• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.506-508
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• 1995

The relay protection engineers are sometimes faced with the difficulties in full protection of high-inertia drive motors during acceleration period. The problem results from lower permitted locked rotor time of the motor compared with motor starting time. Even though the various types of protection relay and other device (Speed switch, Distance relay) are used, the full protections against abnormal starting conditions may not be available. So, the development of a new speed-biased overcurrent relay is suggested in this paper. This paper also presents that speed-biased overcurrent relay can fully protect the high-inertia motor during abnormal starting condition by computer simulation.

• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.45-47
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• 2001

This paper studies the relationship between output and vibration characteristics of Switched Reluctance Motor(SRM) according to switch-on and off angles. Acceleration and motor performance are measured by changing switching angles and the magnetic forces are analyzed by Finite Element Analysis. A proper switching angle from theoretical and several experimental results are presented for satisfying power, efficiency and low vibration.

• The Journal of Korea Robotics Society
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• v.17 no.3
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• pp.303-307
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• 2022

This paper proposes a method that can generate a smooth trajectory from the discontinuous trajectory in kinematic, dynamic, and task-space trajectory constraints. The problem is defined as the minimization of kinetic energy, and then the simulation is performed by using the MATLAB. Kinematic and inverse kinematic equations are derived for the simulation of the 6-DOF robotic arm. The simulation results showed that the trajectory of each joint is generated while satisfying the constraints without any discontinuity. There are small errors in the Cartesian trajectory, but unnecessary deceleration and acceleration can be eliminated. In addition, it is possible to quickly switch between the robotic tasks by applying the proposed method.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.3
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• pp.294-299
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• 2010

ELT(Emergency Locator Transmitter) is used to send distress signal in the event of an aircraft crash. It is very useful but the ELT may transmit wrong signal caused by misjudging between crash and hard-landing. The reason of this problem is the low accuracy of the mechanical G-switch currently in use. To improve the ELT, we developed an ELT system using the MEMS(Micro Electro-Mechanical Sensor) accelerometer. The ELT system consists of acceleration data acquisition/analysis system, program of crash recognition, and GPS receiving system for the position information of an aircraft crash site. A free-drop table was developed for verification of the ELT system. The free-drop table was designed to replicate the acceleration and the pulse duration of the hard landing and the crash. By using the free-drop table, we showed that the ELT system performed well.

• Journal of Electrical Engineering and Technology
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• v.10 no.1
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• pp.216-226
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• 2015

The neutral beam injection generate ultra-high temperature energy in the tokamak of nuclear fusion. The neutral beam injection make up arc power supply, filament power supply and acceleration & deceleration power supply. The arc power supply has characteristics of low voltage and high current. Arc power supply generate arc through constant output of voltage and current. So this paper proposed suitable buck converter for low voltage and high current. The proposed buck converter used parallel switch because it can be increased capacity and decrease conduction loss. When an arc generated, the neutral beam injection chamber occur high voltage. And it will break output capacitor of buck converter. Therefore the output capacitor was removed in the proposed converter. Thus the proposed converter should be designed for the characteristics of low voltage and high current. Also, the arc power supply should be guaranteed for system stability. The proposed parallel buck converter enables the system stability of the divided low output voltage and high current. The proposed converter with constant output be the most important design of the output inductor. In this paper, designed arc power supply verified operation of system and stability through simulation and prototype. After it is applied to the 288[kW] arc power supply for neutral beam injection.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2747-2752
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• 2003

This paper has develops a new framework to understand the human’s driving maneuver based on the expression as HDS focusing on the driver’s stopping maneuver. The driving data has been collected by using the three-dimensional driving simulator based on CAVE, which provides three-dimensional visual information. In our modeling, the relationship between the measured information such as distance to the stop line, its first and second derivatives and the braking amount has been expressed by the PWPS model, which is a class of HDS. The key idea to solve the identification problem was to formulate the problem as the MILP with replacing the switching conditions by binary variables. From the obtained results, it is found that the driver appropriately switches the ‘control law’ according to the following scenario: At the beginning of the stopping behavior (just after finding the stopping point), the driver decelerate the vehicle based on the acceleration information, and then switch to the control law based on the distance to the stop line.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.6
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• pp.50-58
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• 2013

The Neutral Beam Injection(NBI) generates ultra-high temperature energy in the tokamak of nuclear fusion. The NBI consists of filament power supply acceleration and deceleration power supply and arc power supply(APS). The APS has characteristics of low voltage and high current. APS generate arc through constant output of voltage and current. So this paper proposed suitable buck converter for low voltage and high current. The case of proposed buck converter used parallel switch because it can increase capacity and decrease conduction loss. When an arc is generated, the NBI chamber occur high voltage. And it will break output capacitor of buck converter. Therefore the output capacitor was removed in the proposed converter. Thus buck converter with constant output is the most important design of the output inductor. In this paper, designed APS verified operation of system and stability through simulation and prototype.

• Structural Engineering and Mechanics
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• v.26 no.5
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• pp.517-544
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• 2007

This study shows a fuzzy tuning scheme to fuzzy sliding mode controller (FSMC) for seismic isolation of earthquake-excited structures. The sliding surface can rotate in the phase plane in such a direction that the seismic isolation can be improved. Since ideal sliding mode control requires very fast switch on the input, which can not be provided by real actuators, some modifications to the conventional sliding-mode controller have been proposed based on fuzzy logic. A superior control performance has been obtained with FSMC to deal with problems of uncertainty, imprecision and time delay. Furthermore, using the fuzzy moving sliding surface, the excellent system response is obtained if comparing with the conventional sliding mode controller (SMC), as well as reducing chattering effect. For simulation validation of the proposed seismic response control, 16-floor tall building has been considered. Simulations for six different seismic events, Elcentro (1940), Hyogoken (1995), Northridge (1994), Takochi-oki (1968), the east-west acceleration component of D$\ddot{u}$zce and Bolu records of 1999 D$\ddot{u}$zce-Bolu earthquake in Turkey, have been performed for assessing the effectiveness of the proposed control approach. Then, the simulations have been presented with figures and tables. As a result, the performance of the proposed controller has been quite remarkable, compared with that of conventional SMC.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.8
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• pp.434-440
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• 2002

Switched Reluctance Motor (SRM) has been not commonly used because of the severe noise and vibration, although it has many advantages as solidity and economical efficiency. The origin of the acoustic noise and vibration in SRM's can be broadly classified into two types, mechanical and magnetic. Therefore this paper verifies the origin of vibration induced by radial magnetic forces from various experiments, and then studies the relationship between the output and vibration characteristics of SRM according to switch-on and off angles. Acceleration, torque and efficiency is measured by changing switching angles. From the comparison and analysis of the experimental results, a proper switching angle is presented for both satisfying electric performance and reducing vibration.

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.6
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• pp.857-864
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• 2018

This paper describes about the circuit design and test of the electronic Arm Fire Device. Electronic arm fire device consists of igniter, circuit and housing case and it operates without the actuator such as torque motor or solenoid. A high-voltage DC-DC converter was used to generate the voltage for initiating the LEEFI(Low Energy Exploding Foil Initiator). The MEMS switch was used to detect the acceleration that occurs when missile is launched, and the circuit was designed considering the size, performance, and specification of the electronic devices. The performance test was conducted to verify the designed circuit and we confirmed that it operates well.