The Experts below are selected from a list of 51915 Experts worldwide ranked by ideXlab platform

Haruki Tokumaru - One of the best experts on this subject based on the ideXlab platform.

  • high speed flexible Optical Disk for broadcast archival storage
    Japanese Journal of Applied Physics, 2010
    Co-Authors: Daiichi Koide, Takeshi Kajiyama, Haruki Tokumaru, Yoshimichi Takano, Nobuaki Onagi, Yasutomo Aman, Kiyoshi Ohishi
    Abstract:

    We developed a prototype of a flexible Optical Disk (FOD) drive with a mechanical stabilizer. We prepared the FOD that had a high recording sensitivity of a recording layer and had low byte error rates below 2 ×10-4 at speeds from 36 to 252 Mbps, and examined the recording of video data on the FOD and the drive. We could record and play a high-definition television (HDTV) video (MPEG-2, 422P@HL) seamlessly at 144 Mbps over the entire area of the FOD and the FOD drive with broadcast video systems. We confirmed that the FOD and the FOD drive can record and play HDTV signals for professional broadcast use.

  • error prediction robust tracking control system suppressing harmonics disturbance for Optical Disk recording system
    Japanese Journal of Applied Physics, 2010
    Co-Authors: Yoshiya Kamigaki, Daiichi Koide, Haruki Tokumaru, Kiyoshi Ohishi, Toshimasa Miyazaki, Yoshimichi Takano
    Abstract:

    Recently, the memory capacity of media for the Optical Disk recording system has been increasing. The Disk rotation speed has been increasing depending on the large memory capacity. However, the Optical Disk recording system has both periodic primary disturbance and periodic harmonics disturbance. Hence, the tracking control of the Optical Disk recording system is requested to maintain a high-precision tracking performance. We have proposed the robust tracking controller and zero-phase error tracking feed-forward control systems. Results of our study show that the primary disturbance is well suppressed by our conventional method, but it is difficult for our conventional method to suppress the harmonics disturbance. To overcome this problem, in this paper, we propose a new error prediction robust tracking control system suppressing harmonic disturbance. The experimental results show that the proposed tracking control system has a precise tracking response against both periodic primary disturbance and periodic harmonics disturbance.

  • achievement method of high speed response of error prediction tracking control for Optical Disk system
    Electrical Engineering in Japan, 2010
    Co-Authors: Toru Hayano, Daiichi Koide, Kiyoshi Ohishi, Toshimasa Miyazaki, Isao Shibutani, Haruki Tokumaru
    Abstract:

    This paper proposes the new design method of error-prediction control systems combining the ZPET control and the robust feedback control. The error-prediction control system based on ZPET control can reduce the tracking error caused by periodic disturbances more efficiently than the conventional repetitive control technique. However, the proposed tracking servo system does not reduce the residual tracking error caused by the low-pass filter of the feedforward compensation and by the long sampling time. In order to overcome this problem, this paper proposes the new structure of the feedforward tracking control system. The modified ZPET control tracking servo system for Optical Disk recording system does not include the low-pass filter and its sampling time becomes faster. On the other hand, the sudden disturbance observer reduces the influence of nonperiodic disturbances. The experimental results point out that the proposed tracking servo system has a precise tracking response against both the periodic disturbances and the nonperiodic disturbances. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 170(4): 51–59, 2010; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/eej.20800

  • improvement of aerodynamic stability in flexible Optical Disk system with cylindrically concaved stabilizer
    Japanese Journal of Applied Physics, 2009
    Co-Authors: Yasunori Sugimoto, Shozo Murata, Daiichi Koide, Yoshimichi Takano, Nobuaki Onagi, Yasutomo Aman, Haruki Tokumaru
    Abstract:

    To improve the aerodynamic stability in a flexible Optical Disk system with a cylindrically concaved stabilizer, the effects of the curvature of the stabilizer, Disk thickness, and Disk materials on aerodynamic stability were investigated. We clarified that these factors affect the effective working area of the stabilizer. This result shows that the effective working area of the stabilizer could be expanded by adjusting the curvature of the stabilizer, Disk thickness, and Disk material. We also demonstrated recording and reproduction at 4× speed for Blu-ray disc density using flexible Optical Disks with various thicknesses.

