• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.684-687
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• 2002

In optical disk drive(ODD), pickup actuator, which comprises a key part of an optical disk drive equipment. must be thin. compact, and high sensitive. Low tilt is also an important requirement for the actuator, since optical disks are to high density. This tilt occurs from around the axis parallel to the tangential and radial direction of the disk. The main reason of the moment is the coupling effect between focus driving system and tracking driving system. This paper analyzed tut quantity due to focusing and tracking force through coupled fields analysts with electromagnetic analysis and structural analysis.

• 전자공학회논문지T
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• 제36T권4호
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• pp.38-46
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• 1999

본 논문에서는 조미동 구동기의 반복추종제어에 관하여 논의한다. 제안되는 시스템은 조동구동기로 선형 자기드라이브를, 미동구동기로 선형 압전구동기를 사용하여 구성된다. 특히, 선형 자기드라이브에 내재된 비선형 마찰과 선형 압전구동기의 이력현상이 먼저 모델링되고 되먹임선형화 루프가 이들을 추종제어에 사용한다. 주기적인 입력신호를 추종하는 경우 이를 더욱 확장하려 반복제어 알고리즘을 포함하도록 제어기를 설계한다. 즉, 반복제어기는 되먹임선형화가 적용된 PID 제어기에 설치된다. 실험결과에 의하면 정현파 입력을 추종하는 경우 PID 제어기에 되먹임선형화와 반복제어기를 함께 적용함으로써 추종성능을 크게 향상시킬 수 있는 것으로 나타났다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.464-467
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• 1997

In this paper, a high precision track following control algorithm is proposed for micro electrostatic actuator considering of the application for hard disk drive. The micro electrostatic actuator proposed has nonlinear voltage-displacement characteristic in a working range of 0.8.mu.m and has uni-directional movement. Mid range reference and open-loop bias are proposed for the revision of negative position error, and inverse model for linearization.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
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• pp.605-610
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• 1994

This paper discusses the solution to the precise positioning control problem applied to a simple model of a dual stage or redundant positioner. The dual stage actuator presented here uses a VCM(Voice Coil Motor) as a coarse actuator and a piezoelectric actuator as a fine actuator. By adopting controllers with two-degree-of-freedom and by optimizing H$_{2}$ faster precise tracking can be realized. Experimental and numerical results are presented to demonstrate the control effects.

• International Journal of Aeronautical and Space Sciences
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• 제14권3호
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• pp.256-263
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• 2013

The saturation of the actuator impairs the response performance of the near space interceptor control system. A control system based on the properties of linear tracking system is designed for this problem. The properties are that the maximum value of the pseudo-Lyapunov function of the linear tracking control system do not present at the initial state but at the steady state, based on which the bounded stability problem is converted into linear tracking problem. The pseudo-Lyapunov function of the linear tracking system contain the input variables; the amplitude and frequency of the input variables affect the stability of the nonlinear control system. Designate expected closed-loop poles area for different input commands and obtain a controller which is function of input variables. The coupling between variables and linear matrices make the control system design problem non-convex. The non-convex problem is converted into a convex LMI according to the Shur complement lemma and iterative algorithm. Finally the simulation shows that the designed optimal control system is quick and accurate; the rationality of the presented design techniques is validated.

• 한국추진공학회지
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• 제20권4호
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• pp.19-25
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• 2016

모터와 기어를 적용한 구동장치를 이용하여 정밀한 위치제어를 수행하기 위하여 I-PD 제어기법과 이중루프를 시스템에 적용한다. I-PD 제어기법은 과도응답 시 오버슛을 줄이는 동작을 수행함으로써 정밀한 위치 추종 결과를 얻는다. 또한 두 개의 센서와 이중루프를 이용하여 기어 시스템의 end play 성분에 의해 발생할 수 있는 위치추종에 대한 악영향을 저감하여 구동장치가 정밀한 위치추종을 할 수 있도록 한다. 본 연구에서는 이러한 개념을 설명하고, 동특성 변화에 의한 위치추종 결과를 확인하기 위하여 BLDC 모터와 기어를 적용한 구동장치 모델을 이용하여 시뮬레이션 결과로 검증하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.195-199
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• 2004

Recently, optical disc drives are required to have high density and capacity in according with development of high definition images and rapid increase of various informations. Consequently, the numerical aperture becomes larger, the wavelength of laser is coming to be short. However, it deteriorates rolling mode effect on an optical pickup actuator. Therefore, this paper proposes new design and optimization of tracking coils for reducing it. First, we verify that discord between the center of force and the center of mass by restrictions of design condition is an important factor of rolling mode effect. Then, in order to reduce it, we propose new design parameters of tracking coils. Finally, we reduce rolling mode effect through optimization of tracking coils using Taguchi method and response surface method.

• 한국지능시스템학회논문지
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• 제23권1호
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• pp.46-50
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• 2013

본 논문은 다수의 구동기 고장을 가진 유연 관절 로봇의 적응 고장 수용 제어기를 제안한다. 다수의 구동기 고장의 크기와 일어나는 시간은 알려지지 않는다고 가정한다. 구동기 고장을 수용하기 위해 추종 오차의 수렴율과 오버슈트의 최대치로 특성화된 미리 정의된 성능을 보장하는 유계 조건을 갖는 적응 고장 수용 제어기를 설계한다. 르아프노브 안정도 이론을 이용하여 페루트 시스템의 모든 신호가 준 전역적이고 균일하고 궁극적으로 유계됨을 증명하고 추종 오차가 미리 정의된 성능 유계에서 벗어나지 않음을 보인다.

• Smart Structures and Systems
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• 제5권6호
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• pp.613-632
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• 2009

The present paper is concerned with the design of a proper patch actuator network in order to track a desired displacement of the sidewalls of a one-storey frame structure; both, for the static and the dynamic case. Weights for each patch of the actuator network found in our previous work were based on beam theory; in the present paper a refinement of these weights by modeling the sidewalls of the frame structure as thin plates is presented. For the sake of calculating the refined weights approximate solutions of the plate equations are calculated by an extended Galerkin method. The solutions based on the analytical plate model are compared with three-dimensional Finite Element results computed in the commercially available code ANSYS. The patch actuator network is put into practice by means of four piezoelectric patches attached to each of the two sidewalls of the frame structures, to which electric voltages proportional to the analytically refined patch weights are applied. Analytical and numerical results coincide very well over a broad frequency range.

• Journal of Electrical Engineering and Technology
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• 제13권4호
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• pp.1740-1751
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• 2018

This paper proposes a novel fault tolerant tracking control (FTTC) scheme for a class of nonlinear systems with actuator failures based on the policy iteration (PI) algorithm and the adaptive fault observer. The estimated actuator failure from an adaptive fault observer is utilized to construct an improved performance index function that reflects the failure, regulation and control simultaneously. With the help of the proper performance index function, the FTTC problem can be transformed into an optimal control problem. The fault tolerant tracking controller is composed of the desired controller and the approximated optimal feedback one. The desired controller is developed to maintain the desired tracking performance at the steady-state, and the approximated optimal feedback controller is designed to stabilize the tracking error dynamics in an optimal manner. By establishing a critic neural network, the PI algorithm is utilized to solve the Hamilton-Jacobi-Bellman equation, and then the approximated optimal feedback controller can be derived. Based on Lyapunov technique, the uniform ultimate boundedness of the closed-loop system is proven. The proposed FTTC scheme is applied to reconfigurable manipulators with two degree of freedoms in order to test the effectiveness via numerical simulation.