• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.327-331
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• 1997

This paper presents the non-linear modeling and design of a robust sliding mode controller for film transfer systems. The tension of a film is sensitive to the speed difference between a winder and an unwinder. The change of the roll-radius as well as the moment of inertia result in the film transfer system begin variable and non-linear. In designing the robust controller. Two major aims are considered. The first aim is hat the web transferring speed tracks at any given reference speed; the second one is that the tension of the film tracks at any given reference tension. To verify the control algorithm, a Simulink model was built and compared with a conventional PID controller. In a computer simulation study, the suggested robust sliding mode controller shows better performance than the PID controller a various control inputs.

• International Journal of Aeronautical and Space Sciences
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• 제17권1호
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• pp.120-131
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• 2016

The full results of troubleshooting process related to the flight control system of a tilt-rotor type UAV in the flight tests are described. Flight tests were conducted in helicopter, conversion, and airplane modes. The vehicle was flown using automatic functions, which include speed-hold, altitude-hold, heading-hold, guidance modes, as well as automatic take-off and landing. Many unexpected problems occurred during the envelope expansion tests which were mostly under those automatic functions. The anomalies in helicopter mode include vortex ring state (VRS), long delay in the automatic take-off, and the initial overshoot in the automatic landing. In contrast, the anomalies in conversion mode are untrimmed AOS oscillation and the calibration errors of the air data sensors. The problems of low damping in rotor speed and roll rate responses are found in airplane mode. Once all of the known problems had been solved, the vehicle in airplane mode gradually reached the maximum design speed of 440km/h at the operation altitude of 3km. This paper also presents a comprehensive detailing of the control systems of the tilt-rotor unmanned air vehicle (UAV).

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.111.1-111
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• 2001

In this paper, a robust speed control is proposed for Permanent Magnet Synchronous Motor system. PMSM without reduction gear has been widely used in high performance application such as robots and machine tools. It is well known that the control performance of the PMSM is very sensitive to load disturbance and system parameter variation. The idea of the proposed speed controller based on combination of sliding mode control with fuzzy gain scheduling. The sliding mode controller leads to fast system dynamics of slight sensitivity to the load disturbance and system parameter variations, the fuzzy gain scheduling mechanism reduces the chattering phenomenon. The simulation results have proved that the proposed control scheme provides a robust control performance under load disturbance and system parameter variation.

• 한국철도학회논문집
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• 제5권4호
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• pp.267-275
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• 2002

The traction drive system for the urban transit maglev system is described in this paper. To control the magnitude and frequency of the output voltage of induction motor transiently, the vector control strategy is generally used. But in case of the traction drive system for the railway vehicle, it is difficult to use the vector control caused by the one-pulse mode in the high speed region. Therefore, this paper proposes the control strategy combined the vector control in the low speed region and the slip frequency control in the high speed region. And also, the overmodulation PWM method is discussed to make the change to the one-pulse mode softly. The performance of the proposed traction drive system is verified by the MATLAB simulation results.

• 전자공학회논문지SC
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• 제37권3호
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• pp.72-83
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• 2000

본 논문에서는 리칭모드 제어기와 신경 회로망을 이용하여 3상 유도전동기의 위치제어 시스템을 구현한다. 리칭모드 제어기는 위치오차와 속도오차의 궤적을 슬라이딩 평면으로 들어가도록 하고 신경회로망의 초기학습을 담당한다. 리칭모드 제어기의 구조는 슬라이딩 평면의 스위칭 함수로부터 간단히 구성하였다. 또한, 신경 회로망은 전향경로 신경망으로 구성되며 비선형 매핑능력과 탁월한 학습능력을 이용하여 유도전동기의 등가제어입력을 학습하도록 하였고 신경 회로망의 입력으로는 모터의 기준속도, 기준위치 및 엔코더를 이용하여 측정된 모터의 실제속도와 위치 등을 이용하였고 온라인 상태로 학습되도록 하였다. 이와 같이 복합적으로 구성된 제어기들을 유도전동기의 위치제어 시스템에 적용하였다. 본 논문에서 제안된 알고리즘의 타당성을 보이기 위해 기존의 PI 제어기와 비교평가를 하였으며 시뮬레이션과 실험결과로부터 초기운전 상태에서는 리칭모드 제어기가 주로 제어를 담당하지만 시간이 지남에 따라 신경회로망이 학습되어 신경 회로망이 주 제어기가 됨을 확인하였다. 아울러, 제안된 제어기가 PI 제어기보다 우수하고 특히 부하변동과 같은 외란에 강인함을 알 수 있었으며, 정상상태 오차가 현저히 감소하여 정밀한 제어가 가능함을 확인하였다.

