• Title/Summary/Keyword: Disc Drive

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Static fatigue failure of the rotating optical disc (회전 중 원심력에 의한 광디스크의 피로 파손)

  • Hwang, Hyo-Kune;Kim, Nam-Woong;Dan, Byung-Ju;Kim, Jong-Man;Kim, Wae-Yeul;Lee, Jin-Woo
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.150-155
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    • 2004
  • The base material of optical disc is the amorphous polymer, polycarbonate. So crack growth on the rotating optical disc could happen by the static centrifugal force. This phenomenon is called static fatigue. Today's CD-R disc drive is being operated over 10,000 RPM. This is increasing the possibility of the disc fracture when operating. In this reason, new method to measure the static fatigue threshold quality and the way to calculate the threshold J-integral value and the safe crack length of the optical disc are studied. Finally the environmental effect to optical disc is also studied in this paper.

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Direct Seek Control for Swing-arm Type Dual Stage Actuators in Blu-Ray Disc Drive Systems

  • Ryu, Shi-Yang;Jung, Soo-Yul;Yoon, Hyeong-Deok;Park, In-Shik
    • Proceedings of the KIEE Conference
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    • 2003.11c
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    • pp.735-739
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    • 2003
  • This paper presents a direct seek control algorithm for swing-arm type dual stage servo system that consists of a coarse actuator and a fine actuator. The proposed scheme is to design a control system that attenuates the effect of dynamic coupling between the two actuators so that the seek operation can be performed in a single-shot with stability. In an optical drive system with dual stage servo mechanism, the effect of dynamic coupling between the two actuators needs to be handled during the coarse seek operation due to its inherent structure. In an extreme case, the two actuators can collide each other, which leads to critical degradation of the seek performance. To handle this problem, our proposed control scheme is to generate the drive signals such that the two actuators behave as if they are a single fixed body. To this end, a feedforward controller and two feedback controllers are designed that enable the current drive system perform wide range of track seek. Simulation results are provided to show the validity and feasibility of our proposed algorithm.

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2.3mm Height Actuator for Small Form factor Optical Drive (초소형드라이브를 위한 2.3mm 액추에어터)

  • Cheong, Young-Min;Lee, Jin-Won;Kim, Kwang;Kang, Jong-Tae
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2004.11a
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    • pp.61-64
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    • 2004
  • Recently, as the requirements of several mobile products come to the front, to cope with the market needs, various mobile storage applications have appeared. Therefore, the core components and technologies for mobile optical disc drives have been developed continuously. In case of the optical storage, the small sized optical pickup is necessary to realize the mobile optical disc drive, because the optical pickup height is determined by the optical parts and an actuator. In this paper, we propose the optical pickup actuator using the horizontally arranged magnetic circuit, and apply to 5mm height Small Form-factor Optical Drive.

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Study on SRM drive with simplified operating sensing device (동작센서를 단순화한 SRM drive에 관한 연구)

  • Oh, Seok-Gyu;Ahn, Jin-Woo;Hwang, Young-Moon
    • Proceedings of the KIEE Conference
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    • 1994.11a
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    • pp.98-100
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    • 1994
  • Shaft position sensing is essential in Switched Reluctance Motor(SRM) in order to synchronize the phase excitation pulses to the rotor position. In low cost application, particularly at low power level, the shaft position sensor is too costly. This paper describes low cost SRM drive system that can control torque and speed utilizing a optointerrupter with slotted disc. The validity of the proposed scheme is verified by experimental results for 6/4 SRM drive system.

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Experimental Analysis of Axial Vibration in Slim-type Optical Disc Drive (슬림형 광 디스크 드라이브의 축방향 진동에 대한 실험적 해석)

  • 박대경;전규찬;이성진;장동섭
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.05a
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    • pp.694-699
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    • 2002
  • As the demand for slim laptops requires ion'-height optical disc drives, vibration problems of optical disc drives are of great concern. Additionally, with the decrease of a track width and a depth of focus in high density drives, studies on vibration resonance between mechanical parts become more important. From the vibration point of view, the performance of optical disc drives is closely related with the relative displacement between a disc and an objective lens which is controlled by servo mechanism. In other words, to read and write data properly, the relative displacement between an optical disc and an objective lens should be within a certain limit. The relative displacement is dependent on not only an anti-vibration mechanism design but also servo control capability. Good servo controls can make compensation for poor mechanisms, and vice versa. In a usual development process, robustness of the anti-vibration mechanism is always verified with the servo control of an objective lens. Engineers partially modify servo gain margin in case of a data reading error. This modification cannot correct the data reading error occasionally and the mechanism should be redesigned more robustly. Therefore it is necessary to verify a mechanism with respect to the possible servo gain plot. In this study we propose the experimental verification method far anti-vibration mechanism with respect to the existing servo gain plot. This method verifies axial vibration characteristics of optical disc drives on the basis of transmissibility. Using this method, we verified our mechanism and modified the mechanism for better anti-vibration characteristics.

