• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.277-280
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• 2001

This paper presents a speed sensorless implementation of digital speed control system of Surface Permanent-Magnet Synchronous Motor(SPMSM) drives with a direct torque control(DTC). The system presented are stator flux and torque observer of stator flux feedback control model that inputs are current and voltage sensing of motor terminal with estimated rotor angle for a low speed operating area, two hysteresis band controllers, an optimal switching look-up table, rotor speed estimator, and IGBT voltage source inverter by using fully integrated control software. The developed speed sensorless control system are shown a good motion control response characteristic results and high performance features using 1.0Kw purposed servo drive SPMSM.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.397-400
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• 2001

This paper presents a implementation of digital sensorless position control system of surface permanent-magnet synchronous motor (SPMSM) drive with a direct torque control (DTC). The system are stator flux and torque observer of stator flux feedback control model that inputs are current and voltage sensing of motor terminal with estimated rotor angle for a low speed operating area, two hysteresis band controllers, an optimal switching look-up table, rotor speed estimator, and IGBT voltage source inverter by using fully integrated control software. The developed sensorless control system are shown a good motion control response characteristic results and high performance features using 1.0 (kW) purposed servo drive SPMSM.

• Proceedings of the KIEE Conference
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• 2000.07e
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• pp.79-84
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• 2000

This paper presents an implementation of digital position control system for an induction motor vector drives by a direct torque control(DTC) using the 16bit DSP TMS320 F240. The DSP controller enable enhanced real time algorithm and cost-effective design of intelligent controller for motors which can be yield enhanced operation, fewer system components, lower system cost, increased efficiency and high performance. The system presented are stator flux and torque observer using current model that inputs are current sensing of motor terminal and rotor angle for a low speed operating area, two hysteresis controller, optimal switching look-up table, and IGBT voltage source inverter by fully integrated control software. The developed control system are shown a good motion control response characteristic results and high performance features using 2.2Kw general purposed induction motor.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.342-345
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• 2005

This paper describes dynamics analysis of a small training boat and a new type of ship's autopilot not only to keep her course but also to reduce her roll motion. Firstly, statistical analysis through multi-variate auto regressive model is carried out using the real data collected from the sea trial on an actual small training boat Sazanami after the navigational system of the boat was upgraded. It is shown that the roll motion is strongly influenced by the rudder motion and it is suggested that there is a possibility of reducing the roll motion by controlling the rudder order properly. Based on this observation, a new type of ship's autopilot that takes the roll motion into account is designed using the muti-variate modern control theory. Lastly, digital simulations by white noise are carried out in order to evaluate the proposed system and a typical result is demonstrated. As results of simulations, the proposed autopilot had good performance compared with the original data.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.5
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• pp.562-567
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• 2006

Model Predictive Control(MPC) system uses the current input which minimizes the difference between the desired output and the estimated output in the receding horizon scheme. In many cases (for example, system with constraints or nonlinear system), however, it is not easy to find the optimal solution to the above problem. In this paper, we show that real number coding genetic algorithm can be used to solve the optimal problem for MPC effectively. Also, we show by simulation that the real coding algorithm is mote natural and advantageous than the digital coding one.

• Advances in aircraft and spacecraft science
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• v.8 no.1
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• pp.69-85
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• 2021

A modified fuzzy mechanical control of large-scale multiple time delayed dynamic systems in states is considered in this paper. To do this, at the first level, a two-step strategy is proposed to divide a large system into several interconnected subsystems. As a modified fuzzy control command, the next was received as feedback theory based on the energetic function and the LMI optimal stability criteria which allow researchers to solve this problem and have the whole system in asymptotically stability. Modeling the Fisher equation and the temperature gauge for high-speed aircraft and spacecraft shows that the calculation method is efficient.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1281-1283
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• 1995

In this paper, we develop a prototype of the Optical SCM transmission module. This module is possible to application to electric facilities for control and measurements. Transmission channel number is two channels, namely, image and digital signal. In the image transmission, modulation method is AM, baseband signal is NTSC video signal and demodulation use PLL. Modulation of digital signal is QPSK, 1.544Mbps and demodulation use PLL. First, we calculate theoretical analysis about RF and Optical link in the transmission. This calculation is well correspond with practical system and transmission experiment is excellent, but this is only two channel model. And now, we plan to multichannel transmission to measure intermodulation, frequency assignments and optimal channel numbers et al.

• Proceedings of the IEEK Conference
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• 2000.06a
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• pp.69-72
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• 2000

This paper shows the more improved design of MRI receiver compared to conventional one based on Elscint Spectrometer. At first, the low-cost ADC is 16 bits, 3MHz sampling A/D converter Comparing to conventional one with signal bits of 14 bits, this device with those of 16 bits helps getting Improved the image resolution improved. If frequency is designed centering around 7.6 MHz to be satisfied in 10 MHz of maximum input bandwidth of ADC. For 1st demodulation, fixed IF is used for the purpose of the implementing multi nuclei system. Control parts & partial digital parts are integrated on one chip(FPGA). In DDC(Digital Down Converter), we got required bandwidth of LPF by controlling its decimation rate. With above considerations, we designed optimal receiver for high resolution imaging to be implemented through PC interface & experimental test of receiver of MRI after receiver's fabrication.

• Journal of the Korean Institute of Navigation
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• v.4 no.1
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• pp.31-50
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• 1980

It does not seem necessarily practicable to keep the system always in optimal condition, athough the control system of the follow-up mechanism on the most marine gyro compasses is to be adjusted by the operator through the gain adjustment. Sometimes a sustained oscillation or an incorrect gyro reading occurs to the system. For such a system any systematical research or theoretical basis of the guide for the optimal gain adjustment has not been reported yet. As a basic investigation of the theoretical system analysis to solve the problems concerned, the author attempts in this paper to express the system in a mathematical model deduced from the results of the theoretical approach and the experimental observation of each element contained in the follow-up mechanism of Hokshin D-1 gyro compass, and to constitute an over-all closed loop transfer function. This funciton being reverted to a fourth orderlinear differential equation, the first order simultaneous differential equations are obtained by means of the state-variables. The latter equations are solved by the Runge-Kutta method with digital computer. By comparing the characteristic of the simulated over-all output with that of the experimental result, it is shown that both outputs are nearly consistent with each other. It is also expected that the system representation proposed by this paper is valid and will be a prospective means in a further study on the design and optimal adjustment of the system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.448-455
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• 1996

In this study, to reduce vibration of step motor we use Microstep control. Microstep control of stepmotor is usually thought of as an extension of conventional stepmotor control technology. The essence ofmicro stepping is that we divide the full step of a stepmotor into a number of substep called microstep and cause the stepmotor to move through a substep per input pulse. In ideal case, bycontrolling the individual phase currents of a two-phase step motor sinusoidally we can get uniform torque and step angles. But due to the monlinear characteristics of the step motor, we need to compensate current waveform to improve the overall smoothness of the conventional micro stepping system. We implement digital Pulse Width Modulation(PWM) driver to drive step motor and microphone was used for detecting vibration. Driver enables speed change automatically byincreasing or decreasing micro stepping ratio which we call Automatic Switching on the Fly. To compensate the torque harmonics, Neural Networks is applied to the system and we foundcompensated optimal input current waveform. Finally we can get smooth motion of step motor in a wide range of motor speed.