• Aerospace Engineering and Technology
• /
• v.10 no.1
• /
• pp.116-121
• /
• 2011

The tracking radar systems in NARO space center are used in order to acquire the TSPI (Time, Space, and Position Information) data of the launch vehicle. The tracking radar produce the measurements of tracked targets in the radar-centered coordinate system. When the tracking radar is in the Cartesian/Polar tracking mode, the state vector data is sent in radar-centered Cartesian/Polar coordinate system to RCC. RCC also send the slaving data in Test Range coordinate system to the tracking radar. So, the tracking radars have to transform the slaving data in Test Range coordinate system into in radar-centered coordinate system. In this study, we described the coordinate transformation between radar-centered coordinate system and Test Range coordinated system.

• Journal of Power Electronics
• /
• v.17 no.5
• /
• pp.1160-1172
• /
• 2017

A novel space vector modulation strategy in the non-orthogonal three-dimensional coordinate system for multi-level three-phase four-wire inverters is proposed in this paper. This new non-orthogonal three-dimensional space vector modulation converts original trigonometric functions in the orthogonal three-dimensional space coordinate into simple algebraic operations, which greatly reduces the algorithm complexity of three-dimensional space vector modulation and preserves the independent control of the zero-sequence component. Experimental results have verified the correctness and effectiveness of the proposed three-dimensional space vector modulation in the new non-orthogonal three-dimensional coordinate system.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.52 no.1
• /
• pp.22-30
• /
• 2003

A Coordinate-Transformation Extended Robust Kalman Filter (CERKF) designed in the Krein space is proposed, and then applied to a nonlinear incoming ballistic missile tracking system with parameter uncertainties. First, the Extended Robust Kalman filter (ERKF) is proposed to handle the nonlinearity of measurement equation which occurs whenever the polar coordinate system is transformed into the Cartesian coordinate system. Moreover, linearization error inevitably occurs and deteriorates the tracking performance, which is considerably reduced by the proposed CERKF. Through the simulation results, we show that the proposed CERKF, which uses the measurement coordinate system, has less RMS error than the previous ERKF which is designed in the Krein space using the Cartesian system. We also verify that the robustness and the stability of the proposed filter are guaranteed in two radars: the phased way radar and the scanning radar

• Journal of the Ergonomics Society of Korea
• /
• v.21 no.2
• /
• pp.47-58
• /
• 2002

This research suggested the mathematical model (forward kinematics method) to provide the reference points of driver space more easily and accurately in designing the package layout of vehicle interiors. For this purpose, the lengths of body segments of drivers and various joint angles occurred while were used. The length data between joints for the mathematical model were extracted from $SAFEWORK^{\circed{R}}$ as well as 95th percentile male and 5th percentile female body dimensions were utilized. In addition, the angles of body segments were applied on its diverse values within proper ranges in order to compare them each other. the mathematical model in this study was based on the concept of converting polar coordinate system to Cartesian coordinate system so that reference points of driver space were acquired in Cartesian coordinate system after using the segment lengths of drivers and the joint angles of driving postures as an input of polar coordinate system. It is expected that reference points of driver space obtained from this research are helpful to the study on package layout that is appropriate for physical characteristics of drivers.

• Proceedings of the KIEE Conference
• /
• 1992.07a
• /
• pp.411-413
• /
• 1992

This paper proposes a simple and high performance hybrid position/force control of robots based on disturbance compensation by using the disturbance observer in task coordinate space. The disturbance observer linealizes system of robot manipulators in task coordinate space and realizes acceleration control. To realize the strict acceleration control, the disturbance observer whose input is a position signal by simple computation, works as if it were a disturbance detector. The inverse kinematics can be simplified, because the disturbance observer in task coordinate space compensates not only the disturbance but also the error due to the simplification of the inverse kinematics. The new strategy is applied to a three-degrees-of freedom direct drive robot. The robust and simple hybrid position/force control is realized experimentally.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.21 no.2
• /
• pp.352-360
• /
• 1997

An inverse dynamic procedure for spatial multibody systems containing flexible bodies is developed in the relative joint coordinate space. Constraint acceleration equations are derived in terms of relative coordinates using the velocity transformation technique. An inverse velocity transformation operator, which transforms the Cartesian velocities to the relative velocities, is derived systematically corresponding to the types of kinematic joints connecting the bodies and the system reference matrix. Using the resulting matrix, the joint reaction forces and moments are analyzed in the Cartesian coordinate space. The formulation is illustrated by means of two numerical examples.

