles into the universal joint system, but turns out to be lack in consistency and reliability of the analysis. Then to overcome this deficiency in numerical analysis a different methodology is proposed by using quaternion in this system. Its corresponding advantage is discussed in terms of kinetic energy, rotational velocity and rotational displacement. The application of quaternions in the numerical experiment is shown to be a more useful and valid way of establishing the ideal analytical model of the universal joint system.

• Computational Structural Engineering
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• v.10 no.4
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• pp.177-184
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• 1997

In this paper, numerical methods are developed for solving the elastica of simple beams with variable-arc-length subjected to a point loading. The beam model is based on Bernoulli-Euler beam theory. The Runge-Kutta and Regula-Falsi methods, respectively, are used to solve the governing differential equations and to compute the beam's rotation at the left end of the beams. Extensive numerical results of the elastica responses, including deflected shapes, rotations of cross-section and bending moments, are presented in non-dimensional forms. The possible maximum values of the end rotation, deflection and bending moment are determined by analyzing the numerical data obtained in this study.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.1
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• pp.130-137
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• 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
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• v.20 no.6
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• pp.778-784
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• 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$^{(R)}$.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.5
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• pp.541-546
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• 2010

When a flexible arm is rotated by a motor about an joint axis, transverse vibration may occur. The motor torque should be controlled in such a way that the moter rotates by a specified angle, while simultaneously stabilizing vibration of the flexible arm so that it is arrested at the end of rotation. In this paper, the dynamic model of flexible robot arm is modeled by using Bernoulli-Euler beam theory and Lagrange equation. Nonlinear control with hysteresis deadzone using the sliding sector theory with continued input function in the sector is proposed.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10b
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• pp.511-513
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• 2000

최근 들어 WWW(World Wide Web) 환경을 이용한 각종 Entertainment 산업이 활성화되어 있다. WWW상의 실시간 아바타 애니메이션의 구현은 WWW를 이용한 Entertainment 산업 및 가상현실을 위한 중요한 원천기술 역할을 하리라 기대된다. 특히, 모션캡쳐를 통해 얻어진 모션데이터로 아바타의 애니메이션을 구현함으로써 보다 자연스러운 동작을 기대할 수 있다. 한편 일반적인 모션데이터로 Euler Angle로 나타나는데 반하여 VRML 환경하의 아바타에는 Euler Angle을 적용할 수 없다. 이는 VRML의 특성상 현재의 상태(State)를 저장할 수 없기 때문이다. VRML 환경하의 아바타에 적용 가능한 유일한 모션데이터 방식은 특정 축(Axis)과 이 축을 중심으로 한 회전각(Axis Angle)을 이용하는 것이다. 본 연구진은 이를 위하여 일반적인 모션데이터에 나타나는 Euler Angle을 특정 Axis와 Axis Angle로 변환해 주는 이론 및 모션데이터를 실시간으로 공급해주기 위한 JAVA Streaming Server를 직접 개발하였다. 본 논문에서는 이 시스템의 전체적인 구조를 설명하고자 한다.