Patents by Inventor Tadashi Okita

Tadashi Okita 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).

  • Publication number: 20150309500
    Abstract: A motor controller is configured to judge whether or not the amount of displacement of a driven body after the direction of movement of the driven body is reversed, exceeds a predetermined threshold value, and whether or not the amount of displacement of a motor after the direction of movement of the motor is reversed, exceeds another predetermined threshold value. When the amount of displacement of the driven body exceeds the threshold value, or the amount of displacement of the motor exceeds a second threshold value, the correction of the commands to the motor is terminated.
    Type: Application
    Filed: April 22, 2015
    Publication date: October 29, 2015
    Inventors: Shoutarou HASHIMOTO, Tadashi OKITA
  • Patent number: 9136781
    Abstract: In the first synchronous system of the synchronous control unit (1), movement commands of the first motor (23) and the second motor (13) made by the movement command making section (9), which are synchronized with each other, are respectively supplied to the first amplifier (22) and the second amplifier (12) through the first communication path (11) and the second communication path (21). In the second synchronous system switched from the first synchronous system, the first motor (23) is decelerated by a deceleration command made by the deceleration making section (29) and the second motor (13) is decelerated synchronously with the first motor by a movement command made by the position feedback value controlled by the first motor (23) supplied to the second amplifier (12) through the third communication path (31).
    Type: Grant
    Filed: March 28, 2014
    Date of Patent: September 15, 2015
    Assignee: FANUC CORPORATION
    Inventor: Tadashi Okita
  • Patent number: 9092027
    Abstract: A control apparatus includes a converter for converting an AC voltage to a DC voltage, a feed shaft motor inverter for converting the DC voltage to an AC voltage for a feed shaft motor, a main spindle motor inverter for converting the DC voltage to an AC voltage for a main spindle motor, a power outage detection unit for detecting a power outage of the AC power supply, a voltage detection unit for detecting the DC voltage, and a control unit which, upon power outage of the AC power supply side, outputs a feed shaft motor deceleration command to the feed shaft motor inverter and outputs, to the main spindle motor inverter, a main spindle motor acceleration command when a DC voltage is greater than an upper limit and a main spindle motor deceleration command when the DC voltage is less than a lower limit.
    Type: Grant
    Filed: November 6, 2013
    Date of Patent: July 28, 2015
    Assignee: FANUC CORPORATION
    Inventors: Tadashi Okita, Daisuke Tajima
  • Publication number: 20150194921
    Abstract: A motor control device that controls an exciting current and a torque current separately from each other, and drives an induction machine includes: a first exciting current command generating unit that generates a first exciting current command in accordance with a speed and torque command; a second exciting current command generating unit that includes a magnetic flux control unit generating a second exciting current command by using a difference between a first exciting current command and a magnetic flux estimation value, and a magnetic flux estimating unit generating a magnetic flux estimation value from the second exciting current command, the second exciting current command generating unit outputting a second exciting current command; and a switching unit that selects one of a first exciting current command and a second exciting current command in accordance with a control mode or external information.
    Type: Application
    Filed: January 6, 2015
    Publication date: July 9, 2015
    Inventors: Shoutarou Hashimoto, Tadashi Okita
  • Publication number: 20150145460
    Abstract: A motor controller includes: a motor rotation angle acquisition unit acquiring the rotation angle of the motor; a main shaft rotation angle acquisition unit acquiring the rotation angle of the main shaft; a one-rotation signal acquisition unit acquiring a one-rotation signal output every time the main shaft rotates once; a motor rotation speed calculation unit calculating the rotation speed of the motor from the rotation angle of the motor; a main shaft speed calculation unit calculating the rotation speed of the main shaft from the rotation angle of the main shaft; and an abnormality determination unit in which, when a change amount of the rotation angle of the motor or when the difference between the rotation speed of the motor and the rotation speed of the main shaft deviates from a second range, it is determined that an abnormality has occurred in the power transmission unit.
