Patents by Inventor Masashi Miyaji
Masashi Miyaji 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: 11874678Abstract: There are disclosed a vibration control device and a vibration control method that control shaft torsional vibration and machine stand vibration without installing a special sensor or measurement instrument. A vibration control device includes an amplification factor change unit that changes an amplification factor of an amplification unit used for amplifying a deviation between a command value and a detection value in a servo amplifier, a vibration detection unit that measures the frequency and the amplitude of vibration superimposed on a moving part, and a filter change unit that changes a filter based on the frequency and the amplitude detected by the vibration detection unit.Type: GrantFiled: January 14, 2021Date of Patent: January 16, 2024Assignee: OKUMA CORPORATIONInventor: Masashi Miyaji
-
Publication number: 20210223803Abstract: There are disclosed a vibration control device and a vibration control method that control shaft torsional vibration and machine stand vibration without installing a special sensor or measurement instrument. A vibration control device includes an amplification factor change unit that changes an amplification factor of an amplification unit used for amplifying a deviation between a command value and a detection value in a servo amplifier, a vibration detection unit that measures the frequency and the amplitude of vibration superimposed on a moving part, and a filter change unit that changes a filter based on the frequency and the amplitude detected by the vibration detection unit.Type: ApplicationFiled: January 14, 2021Publication date: July 22, 2021Inventor: Masashi MIYAJI
-
Patent number: 10649014Abstract: A method measures a frequency characteristic at a feed axis control unit configured to drive a motor in accordance with a velocity command value to control a velocity or a position of a movable portion of a driven body. The velocity command value includes a velocity reference value from a host device or a velocity command calculator and a sweep signal swept in order to measure the frequency characteristic. The method includes moving the feed axis in one direction by commanding the velocity reference value where a moving velocity of the feed axis is constant, exciting by providing a sine wave having an amplitude less than a magnitude of the velocity reference value to the sweep signal, and measuring the frequency characteristic of a feed axis drive system including the motor.Type: GrantFiled: February 23, 2017Date of Patent: May 12, 2020Assignee: Okuma CorporationInventors: Masashi Miyaji, Takashi Norihisa
-
Patent number: 10008963Abstract: A compensation function constituting device calculates a correlation coefficient based on a moving distance required for reversing a moving direction of a movable unit and a sliding resistance acting on the movable unit, and a compensation amount output device calculates a moving distance on a position command value required until the movable unit starts to move according to the correlation coefficient and a feedback torque when the moving direction is reversed and increases a torque compensation amount in accordance with the moving distance after reversing the moving direction until the moving distance after the moving direction is reversed reaches the moving distance required until the movement is started.Type: GrantFiled: April 14, 2015Date of Patent: June 26, 2018Assignee: OKUMA CORPORATIONInventors: Takeshi Sakai, Masashi Miyaji
-
Patent number: 9993904Abstract: A position controller includes a position detector, a speed command operator, a first adder, a torque command operator, a second adder, a drive unit, a runout amount correcting device, and a third adder. The runout amount correcting device is configured to employ a value related to deviation between a command value and a detection value in physical quantity of a movable part as a reference signal. The runout amount correcting device is configured to calculate a position correction amount from rotation angle information of the main spindle and the reference signal. The runout amount correcting device is configured to estimate a runout amount of a cutting edge of the tool from the reference signal. The runout amount correcting device is configured to calculate the position correction amount such that influences of the respective cutting edges appearing in the reference signal are leveled.Type: GrantFiled: December 4, 2015Date of Patent: June 12, 2018Assignee: Okuma CorporationInventor: Masashi Miyaji
-
Patent number: 9952249Abstract: A torque command value and an acceleration detection value are accumulated when a driven portion is subjected to acceleration/deceleration driving, and, from a ratio between the two, inertia of a movable portion is calculated. By executing the acceleration/deceleration driving about a position where influence of gravity torque is zero, the influence of the gravity torque included in the torque command value before and after the center position is offset, whereby inertia can be estimated correctly even with a machine structure in which the influence of gravity differs depending on the position of the motor.Type: GrantFiled: April 25, 2014Date of Patent: April 24, 2018Assignee: OKUMA CORPORATIONInventor: Masashi Miyaji