  • high speed recording up to 15 000 rpm using thin Optical Disks
    Japanese Journal of Applied Physics, 2008
    Co-Authors: Daiichi Koide, Shozo Murata, Haruki Tokumaru, Yoshimichi Takano, Nobuaki Onagi, Yasutomo Aman, Yasunori Sugimoto, Kiyoshi Ohishi
    Abstract:

    We propose a high-speed Optical Disk system using thin flexible Optical Disks (HS-FOD) recording up to 15,000 rpm. The thin Optical Disk system is composed of three technical elements: media employing a thin and flexible substrate 0.1 mm thick, a mechanical stabilizer, and a high-speed tracking servo employing a feed-forward control with zero phase error tracking (ZPET-FF control). The HS-FOD system has an Optical head with numerical aperture (NA) of 0.85 and is compatible with the Optical system of a Blu-ray disc or a broadcast-use Optical Disk. We have successfully performed Disk rotation stably and have performed precisely a focus servo and a tracking servo at 15,000 rpm. We also achieved writing and reading data at 15,000 rpm and recording 252 Mbps of random pattern data and could get small values of jitter below the tolerance. These results are enough to record professional high-definition television (HDTV) video signals in formats such as HD-D5 for broadcast-use.

Kiyoshi Ohishi - One of the best experts on this subject based on the ideXlab platform.

  • single rate two dimensional feedforward control system for Optical Disk systems in consideration of the phase delay
    Japanese Journal of Applied Physics, 2015
    Co-Authors: Takahiro Ohashi, Kiyoshi Ohishi, Keisuke Yoshida, Toshimasa Miyazaki
    Abstract:

    The size of digital content has been on the increasing in recent times, and this has been led to the need for correspondingly scaling up the capacity of digital storage media. Therefore, a high-precision focusing and tracking control system are required for an Optical Disk. A pickup system for Optical Disks operates in the horizontal and vertical directions for tracking and focusing, respectively. Thus, this paper proposes a new single-rate two-dimensional feedforward control system, which is the concurrent control of focusing and tracking. The feedforward controller is based on a zero phase error tracking (ZPET) control. Experimental results show the effectiveness of the proposed control system.

  • robust double feedforward tracking control system using error based disturbance observer for Optical Disk systems
    International Workshop on Advanced Motion Control, 2014
    Co-Authors: Naohide Sakimura, Kiyoshi Ohishi, Takahiro Ohashi, Toshimasa Miyazaki
    Abstract:

    Recently, the size of digital content has continued to increase. In order to cope, manufacturers of digital storage media have tried to increase capacity by narrowing the track pitch of these digital storage media. In addition, recent advancements in technology have resulted in a new Optical Disk has a rotation speed of over 15,000 rpm. Considering all these factors, we believe that a high-precision tracking control system is needed for Optical Disks. Consequently, this paper proposes a new robust double feedforward control (RDFFC) system for high-precision control. The proposed system is constructed by using two error prediction-based zero phase error tracking (ZPET) control systems, and includes an error-based disturbance observer (EDOB) that uses notch filter to suppress non-periodic disturbances. The proposed control system is designed for DDU-1000 for DVD. The experimental results confirm that our proposed system is practicable and effective.

