• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.81-84
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• 1997

This paper studies an active noise controller in a communication headset. The system is a two inputs(communication signal and noise signal) and single output(error signal) system. The problem is to reduce noise level sufficiently lower than communication signal to receive the communication signal clearly. The approach to this problem is in two steps. In the first step, we solve the noise rejection problem without communication signals. In this step, the problem is transformed to the robust H$_{\infty}$ regulating problem and solved using Linear Matrix Inequalities. In the second step, communication signal is introduced to the system, To verify the performance of the designed controller, a couple of experiments are performed..

• International Journal of Railway
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• v.9 no.2
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• pp.36-40
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• 2016

TETRA communication system is very versatile system which can transmit voice + data and packet data optimized. Direct mode operation permits to connect between mobiles when mobile stain is out of coverage of networks. It can be more secure communication channel for railway signaling systems. Railway signaling systems use many of wayside signal equipment, which require many maintenance efforts and budget. Many railway authorities want to reduce and replace the wayside equipment. Radio based signaling systems are one of candidate for replacing the conventional signaling systems. The radio based signaling systems can replace track circuit and wayside signal. The radio systems permit to connect between control centers and trains. The radio systems have to ensure high quality of the connectivity more or equal to the existed track circuits. We studied the application of TETRA systems for railway radio systems for bridging between train control centers and trains. We provide an operation scenario for radio based train control system to ensure the safety require to the existed trains control system and satisfied the existed operational availability. We showed the data transmission speed, maximum bit error rate, and data coding for the radio-based signal system using TETRA systems.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.13 no.3
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• pp.25-37
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• 2014

Recently, our local governments are conducting the introduction of tram system because it is recognized as an effective public transit that can solve a traffic jam in downtown, decreasing public transit share and environmental issues in world wide cities. We developed the Active Priority Control Strategy to efficiently operate a tram in our existing traffic signal system. This study organized the tram system for operating the Active Priority Signal Control, developed the algorithm that calculates a tram-stop dwell time in order to pass the downstream intersection without a stop. The dwell time is determined by arrival time at tram-stop, downstream signal time, and the location of a opposite tram, it can be reduced by choosing the optimal one among Signal Priority Controls. Using the VISSIM and VISVAP model, we conducted a simulation test for the city of Chang-won that it is expected to install a tram system. It showed that a developed signal control strategy is effective to prevent a tram's stop in intersections, to reduce a tram's travel time.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.6 no.1
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• pp.7-17
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• 1997

During the past decade, there were many well-established theories for the adaptive control of linear systems, but there exists relatively little general theory for the adaptive control of nonlinear systems. Adaptive control technique is essential for providing a stable and robust performance for application of industrial robot control. Neural network computing methods provide one approach to the development of adaptive and learning behavior in robotic system for manufacturing. Computational neural networks have been demonstrated which exhibit capabilities for supervised learning, matching, and generalization for problems on an experimental scale. Supervised learning could improve the efficiency of training and development of robotic systems. In this paper, a new scheme of adaptive-neuro control system to implement real-time control of robot manipulator using digital signal processors is proposed. Digital signal processors, DSPs, are micro-processors that are developed particularly for fast numerical computations involving sums and products of variables. The proposed neuro control algorithm is one of learning a model based error back-propagation scheme using Lyapunov stability analysis method. The proposed adaptive-neuro control scheme is illustrated to be an efficient control scheme for implementation of real-time control for SCARA robot with four-axes by experiment.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.116.1-116
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• 2002

When the teleoperated system has a signal transmission time delay between slave and control system , the system stability as well as the position tracking and the force reflecting performances are likely to be deteriorated. This paper proposed a bilateral control scheme and a controller design method for the teleoperated control systems with a signal transmission time delay. The proposed controller is a modified type of smith predictor for the time delay in each input and output stage of an open loop unstable plant. The proposed controller not only satisfies the system internal stability but also improves the position tracking performance with disturbance rejection capability. The simulation...

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2000.05a
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• pp.288-291
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• 2000

In this paper we implement a robot system consisted of mobile tole robot to be controlled by client through web browser Newly Internet is connected to all network of the whole world. If client uses the network like this, client can control direction of a robot that is selected in free place. In this study, system is embodied in using robot that can move freely in plan place and cod camera that can grab robot image. System transmit image data of cod camera to java server that is placed in web server of internet that is used by client. Java server display incoming data in home page using java applet. Then web browser offer robot image to client and client send remote control signal to robot. Control signal is transmitted to robot by java server and robot receiving signal moves toward direction wanted by client.

• Journal of Electrical Engineering and Technology
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• v.9 no.5
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• pp.1582-1591
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• 2014

This paper presents a hybrid sensorless control for an interior permanent magnet synchronous motor (IPMSM) for zero-, low-, and high-speed regions. Many sensorless control methods such as an observer-based estimator have been introduced. However, most of the observer-based estimators have a disadvantage at start-up and in the low-speed region. To solve this problem, a simple strategy of using a hybrid system is proposed by integrating a high-frequency (HF) signal injection method and a full-order flux observer. In addition, an HF signal injection method with only a low pass filter (LPF) is proposed to simplify the hybrid system. The hybrid system achieves high-performance drive throughout the entire speed range. The effectiveness of the proposed hybrid technique is verified by experiments using an 11-kW IPMSM drive system.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.08a
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• pp.105-108
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• 2000

Many control techniques have been proposed in order to improve the control performance of discrete-time domain control system. In the position control system using a DC servo motor as a driver, the response-characteristic of system is controlled by the PID controller. In the PID control system, the transient response characteristic is more increased and settling time gets longer if gains of PID controller are unsuitable. In this paper, therefore, a expended PID control system is constructed by inserting a pre-compensator at output terminal of PID controller. It is implemented by using the double layers neural network. Form the results of computer simulation in the proposed control algorithm, its usefulness is verified.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2001.06a
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• pp.121-124
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• 2001

In industrial actual control system, PID controller has been used with its high delicate control system in position control system. PID controller has simple structure and superior ability in several characteristics. When the response of system is changed by delay time, variable load , disturbances and external environment, control gain of PID controller must be readjusted on the system dynamic characteristics. Therefore, a control ability of PID controller is degraded when th control gain is inappropriately determined. When the response characteristic of system is changed under a condition, control gain of PID controller must be changed adaptively to be a waited response of system. In this paper an adaptive-tuning type PID controller is constructed by self-recurrent Neural Network(SRNN). applying back-propagation(BP) algorithm. Form the result of computer simulation in the proposed controller, its usefulness is verified.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.606-608
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• 2021

Humans and various devices are interconnected using the Internet of Things and are used in various ways. In this study, a synchronization control system with remote locations was constructed using ICT, and a signal system for pedestrians was implemented using the system. PLC circuits were used to implement controllers, through which wireless control signal transmission and reception, LED lamp emission control, and power control were performed. It was confirmed that signal synchronization from the main controller to the remote sub-controller was possible by establishing a controller and pedestrian traffic light system, and lamp signal synchronization of the pedestrian traffic light system installed on both sides of the road was implemented. As a result, it was confirmed that 1:1 remote control or 1:N remote group control was possible, and this result can be used in various fields.