• Journal of the Korean Society for Precision Engineering
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• v.16 no.5 s.98
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• pp.58-65
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• 1999

A magnetic levitation system requires a robustness to overcome a dynamic instability due to disturbances. In this paper a robust controller for a magnetically levitated fine manipulator is presented. The proposed controller consists of following two parts: a model reference controller and an $H_{\infty}$ controller. First, the model reference control stabilizes the motion of the manipulator. Then, the motion of the manipulator follows that of the reference model. Second, the $H_{\infty}$ control minimizes errors generated from the model reference control due to noise and disturbance since the $H_{\infty}$ control is a kind of robust control. The experiments of position control and tracking control are carried out by use of the proposed controller under the conditions of free disturbances and forced disturbances. Also, the experiments using PID controller are carried out under the same conditions. The results from above two controllers are compared to investigate the control performances. As the results, it is observed that the proposed controller has similar position accuracy but better tracking performances comparing to the PID controller as well as good disturbance rejection effect due to the robust characteristics of the controller. In conclusion. it is verified that the proposed controller has the simple control structure, the good tracking performances and good disturbance rejection effect due to the robust characteristics of the controller.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.9
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• pp.869-874
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• 2011

This paper addresses the trajectory tracking problem for ship berthing by using sliding mode technique. With significant potential advantages: insensitivity to plant nonlinearities, parameter variations, remarkable stability and robust performance with environmental disturbances, the multivariable sliding modes controller is proposed for solving trajectory tracking of ship in harbor area. In this study, the ship position and heading angle are simultaneously tracked to guarantees that the ship follows a given path (geometric task) with desired velocities (dynamic task). The stability of the proposed control law is proved based on Lyapunov theory. The proposed approach has been simulated on a computer model of a supply vessel with good results.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.12
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• pp.1169-1174
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• 2009

In this paper, a prototype of implementable Sun tracking algorithm for mobile systems powered by alternative energy is proposed. The proposed system uses 2-axis tilt sensor and 3-axis magnetic sensor to measure orientation and posture of the system according to the horizon coordinates system, which are used to compensate tilt effects. Then through astronomical calculation using the present time and position informations obtained from GPS sensors, the calculated azimuth and altitude of the Sun in that location. The position of the Sun is converted to that of the mobile Sun tracking system coordinates and used to control A-axis and C-axis of the system.

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.3
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• pp.31-39
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• 2014

In KSLV-I launch mission, real-time data from the tracking stations are acquired, processed and distributed by the Mission Control System to the user group who needed to monitor processed data for safety and flight monitoring purposes. The processed trajectory data by the mission control system is sent to each tracking system for target designation in case of tracking failure. Also, the processed data are used for decision making for flight termination when anomalies occur during flight of the launch vehicle. In this paper, we propose the processing mechanism of slaving data which plays a key role of launch vehicle tracking mission. The best position data is selected by predefined logic and current status after every available position data are acquired and pre-processed. And, the slaving data is distributed to each tracking stations through time delay is compensated by extrapolation. For the accurate processing, operation timing of every procesing modules are triggered by time-tick signal(25ms period) which is driven from UTC(Universial Time Coordinates) time. To evaluate the proposed method, we compared slaving data to the position data which received by tracking radar. The experiments show the average difference value is below 0.01 degree.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.1
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• pp.16-25
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• 1997

This paper shows the development of the high accuracy vehicle positioning algorithm using the differential technique in vehicle tracking systems form the existing vehicle position which is acquired from the global positioning system (GPS). The control center receives the satellite ephemerise data and pseudorange correction from the reference station, and vehicle position from the moving vehicle. The pseudorange is calculated with the satellite position and the vehicle position, and corrected by pseudorange correction. Using this corrected pseudorange and kalman filter, more improved vehicle positioning data were obtained.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.1
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• pp.9-16
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• 2005

Accurate and reliable tracking of train is essential for the train control system. The fixed block system which utilizes track circuit has been used widely for the detection of train position. As an alternative, the moving block system has the advantage over the fixed block system since it enables shorter headway and easier maintenance. This paper presents a new technique for the train tracking system which uses radio signal for the train position detection. The proposed algorithm uses the phase difference of arrival of radio signal for the detection of train position. Experimental verification of the algorithm is presented in the paper.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.10
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• pp.1823-1831
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• 2010

This paper proposes an automatic tracking control algorithm for efficiency improvement of photovoltaic generation. Increasing the power of PV systems should improve the efficiency of solar cells or the power condition system. The normal alignment of the PV module always have to run perpendicular to the sun's rays. The solar tracking system, able to improve the efficiency of the PV system, was initiated by applying that to the PV power plant. The tracking system of conventional PV power plant has been studied with regard to the tracking accuracy of the solar cells. Power generation efficiency were increased by aligning the cells for maximum exposure to the sun's rays. Using a perpendicular position facilitated optimum condition. However, there is a problem about the reliability of tracking systems unable to not track the sun correctly during environmental variations. Therefore, a novel control algorithm needs to improve the generation efficiency of the PV systems and reduce the loss of generation. This control algorithm is the proposed automatic tracking algorithm in this paper. Automatic tracking control is combined the sensor and program method for robust control in environment changing condition. This tracking system includes the insolation, rain sensor and anemometer for climate environment changing. Proposed algorithm in this paper, is compared to performance of conventional tracking control algorithm in variative insolation condition. And prove the validity of proposed algorithm through the experimental data.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.6
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• pp.773-781
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• 2018

In recent years, a study of power-line inspection using an unmanned aerial vehicle (UAV) has been actively conducted. However, relevant studies have been conducting power-line inspection with an UAV operated by manual control, and they have developed just power-line detection algorithm on aerial images. To overcome limitations of existing research, we propose a drone-based power-line tracking system in this paper. The main contributions of this paper are to operate developed system under configured environment and to develop a power-line detection algorithm in real-time. Developed system is composed of the power-line detection and the image-based tracking control. To detect a power-line in real-time, a region of interest (ROI) image is extracted. Furthermore, clustering algorithm is used in order to discriminate the power-line from background. Finally, the power-line is detected by using the Hough transform, and a center position and a tilt angle are estimated by using the Kalman filter to control a drone smoothly. We design a position controller and an attitude controller for image-based tracking control, and both controllers are designed based on the proportional-derivative (PD) control method. The interaction between the position controller and the attitude controller makes the drone track the power-line. Several experiments were carried out in environments where conditions are similar to actual environments, which demonstrates the superiority of the developed system.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.9
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• pp.53-60
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• 2001

This paper presents a position control of a platform at the seaport cargo handling system. After brief description of the operating principles of the cargo handling system, the governing equation of the moving platform is derived. The equation is described in the state space model, and a robust H$_{\infty}$ controller to achieve position tracking of the moving platform. which can carry 200ton of containers, is formulated. In the synthesis of the controller, the weight of the container is treated as uncertain parameter. Both regulating and tracking control responses are analyzed for the loading and unloading procedures of the proposed automatic cargo handling system.

• Journal of Advanced Navigation Technology
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• v.18 no.1
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• pp.56-66
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• 2014

In this paper, the solar cell need the characteristic interpreting because the solar cell changes greatly according to the isolation, temperature and load in the photovoltaic development. Moreover, to get many energy in photovoltaic development need the position tracking of the sun according to the environment change and it is necessary to control the output of solar cells up to the time. Simulation and composed microprocessor and sensor chip an power conversion system with boost converter to experiment results are performed to prove the analysis of the converter operation, and to show the possibility of energy harvesting and photovoltaic development need the position tracking small capacitance, the boost rate of boost converter was similar to 167 percent.