• Journal of Institute of Control, Robotics and Systems
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• v.10 no.7
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• pp.625-633
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• 2004

In this paper, position control of a car-like mobile robot using a neural network is presented. positional information of the mobile robot is given by a laser range finder located remotely through wireless communication. The heading angle is measured by a gyro sensor. Considering these two sensor information as a reference, the robot posture is corrected by a cascaded controller. To improve the tracking performance, a neural network with a cascaded controller is used to compensate for any uncertainty in the robot. The neural network functions as a compensator to minimize the positional errors in on-line fashion. A car-like mobile robot is built as a test-bed and experimental studies of several controllers are conducted and compared. Experimental results show that the best position control performance can be achieved by a cascaded controller with a neural network.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.11
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• pp.1099-1105
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• 2007

In this paper, modified two-port time-domain passivity approach is proposed for stable bilateral control of teleoperators under time-varying communication delay. We separate input and output energy at each port of a bilateral controller, and propose a sufficient condition for satisfying the passivity of the bilateral controller including time-delay. Output energy at the master port should be less than the transmitted input energy from the slave port with time-delay, and output energy at the slave port should be less than the transmitted input energy from the master port with time-delay. For satisfying above two conditions, two passivity controllers are attached at each port of the bilateral controller. A packet reflector with wireless internet connection is used to introduce serious time-varying communication delay of teleoperators. Average amount of time-delay was about 190(msec) for round trip, and varying between 175(msec) and 275(msec). Moreover some data packet was lost during the communication due to UDP data communication. Even under the serious time-varying delay and packet loss communication condition, the proposed approach can achieve stable teleoperation in free motion and hard contact as well.

• Journal of Ocean Engineering and Technology
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• v.30 no.3
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• pp.221-226
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• 2016

An attitude controller for a 6-DOF hovering autonomous underwater vehicle (HAUV) is implemented. We add a vertical thruster, an underwater camera, a wireless communication device, and a DVL to the HAUV that was developed a year ago. The HAUV is composed of 5 thrusters, 2 servo-motors, and 4 apparatus parts. Two rotating thrusters control the surge, heave, and roll of the vehicle. The vertical thruster controls the pitch, and two horizontal thrusters control the sway and yaw of the vehicle. The HAUV’s movement in each direction is controlled by 6 PID controllers. Each PID controller controls the propulsive force and angle of a thruster. In a horizontal and vertical movement experiment, we showed the feasibility of the proposed controller by maintaining a given depth and heading angle of the HAUV.

• Journal of Biosystems Engineering
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• v.25 no.4
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• pp.301-310
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• 2000

An autonomous tractor system was developed and its performance was evaluated. The system consisted of a tractor system of and a remote control station. The tractor and the remote control station communicated each other via wireless modems. The tractor had a DGPS(differential global positioning system), sensors, a controller and a modem. The DGPS collected position data and the tractor status was estimated. The information of tractor status and sensors was transferred to the remote control station. Then, the control station determined the control data such as steering angles using a fuzzy controller. The fuzzy controller used the information from the DGPS, sensors, and GIS(geographic information system) data. The control data were obtained by remote signal processing at the control station The control data for autonomous operation were transferred to the tractor controller. The performances of an autonomous tractor were evaluated for various speeds, different initial positions and different initial headings. About 1.3 seconds of time lag was occurred in transferring the tractor status data and the control data. Compensation the time lag, about 27cm deviation was observed at the speed of 0.5m/s and 37cm at the speed of 1m/s. Error caused mainly by the time lag and it would be reduced by developing a full-duplex radio module for controlling the remote tractor.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.9-12
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• 2005

In this paper. we offer a new monitoring system that controls all of the windfar. it can also apply use general wind turbine systems and real meteorological tower. We propose a hierarchical releiable monitoring system connected by wireless communication channels between monitoring host computer and modular slave measuring subsystems. Our system has two hierarchical subsystems: slave measuring systems, and supervisory host computer. We design and implement that the slave measuring subsystems is placed in meteorological tower and wind turbines, and the supervisory host computer in safety zone, The micro-controller in slave measuring system is duplicated using cold-standby method for reliability. The host computer and slave system constructs a feedback system, with wireless communication channel between them. For monitoring and command function, the supervisory computer is implemented with a Personal Computer using graphic user interface. Consequently. we can get a reliable but economic system.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.905-907
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• 2005

In this paper, we propose the system that can monitor and control the camera in the remote place using the PDA. The server PC attached to the PLC (Programmable Logic Controller) acquires the current status (On/Off) of the devices through the RS-232 serial communications. Also, the moving image frames captured from the wireless camera is compressed in the JPEG format and is stored in the server. The PDA, which is connected to the server through wireless internet, receives the data about the status of the devices and controls the devices according to the circumstances of them. Also, it can receive the images from the server simultaneously. So, we ran monitor and control the specified area in the remote place using the PDA through the wireless communication.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.3117-3119
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• 2005

In this paper, we propose the system that can monitor and control the camera in the remote place using the PDA. The server PC attached to the PLC (Programmable Logic Controller) acquires the current status (On/Off) of the devices through the RS-232 serial communications. Also, the moving image frames captured from the wireless camera is compressed in the JPEG format and is stored in the server. The PDA, which is connected to the server through wireless internet, receives the data about the status of the devices and controls the devices according to the circumstances of them. Also, it can receive the images from the server simultaneously. So, we can monitor and control the specified area in the remote place using the PDA through the wireless communication.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.12
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• pp.1273-1277
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• 2011

This paper proposes a control-based approach for duty cycle adaptation in wireless sensor networks. The proposed method, QCon, controls duty cycle through queue management in order to achieve high performance under variable traffic rates. To minimize energy consumption while meeting delay requirement, we design a feedback controller, which adapts the sleeping time according to dynamically changing traffic by constraining the queue length at a predetermined value. Based on control theory, we analyze the adaptive behavior of QCon and derive conditions for system stability. Results from asymptotic analysis and simulations indicate that QCon outperforms existing scheduling protocol by achieving more energy savings while satisfying delay requirement.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2465-2467
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• 2005

In this paper, we propose the system that can monitor and control the camera in the remote place using the PDA. The server PC attached to the PLC (Programmable Logic Controller) acquires the current status (On/Off) of the devices through the RS-232 serial communications. Also, the moving image frames captured from the wireless camera is compressed in the JPEG format and is stored in the server. The PDA, which is connected to the server through wireless internet, receives the data about the status of the devices and controls the devices according to the circumstances of them. Also, it can receive the images from the server simultaneously. So, we can monitor and control the specified area in the remote place using the PDA through the wireless communication.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1823-1825
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• 2005

In this paper, we propose the system that can monitor and control the camera in the remote place using the PDA. The server PC attached to the PLC(Programmable Logic Controller) acquires the current status(On/Off) of the devices through the RS-232 serial communications. Also, the moving image frames captured from the wireless camera is compressed in the JPEG format and is stored in the server. The PDA, which is connected to the server through wireless internet, receives the data about the status of the devices and controls the devices according to the circumstances of them. Also, it can receive the images from the server simultaneously. So, we can monitor and control the specified area in the remote place using the PDA through the wireless communication.