• Honam Mathematical Journal
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• v.8 no.1
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• pp.21-49
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• 1986

A class of singular quadratic control problem is considered. The state is governed by a higher order system of ordinary linear differential equations and very general nonstandard boundary conditions. These conditions in many important cases reduce to standard boundary conditions and because of the conditions the usual controllability condition is not needed. In the special case where the coefficient matrix of the control variable in the cost functional is a time-independent singular matrix, the corresponding optimal control law as well as the optimal controller are computed. The method of investigation is based on the theory of least-squares solutions of multi-valued operator equations.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1993.06a
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• pp.1330-1333
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• 1993

In this paper, first, the fuzzy Petri net inference mechanism with learning function is proposed by using the extended fuzzy Petri nets. Secondly, a control system with this new inference engine is proposed. This system can do automatically and easily the knowledge acquisition from the operator's empirical data and can also be controller adaptively under the big parameter change.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.622-627
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• 2003

The existing remote control system have some inherent disadvantage of direct control in the limit range. In some special cases, for example, a power apparatus, an unmanned factory, a nuclear factory, a security management system, the tele-operation is needed to control remote robot without limit space. This field is based on the Internet communication. Because the Internet is constructed all over the world. And it is possible that we control remote mobile robot in the long distance. In this paper, we developed a remote control system. This system is divided into two primary parts. These are local site and remote site. There are the moving robot and web server in the remote site and there is the robot control device in local site. The moving robot is moved by two stepper motors and the robot control device consists of SA-1100 micro controller and embedded Linux. And this controller is an embedded system. Public personal computer which is connected the Internet is used for the web server. The web server provides the mobile robot control interface program to the remote controller and captures the image for feedback information. In the whole system, a robot control device is connected with moving robot and web server through the Internet. So the operator can control the moving robot in the distance through the Internet.

• Journal of Drive and Control
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• v.17 no.2
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• pp.45-54
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• 2020

The IMV is a combination of four two-way valve systems which replace a conventional four-way spool valve to improve efficiency mostly in excavator hydraulics. As the environmental regulations for construction equipment have tightened, some overseas advanced companies have released commercial excavators in which the MCV is implemented with the IMVs. Development of the IMV type MCV relies on the control algorithm as well as the robust performance of proportional flow control valves. In this study, the IMV controller was designed and verified with experiments for the excavator working unit, which determines the IMV mode of operation and the extent of the valve opening in consideration of the load conditions on hydraulic actuators. First, the open-loop controller was designed with a joystick command vs. a PSV reference current map comprising several control parameters in to compensate for the different flow characteristics and non-linearities of two-way flow control valves. Second, the closed-loop controller was designed with the PI control fed by the actuator displacement and outputs actuator percent effort equivalent to the operator's joystick command. Finally, the performance of the IMV type MCV was verified with the trajectory control of position references derived from the energy consumption test standard. Experimental results showed the control performance of the IMV developed in this study, and suggest that future studies to be conducted to advance technical progress.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.2
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• pp.185-193
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• 2013

The construction automation provides safer and more productive working environment of construction site. We developed the automation system of bolting operation for high-rise building in the previous research. However, this system has a weak point that the operation has to be processed in the air with the operator in the cabin. This weakness leads operators to considerably dangerous environment. Therefore, we proposed the tele-operation system in order to supplement this weak point. Furthermore, it leads more effective operation by application of more intuitive controller; spherical coordinate based Master Arm than the joystick in the Mobile Bolting Robot system. These proposed system and controller were evaluated based on Fitts' law paradigm, which is a general estimation method of speed accuracy of task. Through the experimental results, new developed tele-operation system is compared with the actual operation and it discloses distinctions between two systems. As a result, it is found that new developed teleoperation system can be possible to replace the operation in the cabin.

• Journal of Drive and Control
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• v.12 no.4
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• pp.28-34
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• 2015

Because heavy-duty construction vehicles such as excavators are required for good engine-room cooling capacity, a hydraulic gear motor is adopted in the cooling fan drive mechanism to actively control the output speed, instead of adopting the conventional ON/OFF type belt drive. While gear motors are normally limited to 140bars of operating pressure, those for the cooling fan are capable of operating at continuous pressures of up to 220bars. After assembly, all gear motors for high pressure must pass an aging test which is a kind of the wearing process between the gear teeth and motor housing. During the aging process with gradual pressure increments, gear sticking sometimes occurs due to abnormal wear, resulting in defects. This paper focuses on a gear-sticking free aging test controller that is designed together with the knowledge of an experienced operator and the analysis results of experimental data of the gear jamming phenomenon. From the aging experiment, it is demonstrated that the developed controller that can alter the setting pressure of the load pump is effective for stabilizing the abrupt increase in the motor input pressure, thus preventing the hydraulic motor from stopping. This is expected to be helpful for the reduction of defects and increase in productivity.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.1
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• pp.40-45
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• 2004

This paper presents the parallel distributed control scheme for shaping of the bent glass. The designed system consists of a PC, a main controller and 11 servo-controllers, the precision motion controllers. Each elements are connected by using RS-232C and 8-bit data bus. In order to guarantee the stability and the control performance, we use a precision PID motion controller and a H-bridge on the servo-drivers. PC calculates position values of 11 DC motors by using the pre-determined curvature value and offers the user interface environment operator. The main controller provides the control instructions and parameter values to 11 servo-controllers by chip enable signal, simultaneously. Using the received commands and parameter values, the servo-controllers control the positions of the DC motors based on PID control scheme.

• Journal of the Institute of Convergence Signal Processing
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• v.19 no.4
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• pp.162-166
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• 2018

Companies that use automatic feeder systems use multiple feeders in close proximity to each other for mass production. Unlike when the feeder is used independently, it does not oscillate to a value that is set to offset or freeze due to symbiosis caused by asynchronous forces hitting each other. This may result in the shipment being damaged by hitting each other or thrown to one side, preventing the transport from being moved to the next process. Whenever an unstable resonance occurs, the operator must reset the value of each feed controller or operate it several times. To address these problems, this paper proposes synchronization algorithm suitable for feed controllers using multiple units and tests are used to confirm performance improvements.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.633-635
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• 2022

If an error occurs during operation of the video wall controller, the control system creates a log file and records the log. In order to minimize the load on the system due to log recording, the log level is set so that the log is not recorded as much as possible under normal operating conditions. When an error occurs, detailed logs are recorded by changing the log level to analyze and respond to the cause of the error. So work efficiency is reduced, and operator intervention is inevitable to change the log level. In this paper, we propose a model that automatically sets the log level according to the operating situation using Contextual Bandit.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.1
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• pp.446-467
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• 2012

In this paper, the analysis and design of a motion simulator (based on the approach taken by interactive virtual reality (VR) entertainment systems) is conducted. The main components of the system include a bilateral control interface, simulation and a motion simulator control scheme. The space entertainment system uses a virtual environment that enables operators to feel the actual feedback sensing and distorted motion from the virtual environment, just as they would in the real environment. The space entertainment system integrates the dynamics of the motion simulator and the virtual environment and the operator maneuvers a steering wheel to interact with the system. The multiple bilateral control schemes employ a dynamical controller, which is designed by considering the velocity and acceleration that the operator imposes on the joystick, the environmental changes imposed on the motion simulator. In addition, we develop a calculated method to evaluate the Ratio of the simulation results. It is shown that the proposed control scheme can improve the performance of the visual entertainment system. Experiments are conducted on the virtual reality entertainment system to validate the theoretical developments.