• 제어로봇시스템학회논문지
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• 제5권2호
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• pp.166-173
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• 1999

Reference models are used in many control algorithms for improvement of transient response characteristics. They provide desired trajectories that the plant should follow Most control systems have bounded control inputs to avoid saturation of the plant. If we design the reference models that do not account for limits of the control inputs, control performance of the system may be deteriorated. In this paper a new approach of avoiding saturation by varying the reference model for TDC(time delay control) based systems subject to step changes in the reference input. In this scheme, the variable reference model is determined based on the information on control inputs and the size of the step changes in the reference inputs. This scheme was verified by application to the BLDC motor position control system in simulations and experiments. The responses of the TDC with the variable reference model showed better tracking performance than that with the fixed reference model.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2018년도 전력전자학술대회
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• pp.57-59
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• 2018

This paper presents a novel reference variable speed control scheme of a BLDC motor for the high-speed blender machine according to the current limit. Because of a pulsating load variation of a high-speed blender machine, the actual speed is pulsated by the current limit in the high-speed region. The proposed control scheme uses a variable reference speed to reduce the speed variation from the current limit in the constant power region. The pulsated load is occurred at the material crushing, then the pulsated load is reduced after grinding. The reference speed is smoothly reduced at the pulsated load variation, then the enough torque can make a constant speed during crushing. When the pulsating load is reduced, the reference speed is automatically increased to the original speed value. The proposed control scheme is verified by experimental result by practical blender machine.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.492-495
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• 1997

Integral type system is that a system is represented by a proper rational function. In this paper, novel control scheme based on model reference approach is proposed for integral type system. The proposed scheme compensates various undesirable effects of the system. In especially, the proposed scheme applied to DC servo control system, analyzed its control characteristic. Performances of the proposed system show excellent control characteristics; complete compensation of the undesirable nonlinear friction and load viscous, For proving realistic validities, LOS(Line Of Sight) stabilization system which has typically many nonlinear effects is experimented. After executing the computer simulation in "MATLAB", then the results are compared with the experiments. The results are very similar in theoretical study and the proposed control scheme is successfully verified. verified.

• Transactions on Control, Automation and Systems Engineering
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• 제3권1호
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• pp.32-42
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• 2001

In this paper, a parameter estimator is developed for the plant model whose structure is represented by the Takagi-Sugeno model. The essential idea behind the on-line estimation is the comparison of the measured stated with the state of an estimation model whose structure is the same as that of the parameterized model. Based on the parameter estimation scheme, and indirect Model Reference Adaptive Fuzzy control(MRAFC) scheme is proposed to provide asymptotic tracking of a reference signal for the systems with uncertain for slowly time-varying parameters. The developed control law and adaptive law guarantee the boundedness of all signals in the closed-loop systems. In addition, the plant state tracks the state of the reference model asymptotically with time for any bounded reference input signal.

• 한국공작기계학회논문집
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• 제15권5호
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• pp.72-78
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• 2006

The paper proposes reference model error feedback control scheme for motion control system with hard non-linear components as like saturation and dead-zone in plant input part. Additionally, the plant has the system uncertainty effected by plant model parameter deviation and disturbance. The control algorithm uses the reference model to apply additional feedback loop with the error between reference model output and actual output effected by disturbance and non-linear components. And the stability evaluation based on Popov stability and controller design method are formulated to be performed. The effectiveness of the proposed scheme is examined by simulations. The results are proven by reasonable performances following reference model responses with good disturbance rejection performance without over-tuning of controller.

• 한국지능시스템학회논문지
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• 제17권1호
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• pp.130-135
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• 2007

In this paper, a direct model reference adaptive fuzzy control (MRAFC) scheme is developed for the plant model whose structure is represented by the MIMO Takagi-Sugeno fuzzy model. The MRAFC scheme is proposed to provide asymptotic tracking of a reference signal lot the systems with uncertain or slowly time-varying parameters. The developed control law and adaptive law guarantee that all signals in the closed-loop system are bounded. In addition, the plant state tracks the state of the reference model asymptotically with time tot any bounded reference input signal.

• 융합신호처리학회논문지
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• 제8권4호
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• pp.297-306
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• 2007

모델 기준 제어(MRC)는 플랜트가 주어진 기준 모델의 거동을 추종하도록 플랜트를 제어하는 제어 기법이다. 기준 모델은 플랜트가 추종할 이상적인 궤적을 제공한다. 지금까지 많은 종류의 MRC가 제안되었지만, 본 논문에서는 모델 기준 슬라이딩 모드 제어(MRSMC)에 대해 제어 대상 플랜트가 불확실성을 갖는 단일 입출력 2차 시변 선형 시스템인 경우에 대해 연구를 수행하였다. 본 논문에서 MRSMC를 위한 기준 모델의 설계 방법이 제안하였다. 제안된 방법은 제한된 제어 입력, 기준 입력, 시스템 파라미터에 대한 정보를 사용하여 기준 모델을 선정한다. 이러한 선정 결과는 고정된 기준 모델의 선정, 계단 입력 인가시의 가변 기준 모델 갱신, 매 샘플링 시간마다 순간 기준 모델의 갱신 등으로 이용할 수 있다. 모터의 위치 제어 시스템에 대한 시뮬레이션 결과는 제안된 방법의 효용성을 보여준다.

• 제어로봇시스템학회논문지
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• 제15권7호
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• pp.711-719
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• 2009

This paper presents a design scheme of torque control for wheeled mobile robot(WMR) to asymptotically track the target reference trajectory. By considering the kinematic model of WMR, trajectory tracking control generates the desired tracking trajectory, which is transformed into the command velocity vector for the real WMR to track the target reference trajectory. The dynamic equation of the state error between the target reference trajectory and the desired tracking trajectory is represented by Takagi-Sugeno fuzzy model, and this model is used as the reference model for the real mobile robot error dynamics to follow. The control parameters are updated by adaptive laws that are designed for the error states of the real WMR to asymptotically follow the states of reference error model for the desired tracking trajectory. The proposed control is applied to a typical wheeled mobile robot and simulation studies are carried out to verify the validity and effectiveness of the control scheme.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권1호
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• pp.9-15
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• 2006

The conventional hysterysis band DTC(Direct Torque Control) strategy have relatively high torque ripple at low speed and variable switching frequency according to motor speed even though it provides a fast torque response with very simple scheme consisted with only two hysteresis band comparators and a switching table for torque and flux control. In this paper, author proposed a new DTC scheme based on the torque slope and reference voltage control. The new scheme can maintain the minimized torque ripple and constant switching frequency. Experimental tests carried out with an 1.5kW induction motor drive system show improved dynamic characteristics and prove the feasibility of proposed strategy.

• 제어로봇시스템학회논문지
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• 제3권2호
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• pp.124-131
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• 1997

This paper presents a modified adaptive control scheme that improves the transient performance of the overall system while maintaining the asymptotic convergence of the output error. The proposed control scheme is characterized as the added outer dynamic feedback loop on the conventional adaptive control scheme. This control scheme enables various robust control methods that were developed for standard model reference adaptive controllers to be applied to the proposed controller. In contrast with the modified adaptive controllers that use augmented errors to provide additional dynamic feedback, the proposed controller uses tracking error directly, thereby reducing the tracking error significantly in the transient state and making the error insensitive to noise.