• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.1
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• pp.129-137
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• 2017

In this paper, we propose a digital controller design methodology for an LLC resonant converter which has been widely used due to the advantages of low switching loss and high efficiency. We establish a mathematical model of an LLC resonant converter using the extended describing function concept and propose a controller design method based on the Ziegler Nichols control parameter tuning criteria. The voltage controller of an LLC resonant converter is designed based on the derived small signal model and the performance of the controller is verified by MATLAB simulations. The validity and the control performance of the designed voltage controller for the LLC resonant converter is analyzed through some simulations for the case of load variations and circuit modeling errors.

• The Journal of Korea Robotics Society
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• v.13 no.1
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• pp.72-78
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• 2018

This paper proposes a Dual Controller System for Precision Control (DCSPC) for control of the gripper. The DCSPC consists of two subsystems, CDSP (Controller based DSP) and CARM (Controller based ARM processor). The CDSP is developed on a DSP processor and controls the gripping motor and LVDT. In particular, the CARM is implemented using Linux and ARM processor according to recent research related to open-source. The robot for high-precision assembly is divided into the robot control and the gripper control section and controls CARM and CDSP systems respectively. In this paper, we also proposed and measured the performance of communication API. As a result, it is expected to recognize improvements in communication between CARM and the robot controller, and will continue to conduct relevant research among other commercial robot controllers.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.1
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• pp.225-229
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• 2019

Magnetic bearings are widely used in vacuum and clean environments or in high-precision applications, because they have no mechanical friction and have stable dynamic characteristics. Despite the aforementioned advantages of magnetic bearings, their applications are generally limited due to the controller complexity. In this paper, we proposed a reduced-complexity digital controller for magnetic bearings. In addition, we analyzed and solved the problems, such as quantization errors in the analog-to-digital conversion and integral windup in a feedback controller, which are known as the main causes of performance degradation. Experiments showed that the proposed digital controller achieves a target magnetic levitation accuracy.

• Transactions on Electrical and Electronic Materials
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• v.12 no.6
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• pp.253-257
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• 2011

This study was carried out to solve problems such as radio frequency band depletion, confusion risk, and security loss in existing visible wireless communication systems, and to determine the applicability of next-generation networks. A light-emitting diode (LED) light communication system was implemented with a controlling switching light module using the ATmega16 micro-controller. To solve the existing modulation effect and disturbance in visible light communication, an integrated interface was evaluated with a driving light module and analyzes its reception property. A transmitter/receiver using the ATmel's micro-controller, high-intensity white LED-6 modules, and infrared sensor KSM60WLM and visible sensor TSL250RD were designed. An experiment from the initial value of distance to 2.5 m showed 0.46 V of the voltage loss, and if in long distance, external light interference occurred and light intensity was lost by external impact and thus data had to be modified or reset repeatedly. Additionally, when we used 6 modules through the remote controller's lighting dimming, data could be transmitted up to 1.76 m without any errors during the day and up to 2.29 m at night with around 2~3% communication error. If a special optical filter can reduce as much external light as possible in the integrated interface, the LED for lighting communication systems may be applied in next generation networks.

• Journal of the Institute of Convergence Signal Processing
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• v.3 no.3
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• pp.54-62
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• 2002

This paper describes a development of the integrated controller system for car electrical signal and sensor input/output control with CAN communication protocol. In order to improve the system reliability and effectiveness for the conventional controller using the wiring harness, a detailed integrated control system is introduced and discussed. The CAN communication protocol is a robust control method with serial bus system for the control of distributed module in the multiplexed network. Therefore, this has high reliability and flexibility in the overall control system implementation. This paper proposes an integrated system with high reliability and stability for control of various car signal, and evaluates the effectiveness of the system using the actual implementation. For these purposes, after a brief of the main features of the CAN will be addressed, this paper presents the result of development of the integrated hardware system and overall control program.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.3
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• pp.549-557
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• 2017

ICMP(Internet Control Message Protocol) is a main protocol in TCP/IP protocol stack. ICMP compensates the disadvantages of the IP that does not support error reporting. If any transmission problem occurred, a router or receiving host sends ICMP message containing the error cause to sending host. However, in this process, an attacker sends a fake ICMP messages to the host so that the communication can be terminated abnormally. An attacker host can paralyzes system of victim host by sending a large number of messages to the victim host at a high rate of speed. To solve this problem, we have designed and implemented outbound traffic controller that prevents various ICMP attacks. By preventing the transmission of attack messages in different ways according to each case, various network attacks can be prevented. In addition, unnecessary network traffic can be filtered before transmitted.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.726-728
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• 2016

In this paper, a realtime MIDI controller is designed using leap motion. The controller makes virtual MIDI port on Windows that it is connected to the port and protocol for communication with DAW or VST. It is converted MIDI data when it is detected a real time the position and shape of hand. This converted data transfer MIDI port by MIDI CC(Control Change). Therefore this controller has the purpose to support flexible MIDI input function than existed MIDI controller.

• Journal of KIISE:Information Networking
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• v.27 no.1
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• pp.39-47
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• 2000

This paper is to propose an efficient and reliable control procedure of Base Station Controller of mobile communication system for bulk input messages which was delivered instantaneously. We divided the input messages that are processed by the base station controller of the mobile communication system into two things ; they are messages related to call connection and o&m(operation and maintenance). In addition, we analyzed the properties of the input messages and then performed computer simulation on each input message by using M/M/1/K queueing model in term of the following viewpoints : the loss probability of input messages, the average queue length, the utilization of process controller(server),the average waiting time in queue. And we compared the performance of the two input messages in the overload controlling which was caused by the congested input messages.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.2
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• pp.267-272
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• 2020

Currently, the petrochemical industry complex always has remained with the explosive riskiness due to explosive and inflammable gases. In order to prevent explosion, all kind of equipment or facility including controller and its panel requires explosive proof. The control panel, which is currently used as explosive proof, has been used as the air injection method by manually from outside to constantly keep the temperature and pressure between inside and outside of the panel. In this paper, we propose the design of integrated controller of explosive proof panel which can control pressure and temperature automatically.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.5
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• pp.481-486
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• 2018

DC motors are classified as DC motors with brush structure and BLDC motors without brush structure. Representing the speed control of the BLDC motor is the PI control. The speed control using the PI controller has a disadvantage that the response characteristic to reach the steady state is slow. Therefore in this paper, a voltage controlled speed controller using a Fuzzy Logic Controller (FLC), which has a short steady response time and usefulness of nonlinear control. The validity and usefulness of the proposed fuzzy speed controller are verified by simulation through Simulink of MATLAB program. Experiments were performed on the PI controller and the proposed fuzzy speed controller in three cases with reference speeds of 500rpm, 800rpm, and 1500rpm. Experimental results show that the proposed fuzzy controller has more 30% improved steady state speed response than PI controller.