Patents by Inventor Keiji Nakatsu

Keiji Nakatsu has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 8285430
    Abstract: Provided is a controlling device for a railway electric car, the controlling device being able to detect a slipping/sliding phenomenon during, in particular, high-speed travel and to exercise slipping/sliding control in an appropriate manner. A slip controlling unit 1 includes a first adhesion level index generating unit and a second adhesion level index generating unit. In a normal slipping state in which an acceleration changes instantaneously, torque control is exercised by using a first adhesion level index generated by the first adhesion level index generating unit based on an acceleration deviation and a speed deviation. In a slipping state during high-speed travel, because the acceleration deviation and the speed deviation are small, torque control is exercised by using a second adhesion level index generated by multiplying the first adhesion level index by a gain equal to or smaller than 1 generated by the second adhesion level index generating unit.
    Type: Grant
    Filed: June 27, 2007
    Date of Patent: October 9, 2012
    Assignee: Mitsubishi Electric Corporation
    Inventors: Masataka Yabuuchi, Hidetoshi Kitanaka, Keiji Nakatsu
  • Patent number: 8280568
    Abstract: A first threshold is determined, with reference to an absolute acceleration that is determined in accordance with a vehicle usage condition, to detect an acceleration change generated in acceleration of a self-axle speed that is a maximum speed (a minimum speed in a decelerating operation) of revolving speeds of plural motors that drive plural driving wheel axles. When the acceleration exceeds the first threshold, a system for generating a target torque command value reduced in accordance with the acceleration deviation is separated by setting an output of a comparator circuit to level “0”, and a first-order delay circuit outputs the target torque command value subjected to a reduction process during a processing period designated by an output of a delay time generating circuit.
    Type: Grant
    Filed: September 18, 2007
    Date of Patent: October 2, 2012
    Assignee: Mitsubishi Electric Corporation
    Inventors: Keiji Nakatsu, Masataka Yabuuchi
  • Publication number: 20100305787
    Abstract: A first threshold is determined, with reference to an absolute acceleration that is determined in accordance with a vehicle usage condition, to detect an acceleration change generated in acceleration of a self-axle speed that is a maximum speed (a minimum speed in a decelerating operation) of revolving speeds of plural motors that drive plural driving wheel axles. When the acceleration exceeds the first threshold, a system for generating a target torque command value reduced in accordance with the acceleration deviation is separated by setting an output of a comparator circuit to level “0”, and a first-order delay circuit outputs the target torque command value subjected to a reduction process during a processing period designated by an output of a delay time generating circuit.
    Type: Application
    Filed: September 18, 2007
    Publication date: December 2, 2010
    Inventors: Keiji Nakatsu, Masataka Yabuuchi
  • Publication number: 20100179713
    Abstract: Provided is a controlling device for a railway electric car, the controlling device being able to detect a slipping/sliding phenomenon during, in particular, high-speed travel and to exercise slipping/sliding control in an appropriate manner. A slip controlling unit 1 includes a first adhesion level index generating unit and a second adhesion level index generating unit. In a normal slipping state in which an acceleration changes instantaneously, torque control is exercised by using a first adhesion level index generated by the first adhesion level index generating unit based on an acceleration deviation and a speed deviation. In a slipping state during high-speed travel, because the acceleration deviation and the speed deviation are small, torque control is exercised by using a second adhesion level index generated by multiplying the first adhesion level index by a gain equal to or smaller than 1 generated by the second adhesion level index generating unit.
    Type: Application
    Filed: June 27, 2007
    Publication date: July 15, 2010
    Applicant: Mitsubishi Electric Corporation
    Inventors: Masataka Yabuuchi, Hidetoshi Kitanaka, Keiji Nakatsu
  • Patent number: 5264911
    Abstract: A laser power measuring jig is adapted for use in measuring a laser power of a laser beam which is emitted from an optical head of an optical disk unit which records and/or reproduces information on and/or from a medium. The laser power measuring jig supplies power information related to the laser power of the laser beam to a power meter which measures the laser power. The laser power measuring jig includes a main jig body which has a size and a shape which are approximately the same as those of the medium, and this main jig body is loaded into the optical disk unit. The laser power measuring jig also includes a mechanism for outputting the power information outside the optical disk unit and supplying the laser power information to the power meter when the main jig body is loaded into the optical disk unit.
