• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.754-756
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• 1998

In this paper the control methods for the synchronous generator is designed based on the two-degree-of-freedom (TDOF) control methods which can safisty the command following property and Robust control property at the same time. The power systems is reduced to one machine infinite-bus system. Robust stability of the proposed power system stabilizer is checked through the simulation considering the circumstance which can happen in real situation.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.357-363
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• 1997

The windup phenomenon appears and results in the performance degradation when the PI controller output is saturated. A new anti-windup PI controller is proposed to improve the control performance of the variable-speed motor drives and it is experimentally applied to the speed control of a vector-controlled induction motor driven by a pulse width modulated(PWM) voltage source inverter (VSI). The integral state is separately controlled corresponding to whether the PI controller output is saturated or not. The experimental results show that the speed response has the much improved performances such as small overshoot and fast settling time over the conventional anti-windup technique. Although the operating speed command is changed, the similar control performance can be obtained by using the PI gains selected in the linear region.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.331-333
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• 1995

A high performance motor drive system must have a good speed command tracking, a insensitivity to a parameter variation and sampling time. In this paper, a robust speed controller for an induction motor is proposed. The speed controller is fuzzy-sliding adaptive controller and its system continuously is varied. That is, only P gain act in dynamic state, I gain in steady-state. Because this system is a sort of adaptive control system, global stability analysis is used to Lyapunov function. Consequently, in this paper application of fuzzy sliding adaptive controller to induction motor controlled by vecter control is presented and the control system is digitally implemented within DSP.

• Journal of IKEEE
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• v.15 no.1
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• pp.104-112
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• 2011

During the ground operation of Korean army, the voice message is mainly used for exchanging informations related to the surveillance and reconnaissance, command and control, and precision strike. However, in order to the battlefield visualization among fighting powers participating in the ground force operation, automatic situational awareness and variable message format (VMF) for command and control are required. For securing core technologies necessary for the battlefield visualization, message standard and message handler are established through several applied researches. Besides, the VMF for equipping a weapon system is in development. In this paper, a study on the Korean variable message format (KVMF), where interoperability of integrated battle management system (BMS) is guaranteed due to performing joint, ground, and combined operations so that the situation awareness and strike system can be automated in almost real time, is presented. From the modeling and simulation (M&S) results of the message processor, delay time is varied in accordance with the number of nodes in unit platoon network, message length, and generation interval of routine messages. Therefore, it is shown that the system performance can be optimized by establishing proper network protocol for each situation.

• Proceedings of the KIEE Conference
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• 2004.05a
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• pp.150-152
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• 2004

The battery charge/discharge process, the final step of the secondary battery production process, requires real-time precision controls for improving both lifetime and performance of the battery cell. In this paper, we present embedded system design for precision control of the secondary battery charge/discharge production process using low power embedded processor based on embedded linux. This system receive charge/discharge command from the main server through ethernet. Compared to existing charge/discharge control system, our design makes low cost and precision control system possible.

• International Journal of Automotive Technology
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• v.6 no.2
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• pp.107-117
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• 2005

A distributed hardware-in-the-loop simulation (HILS) platform is developed for designing an automotive engine control system. The HILS equipment consists of a widely used PC and commercial-off-the-shelf (COTS) I/O boards instead of a powerful computing system and custom-made I/O boards. The distributed structure of the HILS system supplements the lack of computing power. These features make the HILS equipment more cost-effective and flexible. The HILS uses an automatic code generation extension, REAL-TIME WORKSHOP$^{ (RTW$^{) of MATLAB$^{ tool-chain and RT-LAB$^{, which enables distributed simulation as well as the detection and generation of digital event between simulation time steps. The mean value engine model, which is used in control design phase, is imported into this HILS. The engine model is supplemented with some I/O subsystems and I/O boards to interface actual input and output signals in real-time. The I/O subsystems are designed to imitate real sensor signals with high fidelity as well as to convert the raw data of the I/O boards to the appropriate forms for proper interfaces. A lot of attention is paid to the generation of a precise crank/ earn signal which has the problem of quantization in a conventional fixed time step simulation. The detection of injection! command signal which occurs between simulation time steps are also successfully compensated. In order to prove the feasibility of the proposed environment, a simple PI controller for an air-to-fuel ratio (AFR) control is used. The proposed HILS environment and I/O systems are shown to be an efficient tool to develop various control functions and to validate the software and hardware of the engine control system.