  • high speed flexible Optical Disk for broadcast archival storage
    Japanese Journal of Applied Physics, 2010
    Co-Authors: Daiichi Koide, Takeshi Kajiyama, Haruki Tokumaru, Yoshimichi Takano, Nobuaki Onagi, Yasutomo Aman, Kiyoshi Ohishi
    Abstract:

    We developed a prototype of a flexible Optical Disk (FOD) drive with a mechanical stabilizer. We prepared the FOD that had a high recording sensitivity of a recording layer and had low byte error rates below 2 ×10-4 at speeds from 36 to 252 Mbps, and examined the recording of video data on the FOD and the drive. We could record and play a high-definition television (HDTV) video (MPEG-2, 422P@HL) seamlessly at 144 Mbps over the entire area of the FOD and the FOD drive with broadcast video systems. We confirmed that the FOD and the FOD drive can record and play HDTV signals for professional broadcast use.

  • error prediction robust tracking control system suppressing harmonics disturbance for Optical Disk recording system
    Japanese Journal of Applied Physics, 2010
    Co-Authors: Yoshiya Kamigaki, Daiichi Koide, Haruki Tokumaru, Kiyoshi Ohishi, Toshimasa Miyazaki, Yoshimichi Takano
    Abstract:

    Recently, the memory capacity of media for the Optical Disk recording system has been increasing. The Disk rotation speed has been increasing depending on the large memory capacity. However, the Optical Disk recording system has both periodic primary disturbance and periodic harmonics disturbance. Hence, the tracking control of the Optical Disk recording system is requested to maintain a high-precision tracking performance. We have proposed the robust tracking controller and zero-phase error tracking feed-forward control systems. Results of our study show that the primary disturbance is well suppressed by our conventional method, but it is difficult for our conventional method to suppress the harmonics disturbance. To overcome this problem, in this paper, we propose a new error prediction robust tracking control system suppressing harmonic disturbance. The experimental results show that the proposed tracking control system has a precise tracking response against both periodic primary disturbance and periodic harmonics disturbance.

  • achievement method of high speed response of error prediction tracking control for Optical Disk system
    Electrical Engineering in Japan, 2010
    Co-Authors: Toru Hayano, Daiichi Koide, Kiyoshi Ohishi, Toshimasa Miyazaki, Isao Shibutani, Haruki Tokumaru
    Abstract:

    This paper proposes the new design method of error-prediction control systems combining the ZPET control and the robust feedback control. The error-prediction control system based on ZPET control can reduce the tracking error caused by periodic disturbances more efficiently than the conventional repetitive control technique. However, the proposed tracking servo system does not reduce the residual tracking error caused by the low-pass filter of the feedforward compensation and by the long sampling time. In order to overcome this problem, this paper proposes the new structure of the feedforward tracking control system. The modified ZPET control tracking servo system for Optical Disk recording system does not include the low-pass filter and its sampling time becomes faster. On the other hand, the sudden disturbance observer reduces the influence of nonperiodic disturbances. The experimental results point out that the proposed tracking servo system has a precise tracking response against both the periodic disturbances and the nonperiodic disturbances. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 170(4): 51–59, 2010; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/eej.20800

Toshimasa Miyazaki - One of the best experts on this subject based on the ideXlab platform.

  • single rate two dimensional feedforward control system for Optical Disk systems in consideration of the phase delay
    Japanese Journal of Applied Physics, 2015
    Co-Authors: Takahiro Ohashi, Kiyoshi Ohishi, Keisuke Yoshida, Toshimasa Miyazaki
    Abstract:

    The size of digital content has been on the increasing in recent times, and this has been led to the need for correspondingly scaling up the capacity of digital storage media. Therefore, a high-precision focusing and tracking control system are required for an Optical Disk. A pickup system for Optical Disks operates in the horizontal and vertical directions for tracking and focusing, respectively. Thus, this paper proposes a new single-rate two-dimensional feedforward control system, which is the concurrent control of focusing and tracking. The feedforward controller is based on a zero phase error tracking (ZPET) control. Experimental results show the effectiveness of the proposed control system.

