• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1507-1508
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• 2008

In this paper, we propose a direct robust adaptive backstepping speed controller for induction motors system. A robust adaptive backstepping controller is designed using high order neural networks(HONN), which avoids the singularity problem in adaptive nonlinear control. The stability of the resulting adaptive system with proposed adaptive controller is guaranteed by suitable choosing the design parameter and initial conditions. HONN are used to approximate most of uncertainties which are derived from unknown motor parameters, load torque disturbances and unknown nonlinearities. The applicability of the proposed scheme is tested simulation.

• Journal of Advanced Marine Engineering and Technology
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• 제27권3호
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• pp.388-394
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• 2003

Hydraulic system is difficult to obtain a suitable performance due to the nonlinearity load pressure change and system parameter variation. The requirement of control a1gorithm has been complex in order to satisfy the performance. The adaptive control is a control method which is suggested to achieve the control object under the plant characteristics change. In spite of the case that plant characteristics and the degree of variation are difficult to grasp. the adaptive control could keep the characteristics of closed-loop system generally. In this study. a method of combined generalized minimum variance adaptive control (GMVAC) and output error feedback is proposed, in order to solve the problem of non-minimum phase of plant and the vibration and overshoot in initial response. The control performance according to the variation of characteristics of plant is evaluated by changing the supply pressure. The experimental results show the effectiveness of the proposed scheme.

• Journal of Advanced Marine Engineering and Technology
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• 제29권3호
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• pp.251-259
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• 2005

A discrete time model reference adaptive control has been applied in order to compensate the nonlinear friction characteristics in a hydraulic proportional position control system. As nonlinear friction, static and coulomb friction forces are considered and modeled as dead zone and external disturbance respectively. The model reference adaptive control system consists of a cascade combination of the dead zone. external disturbance and linear dynamic block. For adaptive control experiment. the DSP(Digital Signal Processor) board has been interfaced the hydraulic proportional position control system. The experimental results show that the MRAC(Model Reference Adaptive Control) for compensation of static and coulomb friction are very effective.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 추계학술대회 논문집 학회본부
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• pp.430-433
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• 1988

An adaptive control system for D.C servo drive is developed via minimum variance control theory. The problem of designing this controller under varying load conditions is discussed. A robust self tuning controller that can track a constant reference and reject constant load disturbance is developed. Simulation study shows that the controller has excellent adaptation, capability as well as transient recovery under load changes.

• 한국통신학회논문지
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• 제17권2호
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• pp.121-131
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• 1992

포스트 필터링(adaptive postfiltering)을 수신단의 마지막에세 수행 하였다. 첫째는, SBC 시스템의 대역 필터를 QMF(Quadrature Mirror Filter) 대신 GQMF(Generalized QMF)를 사용하여 성능을 향상시켰고, 둘째는, 각 대역에 적응 비트 할당을 함으로써 음질의 향상뿐 아니라 variable rate 부호화할 수도 있었다. 세번째로는 APCM(Adaptive Plulse Code Modulation)과 ADPCM(Adaptive Differential Pulse Code Modulation)을 부호화기로 사용하여 각각의 성능을 평가 한 결과, SB-APCM 의 성능이 우수하였다.또한, 수신단의 마지막에서 적응 포스트 필터링을 수행하여 부호화된 음성의 음질을 개선할 수 있었다. 본 논문에서는 두가지의 적응 포스트 필터링 기법을 제안하였는데 낮은 복잡성을 가지고도 부호화된 음성에서 상당량의 잡음 감쇄를 이룰 수 있었다.

