• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.76.3-76
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• 2001

In this paper, an adaptive disturbance compensation technique is used in a tracking problem, under which the tracking reference is unknown. Based on a simple disturbance observer that effectively estimates the low frequency components of disturbance, the feedforward compensation is applied in addition to the conventional feedback control. Under the proposed compensation method, sensitivity analysis is given to illustrate the effectiveness. Finally, the proposed method is applied to the tracking problem in an optical storage system.

• 전자공학회논문지 IE
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• 제45권3호
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• pp.36-41
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• 2008

실제 프로세스 제어 중의 3개의 탱크 액체가 이 결합 시스템을 통제하는 작업 원리에 근거하여 두 개의 입력과 두 개의 출력 시스템의 수학적 모델을 제시하였다. 귀로 사이의 결합 작용을 한 종류의 형식의 요소로 간주하고 Feedforward 보상에 근거하여 정형화한 형태의 통제 분리 방법을 제시하였다. 그리고 두 개의 입출력 결합 시스템에 대해 통제 분리를 진행하고 마지막으로 프로그래밍을 통해 이 통제 분리 프로세스의 실험을 수행하였다. 또한 시뮬레이션 결과는 그 방법이 양호한 통제 분리 효과를 얻을 수 있다는 것을 나타내었다.

• 한국정밀공학회지
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• 제21권2호
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• pp.83-91
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• 2004

This paper illustrates the feasibility and the effectiveness of the disturbance feedforward compensation control proposed in the previous paper. The compensator is designed experimentally by means of the Multiple Filtered-x Least Mean Square algorithm. A 2-DOF active magnetic bearing system subject to base motion is built and the compensation control is applied. The experimental results demonstrate that the compensation control reduces the air-gap responses within 10$%$ of those by the feedback control alone without increasing the control inputs.

• 소음진동
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• 제11권1호
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• pp.49-56
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• 2001

In this paper, two plant models, of which one is newly developed and the other one is the conventional one, of the focus servo system of DVD drive are presented and a two-degree-of freedom controller consisted of Inverse dynamics feedforward and LQG/LTR feedback controller is designed. The newly developed plant model is used to design the feedforward controller and the conventional model is used for the design of feedback controller. The output of newly developed model is the displacement of objective lens and the output of conventional model is the focus error of the DVD focus servo system. The displacement of the objective lens is estimated by the dynamics model of the DVD focus servo system. The disturbance rejection performance of the two-degree-of freedom controller is compared with that of an LQG/LTR one.

• 전력전자학회논문지
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• 제7권6호
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• pp.531-536
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• 2002

기존의 속도센서가 없는 유도전동기의 고정자자속 기준제어 구동시스템에서, 추정된 속도는 저역통과필터의 사용으로 과도기에 지연이 생긴다. 이 지연으로 인한 응답속도의 과도한 오버슈트를 방지하기 위하여 속도제어기의 이득은 작아야 하는데, 이 때문에 부하토크의 영향을 크게 받게 된다. 본 논문에서는 부하토크 관측기와 전향제어를 사용하여 속도센서가 없는 시스템을 위한 강인한 속도제어기를 설계하였다.

• 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.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.926-931
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• 2008

In order to design a high-performance controller with excellent positioning and tracking performance, an optimal tuning method based on the integrated design concept is studied. DOBs, feedforward controllers and CCC are applied to control the bi-axial linear servomechanism. To derive accurate dynamic models of mechanical subsystems equipped with linear servos for the integrated tuning, system identification processes are conducted through the sine sweeping. An optimal tuning problem with stability, robustness and overshoot constraints is formulated as a nonlinear constrained optimization problem. Optimal gains are obtained through the SQP method. Experimental results confirm that both tracking and contouring errors are significantly reduced by applying the proposed controller and integrated tuning method.

• 한국정밀공학회지
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• 제28권12호
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• pp.1379-1387
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• 2011

A PID-feedforward controller and Robust Internal-loop Compensator (RIC) based on reinforcement learning using random variable sequences are provided to auto-tune parameters for each controller in the high-precision position control of PMLSM (Permanent Magnet Linear Synchronous Motor). Experiments prove the well-tuned controller could be reduced up to one-fifth level of tracking errors before learning by reinforcement learning. The RIC compared to the PID-feedforward controller showed approximately twice the performance in reducing tracking error and disturbance rejection.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.586-591
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• 2004

A load/unload mechanism is applied to most small form factor hard disk drives. Loading velocity is ones of the most important factors to ensure the reliability of the load/unload operations. Especially, the lower the flying height of the head becomes, the more important the accuracy of the loading velocity control becomes. Because there is no sensor during the load/unload operations, BEMF voltage is used to sense the head velocity. To measure BEMF voltage, a simple circuit is added to the load/unload HDD control system. Overall acceptable results are obtained by using the simple PI controller but the errors from the target velocity occur when the head moves along the ramp and then reaches the disk. Feedforward profile and disturbance observer are used to remove those errors effectively.