  • robust double feedforward tracking control system using error based disturbance observer for Optical Disk systems
    International Workshop on Advanced Motion Control, 2014
    Co-Authors: Naohide Sakimura, Kiyoshi Ohishi, Takahiro Ohashi, Toshimasa Miyazaki
    Abstract:

    Recently, the size of digital content has continued to increase. In order to cope, manufacturers of digital storage media have tried to increase capacity by narrowing the track pitch of these digital storage media. In addition, recent advancements in technology have resulted in a new Optical Disk has a rotation speed of over 15,000 rpm. Considering all these factors, we believe that a high-precision tracking control system is needed for Optical Disks. Consequently, this paper proposes a new robust double feedforward control (RDFFC) system for high-precision control. The proposed system is constructed by using two error prediction-based zero phase error tracking (ZPET) control systems, and includes an error-based disturbance observer (EDOB) that uses notch filter to suppress non-periodic disturbances. The proposed control system is designed for DDU-1000 for DVD. The experimental results confirm that our proposed system is practicable and effective.

  • error prediction robust tracking control system suppressing harmonics disturbance for Optical Disk recording system
    Japanese Journal of Applied Physics, 2010
    Co-Authors: Yoshiya Kamigaki, Daiichi Koide, Haruki Tokumaru, Kiyoshi Ohishi, Toshimasa Miyazaki, Yoshimichi Takano
    Abstract:

    Recently, the memory capacity of media for the Optical Disk recording system has been increasing. The Disk rotation speed has been increasing depending on the large memory capacity. However, the Optical Disk recording system has both periodic primary disturbance and periodic harmonics disturbance. Hence, the tracking control of the Optical Disk recording system is requested to maintain a high-precision tracking performance. We have proposed the robust tracking controller and zero-phase error tracking feed-forward control systems. Results of our study show that the primary disturbance is well suppressed by our conventional method, but it is difficult for our conventional method to suppress the harmonics disturbance. To overcome this problem, in this paper, we propose a new error prediction robust tracking control system suppressing harmonic disturbance. The experimental results show that the proposed tracking control system has a precise tracking response against both periodic primary disturbance and periodic harmonics disturbance.

  • achievement method of high speed response of error prediction tracking control for Optical Disk system
    Electrical Engineering in Japan, 2010
    Co-Authors: Toru Hayano, Daiichi Koide, Kiyoshi Ohishi, Toshimasa Miyazaki, Isao Shibutani, Haruki Tokumaru
    Abstract:

    This paper proposes the new design method of error-prediction control systems combining the ZPET control and the robust feedback control. The error-prediction control system based on ZPET control can reduce the tracking error caused by periodic disturbances more efficiently than the conventional repetitive control technique. However, the proposed tracking servo system does not reduce the residual tracking error caused by the low-pass filter of the feedforward compensation and by the long sampling time. In order to overcome this problem, this paper proposes the new structure of the feedforward tracking control system. The modified ZPET control tracking servo system for Optical Disk recording system does not include the low-pass filter and its sampling time becomes faster. On the other hand, the sudden disturbance observer reduces the influence of nonperiodic disturbances. The experimental results point out that the proposed tracking servo system has a precise tracking response against both the periodic disturbances and the nonperiodic disturbances. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 170(4): 51–59, 2010; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/eej.20800

  • high speed tracking servo using zero phase error tracking feed forward method for professional use Optical Disks over 10000 rpm
    Japanese Journal of Applied Physics, 2007
    Co-Authors: Daiichi Koide, Haruki Tokumaru, Kiyoshi Ohishi, Toru Hayano, Isao Shibutani, Toshimasa Miyazaki
    Abstract:

    We have realized a high-speed and precise tracking servo using a feed-forward control with the zero phase error tracking method (ZPET-FF control) on an Optical Disk at the Disk rotation speed of 10800 rpm. To realize a high-data-transfer-rate recording of more than 200 Mbps over the entire Disk area, the Optical head must be controlled with an accuracy of better than 9 nm at the maximum rotation speed of about 10800 rpm for track following on a high-density Optical Disk. We performed high-speed tracking, and the experimental results show that the ZPET-FF control is more precise than feedback control. The residual tracking error is suppressed to 6.3 nm at a Disk rotation speed of 10800 rpm on Optical Disk drives having an object lens with a numerical aperture (NA) of 0.85 and media with a track pitch of 0.32 µm, such as the Blu-ray disc and broadcast-use Optical Disk.

