• Proceedings of the KIEE Conference
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• 1999.11a
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• pp.52-55
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• 1999

In recent years, much attention has been paid to the voltage collapse phenomena. There has been reported many cases about the voltage collapse in many countries. These voltage collapse phenomena are known as the event that can occur due to reactive power deficits. This paper proposes an efficient method that can pursue the reactive power loss changes and gives the simple voltage collapse proximity indicator(VCPI) based on the reactive power loss sensitivities using optimal techniques. By comparing reactive power loss sensitivity with active power loss sensitivity, it is also proved that VCPI based on reactive power loss sensitivities is more effective. The developed VCPI is derived from the Jacobian matrix of Load Flow and the computational burden is very low and on-line implementation is possible. The proposed method is applied to a IEEE-14 bus test system and reliable and promising results are obtained.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1136-1139
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• 1996

For on-line trajectory planning such as teleoperation it is desirable to keep good manipulability of the robot manipulators since the motion command is not given in advance. To keep good manipulability means the capability of moving any arbitrary directions of task space. An optimization process with different manipulability measures are performed and compared for a redundant robot system moving in 2-dimensional task space, and gives results that the conventional manipulability ellipsoid based on the Jacobian matrix is not good choice as far as the optimal direction of motion is concerned.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.539-542
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• 1996

The forces exerted on an object by the end-effectors of multi-manipulators are decomposed into the motion-inducing force and the internal force. Motion-inducing force effects the motion of an object and internal force can't effect it. The motion of an object can't track exactly the desired motion because of internal force component, therefore internal force component must be considered. In this paper using the resolved acceleration control method and the fact that internal force lies in the null space of jacobian matrix, we construct independently the position, motion-inducing force and internal force controller. Secondly we construct the robust controller to preserve the robustness with respect to the uncertainty of manipulator parameters.

• Transactions on Control, Automation and Systems Engineering
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• v.3 no.4
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• pp.210-216
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• 2001

In this paper, design of a 3-degree-of-freedom mobile robot with three caster wheels is performed. Initially, kinematic modeling and singularity analysis of the mobile robot is performed. It is found that the singularity can be avoided when the robot has more than two wheels on which two active joints are located. Optimal kinematic parameters of mobile robots with three active joint variables and with four active joint variables are obtained and compared with respect to kinematic isotropic index of the Jacobian matrix of the mobile robot which is functions of the wheel radius and the length of steering link.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.848-855
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• 1989

By structural comparison of process optimization strategies based on Simultaneous Modular Approach, they can be classified into two groups : the Sequential Module Based Approach and the Two-Tier Approach. The Sequential Module Based Approach needs rigorous models and a set of accurate solutions are guranteed. However, it requires large amount of computation time. In the Two-Tier Approach composed of rigorous and simplified models, optimization calculation uses simplified models, therefore comparatively smaller amount of computation time is required but the obtained solutions may not be accurate. These optimization problems were somewhat improved by the alternate application of the two strategies. In this study, improved optimization strategy is suggested, in which Jacobian Matrix is modified to accomodate the strong points of above mentioned strategies. The results of case study show that this approach is superior to the other strategies.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.04a
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• pp.127-132
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• 1992

To relize the future intelligent robot the development of a special-purpose processor for a coordinate transformation is evidently challenging task. In this case the complexity of a hardware architecture strongly depends on the adopted algorithm. In this paper we have used an inverse kinemetics algorithm based on incremental unit computation method. This method considers the 3-axis articulated robot as the combination of two types of a 2-axis robot: polar robot and 2-axis planar articulated one. For each robot incremental units in the joint and Cartesian spaces are defined. With this approach the calculation of the inverse Jacobian matrix can be realized through a simple combinational logic gate. Futhermore, the incremental computation of the DDA integrator can be used to solve the direct kinematics. We have also designed a hardware architecture to implement the proposed algorithm. The architecture consists of serveral simple unitsl. The operative unit comprises several basic operators and simple data path with a small bit-length. The hardware architecture is realized byusing the EPLD. For the straight-line motion of the KAIST arm we have obtained maximum end effector's speed of 12.6 m/sec by adopting system clock of 8 MHz.

• Journal of Mechanical Science and Technology
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• v.19 no.spc1
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• pp.377-387
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• 2005

The equations of motion of two-wheeled vehicles, e.g. bicycles or motorcycles, are developed by using Lagrange's equations for quasi-coordinates. The pure rolling constraints between the ground and the two wheels are considered in the dynamical equations of the system. For each wheel, two nonholonomic and two holonomic constraints are introduced in a set of differential-algebraic equations (DAE). The constraint Jacobian matrix is obtained by collecting all the constraint equations and converting them into the velocity form. Equilibrium, an algorithm for searching for equilibrium points of two-wheeled vehicles and the associated problems are discussed. Formulae for calculating the radii of curvatures of ground-wheel contact paths and the reference point are also given.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.7 s.172
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• pp.102-111
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• 2005

In this paper, we address a position control for a parallel stage, which is levitated and driven by electric magnetic force. This consists of a levitating object (called platen) with 4 permanent magnetic linear synchronous motors in parallel. Each motor generates vertical force for suspension against gravity and propulsion force horizontally as well. This stage can generate six degrees of freedom motion by the vertical and horizontal force. A dynamic equation of the stage system is derived based on Newton-Euler method and it's special Jacobian matrix describing a relation between the limited velocity and Cartesian velocity is done. There are proposed two control methods for positioning which are Cartesian space controller and Actuator space controller. The control performance of the Cartesian space controller is better than the Actuator space controller in task space trajectory while the Actuator space controller is simpler than the Cartesian space controller in controller realization.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.4
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• pp.9-17
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• 1996

This paper develops a sequential updating method of the Euler parameter generalized coordinates for the machine kinematics and dynamics, The Newton's method is slightly modified so as to utilize the Jacobian matrix with respect to the virtual rotation instead of this with repect to the Euler parameters. An intermediate variable is introduced and the modified Newton's method solves for the variable first. Relational equation of the intermediate variable is then solved for the Euler parameters. The solution process is carried out efficiently by symoblic inversion of the relational equation of the intermediate variable and the iteration equation of the Euler parameter normalization constraint. The proposed method is applied to a kinematic and dynamic analysis with the Generalized Coordinate Partitioning method. Covergence analysis is performed to guarantee the local convergence of the proposed method. To demonstrate the validity and practicalism of the proposed method, kinematic analysis of a motion base system and dynamic analysis of a vehicle are carried out.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.11
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• pp.542-548
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• 2000

In this paper, we proposed a new load flow analysis algorithm. In order to develop it, we converted typical power flow problem into optimal problem. This problem has the objective function that minimize the difference between calculated values and specified values of bus powers and subject to bus power equations of P and Q. Using it, we solved the divergence by singularity of Jacobian matrix, the divergence by initial value in the typical power flow study. In the study of a sample system, we verified the superiority of proposed algorithm.