• ETRI Journal
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• 제37권6호
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• pp.1154-1164
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• 2015

This paper proposes a fully sensorless driver for a permanent magnet synchronous motor (PMSM) integrated with a digital motor controller and an analog pre-driver, including sensing circuits and estimators. In the motor controller, a position estimator estimates the back electromotive force and rotor position using a sliding-mode observer. In the pre-driver, drivers for the power devices are designed with a level shifter and isolation technique. In addition, a current sensing circuit measures a three-phase current. All of these circuits are integrated in a single chip such that the driver achieves control of the speed with high accuracy. Using an IC fabricated using a $0.18{\mu}m$ BCDMOS process, the performance was verified experimentally. The driver showed stable operation in spite of the variation in speed and load, a similar efficiency near 1% compared to a commercial driver, a low speed error of about 0.1%, and therefore good performance for the PMSM drive.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.194-199
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• 2003

The traction drive system for the urban transit Rubber-tire system is described in this paper. To control the magnitude and frequency of the output voltage of induction motor transiently, the vector control strategy is generally used. But in case of the traction drive system for the railway vehicle, it is difficult to use the vector control caused by the one-pulse mode in the high speed region. Therefore, this paper proposes the control strategy combined the vector control in the low speed region and the slip frequency control in the high speed region. And also, the overmodulation PWM method is discussed to make the change to the one-pulse mode softly. The performance of the Proposed traction drive system is verified by the MATLAB simulation results.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.86-90
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• 2002

In this paper, traction system for urban transit maglev system is proposed. Using vector control strategy to control magnitude and frequency of output voltage transiently is general. But in case of traction system for railway vehicle, it is impossible that adapt vector control because there is one-pulse mode in a high speed region. So this paper proposes the control strategy using vector control in a low speed region and slip frequency control in a high speed region. And also proposes overmodulation method that makesto change in one-pulse mode softly. The performance of traction system will be verified by simulation results using ACSL.

• 전력전자학회논문지
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• 제17권3호
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• pp.238-245
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• 2012

This paper presents a sensorless speed control of a 2-phase switch reluctance motor(SRM). The proposed sensorless control scheme is based on the slide mode observer with parameter compensator to improve the estimation performance. In the stand still position, the initial rotor position is determined by pulse current responses of each phase windings and the current difference. In order to determine an accurate initial rotor position, the two initial rotor positions are estimated by the difference of the pulse currents. From the stand still to the operating region, a simple open loop control which determines the commutation sequence by the pulse current of the unexcited phase winding is used. When the motor speed is reached to the sensorless control region, the estimated rotor position and speed by the slide mode observer are used to control the SRM. The flux calculator used in the slide mode observer is designed by phase voltage and the voltage drops in the phase resistance of the winding. The accuracy of the flux calculator is dependent on the phase resistance. For the continuous update of the phase resistance, current gradient at the inductance break point is used in this paper. The error of the estimated rotor position at the current gradient position is used to update the phase resistance to improve the sensorless scheme. The proposed sensorless speed control scheme is verified with a practical compressor used in home appliances. And the results show the effectiveness of the proposed control scheme.

• 한국정밀공학회지
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• 제2권1호
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• pp.72-81
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• 1985

This paper deals with the Z-8000 microprocessor based optimal controller problem of large rotating system. Control algorithm consists of Global Mode and Fine Mode. In Global Mode, motor is driven with maximum torque, while, in Fine Mode, the speed of response and overshoot improved by multi-gains. Friction term of the plant was measured in the 1-st test, jerking effect by the nonlinearity of friction was compensated in the 2-nd test and the 3-rd test was carried out to finalize the control system model. Test results show that the speed of response and overshoot are highly improved.