• Journal of the Korean Society for Precision Engineering
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• v.14 no.4
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• pp.88-96
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• 1997

This paper suggests a new non-linear friction compensation for digital control systems. This control adopts a hysteresis nonlinear element which can introduce the phase lead of the control system to compensate the phase delay comes from the inherent time delay of a digital control. A proper Lyapunov function is selected and the Lyapunov direct method is used to prove the asymptotic stability of the suggested control.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.987-993
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• 1996

This report suggests a new non-linear friction compensation for digital control systems. This control adopts a hysteric nonlinear clement which can introduce the phase lead of the control system to compensate the phase delay comes from the inherent time delay of a digital control. The Lyapunov direct method is used to prove the asymtotic stability of the suggested control, and the stability and the effectiveness are verified analytically and experimentally on a single axis servo driving system.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1527-1539
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• 2015

In this paper the hardware implementation of the direct torque control based on the fuzzy logic technique of induction motor on the Field-Programmable Gate Array (FPGA) is presented. Due to its complexity, the fuzzy logic technique implemented on a digital system like the DSP (Digital Signal Processor) and microcontroller is characterized by a calculating delay. This delay is due to the processing speed which depends on the system complexity. The limitation of these solutions is inevitable. To solve this problem, an alternative digital solution is used, based on the FPGA, which is characterized by a fast processing speed, to take the advantage of the performances of the fuzzy logic technique in spite of its complex computation. The Conventional Direct Torque Control (CDTC) of the induction machine faces problems, like the high stator flux, electromagnetic torque ripples, and stator current distortions. To overcome the CDTC problems many methods are used such as the space vector modulation which is sensitive to the parameters variations of the machine, the increase in the switches inverter number which increases the cost of the inverter, and the artificial intelligence. In this paper an intelligent technique based on the fuzzy logic is used because it is allows controlling the systems without knowing the mathematical model. Also, we use a new method based on the Xilinx system generator for the hardware implementation of Direct Torque Fuzzy Control (DTFC) on the FPGA. The simulation results of the DTFC are compared to those of the CDTC. The comparison results illustrate the reduction in the torque and stator flux ripples of the DTFC and show the Xilinx Virtex V FPGA performances in terms of execution time.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2668-2670
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• 2004

This paper presents an advanced load control method in Direct Load Control(DLC) system. It is important to aggregate a various demand side resource which is surely controllable at the peak power time for a successful DLC system. Because the DLC system use simple On/Off control that may cause a harmful effect on a plant to reduce a peak power load, there are some restriction on deriving a voluntary participation of demand side resource. So it needs a new approach to direct load control method, and this paper describes an advanced load control method using control logic which is based on load properties. This method is easy to take account of a various characteristic of load, it can be use as a dynamic control logic which is good for adaptive control. The suggested control logic method is verified by modeling a control logic for a turbo refrigerator which affects on peak power in summer season.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.480-483
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• 2008

The cold-air distribution system is expected as an efficient method to reduce energy consumption in the air-conditioning system. We introduced some control strategies for the system by summarizing some references in the view point of energy saving. Direct digital control is specially emphasized as an important control technique for the system. Some drawbacks which habe been conventionally mentioned to apply the cold-air distribution to real fields can be solved by using the technique. The control strategy which is introduced in here will be available to build control system for the air-conditioning based on the cold-air distribution for energy saving.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.588-593
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• 1987

In this study, direct-drive position controllers are designed and implemented for the flying vehicles actuating system with both positive and negative load factors, where the load factors are assumed proportional to the deflection angle of control surface. Its analog and digital controllers are verified through software simulation and hardware-in-the-loop simulation.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.32 no.4_1
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• pp.293-298
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• 2014

Recently, the direct georeferencing has been becoming a common method in the aerial photogrammetry. As this direct georeferencing method using converged sensor of the digital photogrammetry camera and GPS(Global Positioning System)/INS(Inertial navaigation System), more rapid and accurate aerial photogrammetry has improved following advanced performance in photogrammetry. Since the accuracy of EO parameters from the direct georeferencing is determined by GPS/INS accuracy, it is significant to calculate the exact attitude information using values of INS rotations. For following calculations, the misalignment, such as INS rotation and the gap of GPS/INS, has to be decided. Because the number of ground control points are used for tirangulation and boresight calibration, those results should be different according to array and location of ground control points. In the study, those location and array of ground control points were tested to be used boresight calibration. As a result, there is no significant change of misalignment and exterior orienation parameters in the case when ground control points were at all course. On the contrarily, the difference has been shown in the case of no ground control point at course.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1036-1038
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• 2000

This paper presents an implementation of digital motion control system of induction motor vector drives with a direct torque control(DTC) using the 16bit DSP TMS 320F240. The DSP controller enable enhanced real time algorithm and cost-effective design of intelligent controllers for induction motors which can be yield enhanced operation, fewer system components, lower system cost, increased efficiency and high performance. The system presented are stator flux observer of current model that inputs are current sensing of motor terminal and rotor angle, and optimal switching look-up table by using fully integrated control software. The developed 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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• 1996.10b
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• pp.1265-1268
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• 1996

This paper describes a new pulse width modulation (PWM) scheme suitable for microprocessor-based PWM inverters. Optimal switching patterns minimizing the performance index corresponding to the distortion factor are decided in real time by numerical calculation using the microprocessor-implemented control system. This PWM method is compared with conventional methods, such as the natural PWM and the direct PWM. Harmonic analysis using digital simulations shows that the proposed PWM scheme has much less low-order harmonics than the other methods. The validity of this method is verified in experiments using a microprocessor-based control system, where a 16-bit single-chip microcontroller, Intel 80c196kc is used.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.24-29
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• 1991

RCCL(Robot Control C Library) is general purpose robot control language. It is programmed with C language and composed of C library. So it is well portable and supports sensor integration control and high level force control algorithms. We implemented RCCL on PUMA. We developed servo controller of DDC(Direct Digital Control). We used intel 8097BH one chip micro controller as CPU. One digital servo board controls three motors. Host computer is IBM PC 386DX-33 with RCCL.