• 제목/요약/키워드: Gap servo

검색결과 43건 처리시간 0.009초

공압서보시스템에 의한 미세 간극제어 시스템 설계 (Fine Gap Control Using Pneumatic Servo System)

  • 김동환;김영진;정대화
    • 한국정밀공학회지
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    • 제19권12호
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    • pp.45-56
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    • 2002
  • A pneumatic servo system requiring a fine gap control in a photo-electric sensor which is used for a LCD array detection device is introduced. The gap controlled by the pneumatic servo system remains within around 50~80 ${\mu}{\textrm}{m}$, and the system possesses an effect to eliminate undesirable particles on the LCD plate by blowing air out. The air flow rate is initially controlled by a servo valve and expanded by a booster valve, thus the controlled air pressure contributes to maintaining an appropriate gap between the LCD plate and photo-electric sensor An air floating plate of two degrees of freedom is designed and fabricated, and a fine tilting motion control is also implemented by assigning different gap commands. The pressure control and direct gap control are proposed, and each performance is verified experimentally.

SIL을 이용한 근접장 기록계에서의 서보 방식의 개발 (Improvement Air Gap Control for SIL based Near-Field Recording System)

  • 김중곤;김태훈;정준;박노철;양현석;박영필
    • 정보저장시스템학회논문집
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    • 제3권1호
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    • pp.1-4
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    • 2007
  • A high density optical data storage device has been required for many years. In the field of the optical data storage, a near-field recording (NFR) technology is considered as a next generation one for achieving the high data density. Due to an evanescent wave effect occurred under 100nm distance which is the excessively small distance between the SIL and the disc, the most significant and difficult problem in this technology is to maintain a gap between a solid immersion lens (SIL) and a disc. Also, maintaining the gap under at least 50nm is required in the NFR gap servo system to use the evanescent wave effect efficiently. There are some institutes that have shown the novel gap servo control. In general, they use a mode switching servo method which consists of approach, hand-over and gap control mode. However there is a critical problem such as an overshoot at the tuning point from the approach mode to the hand-over mode, which may cause a collision between the SIL and the disc. In this paper, we show our NFR system and an improved gap servo system using an exponential function as the approach mode which can reduce the overshoot.

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Fine Gap Control System Design Using Pneumatics servo System

  • Kim, Dong-Hwan;Kim, Young-Jin;Jeong, Dae-Hwa
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2001년도 ICCAS
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    • pp.111.2-111
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    • 2001
  • The research focuses on controlling a gap to measure the surface defect in semi-conductor fabrication device. The measurement is available accompanying a near field image gap control. In this article, a pneumatic servo system is adopted for the near field gap control. The advantage of the pneumatic servo system is on the preventing the possibility of contacting the device to the wapper surface, fence arising fatal damage. Furthermore, the air from the pneumatic system blows the some particle on the wapper during controlling. The target gap is less than 20 $\mu$m and the gap should keep same amount while the device moves around the surface. The experiment by the pneumatic servo control system is done by employing a simple PID control, and the tracking performance is remarkably verified. The target gap is set from 10 $\mu$m to 100 $\mu$m ...

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근접장 광 저장 장치의 Gap 서보 (Gap Servo for High Density Near Field Optical Storage Devices)

  • 이정욱;서정교;신윤섭;박진무;정미현;최인호
    • 정보저장시스템학회:학술대회논문집
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    • 정보저장시스템학회 2005년도 추계학술대회 논문집
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    • pp.12-13
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    • 2005
  • Near field recording (NFR) technology with SIL has been thought as the most promising generation optical storage device. A gap distance between the SIL and the disc should be controlled to be 20${\~}$40nm. We observed gap error signal in our NFR test-bed using a blue LD (405nm). The digital gap servo filter and control algorithm were developed to maintain a constant air gap by adopting a conventional actuator.

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근접장 시스템의 2 축 deck mechanism (2-axis deck mechanism for gap servo NFR system)

  • 정미현;박홍수;이성훈;서정교;최인호;민병훈
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2007년도 추계학술대회논문집
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    • pp.1031-1032
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    • 2007
  • Gap servo NF (Near Field) system is one of technologies to reduce beam spot size by increasing NA (Numerical Aperture) of lens. To achieve higher NA, SIL (Solid Immersion Lens) is used. In the case of using a blue LD (405 nm) as the light source the gap distance should be controlled under 100 nm with much tighter margin. Because of very small gap distance between SIL bottom and the surface of media, relative tilt tolerance is limited. In this paper, we presented 2-axis tilt mechanism for skew adjustment within small tilt margin.

