• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1946-1947
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• 2011

본 논문은 파라미터의 불확실성을 포함한 비선형 무인 잠수정(autonomous underwater vehicles: AUVs)의 속도 제어를 위한 강인 퍼지 제어기를 제안한다. 효율적이고 안정적인 접근을 위해 불확실성을 포함한 비선형 무인 잠수정의 속도 시스템은 타카기-수게노(Takagi-Sugeno: T-S) 퍼지 모델로 표현된다. 리아푸노프(Lyapunov) 안정도 이론을 이용하여, 무인 잠수정의 제어 성능을 보장하는 선형 행렬 부등식(linear matrix inequality: LMI) 형태의 제어기 설계 조건을 유도한다. 제안된 강인 속도 제어기 성능의 유효성을 검증하기 위해 모의실험을 수행한다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.5
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• pp.62-65
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• 2000

This paper deals with the design and evaluation of the evaluation of the robust controller for a synchronous generator excitation system to improve the steady state and transient stability. The nonlinear characteristics of the system is treated as model uncertainties, and then the robust control techniques are introduced into the power system stability design to take into account these uncertainties at the controller design stage. The performance of the designed controller is examined by extensive non-linear time domain simulation. It is shown that the performance of the robust controller is superior to that of the conventional PI controller.

• Proceedings of the KIEE Conference
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• 2006.10d
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• pp.229-231
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• 2006

본 논문은 매입형 영구자석 전동기의 고정자 전압방정식으로부터 관측기를 구성하고, 회전자 좌표계상에서 추정속도를 구하여 퍼지제어기를 이용한 속도 보상 센서리스제어를 수행하였다. 전동기의 전압방정식과 퍼지제어기만을 이용하기 때문에 전동기의 기계적 방정식에서 발생하는 기계적 제정수의 영향에 대해 강인한 특성을 갖는다. 제안된 알고리즘의 타당성과 강인함은 실제 구동을 통하여 증명한다.

• Journal of the Korean Institute of Intelligent Systems
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• v.12 no.4
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• pp.311-316
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• 2002

Difficulties of the level control in the steam generator are increased due to their nonlinear characteristics. Futhermore, parameter uncertainties of the steam generator is related with control performance and stability. The efficiency of digital conversion in control systems is proved in many recent researches. In order to solve this problem, this paper suggests robust digital fuzzy controller design methodologies of the steam generator which have unstable parameters. Takagi-Sugeno (TS) fuzzy model is used to construct a fuzzy model which has uncertainties in the steam generator. In designing procedure, intelligent digital redesign method is used to control the nonlinear system. This digital controller keeps the performance of the analog controller. Simulation examples are included for ensuring the proposed control method.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1767-1768
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• 2008

본 논문의 목적은 선회구동장치의 최단시간으로 외란 및 시스템 불확실성에 강인한 구동을 위한 최단시간 강인제어기를 설계하는 것이다. 먼저 선회구동장치의 시스템 식별을 통해 플랜트의 전달함수를 유도하고 얻어진 전달함수를 이용하여 High-gain PDC와 RNTOC의 스위칭 함수를 정의한다. 그리고 각각의 제어 법칙을 적용하여 제어기를 설계한다. 두 제어기의 제어 성능을 시뮬레이션 및 실험으로 입증한다.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.6 s.52
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• pp.93-102
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• 2006

Control input's saturation of active control devices for large structures under large external disturbances are often occurred. It is more difficult to obtain the exact values of mass and stiffness as structures are higher. The modelling errors between mathematical models and real structures must be also included as parameter uncertainties. Therefore, in active vibration control of civil engineering structures like buildings and bridges, the robust saturation controller design method considering both control input's saturation and parameter uncertainties of system is needed. In this paper, stabilities of linear optimal controller LQR, modified bang-bang controller, saturated sliding mode controller, and robust saturation controller among various controllers which have been studied and applied to active vibration control of buildings are investigated. Especially, unstable phenomena of the LQR, the modified bang-bang controller and the saturated sliding mode controller when the control input is saturated or parameter uncertainties exist are presented to show the necessity of the robust saturation controller. The robust stability of the robust saturation controller are shown through a numerical example of a 2DOF linear vibrating system and an experimental test of the two-story structure with an active mass damper (AMD).

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.5
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• pp.56-61
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• 2000

Robust control for DC motor is needed according to the highest precision of industrial automation. However, when a motor control system with PID controller has an effect of load disturbance, it is very difficult to guarantee the robustness of control systems.In this paper, PID-Expert hybrid control method for motor control system as a compensation method solving this problem is presented. If PID control system is stable, the Expert controller is idle. if the error hits the boundary of the constraint, the Expert controller begins operation to force the error back to the constraint set. The disturbance effect decrease remarkably, robust speed control of DC motor using PID-Expert Hybrid controller is demonstrated by the simulation.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.1
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• pp.1-12
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• 1999

A design and DSP-based implementation of robust nonlinear speed control of a permanent magnet synchronous motor(PMSM) under the unknown parameter variations and speed measurement error is presented. The model reference adaptive system(MRAS) based adaptation mechanisms for the estimation of slowly varying parameters are derived using the MIT rule. For the disturbances or quickly varying parameters, a quasilinearized and decoupled model which includes the influence of parameter variations and speed measurement error on the nonlinear speed control of a PMSM is derived. Based on this model, a boundary layer integral sliding mode controller to improve the robustness and performance of the nonlinear speed control of a PMSM is designed and compared with the conventional controller which employs Proportional plus Derivative(PD) control. To show the validity of the proposed scheme, simulations and DSP-based experimental works are carried out and compared with the conventional control scheme.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.39 no.5
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• pp.8-17
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• 2002

This paper considers the problems of robust decentralized control for uncertain discrete-time large-scale systems with delays in interconnections and state feedback gain perturbations. Based on the Lyapunov method, the state feedback control design for robust stability is given in terms of solutions to a linear matrix inequality (LMI), and the measure of non-fragility in controller is presented. The solutions of the LMI can be easily obtained using efficient convex optimization techniques. A numerical example is included to illustrate the design procedures.

• ICROS
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• v.22 no.2
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• pp.34-41
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• 2016

슬라이딩 모드 기법을 실제 적용하는데 있어서 고려해야 할 중요한 문제 중 하나는 스위칭 동작에 의한 채터링 현상이다. 본 논문은 슬라이딩 모드 제어기 및 관측기의 게인을 줄임으로써 채터링을 완화하기 위한 방법으로 슬라이딩 모드 외란 관측기와 적분 제어를 포함하는 슬라이딩 모드 제어 기법에 대해 소개한다. 슬라이딩 모드 외란 관측기는 시스템 불확실성에 의해 발생하는 등가 외란의 상대적으로 느리게 변하는 부분을 추정하도록 설계한다. 슬라이딩 모드 관측기로 추정된 불확실성을 슬라이딩 모드 제어 입력에 결합함으로써 제안하는 관측기 기반 제어기는 상대적으로 낮은 게인을 사용하여 제어 목표를 달성할 수 있다. 본 논문에서 제안하는 제어기의 성능을 기존 방법과 비교하기 위해 DC 모터 전류 제어 모의실험을 수행한다. 모의실험 결과를 통해 제안하는 슬라이딩 모드 외란 관측기 기반 제어기는 낮은 게인으로 강인한 성능을 달성하고 전류 맥동을 줄일 수 있음을 확인할 수 있다.