• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.4
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• pp.385-391
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• 2014

This paper proposes fuzzy disturbance observer based multiple sliding surface control scheme for nonlinear systems with mismatched disturbance. In order to stabilize nonlinear systems with mismatched disturbance, a controller based on multiple sliding surface control scheme is designed. In addition, a fuzzy disturbance observer is used to estimate the disturbance. Using the fuzzy disturbance observer, "explosion of terms" problem and chattering problem were solved. The stability of the proposed control scheme is analyzed by Lyapunov stability theory. For the verification, we apply the proposed method to numerical examples and compare its result with that of the applied nonlinear disturbance observer based sliding mode control.

• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.2
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• pp.138-147
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• 1998

This paper describes design and implementation results of a fuzzy logic speed controller of EV(Electric vehicle)'s induction motor for the purpose of realizing comfortable driving. The fuzzy controller is suitable for speed control of EV since that without detailed knowledge about the induction motor, it is easier to design a well-performing speed control system with good stability. PWM wave for driving the induction motor is generated by space vector modulation method and all the control algorithms are realized digitally. The results of experiment show excellence of the proposed system and that the proposed system is appropriate to control the speed of induction motor for commercial EVs.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.06a
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• pp.17-20
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• 2013

Many researches have been conducted in the field of constructing controllers for ships over 20 years. But still, ship automatic track-keeping controllers has not been designed for ship's automatic berthing as they considered nearly constant ship's speed. This study dealt with this problem to design track-keeping control on ship's model of SAE NURI using nonlinear mathematical expression. By using this control, the ship is auto track-kept in fare-way at reducing speed to anchorage place. The simulation results proved that this control can be adapted in ship's auto berthing in near future.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.1
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• pp.150-156
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• 2001

This paper proposed a speed estimator using MRAC(Model Reference Adaptive Control) for sensorless vector control. It is robust for parameter variation or disturbance and the estimated speed is used as feedback in a vector control system. Experiment is presented to confirm the theoretical analysis.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.8
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• pp.1743-1750
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• 2003

DC motor requires a rotor speed sensor for accurate speed control. The speed sensors such as resolvers and encoders are used as a speed detector, but they increase cost and size of the motor and restrict the industrial drive applications. So in these days, many papers have reported in the sensorless operation of DC motor〔3­5〕. This paper presents a new sensorless strategy using neural networks〔6­8〕. Neural network has three layers which are input layer, hidden layer and output layer. The optimal neural network structure was tracked down by trial and error, and it was found that 4­16­1 neural network structure has given suitable results for the instantaneous rotor speed. Also, learning method is very important in neural network. Supervised learning methods〔8〕 are typically used to train the neural network for learning the input/output pattern presented. The back­propagation technique adjusts the neural network weights during training. The rotor speed is gained by weights and four inputs to the neural network. The experimental results were found satisfactory in both the independency on machine parameters and the insensitivity to the load condition.

• ICROS
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• v.21 no.2
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• pp.47-51
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• 2015

극점은 제어시스템의 안정성, 수렴속도를 결정하는 중요한 요소이다. 본고에서는 출력 되먹임을 이용하여 임의의 원하는 극점을 배치하고, 또한 외란을 극복하면서 기준 명령을 추종할 수 있는 제어기를 설계하는 방법을 살펴 보았다. 이를 위해서는 기준 입력 또는 외란의 불안정한 극점들이 제어루프에 포함되도록 한다. 즉, 불안정한 극점들이 마치 플랜트에 첨가된 것처럼 간주하고 제어기를 설계하면 된다. 제어기 차수를 줄이기 위해서는 제어기 설계과정에서 남는 자유도를 이용하여 불안정한 극점들이 제어기에 포함되도록 하면 된다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.713-714
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• 2013

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.5
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• pp.361-368
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• 2015

This paper deals with a robust fine seek controller design problem with multiple constraints using a genetic algorithm. A robust $H\infty$ constraint is introduced to attenuate effectively velocity disturbance caused by the eccentric rotation of the disk. A weighting function is optimally selected based on the estimation of velocity disturbance and the estimated minimum velocity loop gain. A robust velocity loop constraint is considered to minimize the variances of the velocity loop gain and bandwidth against the uncertainties of fine actuator. Finally, a robust fine seek controller is obtained by solving a genetic algorithm with an LMI condition and an appropriate objective function. The proposed controller design method is applied to the fine seek control system of a DVD recording device and is evaluated through the experimental results.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.3
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• pp.240-248
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• 1999

This paper presents the application of fuzzy algorithm for speed control of Switched Reluctance Motor. SRM has a h highly nonlinear control characteristic and operates in saturation to maximize the motor torque. A systematic approach t to the modeling of highly nonlinear SRM drive system which includes the fuzzy controller with coarse control and fine C control is presented. PelfOlmance analysis of SRM dJive is reported for a wide range of operating conditions through s speed variation and load perturbation dynamics. The pelfOlmance indices of SRM drive system operating with fuzzy 1 logic controller are compared with the conventional controller to highlight the merits. The expel1mental results are p presented to confilm the validity of proposed fuzzy 10밍c controller.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.1175-1177
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• 2002

본 논문에서는 외란에 매우 강인한 특성을 갖는 유전자 알고리즘에 의한 PI 제어기를 통하여 속도 제어기를 설계하고 성능평가를 하였다. 유전자 알고리즘의 파라미터인 교배율, 돌연변이율, 세대내 개체수 세대수를 선정하여 최적해를 구하는데 적절한 선정이 필요하다. 따라서 Matlab/Simulink 환경 하에서 유도전동기 제어 시스템을 모델링하고 시뮬레이션 결과를 통해서 유전자 알고리즘의 적절한 파라미터 선정 후 제어기의 유용성을 입증하였다.