    Type: Application
    Filed: November 21, 2014
    Publication date: May 28, 2015
    Applicant: FANUC CORPORATION
    Inventors: Daisuke Tajima, Tadashi Okita
  • Publication number: 20150102756
    Abstract: A controller and a method for a machine tool, capable of discriminating the factors in overheating, and taking appropriate measures depending on each factor. A first amplifier of the controller has an acceleration/deceleration judging part which judges as to whether the spindle motor is accelerated or decelerated; a first temperature estimating part which estimates a first amount of change in temperature of the spindle motor when the spindle motor is in the acceleration/deceleration state; a second temperature estimating part which estimates a second amount of change in temperature of the spindle motor when the spindle motor is in the steady state; a comparing part which compares the first and second estimated values. A numerical controlling part of the controller transmits an operation command for changing the operation of at least one of the spindle motor and a feed shaft motor, when the spindle motor is overheated.
    Type: Application
    Filed: October 9, 2014
    Publication date: April 16, 2015
    Applicant: FANUC CORPORATION
    Inventor: Tadashi Okita
  • Patent number: 9008821
    Abstract: A servo control system capable of using an angle-based synchronization learning control, even when a reference position is not given, while maintaining the advantage of the angle-based synchronization method. The servo control system has X-, y- and z-axes servo controllers, each configured to control x-, y- and z-axes servomotors, respectively. Each of x- and y-axes servo controllers has a reference signal generating part configured to generate a reference signal which monotonically increases or varies in one direction, based on the position command of each axis transmitted from a higher-level controller.
    Type: Grant
    Filed: August 23, 2011
    Date of Patent: April 14, 2015
    Assignee: FANUC Corporation
    Inventors: Tadashi Okita, Yukio Toyozawa, Kazuomi Maeda, Naoto Sonoda
  • Patent number: 8884571
    Abstract: A motor control apparatus includes, a converter which converts input AC to DC for output, an inverter which converts the DC output of the converter to provide an AC output for driving a motor, and an inverter control part for controlling the same, and a numerical control part which outputs a motor operation command for commanding the operation of the motor, and wherein when AC current or power input to the converter lies outside a predetermined range, the inverter control part controls the AC output of the inverter so that the motor is operated in accordance with a limited torque command produced by limiting a torque command originally specified in the motor operation command.
    Type: Grant
    Filed: November 30, 2012
    Date of Patent: November 11, 2014
    Assignee: Fanuc Corporation
    Inventors: Tadashi Okita, Daisuke Tajima
  • Publication number: 20140292251
    Abstract: In the first synchronous system of the synchronous control unit (1), movement commands of the first motor (23) and the second motor (13) made by the movement command making section (9), which are synchronized with each other, are respectively supplied to the first amplifier (22) and the second amplifier (12) through the first communication path (11) and the second communication path (21). In the second synchronous system switched from the first synchronous system, the first motor (23) is decelerated by a deceleration command made by the deceleration making section (29) and the second motor (13) is decelerated synchronously with the first motor by a movement command made by the position feedback value controlled by the first motor (23) supplied to the second amplifier (12) through the third communication path (31).
    Type: Application
    Filed: March 28, 2014
    Publication date: October 2, 2014
    Applicant: FANUC CORPORATION
    Inventor: Tadashi OKITA
  • Publication number: 20140132194
    Abstract: A control apparatus includes a converter for converting an AC voltage to a DC voltage, a feed shaft motor inverter for converting the DC voltage to an AC voltage for a feed shaft motor, a main spindle motor inverter for converting the DC voltage to an AC voltage for a main spindle motor, a power outage detection unit for detecting a power outage of the AC power supply, a voltage detection unit for detecting the DC voltage, and a control unit which, upon power outage of the AC power supply side, outputs a feed shaft motor deceleration command to the feed shaft motor inverter and outputs, to the main spindle motor inverter, a main spindle motor acceleration command when a DC voltage is greater than an upper limit and a main spindle motor deceleration command when the DC voltage is less than a lower limit.