Daiichi Koide - One of the best experts on this subject based on the ideXlab platform.

  • high speed flexible Optical Disk for broadcast archival storage
    Japanese Journal of Applied Physics, 2010
    Co-Authors: Daiichi Koide, Takeshi Kajiyama, Haruki Tokumaru, Yoshimichi Takano, Nobuaki Onagi, Yasutomo Aman, Kiyoshi Ohishi
    Abstract:

    We developed a prototype of a flexible Optical Disk (FOD) drive with a mechanical stabilizer. We prepared the FOD that had a high recording sensitivity of a recording layer and had low byte error rates below 2 ×10-4 at speeds from 36 to 252 Mbps, and examined the recording of video data on the FOD and the drive. We could record and play a high-definition television (HDTV) video (MPEG-2, 422P@HL) seamlessly at 144 Mbps over the entire area of the FOD and the FOD drive with broadcast video systems. We confirmed that the FOD and the FOD drive can record and play HDTV signals for professional broadcast use.

  • error prediction robust tracking control system suppressing harmonics disturbance for Optical Disk recording system
    Japanese Journal of Applied Physics, 2010
    Co-Authors: Yoshiya Kamigaki, Daiichi Koide, Haruki Tokumaru, Kiyoshi Ohishi, Toshimasa Miyazaki, Yoshimichi Takano
    Abstract:

    Recently, the memory capacity of media for the Optical Disk recording system has been increasing. The Disk rotation speed has been increasing depending on the large memory capacity. However, the Optical Disk recording system has both periodic primary disturbance and periodic harmonics disturbance. Hence, the tracking control of the Optical Disk recording system is requested to maintain a high-precision tracking performance. We have proposed the robust tracking controller and zero-phase error tracking feed-forward control systems. Results of our study show that the primary disturbance is well suppressed by our conventional method, but it is difficult for our conventional method to suppress the harmonics disturbance. To overcome this problem, in this paper, we propose a new error prediction robust tracking control system suppressing harmonic disturbance. The experimental results show that the proposed tracking control system has a precise tracking response against both periodic primary disturbance and periodic harmonics disturbance.

  • achievement method of high speed response of error prediction tracking control for Optical Disk system
    Electrical Engineering in Japan, 2010
    Co-Authors: Toru Hayano, Daiichi Koide, Kiyoshi Ohishi, Toshimasa Miyazaki, Isao Shibutani, Haruki Tokumaru
    Abstract:

    This paper proposes the new design method of error-prediction control systems combining the ZPET control and the robust feedback control. The error-prediction control system based on ZPET control can reduce the tracking error caused by periodic disturbances more efficiently than the conventional repetitive control technique. However, the proposed tracking servo system does not reduce the residual tracking error caused by the low-pass filter of the feedforward compensation and by the long sampling time. In order to overcome this problem, this paper proposes the new structure of the feedforward tracking control system. The modified ZPET control tracking servo system for Optical Disk recording system does not include the low-pass filter and its sampling time becomes faster. On the other hand, the sudden disturbance observer reduces the influence of nonperiodic disturbances. The experimental results point out that the proposed tracking servo system has a precise tracking response against both the periodic disturbances and the nonperiodic disturbances. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 170(4): 51–59, 2010; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/eej.20800

  • improvement of aerodynamic stability in flexible Optical Disk system with cylindrically concaved stabilizer
    Japanese Journal of Applied Physics, 2009
    Co-Authors: Yasunori Sugimoto, Shozo Murata, Daiichi Koide, Yoshimichi Takano, Nobuaki Onagi, Yasutomo Aman, Haruki Tokumaru
    Abstract:

    To improve the aerodynamic stability in a flexible Optical Disk system with a cylindrically concaved stabilizer, the effects of the curvature of the stabilizer, Disk thickness, and Disk materials on aerodynamic stability were investigated. We clarified that these factors affect the effective working area of the stabilizer. This result shows that the effective working area of the stabilizer could be expanded by adjusting the curvature of the stabilizer, Disk thickness, and Disk material. We also demonstrated recording and reproduction at 4× speed for Blu-ray disc density using flexible Optical Disks with various thicknesses.

