• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1986년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 17-18 Oct. 1986
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• pp.83-85
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• 1986

The error differential equations which are derived by using the first error model are uniformly asymptotial stable if the input is bounded and sufficiently rich. In the adaptive control, the speed of convergence of system output or parameter error in such cases is of both practical and theoretical interest. In this paper, the adaptive algorithms(Gradient algorithm, Intergral algorithm) are discussed from the point of view of speed convergence and the modification of adaptive law for prohibition of overadaptation is discussed. The result is compared among this algorithms and the adaptive gain is choosed by this result(the speed of convergence).

• 전력전자학회:학술대회논문집
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• 전력전자학회 1999년도 전력전자학술대회 논문집
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• pp.4-9
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• 1999

A new control method for precision robust position control of a brushless DC (BLDC) motor using asymptotically stable adaptive load torque observer is presented in the paper. Precision position control is obtained for the BLDC motor system approximately linearized using the field-orientation method Recently, many of these drive systems use BLDC motors to avoid backlashe. However, the disadvantages of the motor are high cost and complex control because of nonlinear characteristics. Also, the load torque disturbance directly affects the motor shaft. The application of the load torque observer is published in [1] using fixed gain. However, the motor flux linkage is not exactly known for a load torque observer. There is the problem of uncertainty to obtain very high precision position control. Therefore a model reference adaptive observer is considered to overcome the problem of unknown parameter and torque disturbance in this paper. The system stability analysis is carried out using Lyapunov stability theorem. As a result, asymptotically stable observe gain can be obtained without affecting the overall system response. The load disturbance detected by the asymptotically stable adaptive observer is compensated by feedforwarding the equivalent current which gives fast response. The experimenta results are presented in the paper.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1983년도 하계학술회의강연.논문초록집
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• pp.135-138
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• 1983

This paper studies a variable structure adaptive model following control system which can control a plant in which the parameters of the controlled plant can not be estimated because they vary with time and in which the controlled plant has noise. The values of the feedback gain matrices for given states are obtained the equivalent control law, and the adaptive controller has been designed using the adaptive mechanism which switches the matrices. The adaptive controller minimizes the state error vector, that is, the difference between the state vector of the model and the state vector of the controlled plant. A controlled plant which has time varying parameters, a controlled plant which has only noise, and a controlled plant which has both have been controlled by the designed adaptive controller. The continuous single input-output system has been analysed by computer. This control system may be used to control practical systems by the addition of a microcomputer.

• Nuclear Engineering and Technology
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• 제25권1호
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• pp.110-124
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• 1993

적응 비례-적분-추정 (PIF) gain 및 가변구조 제어기를 사용하는 비선형 모델에 의한 하이브리드 제어방법 (NHC)이 개발되었다. 이 제어기는 모델의 불확실성에 대해 robust한 성질을 가지며 단일 입-출력 비선형 시스템의 추적제어 (tracking control)에 응용된다. 이 방법의 특징은 제어기가 각각 특정 역할을 수행하는 4개 부분으로 구성되는 것이다. 즉, 적응 P-I-F 및 가변구조 제어기로 구성된다. Lyapunov의 제 2방법으로 결정된 적응 PIF gain에 의한 제어성능 확보 및 모델의 불확실도를 평가하여 피이드백 함으로써 모델의 불확실성에 대해 robust한 제어기를 구성하였다. 가변구조 제어기는 PIF gain이 적절히 결정되지 않은 상태인 초기의 오차증가를 제어하기 위해 도입되었다. 새로 개발된 NHC방법을 원자로의 출력변동 제어에 응용한 결과 기존의 모델을 이용한 제어방법 (model-based controller)들에 비해 제어성능이 크게 개선되었다.

• 전자공학회논문지S
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• 제34S권7호
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• pp.48-55
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• 1997

An adaptive output feedback controller is designed for tracking control of an n-link robot manipulator with unknown load. High-gain obwserver that is used to estimate joint velocities is designed to avoide the restriction of the allowable variation range of unknown parmeters as well as improve the state estimation error. We saturate the control inut outside a domain of interest and use an adaptive law with a parameter projection feature to guarantee boundedness of all the trajectories in the closed-loop system. Simulation resutls on a 2-link manipulator illustrate that when the speed of the high-gain observer is sufficiently high, the proposed controller recovers the performance under state feedback control.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.139-144
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• 1993

In this paper, a robust reduced order adaptive controller is proposed based on Internal Model Control(IMC) structure for stochastic linear stable systems. The concept of gain margin is utilized to make the adaptive IMC controller robust. We prove the stability of the proposed adaptive IMC system for stable plants under the assumption that upper bounds for system orders are known. Simulation results show that the proposed method has good performance and stability robustness.