    Type: Application
    Filed: November 6, 2013
    Publication date: May 15, 2014
    Applicant: FANUC CORPORATION
    Inventors: Tadashi OKITA, Daisuke TAJIMA
  • Patent number: 8698442
    Abstract: If it is predicted that the sum of the output of a servo motor and the output of a spindle motor exceeds power supplied by a rectifier unit, during a cutting operation, a motor drive control device controls alternating-current power of a first inverter unit so as to reduce the feed speed of at least one feed axis and controls alternating-current power of a second inverter unit so as not to limit torque of the spindle motor. Further, if it is predicted that the sum of the output of the servo motor and the output of the spindle motor exceeds power supplied by the rectifier unit, during an operation other than the cutting operation, the motor drive control device controls the alternating-current power of the second inverter unit so as to limit the torque so as not to reduce the feed speed.
    Type: Grant
    Filed: January 11, 2013
    Date of Patent: April 15, 2014
    Assignee: FANUC Corporation
    Inventors: Tadashi Okita, Daisuke Tajima
  • Patent number: 8669727
    Abstract: A detection device for detecting a magnetic pole position of a synchronous motor includes a generating unit for generating a magnetic pole correction value based on the difference between a forward rotation d-phase voltage command and a reverse rotation d-phase voltage command, the d-phase voltage commands being used for rotating the synchronous motor and generated when the synchronous motor is driven in forward and reverse directions, respectively, by applying a prescribed d-phase current command after detecting a magnetic pole initial position at power-on of the synchronous motor, and a correcting unit for correcting the magnetic pole initial position based on the magnetic pole correction value and on a sensor reference position which defines a reference position of a sensor attached to the synchronous motor, and a control apparatus equipped with the detection device controls the rotation of the synchronous motor based on the corrected magnetic pole initial position.
    Type: Grant
    Filed: March 27, 2012
    Date of Patent: March 11, 2014
    Assignee: Fanuc Corporation
    Inventors: Tadashi Okita, Yukio Toyozawa, Kenji Takahashi
  • Patent number: 8664897
    Abstract: A motor drive apparatus includes a rectifier which converts AC power to DC power and DC power to AC power, an inverter which converts the DC power output by the rectifier to AC power and supplies the AC power to a motor, and which converts regenerative power from the motor to DC power and returns the DC power to the rectifier, a DC voltage detection unit which detects a DC output voltage of the rectifier, an AC voltage detection unit which detects an AC output voltage of the rectifier, a frequency calculation unit which calculates the frequency of the AC voltage; a storage unit which stores as a reference value the DC voltage at the start of the regenerative operation, and a power failure detection unit which determines the presence or absence of a power failure by using the DC voltage, the reference value, and the AC voltage frequency.
    Type: Grant
    Filed: September 13, 2012
    Date of Patent: March 4, 2014
    Assignee: Fanuc Corporation
    Inventors: Yasusuke Iwashita, Tadashi Okita, Masakazu Niwa
  • Patent number: 8662799
    Abstract: A tapping machine (1) executes a tapping operation by operating a spindle motor (21) and a feed axis motor (31) in synchronization, and includes a spindle reversal detector unit (34) for detecting the reversed operation of the spindle during the tapping operation, and a reverse correction amount production unit (35) for producing a reverse correction amount for improving follow-up performance of reversed operation of the feed axis at the time when the reversed operation of the spindle is detected by the spindle reversal detector unit (34). When the reversed operation is detected by the spindle reversal detector unit, the reverse correction amount produced by the reverse correction amount production unit (35) is added to the speed instruction on a speed control loop of the feed axis control unit (30) or to an integrator (41) of the speed control loop.
    Type: Grant
    Filed: June 29, 2012
    Date of Patent: March 4, 2014
    Assignee: FANUC Corporation
    Inventors: Kenichi Takayama, Tadashi Okita
  • Patent number: 8483865
    Abstract: Coordinate values of a tool center point is calculated by obtaining coordinate values at each time of respective drive axes driven by a numerical controller. A tool radius compensation vector connecting the calculated tool center point at each time and an actual machining point is obtained. Then, coordinate values of the actual machining point are calculated based on the calculated coordinate values of the tool center point and the obtained tool radius compensation vector, and the trajectory of the actual machining point is displayed on a display.