  • high speed recording up to 15 000 rpm using thin Optical Disks
    Japanese Journal of Applied Physics, 2008
    Co-Authors: Daiichi Koide, Shozo Murata, Haruki Tokumaru, Yoshimichi Takano, Nobuaki Onagi, Yasutomo Aman, Yasunori Sugimoto, Kiyoshi Ohishi
    Abstract:

    We propose a high-speed Optical Disk system using thin flexible Optical Disks (HS-FOD) recording up to 15,000 rpm. The thin Optical Disk system is composed of three technical elements: media employing a thin and flexible substrate 0.1 mm thick, a mechanical stabilizer, and a high-speed tracking servo employing a feed-forward control with zero phase error tracking (ZPET-FF control). The HS-FOD system has an Optical head with numerical aperture (NA) of 0.85 and is compatible with the Optical system of a Blu-ray disc or a broadcast-use Optical Disk. We have successfully performed Disk rotation stably and have performed precisely a focus servo and a tracking servo at 15,000 rpm. We also achieved writing and reading data at 15,000 rpm and recording 252 Mbps of random pattern data and could get small values of jitter below the tolerance. These results are enough to record professional high-definition television (HDTV) video signals in formats such as HD-D5 for broadcast-use.

S S Lee - One of the best experts on this subject based on the ideXlab platform.

  • novel monolithic free space Optical Disk pickup head realized by surface micromachining
    Conference on Lasers and Electro-Optics, 1996
    Co-Authors: Lih Y Lin, J I Shen, S S Lee
    Abstract:

    Summary form only given. A novel monolithic Optical Disk pickup head with four integrated free-space micro-Optical elements has been realized by the surface-micromachined free-space micro-Optical bench technology. A symmetric focused beam with FWHM width of 1.8 /spl mu/m is successfully observed. Because the pickup head is very compact (2 mm x 3.5 mm), it is possible to integrate multiple pickup heads on the same chip for parallel data access, or pickup head arrays with different focal length for multilayer Optical data storage systems.

  • realization of novel monolithic free space Optical Disk pickup heads by surface micromachining
    Optics Letters, 1996
    Co-Authors: Lih Y Lin, J L Shen, S S Lee
    Abstract:

    A novel monolithic free-space Optical Disk pickup head has been fabricated by micromachined micro-Optical bench technology. The pickup head contains a self-aligned semiconductor edge-emitting laser, a collimating lens, a beam splitter, two focusing lenses, and two 45° mirrors. All Optical components are built monolithically on Si substrates. The 45° mirror directs the Optical output beam in the surface-normal direction. This novel design could significantly reduce the size and the weight of the Optical pickup head as well as the cost of the assembly processes. The weight reduction could also greatly increase the data access rate.

  • a micromachined free space integrated Optical Disk pickup head
    Lasers and Electro-Optics Society Meeting, 1995
    Co-Authors: J L Shen, Lih Y Lin, S S Lee
    Abstract:

    Summary form only given. In summary, a novel free-space integrated micro-Optical Disk pickup head has been realized using surface-micromachining techniques. A focal spot with the FWHM equal to 2.6 /spl mu/m/spl times/6.7 /spl mu/m is obtained. This new integrated Optical Disk pickup head can significantly reduce its size and weight as well as improve the transfer rate of Optical data storage systems. The freespace micro-Optical bench technology can be extended to many other micro-optics systems.