• 반도체디스플레이기술학회지
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• 제12권1호
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• pp.53-59
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• 2013

Chip mounter which is used to pick chips from the pre-specified position and place them on the target location of PCB is an essential device in semiconductor and LCD industries. Quick and high precision positioning is the key technology needed to increase productivity of chip mounters. As increasing acceleration and deceleration of placing motion, structural vibration induced from inertial reactive force and flexibility of mounter structure becomes a serious problem degrading positioning accuracy. Motivated from these, this paper proposed a new control design algorithm which combines a mounter structure acceleration feedforward compensation and an extended sliding mode control for fine positioning and suppression of structural vibration, simultaneously. The feasibility of the proposed control design was verified along with some simulation results.

• 제어로봇시스템학회논문지
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• 제8권11호
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• pp.907-915
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• 2002

We present a state-space approach to design a passivity-based dynamic output feedback control of a finite collection of non-square linear systems. We first determine a squaring gain matrix and an additional dynamics that is connected to the systems in a feedforward way, then a static passivating (i.e. rendering passive) control law is designed. Consequently, the actual feedback controller will be the static control law combined with the feedforward dynamics. A necessary and sufficient condition for the existence of the parallel feedfornward compensator (PFC) is given by the static output feedback fomulation, which enables to utilize linear matrix inequality (LMI). The effectiveness of the proposed method is illustrated by some examples including the systems which can be stabilized by the proprotional-derivative (PD) control law.

• International Journal of Precision Engineering and Manufacturing
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• 제6권1호
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• pp.31-35
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• 2005

Higher productivity requires high-speed motion of machine tool axes. The iron core linear DC motor (LDM) is widely accepted as a viable candidate for high-speed machine tool feed unit. LDM, however, has two inherent disturbance force components, namely cogging and thrust force ripple. These disturbance forces directly affect the tracking accuracy of the feeding system and must be eliminated or reduced. In order to reduce motor ripple, this research adapted the feedforward compensation method and neural network control. Experiments carried out with the linear motor test setup show that these control methods are effective in reducing motor ripple.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 추계학술대회 논문집
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• pp.358-362
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• 2004

Higher productivity requires high-speed motion of machine tool axes. The iron core linear DC motor (LDM) is widely accepted as a viable candidate for high-speed machine tool feed unit. LDM, however, has two inherent disturbance force components, namely cogging and thrust force ripple. These disturbance forces directly affect the tracking accuracy of the feeding system and must be eliminated or reduced. In order to reduce motor ripple, this research adapted the feedforward compensation method and neural network control. Experiments carried out with the linear motor test setup show that these control methods are effective in reducing motor ripple.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.864-867
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• 2003

In this study, a controller which has a feedforward controller and two additional PI integrators was designed. But if a controller is used by only the integration of a feedforward controller and two additional PI integrators, the capability of a controller will decrease because the decoupling terms of current is feedback as the disturbance. Therefore the feedforward method with the decoupling compensation was proposed. The two additional PI integrators were replaced by two decoupling terms to simplify the calculation. The simulation and experimental using SynRM driving system were performed to verify the design of a improved decoupling feedforward controller.

• 한국정밀공학회지
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• 제22권7호
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• pp.94-101
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• 2005

This work proposes a new method for describing the hysteresis non-linearity of a piezoelectric actuator. The hysteresis behaviour of piezoelectric actuators, including the minor loop trajectory, are modeled by geometrical relationship between a reference major loop and its minor loops. This hysteresis model is transformed into inverse hysteresis model in order to output compensated voltage with regard to the given input displacement. A feedforward neural network, which is trained by a feedback PID control module, is incorporated to the inverse hysteresis model to compensate unknown dynamics of the piezoelectric system. To show the feasibility of the proposed feedforward-feedback controller, some experiments have been carried out and the tracking performance was compared to that of simple PTD controller.

• 전력전자학회논문지
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• 제6권1호
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• pp.90-97
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• 2001

본 논문에서는 시스템의 광성 추정에 의한 가속도 전향보상 방법을 이용한 새로운 속도제어 기법을 제안한다. 제안된 가속도 전향보상 방법에 의해 속도제어기의 대역폭을 충분히 크게 할 수 없는 백터제어 유도전동기 구동시스템에서 속도제어 성능을 향상시킬 수 있고, 외란 토크에 대한 속도회복특성도 개선될 수 있다. 3.7kW 유도전동기 구동시스템에 대한 시뮬레이션과 실험을 통해 제안된 기법의 타당성을 확인하였다.

• 전력전자학회논문지
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• 제8권5호
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• pp.442-449
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• 2003

본 논문은 PQR 순시전력 이론을 이용하여 순시전압보상장치 (DVR)에서 기준보상전압을 결정하는 방법을 제시한다. 측정된 3상 단자 전압은 시간지연 없이 PQR 좌표계로 변환된다. PQR 좌표계의 기준전압은 단일한 직류값이므로 DVR의 전압제어기는 단순하고 쉽게 설계가 가능해 진다. 제안된 제어방식은 피드백 제어기나 피드포워드 제어기에 모두 적용될 수 있다. 본 논문에서는 피드포워드 제어기에 대하여 이론을 적용하였으며 실험 및 시뮬레이션으로 검증을 하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.431-431
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• 2000

The modeling of 5-bar linkage robot manipulator dynamics by means of a mathematical and neural architecture is presented. Such a model is applicable to the design of a feedforward controller or adjustment of controller parameters. The inverse model consists of two parts: a mathematical part and a compensation part. In the mathematical part, the subsystems of a 5-bar linkage robot manipulator are constructed by applying Kawato's Feedback-Error-Learning method, and trained by given training data. In the compensation part, MLP backpropagation algorithm is used to compensate the unmodeled dynamics. The forward model is realized from the inverse model using the inverse of inertia matrix and the compensation torque is decoupled in the input torque of the forward model. This scheme can use tile mathematical knowledge of the robot manipulator and analogize the robot characteristics. It is shown that the model is reasonable to be used for design and initial gain tuning of a controller.

• 전기학회논문지
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• 제64권9호
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• pp.1297-1305
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• 2015

This paper proposes a power feedforward technique for the performance improvement of DC-link voltage control in the dynamic voltage restorer (DVR). The DC-link Voltage is able to be unstable for an instant owing to any change in the load and voltage sag. The distortion of the DC-link voltage leads to the negative influence on the performance of DVR. To mitigate the distortion of the DC-link voltage, the power feedforward component is calculated by the load power and the grid voltage, and then it is added to the reference current of the conventional DC-link voltage controller. By including output power feedforward component on the DC-link controller, the DC-link voltage can settle down more quickly than when the conventional DC-link voltage controller applied. The proposed technique was validated through the simulation and experimental results.