• 전력전자학회논문지
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• 제11권3호
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• pp.274-283
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• 2006

Permanent Magnet Synchronous Motor(PMSM)는 볼스크류, 기어 및 타이밍 벨트를 이용하여 NC, 가공기, 로봇 및 공장 자동화를 포함하여 산업 시스템 전반에 널리 사용되고 있다. 이러한 PMSM과 부하의 결합으로 구성된 시스템은 동력의 전달에 있어서, 고유의 공진 주파수를 가지며 공진 주파수 대역에서의 기계계의 응답 특성은 매우 불안정하고, 기계 시스템의 손상을 일으키게 된다. 본 논문에서는 PMSM을 이용한 직선 운동 시스템에서 기계적인 결합에 의한 기구부의 진동을 억제하기 위하여 진동 주파수를 자동으로 검출하여, 진동의 원인이 되는 토크 지령 신호를 억제하는 적응형 노치 필터를 포함하는 속도 제어 시스템을 제안한다. 하지만, 기계적인 진동 주파수와 주파수의 대역은 전동기에 결합된 결합 기구 및 부하에 따라서 변동하는 특성을 가지고 기계적인 진동의 크기도 진동원이 되는 신호에 따라 변동하므로, 이를 적응형 노치 필터부에서 이를 진단하여 진동 주파수를 자동으로 억제함으로써 안정적인 운전이 가능하도록 설계된다. 본 논문에서 제안된 기계적인 진동을 억제하기 위한 적응형 노치 필터의 성능은 시뮬레이션 및 실험을 통하여 검증하였다.

• 제어로봇시스템학회논문지
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• 제9권5호
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• pp.347-353
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• 2003

A nonlinear speed controller for a surface mounted permanent magnet synchronous motor (PMSM) based on a newly developed adaptive backstepping approach is presented To compensate parameter uncertainties and load torque disturbance, a nonlinear adaptive backstepping control law and adaptive law are derived systematically through virtual control input and suitable Lyapunov function. Also, speed observer without using costly speed sensor is presented. Simulation results show that the proposed controller can observe the speed and track the reference speed signal generated by a reference model.

• 한국전산구조공학회논문집
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• 제12권3호
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• pp.447-455
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• 1999

본 연구에서는 대변형 쉘 구조물에 효과적인 적응적 유한요소 자동생성 기법을 제안한다. 사후 오차평가에 기초하여 기하학적 비선형 해석시 각 하중 단계에서의 요소 재생성에 초점을 맞추고 있다. 응력오차로부터 얻어진 요소크기 함수로 등고선을 구성하고, 요소 재생성 기법으로 advancing front method의 일종인 패이빙법(paving method)을 이용하여 적응적 요소 자동생성을 수행한 결과, 그 유용성을 확인하였다.

• 드라이브 ㆍ 컨트롤
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• 제17권1호
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• pp.13-20
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• 2020

Adaptive neural networks based lateral controller is presented to guarantee path following performance for vehicle lane keeping in the presence of parameter time-varying characteristics of the vehicle lateral dynamics due to the road surface condition, load distribution, tire pressure and so on. The proposed adaptive controller could compensate vehicle lateral dynamics deviated from nominal dynamics resulting from parameter variations by incorporating it with neural networks that have the ability to approximate any given nonlinear function by adjusting weighting matrices. The controller is derived by using Lyapunov-based approach, which provides adaptive update rules for weighting matrices of neural networks. To show the superiority of the presented adaptive neural networks controller, the simulation results are given while comparing with backstepping controller chosen as the baseline controller. According to the simulation results, it is shown that the proposed controller can effectively keep the vehicle tracking the pre-given trajectory in high velocity and curvature with much accuracy under parameter variations.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 추계학술대회 논문집 학회본부
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• pp.393-396
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• 1989

This paper deals with the design of the adaptive controller using a decentralized control for Large-Scale system formed of an arbitrary interconnection of subsystem with unknown parameters, non linearity and bounded disturbance. In order to reduce the load and frequency deviations, now decentralized adaptive controllers are developed for stabilization and tracking the parameters. In the simulation studies of the decentralized adaptive control of a two-area interconnected power system, the effectiveness of the proposed adaptive is demonstrated.