• 한국항공운항학회지
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• 제17권4호
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• pp.1-7
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• 2009

The surge control system in unmanned turbojet engine must be capable of accounting uncertainties from engine transient conditions, random fluctuations of key parameters such as air pressure and fuel flow and engine modeling errors. In this paper, taking into consideration of its effectiveness as well as system stability, a fuzzy PI controller is proposed. The role of the fuzzy PI controller is to stabilize the unmanned aircraft upon occurring unexpected engine surge. The proposed control scheme is proved by computer simulation using a linear engine model. The simulation results on the state space model of a small turbojet engine illustrate the proposed control system achieves the desired performance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1114-1115
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• 2007

In this paper, a new speed sensorless control based on a fuzzy compensator are proposed for the interior permanent magnet synchronous motor (IPMSM) drives. The conventional proportional plus integrate(PI) control are very sensitive to step change of the command speed, parameter variations and load disturbance. To cope with these problems of the PI control, the estimated speeds are compensated by using the fuzzy logic controller (FLC). In the FLC used by the speed compensator of the IPMSM, the system control parameters are adjusted by the fuzzy rule based system, which is a logical model of the human behavior for process control. The effectiveness of algorithm is confirmed by the experiments.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.460-463
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• 2000

Fuzzy logic control(FLC) has been studied extensively and has been applied in various applications. The most popular control strategy takes the Fuzzy Proportional-Integral(FPI) form while systematic methods have been developed to derive the fuzzy rules and membership functions the choice of the scaling factors remains an open problem, In this paper an analytical FPI scaling factor determining method is derived based on the functional equivalence of the PI and FPI controllers. Simulation have been carried out with a brushless DC motor drive system as test-bed the obtained results drive system as test-bed the obtained results have verified that the derived method is applicable to both the initial choice and further tuning of the FPI scaling factors.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 B
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• pp.522-524
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• 1998

In this paper, the cross-coupling controller with fuzzy logic for AGV is developed, Cross-coupling control directly minimizes orientation' error by coordinating the motion of the two drive wheels and uses PI controller for compensation. But, the transient response of PI controller results in deviation from trajectory. The Fuzzy Cross-coupling controller enhances transient performance without steady-state error. The performance of the above controller is demonstrated by simulation and is compared with that of PI controller.

• Journal of Power Electronics
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• 제5권1호
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• pp.20-28
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• 2005

This paper presents a fuzzy predictive sliding mode control for high performance induction motor position drives. A new simplified inner-loop sliding-mode current control scheme based on a nonlinear mathematical model of an induction motor is introduced. Novel predictive fuzzy logic PI and PID controllers are used in speed and position loops, respectively. Sliding-mode current controllers and fuzzy predictive logic controllers are designed based on indirect vector control. The overall system performance is examined under different dynamic operating conditions. The performance of the drive system is robust and stable, and insensitive to parameters and operating condition variations even though non-exact system parameters are used in the implementation of the proposed controllers.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.758-761
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• 1991

Using one chip microcontroller 87Cl96 (On chip EPROM type) and EPLD (Erasable & Programable Logic Device), an implantable control system to drive pendulum type electromechanical total artificial heart was developed. This control system consists of 4 parts, main management system, motor driver with power regulator, state monitoring system and communication part. The main system has the functions for speed detection, PI(proportional and integration) control, PWM generation, communication and analog data processor. Two kinds of power system were used and separated by 8 photo coupler arrays to improve the system stability. The performances of each compartments were compared with our previous z80 microprocessor based control system and good correspondences was shown. Logic power consumption was reduced to a one third of our previous controller. Using mock circulation tests, the overall performances of control system are evaluated.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.754-757
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• 1998

In this paper, the fuzzy control logic of Switched Reluctance Motor(SRM) is introduced to apply the variable speed drive system. Since the speed-torque property of SRM has high speed variation to the changes of torque like a DC motor, to apply SRM to the variable speed driving system, the optimal speed-torque control method is required. As the control method like this, the fuzzy logic and PI control are proposed, and characteristics of them are compared and verified through the experimental results

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.704-707
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• 1997

In this paper, we present a fuzzy logic based tuner for continuous on-line tuning of PID controllers. The essential idea of the scheme is to parameterize a Ziegler-Nichols-like tuning formula by a singler parameter .alpha., then to use an on line fuzzy logic to self-tune the parameter. The adaptive scaling makes the controller robust against large variations in parametric and dynamics uncertainties in the plant model. New self-tuning controller has the ability to decide when to use PI or PID control by extracting process dynamics from relay experiments. These scheme lead to improved performance of the transient and steady state behavior of the closed loop system, including processes with nonminimum phase processes.

• 한국멀티미디어학회논문지
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• 제20권2호
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• pp.271-278
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• 2017

This paper introduces a user-friendly PLC (programmable logic controller) monitoring and control system of heavy machinery using Android based smartphone. The proposed system will control diesel generator and many such like machine without a dedicated PC with respect to similar system and offers a new communication protocol for handling it. The smartphone controls the generator via Wi-Fi, through which it connects to the Raspberry pi which will be installed in the PLC panel to setup the communication between them. Furthermore, Raspberry pi connects to two devices, one is PLC which gives the status and current information of the machine and to ON/OFF the machine. This proposed system used RS485 as a key mediator for data exchanging between Raspberry PI(master) and PLC(slave). RS485 allows multiple devices (up to 32) to communicate at half duplex on single pair of wires and provides a long connectivity area (up to 1200 meters) as compared to another device. This proposed system specially focused on accurate data flow between smartphone and PLC panel.

• Journal of information and communication convergence engineering
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• 제3권1호
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• pp.43-48
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• 2005

In this paper, the adaptive fuzzy logic controller(AFLC) is proposed, which uses real-coding genetic algorithm showing a good performance on convergence velocity and diversity of population among evolutionary computations. The effectiveness of the proposed AFLC was demonstrated by computer simulation for speed control system of AC servo motor. As a result of simulation for the AC servo motor, it is shown the proposed AFLC has the better performance on overshoot, settling time and rising time than the PI controller which is used when tuning AFLC.