    Type: Grant
    Filed: February 3, 2011
    Date of Patent: July 9, 2013
    Assignee: Fanuc Corporation
    Inventors: Yasusuke Iwashita, Tadashi Okita, Junichi Tezuka
  • Publication number: 20130134910
    Abstract: A motor drive apparatus includes a rectifier which converts AC power to DC power and DC power to AC power, an inverter which converts the DC power output by the rectifier to AC power and supplies the AC power to a motor, and which converts regenerative power from the motor to DC power and returns the DC power to the rectifier, a DC voltage detection unit which detects a DC output voltage of the rectifier, an AC voltage detection unit which detects an AC output voltage of the rectifier, a frequency calculation unit which calculates the frequency of the AC voltage; a storage unit which stores as a reference value the DC voltage at the start of the regenerative operation, and a power failure detection unit which determines the presence or absence of a power failure by using the DC voltage, the reference value, and the AC voltage frequency.
    Type: Application
    Filed: September 13, 2012
    Publication date: May 30, 2013
    Applicant: FANUC CORPORATION
    Inventors: Yasusuke IWASHITA, Tadashi OKITA, Masakazu NIWA
  • Publication number: 20130110278
    Abstract: A control device (1) of a gear processing machine has a bus (51) that communicates by directly connecting between a tool axis controller (22) and a workpiece axis controller (12), and, in this control device, the position of a tool axis (40) that is detected by a tool axis position detection sensor (25) is supplied to a workpiece axis controller via a bus, an upper controller (10) supplies a predetermined synchronization ratio and a superimposition command for applying a twisting operation to a workpiece axis controller, and the workpiece axis controller adds a value that is generated by multiplying the position of the tool axis that is supplied via the bus, by the synchronization ratio, and the superimposition command, and generates a motion command for a workpiece axis (30).
    Type: Application
    Filed: August 10, 2012
    Publication date: May 2, 2013
    Applicant: FANUC CORPORATION
    Inventors: Tadashi OKITA, Yasusuke IWASHITA
  • Patent number: 8432120
    Abstract: A numerical controller calculates a first position command from a machining program, converts the first position command into a second position command for restricting a tangential speed of a tool, and delivers the second position command and a status signal indicative of the achievement of the conversion of the first position command into the second position command to a tool path display apparatus. The tool path display apparatus displays the path of the tool in a color corresponding to the status signal and can thereby determine the point on the tool path at which the speed restriction is performed.
    Type: Grant
    Filed: May 27, 2011
    Date of Patent: April 30, 2013
    Assignee: Fanuc Corporation
    Inventors: Yasusuke Iwashita, Tadashi Okita, Junichi Tezuka
  • Publication number: 20130039707
    Abstract: A tapping machine (1) executes a tapping operation by operating a spindle motor (21) and a feed axis motor (31) in synchronization, and includes a spindle reversal detector unit (34) for detecting the reversed operation of the spindle during the tapping operation, and a reverse correction amount production unit (35) for producing a reverse correction amount for improving follow-up performance of reversed operation of the feed axis at the time when the reversed operation of the spindle is detected by the spindle reversal detector unit (34). When the reversed operation is detected by the spindle reversal detector unit, the reverse correction amount produced by the reverse correction amount production unit (35) is added to the speed instruction on a speed control loop of the feed axis control unit (30) or to an integrator (41) of the speed control loop.
    Type: Application
    Filed: June 29, 2012
    Publication date: February 14, 2013
    Applicant: FANUC Corporation
    Inventors: Kenichi TAKAYAMA, Tadashi OKITA
  • Patent number: 8305016
    Abstract: A control device for electric motors, capable of precisely moving one object by using two electric motors based on periodically repeated commands. The control device includes a first learning controller for calculating an amount of correction so that a positional deviation of a first electric motor is minimized, and a second learning controller for calculating an amount of correction so that a positional deviation of a second electric motor is minimized. The first and second learning controllers are independent from each other, and configured to minimize the positional deviation of the corresponding electric motor. The parameters set in the learning controllers, each defining the response of learning control of each electric motor, are equal to each other.
    Type: Grant
    Filed: September 17, 2008
    Date of Patent: November 6, 2012
    Assignee: Fanuc Ltd
    Inventors: Tadashi Okita, Yukio Toyozawa, Naoto Sonoda