• Journal of the Institute of Convergence Signal Processing
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• v.10 no.4
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• pp.280-288
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• 2009

In this paper, we developed new time information recording module of VSI (VLBI Standard Interface) format by analyzing the Mark5B recorder control and operation software with 1Gbps speed, which is able to record the weak signal of space radio source, through the Korean VLBI Network (KVN). The control and operation software of high-speed recorder consists of 2 kinds of software, which is that it can operate RAID control board by controlling large capacity HDD drive and the network control and operation. Especially, core software in high-speed recorder is able to output the results after performing and analyzing the input command. Through the analysis of control and operation software, new time information recording module, which is needed to process the observed data for correlation, is developed. New developed time information recording module can record the time information together after checking the interrupt of 1PPS(Pulse Per Second) input signal when the observed data will be recorded. To verify the normal operation of the developed time information recording module, we performed the real observation test and confirmed the effectiveness of developed software through analyzing the recorded observation data.

• Strategy21
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• s.41
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• pp.294-332
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• 2017

The aim of this study is to find ways to apply the strategic communications to the Republic of Korea Navy. It may be a little bit late for the ROK Navy to accommodate the SC in these days because the adoption and implementation of the SC by the Combined Forces Command has already been begun. It was in 2007 when the SC was in place in the CFC. ROK's Ministry of National Defense and Joint Chiefs of Staff have also mulled over the SC and begun to apply it in part in the annual exercises such as Key Resolve command post drills and Foal Eagle field training exercise, etc. For the ROK Navy, in addition to those exercises, it is faced with further areas like North Korean maritime provocations and other maritime incidents where its version of SC is needed. As noted, the SC is not intended to deter or defend directly those provocations and incidents, but aims to create conditions favorable to the achievement of the navy's strategic objectives. The ROK Navy has to establish a SC planning center and implementing organizations within the Headquarters to be consistent with its above organizations such as MND, JCS, and CFC that have already applied the SC in part or in entirety. SC center and other related organizations need to be under the control of VCNO and the center needs to be located and administered by the policy division in N-5 at the HQs. The vision of the navy's SC is the winning without combats and the least damages in time of war. In other for the navy to reach the vision, the strategies to be executed are early establishment of SC implementing organizations, forming consensus over the need for the SC within the navy, strengthening core competencies to apply the SC, acquiring the SC experts and making doctrines on the SC. The SC, in addition, in the navy has to be planned and implemented in not only peace time and crisis time but also war time.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.5
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• pp.871-885
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• 2015

The improved DFSA for 2.4GHz multi-tags active RFID is suggested in 2 different ways: 1) simplified tag collection and Ack procedure using query command and 2) modified Schoute's method to control the number of slots in the frame. To evaluate the performance of the improved system we develop the simulation model. Varying the number of tags in the system we track the performance measures such as throughput, recognition time for multi-tags and tag recognition rate during a given time. The suggested method shows the best performance over all measures. Simplification of collection and Ack commands using query commands contributes to reducing tag recognition time. And the modified Schoute's method which controls the frame size using $k_1$ and $k_2$ contributes to throughput improvement and reduces target cognition time by reducing the number of collection rounds.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.3 no.2
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• pp.166-172
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• 2003

The dynamics of the DDWMR depends on the velocity difference of the two driving wheels. And which is known as a type of non-holonomic equation. By this reason, the treatment of DDWMR had become difficult and conservative. In this paper, the differential-driving wheeled mobile robot is considered. The Takaki-Surgeno fuzzy model and a control method for DDWMR is presented. The suggested controller has three control elements. The first element is fuzzy state feedback designed for eliminating the dependence of time-varying parameter. The second element is weighting controller which is designed for good frequency response. The third controller is PI-controller which is designed for good command following and robustness with un-modeled dynamics. In order for achieving the performance objective, the design of controller is based on the loop-shaping algorithm.