-
Publication number: 20170292980Abstract: A method measures a frequency characteristic at a feed axis control unit configured to drive a motor in accordance with a velocity command value to control a velocity or a position of a movable portion of a driven body. The velocity command value includes a velocity reference value from a host device or a velocity command calculator and a sweep signal swept in order to measure the frequency characteristic. The method includes moving the feed axis in one direction by commanding the velocity reference value where a moving velocity of the feed axis is constant, exciting by providing a sine wave having an amplitude less than a magnitude of the velocity reference value to the sweep signal, and measuring the frequency characteristic of a feed axis drive system including the motor.Type: ApplicationFiled: February 23, 2017Publication date: October 12, 2017Applicant: Okuma CorporationInventors: Masashi MIYAJI, Takashi NORIHISA
-
Patent number: 9599969Abstract: A position control apparatus is configured to perform full-closed control for controlling the position of a driven member. The position control apparatus includes a vibration period and amplitude detector that detects a vibration period and a vibration amplitude included in a difference value between the position command value and the driven member position detection value. The position control apparatus also includes a constant vibration detector that outputs, as a vibration period of the constant vibration, a vibration period obtained while the driven member is not in an acceleration/deceleration state and the vibration period and the vibration amplitude detected by the vibration period and amplitude detector are equal to or greater than a vibration period threshold value and a vibration amplitude threshold value, respectively. The position control apparatus also includes a control parameter changer that changes the control parameter based on the vibration period output from the constant vibration detector.Type: GrantFiled: February 7, 2014Date of Patent: March 21, 2017Assignee: OKUMA CORPORATIONInventor: Masashi Miyaji
-
Publication number: 20160176004Abstract: A position controller includes a position detector, a speed command operator, a first adder, a torque command operator, a second adder, a drive unit, a runout amount correcting device, and a third adder. The runout amount correcting device is configured to employ a value related to deviation between a command value and a detection value in physical quantity of a movable part as a reference signal. The runout amount correcting device is configured to calculate a position correction amount from rotation angle information of the main spindle and the reference signal. The runout amount correcting device is configured to estimate a runout amount of a cutting edge of the tool from the reference signal. The runout amount correcting device is configured to calculate the position correction amount such that influences of the respective cutting edges appearing in the reference signal are leveled.Type: ApplicationFiled: December 4, 2015Publication date: June 23, 2016Inventor: Masashi MIYAJI
-
Publication number: 20150295522Abstract: A compensation function constituting device calculates a correlation coefficient based on a moving distance required for reversing a moving direction of a movable unit and a sliding resistance acting on the movable unit, and a compensation amount output device calculates a moving distance on a position command value required until the movable unit starts to move according to the correlation coefficient and a feedback torque when the moving direction is reversed and increases a torque compensation amount in accordance with the moving distance after reversing the moving direction until the moving distance after the moving direction is reversed reaches the moving distance required until the movement is started.Type: ApplicationFiled: April 14, 2015Publication date: October 15, 2015Inventors: Takeshi Sakai, Masashi Miyaji
-
Publication number: 20140318246Abstract: A torque command value and an acceleration detection value are accumulated when a driven portion is subjected to acceleration/deceleration driving, and, from a ratio between the two, inertia of a movable portion is calculated. By executing the acceleration/deceleration driving about a position where influence of gravity torque is zero, the influence of the gravity torque included in the torque command value before and after the center position is offset, whereby inertia can be estimated correctly even with a machine structure in which the influence of gravity differs depending on the position of the motor.Type: ApplicationFiled: April 25, 2014Publication date: October 30, 2014Applicant: OKUMA CorporationInventor: Masashi Miyaji
-