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개구형 근접장 헤드장치의 간극제어를 위한 이중 서보 제어 (Dual Servo Control for Aperture Type Near Field Storage Head)

  • 이성규;김은경;박강호
    • 한국소음진동공학회논문집
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    • 제16권5호
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    • pp.479-484
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    • 2006
  • This paper presents an active control of the aperture type near-field storage head. In order to achieve a fast and accurate control, a dual servo control algorithm is applied. Based on the big difference in time constants of two actuators, they are used independently. With the combination fine and coarse actuator, the disk is rotated up to 10 rpm speed until the gap is controlled within 100 nm. From the experimental results, the feasibility and the performance of active dual servo gap control is proved.

IMP를 이용한 근접장 기록 장치의 디스크 진동 및 편심 보상 (Disk Vibration and Eccentricity Compensation of Near Field Recoding Systems Based on the Internal Model Principle)

  • 정준;김중곤;박노철;양현석;박영필
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2007년도 춘계학술대회논문집
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    • pp.837-842
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    • 2007
  • Information storage devices using disks have a disk vibration at the frequency which is equivalent to the disk rotational speed. They also have a track vibration due to the disk eccentricity at the same frequency. In near field recording systems, the former affects the air-gap servo and the latter affects the tracking servo. In this paper, we introduce a novel control algorithm based on the internal model principle to both servos. A controller block designed by the principle is connected to the base lead-lag type compensator in parallel in order to cancel the repeatable run-out due to the disk vibration or eccentricity. Simulation and practical application of the algorithm on a near field recording system show good servo performance.

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IMP를 이용한 근접장 기록 장치의 디스크 진동 및 편심 보상 (Disk Vibration and Eccentricity Compensation of Near Field Recording Systems Based on the Internal Model Principle)

  • 정준;김중곤;박노철;양현석;박영필
    • 한국소음진동공학회논문집
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    • 제17권6호
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    • pp.539-546
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    • 2007
  • Information storage devices using disks have a disk vibration at the frequency which is equivalent to the disk rotational speed. They also have a track vibration due to the disk eccentricity at the same frequency. In near field recording systems, the former affects the air-gap servo and the latter affects the tracking servo. In this paper, we introduce a novel control algorithm based on the internal model principle to both servos. A controller block designed by the principle is connected to the base lead-lag type compensator in parallel in order to cancel the repeatable run-out due to the disk vibration or eccentricity. Simulation and practical application of the algorithm on a near field recording system show good servo performance.

개구형 근접장 헤드장치의 간극제어를 위한 이중 서보 제어 (Dual servo control for aperture type near field storage head)

  • 이성규;김은경;박강호
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2005년도 추계학술대회논문집
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    • pp.875-878
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    • 2005
  • This paper presents active control of aperture type near-field storage head. In order to achieve fast and accurate control, dual servo control algorithm is applied. Based on the big difference in time constant, we seperate two actuator and control independently. With the combination of fine and coarse actuator, gap is controlled within 100nm until the disk rotates upto 10 rpm speed. From the experimental results, the feasibility and performance of active gap control is proved.

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SIL 기반 근접장 기록 시스템의 간극 제어를 위한 최적화된 PID 제어 알고리즘 성능평가 (Air-Gap Control Using Optimal PID Controller for SIL-Based Near-Field Recording System)

  • 신원호;김중곤;박노철;양현석;박영필;박경수
    • 정보저장시스템학회논문집
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    • 제5권1호
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    • pp.41-46
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    • 2009
  • In SIL-based NFR servo systems, the residual error and the overshoot that are occurred in the process of the modes-witching servo which consists of approach, gap-control modes, and safety mode are reduced by using PID controller. However, the design method of conventional PID controller is not sufficient for the stable air gap control system. Therefore, the optimal PID controller using LQR manner is more useful to find the designed parameters of PID controller. In this paper, we show that the performance of the optimal PID controller is better than that of the lead-lag controller.

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