• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.2
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• pp.281-287
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• 1997

In the conventional inverse modeling method for on-line modeling of the secondary path transfer function, the signal to noise ratio between the arbitrary random signal and the plant noise have to keep at -10 - -20 dB. For these reasons, the modeling can't be exactly implemented by the conventional method alone and the convergence time for modeling becomes too long. In this study, by combining the conventional inverse modeling method with an adaptive line enhancer, or with an adaptive noise canceller, a rigorous transfer functions of secondary path modeling and the control of a primary noise have been implemented simultaneously.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.11
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• pp.1291-1297
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• 2014

This paper proposes integrated chassis control (ICC) with electronic stability control (ESC) and active rear steering (ARS). Direct yaw moment control is used to generate a control yaw moment. A weighted pseudo-inverse-based control allocation (WPCA) method is adopted to distribute the control yaw moment into tire forces, generated by ESC and ARS. Simulation-based tuning of variables weights in the WPCA is used to enhance the yaw moment distribution performance. Simulations using the vehicle simulation software $CarSim^{(R)}$ show that the proposed ICC is effective in improving maneuverability and lateral stability.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.8 s.179
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• pp.1931-1939
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• 2000

Operating excitation forces of the linear vibratory system are normally determined by direct measurement techniques using load cells, strain gauges, etc. But, hydraulic forces of the rotating turbomachinery such as centrifugal pumps are exerted on an impeller due to asymmety of the flow by the interaction between pump impeller and volute. So, investigations of wide range of hydraulic designs and geometric deviations are difficult by direct method. This paper presents a hybrid approach for fourier transformed operational excitation forces, which uses pseudo-inverse matrix of the transfer matrix for the system and the measured vibrational data with standard installed pump. The determination of the transfer function matrix is based on a linear rotor/stationary system and steady state harmonic response in finite element analysis. And, vibrational data is collected in both vertical and horizontal directions at inboard and outboard bearing housings. The results of the process may be enhanced by making acceleration measurements at many more locations than there are forces to be determined.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.7
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• pp.651-657
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• 2008

A new approach for maximizing torque capability of low efficient reaction wheel assembly is addressed in this paper. At first, to find out a solution in constrainted field, weighted pseudo-inverse and momentum minimized allocation are suggested instead of a general control allocation called pseudo-inverse. The second method is a structural manner to enlarge torque capability of specific axis by changing installed skew angle of wheels. Two proposed methods are applied to large angle maneuvers of satellite. Improvement of control performance and feasibility for applying to commercial satellite attitude control are demonstrated by numeric simulations.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.93.1-93
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• 2001

An evolutionary approach for the design of Fuzzy Logic Systems(FLSs) is proposed. Membership functions(MFs) in Takagi-Sugeno type fuzzy logic system is optimized through evolutionary process. Output singleton values are obtained through pseudo-inverse method. The proposed technique is unique for that, to prevent overfilling phenomenon, limited-level RBF membership functions are used and the new fitness function is invented. To show the effectiveness of the proposed method, some simulations results on model identification are given.

• Communications of the Korean Mathematical Society
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• v.16 no.3
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• pp.487-508
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• 2001

We consider the Cauchy problem for Laplacian. Using the single layer representation, we obtain an equivalent system of boundary integral equations. We show the singular values of the ill-posed Cauchy operator decay exponentially, which means that a small error is exponentially amplified in the solution of the Cauchy problem. We show the decaying rate is dependent on the geometry of he domain, which provides the information on the choice of numerically meaningful modes. We suggest a pseudo-inverse regularization method based on singular value decomposition and present various numerical simulations.

• Smart Structures and Systems
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• v.31 no.5
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• pp.437-454
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• 2023

Real-time hybrid simulation (RTHS), which has the advantages of a substructure pseudo-dynamic test, is widely used to investigate the rate-dependent mechanical response of structures under earthquake excitation. However, time delay in RTHS can cause inaccurate results and experimental instabilities. Thus, this study proposes a model-based adaptive control strategy using a Kalman filter (KF) to minimize the time delay and improve RTHS stability and accuracy. In this method, the adaptive control strategy consists of three parts-a feedforward controller based on the discrete inverse model of a servohydraulic actuator and physical specimen, a parameter estimator using the KF, and a feedback controller. The KF with the feedforward controller can significantly reduce the variable time delay due to its fast convergence and high sensitivity to the error between the desired displacement and the measured one. The feedback control can remedy the residual time delay and minimize the method's dependence on the inverse model, thereby improving the robustness of the proposed control method. The tracking performance and parametric studies are conducted using the benchmark problem in RTHS. The results reveal that better tracking performance can be obtained, and the KF's initial settings have limited influence on the proposed strategy. Virtual RTHSs are conducted with linear and nonlinear physical substructures, respectively, and the results indicate brilliant tracking performance and superb robustness of the proposed method.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.12
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• pp.679-684
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• 2000

Closing switch, key component of pulsed power system, is constructed simply and used frequently due to the easy control and manufacture of one. The kind of one are spark-gap, triggered vacuum switch, pseudo-spark switch and INPIStron. But the electrode of spark gap switch is damaged with the hot spot by Z-pinch and then the life of one become short. INPIStron with inverse pinch effect has long life but it is difficult trigger system to provide uniform discharge between cathode and anode. In this paper, the design and manufacturing of INPIStron with gas puffing trigger method in order to supply uniform discharge inter-electrode and the performance of the developed INPIStron applied to 500[kA]-2[MJ] pulsed power system is presented.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.4
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• pp.200-205
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• 1993

In many applications, the typical parallel-jaw end-effector of a robot arm has been remarkably satisfactory. But, it is not adequate for the applications such as complicated manipulation. In the study, a finger with 4 joints (so, having redundancy) was consturcted to investigate the characteristics of an articulated hand. Each joint was driven by one actuator, and the motor torque was transmited to each joint through a tendon-pulley system. In the context, major considerations for hardware design and the method to solve the inverse kinematics of a redundant manipulator were presented. Finally, the basic capabilities of an articulated hand were presented through experiments.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.2
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• pp.170-177
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• 1993

In robotic arc welding, the roll (rotation) of the torch about its direction vector does not have any effect on the welding operation. Thus we could use this redundant degree of greedom for the motion control of the robot manipulator. This paper presents an algorithm for the pseudo- inverse kinematic motion control of the 6-axis robot, which utilizes the above mentioned redunancy. The prototype welding operation and the tool path are also graphically simulated. Since the proposed algorithm requires only the position and normal vector of the weldine as an input data, it is useful for the CAD-based off-line programming of the arc welding robot. In addition, it also has the advantages of the redundant manipulator motion control, like singularity avoidance and collision free motion planning, when compared with the other motion control method based on the direct inverse kinematics.