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Experimental Analysis of Axial Vibration in Slim-type Optical Disc Drive (슬림형 광 디스크 드라이브의 축방향 진동에 대한 실험적 해석)

  • 박대경;전규찬;이성진;장동섭
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.12 no.11
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    • pp.833-839
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    • 2002
  • As the demand for slim laptops requires low-height optical disc drives, vibration problems of optical disc drives are of great concern. Additionally, with the decrease of a track width and a depth of focus in high density drives, studies on vibration resonance between mechanical parts become more important. From the vibration point of view, the performance of optical disc drives is closely related with the relative displacement between a disc and an objective lens which is controlled by servo mechanism. In other words, to read and write data properly, the relative displacement between an optical disc and an objective lens should be within a certain limit. The relative displacement is dependent on not only an anti-vibration mechanism design but also servo control capability. Good servo controls can make compensation for poor mechanisms, and vice versa. In a usual development process, robustness of the anti-vibration mechanism is always verified with the servo control of an objective lens. Engineers partially modify servo gain margin in case of a data reading error. This modification cannot correct the data reading error occasionally and the mechanism should be redesigned more robustly. Therefore it is necessary to verify a mechanism with respect to the possible servo gain plot. In this study we propose the experimental verification method for anti-vibration mechanism with respect to the existing servo gain plot. Thismethod verifies axial vibration characteristics of optical disc drives on the basis of transmissibility. Using this method, we verified our mechanism and modified the mechanism for better anti-vibration characteristics.

Robust and Non-fragile $H^{\infty}$ Controller Design for Tracking Servo of Blu-ray disc Drive System (Blu-ray 디스크 드라이브 시스템 트래킹 서보시스템에 대한 견실비약성 $H^{\infty}$ 상태궤환 제어기 설계)

  • Lee, Hyung-Ho;Kim, Joon-Ki;Kim, Woon-Ki;Jo, Sang-Woo;Park, Hong-Bae
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.45 no.3
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    • pp.32-41
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    • 2008
  • In this paper, we describe the synthesis of robust and non-fragile $H^{\infty}$ state feedback controllers for linear systems with affine parameter uncertain tracking servo system of blu-ray disc drive, as well as static state feedback controller with polytopic uncertainty Similarity any other control system, the objective of the track-following system design for optical disc drives is to construct the system with better performance and robustness against modeling uncertainties and various disturbances. Also, the obtained condition can be rewritten as parameterized linear matrix inequalities(PLMIs), that is, LMIs whose coefficients are functions of a parameter confined to a compact set. We show that the resulting controller guarantees the asymptotic stability and disturbance attenuation of the closed loop system in spite of controller gain variations within a resulted polytopic region.

Slim Tilt Actuator for High density Recording in the Optical Disc (기록용 고밀도 광디스크를 위한 박형 틸트 구동기)

  • Jeong, Ho-Seop;Lee, Ho-Cheol;Yoon, Yong-Han
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.11b
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    • pp.788-793
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    • 2002
  • Hybrid type slim tilt actuator and 6-wire supported are developed for DVD recording in the optical disc drive of notebook PC, which can compensate the inclination of disc and objective lens. The hybrid actuator uses the actuating method of moving coil in the focus and track direction and that of moving magnet in the tilt direction. Comparing with 6-wire supported actuator and hybrid type actuator, we can choose an actuator for slim super combo pickup. Two actuator are designed through the modal analysis and magnetic field analysis and experimental results shows dynamic characteristics. Finally, it is verified that the actuator can compensate the disc tilt of ${\pm}0.4^{\circ}$.

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A Study on Clutch-disc Characteristics for the Torsional Vibration Reduction of the Drive-Line at Creeping (최저속주행시 동력전달계의 비틀림진동 저감을 위한 클러치특성 연구)

  • Chung, T.J.;Hong, D.P.;Kim, S.S.;Kim, S.S.
    • Transactions of the Korean Society of Automotive Engineers
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    • v.3 no.2
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    • pp.102-111
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    • 1995
  • The non-periodic fluctuation of the engine torque appears to be the major source of the torsional vibration of the automotive driveline. The reduction of this torsional vibration has become a significant problem along with the requirements of higher performance. The torsional vibration of the automotive driveline can be reduced by smoothing the fluctuation by adjusting the torsional characteristics of the clutch-disc. Computer simulation of the driveline is a useful investigative tool on studying the torsional characteristics of the clutch-disc. In this paper, a dynamic model for the automotive driveline was developed, and the engine torque of the model were evaluated with experimental data. By executing a simulation using the model, it has become possible to obtain the clutch-disc torsional characteristics for reducting the torsional vibration at creeping.

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