• Proceedings of the KSME Conference
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• 2004.04a
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• pp.899-904
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• 2004

Multibody dynamics formulation has been developed based on relative cartesian coordinates for subsystem analysis. Relative cartesian coordinates are defined with respect to a reference body of a subsystem. Relative cartesian formulation inherits the same merits of absolute cartesian formulation, such as generality and easy implementation. Two methods have been applied. One is Largrange Multiplier Elimination method and the other is independent coordinate method. A 1/4 car simulation has been carried out to verify the formulations. Since both methods provide identical results, it proves the validity of the formulation.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.6
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• pp.98-104
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• 2002

In this study, we have developed an algorithm by attaching a camera at the end-effector of industrial six-axis robot in order to determine position and orientation of the camera system from cartesian coordinates. Cartesian coordinate as a starting point to evaluate for suggested algorithm, it was easy to confront increase of orientation vector for a linear line point that connects two points from coordinate space applied by recursive least square method which includes previous data result and new data result according to increase of image point. Therefore, when the camera attached to the end-effector has been applied to production location, with a calibration mask that has more than eight points arranged, this simulation approved that it is possible to determine position and orientation of cartesian coordinates of camera system even without a special measuring equipment.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.3
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• pp.389-394
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• 2014

Two evolutionary gait generation methods for Cartesian and Joint coordinates space are compared to develop a fast locomotion for quadruped robots. GA(Genetic Algorithm) based approaches seek to optimize a pre-selected set of parameters for the locus of paw and initial position in cartesian coordinates space. GP(Genetic Programming) based technique generate few joint trajectories using symbolic regression in joint coordinates space as a form of polynomials. Optimization for two proposed methods are executed using Webots simulation for the quadruped robot which is built by Bioloid. Furthermore, simulation results for two proposed methods are analysed in terms of different coordinate spaces.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.11-16
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• 2002

The differential equations governing free vibrations of the elastic, horizontally curved beams with unsymmetric axis are derived in Cartesian coordinates rather than in polar coordinates, in which the effect of torsional inertia is included. Frequencies are computed numerically for the sinusoidal curved beams with both clamped ends and both hinged ends. Comparisons of natural frequencies between this study and SAP 2000 are made to validate theories and numerical methods developed herein. The convergent efficiency is highly improved under the newly derived differential equations in Cartesian coordinates. The lowest four natural frequency parameters are reported, with and without torsional inertia, as functions of three non-dimensional system parameters: the horizontal rise to chord length ratio, the span length to chord length ratio, and the slenderness ratio.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1724-1729
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• 2003

Two different subsystem synthesis methods with independent generalized coordinates have been developed and compared. In each formulation, the subsystem equations of motion are generated in terms of independent generalized coordinates. The first formulation is based on the relative Cartesian coordinates with respect to moving subsystem base (virtual) body. The second formulation is based on the relative joint coordinates using recursive formulation. Computational efficiency of the formulations has been compared theoretically by the operational counting method.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.12
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• pp.970-978
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• 2002

The differential equations governing free vibrations of the elastic arches with unsymmetric axis are derived in Cartesian coordinates rather than in polar coordinates. in which the effect of rotatory inertia is included. Frequencies and mode shapes are computed numerically for parabolic arches with both clamped ends and both hinged ends. Comparisons of natural frequencies between this study and SAP 2000 are made to validate theories and numerical methods developed herein. The convergent efficiency is highly improved under the newly derived differential equations in Cartesian coordinates. The lowest four natural frequency parameters are reported, with and without the rotatory inertia, as functions of three non-dimensional system parameters the rise to chord length ratio. the span length to chord length ratio, and the slenderness ratio. Also typical mode shapes of vibrating arches are presented.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.8 no.1
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• pp.67-80
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• 2004

In the present paper, a numerical algorithm for the kinematic analysis of a MacPherson strut motor-vehicle suspension system is developed. The kinematic analysis is carried out in terms of the rectangular Cartesian coordinates of some defined points in the links and at the joints. The presented formulation in terms of this system of coordinates is simple and involves only elementary mathematics. The resulting constraint equations are mostly either linear or quadratic in the rectangular Cartesian coordinates. The proposed formulation eliminates the need to write redundant constraints and allows to solve a reduced system of equations which leads to better accuracy and a reduction in computing time. The algorithm is applied to solve the initial positions as well as the finite displacement, velocity and acceleration problems for the MacPherson strut motor-vehicle suspension system.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.46.1-46.1
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• 2019

We present an accurate and efficient method to calculate the gravitational potential of an isolated system in three-dimensional Cartesian and cylindrical coordinates subject to vacuum (open) boundary conditions. Our method consists of two parts: an interior solver and a boundary solver. The interior solver adopts an eigenfunction expansion method together with a tridiagonal matrix solver to solve the Poisson equation subject to the zero boundary condition. The boundary solver employs James's method to calculate the boundary potential due to the screening charges required to keep the zero boundary condition for the interior solver. A full computation of gravitational potential requires running the interior solver twice and the boundary solver once. We develop a method to compute the discrete Green's function in cylindrical coordinates, which is an integral part of the James algorithm to maintain second-order accuracy. We implement our method in the {\tt Athena++} magnetohydrodynamics code, and perform various tests to check that our solver is second-order accurate and exhibits good parallel performance.

• Journal of Mechanical Science and Technology
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• v.17 no.8
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• pp.1133-1139
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• 2003

In this paper, a numerical algorithm for the kinematic analysis of a multi-link five-point suspension system is presented. The kinematic analysis is carried out in terms of the rectangular Cartesian coordinates of some defined points in the links and at the joints. Geometric constraints are introduced to fix the relative positions between the points belonging to the same rigid body. Position, velocity and acceleration analyses are carried out. The presented formulation in terms or this system of coordinates is simple and involves only elementary mathematics. The results of the kinematic analysis are presented and discussed.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.35 no.5
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• pp.177-184
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• 1986

An effective cartesian coordinate model is presented to control a robot motion along a prescribed timebased hand trajectory in cartesian coordinates and to provide an adaptive feedback design approach utilizing self-tuning control methods without requiring a detailed mathematical description of the system dynamics. Assuming that each of the hybrid variable set of velocities and forces at the cartesian coordinate level is mutually independent, the dynamic model for the cartesian coordinate control is reduced to first-order SISO models for each degree of freedom of robot hand, including a term to represent all unmodeled effects, by which the number of parameters to be identified is minimized. The self-tuners are designde to minimize a chosen performance criterion, and the computed control forces are resolved into applied joint torques by the Jacobian matrix. The robustness of the model and controller is demonstrated by comparing with the other catesian coordinate controllers.