• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.844_845
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• 2009

Inductance and back EMF are important parameters in characteristic analysis of brushless motor. Inductance is constant value in surface permanent magnet type brushless motor. But it is change depending on the position of the rotor in interior permanent magnet type brushless motor. So this paper is considering for change inductance in characteristic analysis of brushless motor. Characteristic analysis is executed by the method that three-phase bipolar 120 degree commutation drive type.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.10a
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• pp.99-104
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• 2001

The neural network method has been introduced to design a controller for linear motor feed system and system operation status was monitored. It is most difficult to achieve controller gain tuning because of the information limit. Regardless of the system structure, conventional control gain could be adjusted minimizing the resulting error for both position and velocity using the proposed method. Slight performance deterioration was observed at the small value of training epoch. Different controller performance for position was observed with respect changed sampling time. Actuated system performance was monitored using neural network signal processing and operational status was predicted with the rate of 80% approximately.

• Proceedings of the KIEE Conference
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• 2007.10c
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• pp.160-162
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• 2007

Switched-reluctance motor(SRM) has advantages such as simple structure, low cost and so on compared with induction motor. This paper proposes a new sensorless method that is based on the impressed voltage pulse method to estimate rotor position. Current sensors detect the SRM currents in the unenergised phases and output the voltage. The rotor position can be inferred by the above calculations when the peak values exceed a fixed threshold value.

• The Journal of Korea Robotics Society
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• v.15 no.1
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• pp.32-38
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• 2020

This paper describes a method for tracking attitude and position of underwater robots. Underwater work with underwater robots is subject to differences in work efficiency depending on the skill of the operator and the utilization of additional sensors. Therefore, this study developed an underwater robot that can operate autonomously and maintain a certain attitude when working underwater to reduce difference of work efficiency. The developed underwater robot uses 8 thrusters to control 6 degrees of freedom motion, IMU (Inertial Measurement Unit), DVL (Doppler Velocity Log) and PS (Pressure Sensor) to measure attitude and position. In addition, the thruster allocation algorithm was designed to follow the control desired value using 8 thrusters, and the motion control experiments were performed in the engineering water basin using the thruster allocation method.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.210-213
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• 2004

In a switched reluctance motor drive, it is important to synchronize the stator phase excitation with the rotor position, because the position of rotor is an essential information. In the high-speed region, switching angles are fluctuated back and forth out of the preset value, which is caused by the sampling period of the microprocessor. In this paper, a low cost analog encoder to be suitable for practical applications is proposed. The validity of the proposed analog encoder with a proper logic controller is verified from the experiments.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.677-680
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• 2004

In the mobile environment, according to the movement of the object, the query finds the nearest special object or place from object position. However, because query object moves continuously in the mobile environment, query demand changes according to the direction attribute of query object. Also, in the case of moving of query object and simply the minimum distance value of query result, sometimes we find the result against the query object direction. Especially, in most road condition, as user has to return after reaching U-turn area, user rather spends time and cost. Therefore, in order to solve those problems, in this paper we propose the nearest neighbor method considering moving object position and direction for mobile recommendation system.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.749-752
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• 1998

Recognizing a human part becomes very important for applications which are based on the interaction between computers and their users. In this paper, we design and implement a system which recognizes and tracks a human head using a sequence of images. Difference images are used to easily extract feature vectors from images with very complex backgrounds. A human bhead is represented with an ellipse and recognized by searching for a maximum value from preprocessed gradient images. The method is developed by considering the fact that the tracking system should be real-time. The designed system not only shows an excellent performance for the normal up-right position of the head, but also for the cases of 360.deg. rotated head position, occluded images of heads, and tilted head positions.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.517-518
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• 2015

In this research, the application of GPS and Gyro sensor based FlyingDisc with the value of 3D position and circulation sensors was proposed for school physical education. 3D Unity for 3 dimensional expression of sensors was applied for the 3D position and circulation direction from the FlyingDisc.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.9
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• pp.1103-1111
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• 1999

STACOM will be utilized to control substation voltage in the near future. Although STACOM shows good voltage regulation performance owing to its rapid and continuous response, it needs additional reactive power compensation device to keep control margin for emergency such as fault. ULTC transformer is one of good candidates. This paper presents a Kohonen Neural Network (KNN) based coordination control scheme of ULTC transformer and STACOM. In this paper, the objective function of the coordination control is minimization of both STACOM output and the number of switchings of ULTC transformer while maintaining substation voltage magnitude to the predefined constant value. This coordination, control is performed based on reactive load trend of the substation and KNN which offers optimal tap position in view of STACOM output minimization. The input variables of KNN are active and reactive power of the substation, current tap position, and current STACOM output. The KNN is trained by effective Iterative Condensed Nearest Neighbor (ICNN) rule. This coordination control applied to IEEE 14 bus system and shows satisfactory results.

• 한국전산유체공학회:학술대회논문집
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• 2008.03a
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• pp.118-124
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• 2008

The characteristics of heat transfer in a two-dimensional channel obstructed by a square rod is investigated by a turbulence model. The computation is made for the six cases of different rod positions between channel walls. To analyze the wall heat transfer, the heat flux of channel walls is set as a constant value and the $k-{\epsilon}-f_{\mu}$ model is employed. Downstream the square rod, the flow recirculation region appear and they are varied by the rod position. The enhancement of the turbulent heat transfer to the wall is induced by the flow instability using a square rod. The averaged heat transfer rate is maximized at a specific rod position. Finally, the effects of square rod on unsteady flows are scrutinized with the frequency analysis.