• Journal of the Korea Computer Graphics Society
• /
• v.3 no.2
• /
• pp.55-63
• /
• 1997

This paper presents a method of detecting motion isometry from the motions of two objects in a three-dimensional space. We define the motion isometry based on the group theory and a newly defined coordinate system. Motion isometry can be detected using the coordinate system which we call Motion Specific Coordinate System(MSCS). In addition, we present an algorithm if two motions are isometric using the coordinate system. The algorithm can detect the difference in the motions of objects irrespective of their positions or the directions of their motions in a space. The algorithm can also detect the motion difference in the case of segmented objects which have several joints. The motion quantity is represented by translation values or rotation angles about some axes.

• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.3 s.96
• /
• pp.164-173
• /
• 1999

Robot calibration needs accurate measurements of robot end-effector position at a number of different robot configurations. One of the efficient ways of the measurement is "Touching on Jig" method suggested in [7], which utilizes a touch sensor and a fixture consisting of various sizes of blocks. By moving the end-effector to touch the surface of a block whose position relative to the other is known, the end-effector position relative to the fixture coordinate system can be obtained at the instant of touching. However, the global size of fixture is too small to cover the various configurations of the robot. Because of the manufacturing difficulties, the fixture cannot be manufactured large enough for well distributed position measurement. It results in the improvement of robot accuracy only in the limited space near to the fixture rather than over the whole space of the robot working volume. The paper proposes a method to resolve the above problem by measuring the end-effector positions with respect to several different coordinate system using the same measurement devices. It is found that the proposed method leads the improvements of robot position accuracy over the large space of working volume. The experimental studies are performed to show the validity of the method and their results are discussed.

• Steel and Composite Structures
• /
• v.22 no.1
• /
• pp.161-182
• /
• 2016

A state space differential reproducing kernel (DRK) method is developed for the three-dimensional (3D) analysis of functionally graded material (FGM) axisymmetric circular plates with simply-supported and clamped edges. The strong formulation of this 3D elasticity axisymmetric problem is derived on the basis of the Reissner mixed variational theorem (RMVT), which consists of the Euler-Lagrange equations of this problem and its associated boundary conditions. The primary field variables are naturally independent of the circumferential coordinate, then interpolated in the radial coordinate using the early proposed DRK interpolation functions, and finally the state space equations of this problem are obtained, which represent a system of ordinary differential equations in the thickness coordinate. The state space DRK solutions can then be obtained by means of the transfer matrix method. The accuracy and convergence of this method are examined by comparing their solutions with the accurate ones available in the literature.

• Proceedings of the KSRS Conference
• /
• 1998.09a
• /
• pp.349-354
• /
• 1998

The grid reference system (GRS) has been useful for identifying the geographical location of satellite images. In this study we derive a GRS for the KOMPSAT Electro-Optical Camera (EOC) images. The derivation substantially follows the way that SPOT defines for its GRS, but incorporates the KOMPSAT orbital characteristics. The KOMPSAT EOC GRS (KEGRS) is designed to be a (K,J) coordinate system. The K coordinate parallel to the KOMPSAT ground track denotes the relative longitudinal position and the J coordinate represents the relative latitudinal position. The numbering of K begins with the prime meridian of K=1 with K increasing eastward, and the numbering of J uses a fixed value of J=500 at all center points on the equator with J increasing northward. The lateral and vertical intervals of grids are determined to be 12.5 km about at the 38$^{\circ}$ latitude to allow some margins for the value-added processing. The above design factors are being implemented in a satellite programming module of the KOMPSAT Receiving and Processing System (KRPS) to facilitate the EOC data collection planning over the Korean peninsula.