Publication number: 20140217952Abstract: A position control apparatus is configured to perform full-closed control for controlling the position of a driven member. The position control apparatus includes a vibration period and amplitude detector that detects a vibration period and a vibration amplitude included in a difference value between the position command value and the driven member position detection value. The position control apparatus also includes a constant vibration detector that outputs, as a vibration period of the constant vibration, a vibration period obtained while the driven member is not in an acceleration/deceleration state and the vibration period and the vibration amplitude detected by the vibration period and amplitude detector are equal to or greater than a vibration period threshold value and a vibration amplitude threshold value, respectively. The position control apparatus also includes a control parameter changer that changes the control parameter based on the vibration period output from the constant vibration detector.Type: ApplicationFiled: February 7, 2014Publication date: August 7, 2014Applicant: OKUMA CorporationInventor: Masashi Miyaji
-
Patent number: 8508171Abstract: A position control apparatus calculates a position detection value by adding an output of a first-order delay circuit 17 that receives a difference between a driven member position detection value Pl and a motor position detection value Pm to the motor position detection value Pm, and uses the obtained position detection value as a position feedback value. An aging corrector 30 suppresses low frequency vibrations by controlling a time constant Tp of the first-order delay circuit 17 in such a way as to increase the time constant when a vibratory state of the driven member is detected.Type: GrantFiled: January 27, 2012Date of Patent: August 13, 2013Assignee: OKUMA CorporationInventor: Masashi Miyaji
-
Publication number: 20120194121Abstract: A position control apparatus calculates a position detection value by adding an output of a first-order delay circuit 17 that receives a difference between a driven member position detection value Pl and a motor position detection value Pm to the motor position detection value Pm, and uses the obtained position detection value as a position feedback value. An aging corrector 30 suppresses low frequency vibrations by controlling a time constant Tp of the first-order delay circuit 17 in such a way as to increase the time constant when a vibratory state of the driven member is detected.Type: ApplicationFiled: January 27, 2012Publication date: August 2, 2012Applicant: OKUMA CORPORATIONInventor: Masashi Miyaji
-
Patent number: 8093856Abstract: In a position control apparatus that drives a feed-axis with a servomotor of a machine tool, the machine tool may be quickly accelerated or decelerated in a state where a machine structural member that supports and fixes a structural member including a driving system has a lower rigidity, or in a state where an element having a lower rigidity is present beyond a load position where the detection by a linear scale is performed. In such cases, a generated deflection may induce a displacement in a mechanical system. A relative locus error may be generated between a workpiece to be processed and a front end portion of the tool. Further, a mechanism rigidity generally changes according to a machine posture. The generated deflection amount changes in magnitude. The present embodiment estimates and compensates a displacement amount of the front end portion of the tool that may be caused by the deflection of the mechanical system.Type: GrantFiled: October 19, 2009Date of Patent: January 10, 2012Assignee: Okuma CorporationInventor: Masashi Miyaji
-
Publication number: 20100109594Abstract: In a position control apparatus that drives a feed-axis with a servomotor of a machine tool, the machine tool maybe quickly accelerated or decelerated in a state where a machine structural member that supports and fixes a structural member including a driving system has a lower rigidity, or in a state where an element having a lower rigidity is present beyond a load position where the detection by a linear scale is performed. In such cases, a generated deflection may induce a displacement in a mechanical system. A relative locus error may be generated between a workpiece to be processed and a front end portion of the tool. Further, a mechanism rigidity generally changes according to a machine posture. The generated deflection amount changes in magnitude. The present embodiment estimates and compensates a displacement amount of the front end portion of the tool that may be caused by the deflection of the mechanical system.Type: ApplicationFiled: October 19, 2009Publication date: May 6, 2010Applicant: OKUMA CORPORATIONInventor: Masashi Miyaji
-
Publication number: 20080001481Abstract: In a linear motor, the stators and sliders are arranged to fill a predetermined relationship. In one configuration, two stators each include a plurality of stator blocks arranged in a moving direction of sliders so that projecting poles are maintained at predetermined intervals. Boundary surfaces are formed in adjacent stator blocks so as to be displaced relative to one another between the two opposite blocks by a distance Ld in the moving direction of the sliders. When a distance between end surface of the slider blocks is defined as L and the overall length of one stator block is defined as L0, the components are arranged such that Ld>L/3 and (L0?Ld)>L/3.Type: ApplicationFiled: May 16, 2007Publication date: January 3, 2008Applicant: OKUMA CORPORATIONInventors: Masashi Miyaji, Yoichi Kawai