    Type: Grant
    Filed: December 19, 1991
    Date of Patent: November 23, 1993
    Assignees: Mitsubishi Electric Corporation, Teac Corp.
    Inventors: Kazuhiko Nakane, Masayoshi Shimamoto, Yoshihiro Kiyose, Keiji Nakatsu, Isao Watanabe, Masami Horita, Kenichi Sato, Kenji Shimozawa, Hiroshi Konuma, Masaharu Yoshimura
  • Patent number: 4955009
    Abstract: In an optical disk drive apparatus for driving an optical disk having tracks for recording information, an optical head focuses a light beam onto a spot on a track on the optical disk, and an actuator moves the optical head, thereby causing the spot of the light beam to move from its current track to a target track in order to access the target track. A track counter counts the tracks moved by the spot of the light beam. The counting of tracks is disabled for an interval at the start of each track access operation to prevent miscounting caused by jitter that occurs when initiating a track access operation.
    Type: Grant
    Filed: April 22, 1988
    Date of Patent: September 4, 1990
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Keiji Nakatsu, Masaharu Ogawa
  • Patent number: 4901299
    Abstract: An optical disk reading apparatus having a carriage on which a tracking actuator and a photosensor unit are mounted and driven by a head actuator for moving a spot of a light beam in a direction traversing tracks on an optical disk and for detecting first position and second position signals indicative of the position of the spot on the tracks through addition and subtraction of the electric signals corresponding to changes in the quantities of light reflected from the tracks upon the movement of the spot and including circuitry for accurately placing the spot on a desired track of the disk even when the first and second position signals contained omissions.
    Type: Grant
    Filed: December 29, 1987
    Date of Patent: February 13, 1990
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Keiji Nakatsu
  • Patent number: 4887254
    Abstract: A retract device includes a signal instruction circuit for providing the number of tracks to be traversed, the access start instruction, and the retract instruction and the reference voltage generating circuit responsive to these instructions to provide the residual track number and the carriage moving signal and operates such that, immediately before the drive device is to stop operating a carriage having an optical head mounted thereon is moved by an access operation from a track to a first predetermined position according to the access start instruction, and is then moved from the first predetermined position to a second predetermined position according to the retract instruction at a predetermined reference speed.
    Type: Grant
    Filed: March 24, 1988
    Date of Patent: December 12, 1989
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Keiji Nakatsu, Katsuaki Kamitsu, Masaharu Ogawa
  • Patent number: 4835752
    Abstract: A device for driving and controlling an optical head by forming a spot of a light beam on an optical disk having a plurality of tracks and detecting light from the spot reflected on the optical disk by a pair of optical detectors disposed in the head.
    Type: Grant
    Filed: December 14, 1987
    Date of Patent: May 30, 1989
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Keiji Nakatsu, Shigeo Hayashi, Masaharu Ogawa, Osamu Itou, Isao Watanabe, Kunimaro Tanaka
  • Patent number: 4788421
    Abstract: A control apparatus comprises a linear actuator (49) which moves an optical head (37) having a photo detector (45) in a radial direction of an optical disk (33), a velocity detection circuit (57) which detects relative moving velocity of the optical head (37) to the optical disk (33) during track accessing, and a linear actuator drive control circuit (50) which controls the actuator (49) in response to the detected velocity. The velocity detection circuit (57) generates a digital signal which corresponds to a cycle of an RF output signal of the photo detector (45) and, in response to this digital signal, it further generates an analog signal, which corresponds to the inverse of the cycle of the RF signal, to be outputted as the relative moving velocity of the optical head (37).
    Type: Grant
    Filed: May 14, 1986
    Date of Patent: November 29, 1988
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Masaharu Ogawa, Keiji Nakatsu