• 한국통신학회논문지
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• 제37권6C호
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• pp.462-468
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• 2012

본 논문은 SDR(software-defined radio)기반 무선 통신장비를 위한 디지털 AGC(Automatic Gain Control) 알고리즘에 대한 것이다. 수신신호는 무선 채널 구간에서 발생하는 경로 감쇄 및 수신단 front-end 동작에 의해 시간에 따라 변하는데, 신뢰성 있는 신호 복호를 위해서는 빠르고 정확한 AGC 기술이 적용되어야 한다. 또한, 하나의 수신기에서 다양한 웨이브폼을 수신하는 SDR 통신장비를 위해서는 적응적인 AGC 기술이 필요하다. 본 논문에서 다양한 웨이브폼에 대해 적용하기 위한 2단계로 구성된 적응적 구조를 제안한다. 제안한 적응적 구조는 수신신호 크기에 따라 이득값(gain) 선택 단계를 선택, 변경함으로써 빠르고 안정적인 이득값 조절을 가능하게 한다. 컴퓨터 모의실험을 통하여 제안하는 방식의 수렴속도 및 안정화 정도를 검증하고, 기존 방식과 비교하여 빠른 수렴 속도를 보임을 확인한다.

• Transactions on Control, Automation and Systems Engineering
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• 제3권1호
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• pp.15-20
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• 2001

In this paper, adaptive algorithms on the sliding model control for robust tracking control of robust manipulators are presented. The presented algorithms use adaption laws for tuning both the sliding mode gain and the thickness of the boundary layer to reject a disconitnuous control input, and to improve the tracking performance. It is shown that the robustness of the developed adaptive algorithms are guaranteed by the sliding mode control law and that the algorithms are globally convergent in the presence of disturbances and modeling uncertainties. Computer simulations are performed for a two-link manipulator, and the results show good properties of the proposed adaptive algorithms under large mainpulator parameter uncertainties and disturbances.

• 융합신호처리학회논문지
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• 제9권2호
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• pp.159-163
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• 2008

본 논문에서는 유연모드 부속물을 갖는 우주선의 제어를 위해서 누스범 이득을 갖는 간단한 형태의 적응제어기를 제안한다. 이 방법은 전달함수에서 고주파 이득의 정보가 필요하지 않는다. 본 논문의 방법을 사용하여 피치각도가 목표치를 추종하는 중에, 아울러 유연모드의 안정화도 이룬다. 피치각과 피치각속도 성분만 사용하여 출력궤환제어기를 설계한다. 특히 모든 시스템 파라미터 및 고주파성분은 미지로 한다. 설계의 간편성을 위해서 선형함수만을 사용하여 설계한 제어기가 전체 비선형시스템을 만족함을 시뮬레이션을 통하여 보이고, 그 근거도 설명한다. Lyapunov 함수를 구성하여 제안한 방법의 안정성을 증명하고, MATLAB을 이용한 컴퓨터 시뮬레이션 결과를 제시하여 제안한 방법의 유용성을 증명한다.

• 소음진동
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• 제5권3호
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• pp.385-394
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• 1995

Recently, since robot manipulator becomes faster and lighter, its link is no longer regarded as rigid body, and robot controller which only controls robot position cannot reduce vibration of the flexible link. Therefore vibration control is needed in robot manipulator control in addition to position control. In the case that tip mass changes when robot manipulator in working, it is clear that the efficiency of the vibration/position controller designed for the fixed system goes down. In this paper, the system with time varying parameters, adaptive control theory is adopted which estimates parameters changed by the variation of the tip mass and re-calculates the gain of the controller. Validify of the proposed adaptive controller and capability of the estimator are evaluated by computer simulations and experiments. Comparison results of the optimal controller for the fixed system and proposed adaptive controller and carried out.