Patents by Inventor Takao Akiyama

Takao Akiyama 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: 10895511
    Abstract: An electric inertia control device 5A simulates the behavior of an inertial body having a predetermined set moment of inertia Jset by means of a dynamometer, and is provided with: an inertia compensator 51A which generates a torque signal by multiplying a signal obtained by subtracting a shaft torque detection signal T12 from a higher-level command torque signal T* by the ratio of a moment of inertia J1 of the dynamometer to the set moment of inertia Jset, and generates an inertia compensation torque signal Tref by summing the torque signal and the shaft torque detection signal J1; and a resonance suppression control circuit 53A which uses the inertia compensation torque signal Tref and the shaft torque detection signal T12 to generate a torque current command signal T1 in such a way as to suppress resonance in a mechanical system including a test piece and the dynamometer.
    Type: Grant
    Filed: April 9, 2018
    Date of Patent: January 19, 2021
    Assignee: MEIDENSHA CORPORATION
    Inventors: Takashi Yamaguchi, Takao Akiyama
  • Publication number: 20210010903
    Abstract: A control device of a dynamometer system is provided with: a driving force observer which estimates a generated driving force of a vehicle; an electrical inertia control unit which uses the driving force to generate a front wheel basic torque command signal and a rear wheel basic torque command signal; a synchronization control unit which generates a synchronization control torque command signal with respect to the basic torque command signal and the basic torque command signal in such a way as to eliminate a speed difference; and torque command signal generating units which use the synchronization control torque command signal to adjust the basic torque command signal and the basic torque command signal. The synchronization control unit is defined in such a way that the poles of a denominator polynomial of a transfer function from the driving force to the speed difference are all negative real numbers.
    Type: Application
    Filed: December 11, 2018
    Publication date: January 14, 2021
    Inventors: Takao AKIYAMA, Tomoaki KIMURA
  • Publication number: 20210011454
    Abstract: This overall control device for a testing system comprises: a plurality of resonance suppression controllers that each generate a torque current command signal for suppressing mechanical resonance between a specimen and a dynamometer upon receiving a base torque current command signal and axial torque detection signal and have different input/output characteristics; a specimen characteristic acquisition unit for acquiring the value of the moment of inertia of the specimen connected to the dynamometer; and a resonance-suppression-controller selection unit for selecting one of the plurality of resonance suppression controllers on the basis of the value of the moment of inertia acquired by the specimen characteristic acquisition unit and mounting the selected resonance suppression controller in a dynamometer control module.
    Type: Application
    Filed: December 19, 2018
    Publication date: January 14, 2021
    Applicant: Meidensha Corporation
    Inventors: Masayasu KANKE, Takao AKIYAMA
  • Patent number: 10892695
    Abstract: A low-frequency torque controller 9 outputs a low-frequency torque controller output ?dc* based on a torque command value ?* and a torque detection value ?det, and a vibrational torque controller 11 outputs a vibrational torque command value ?pd* based on the torque command value ?*, the torque detection value ?det, and a rotational phase detection value ?. Meanwhile, in a high-frequency resonance suppression controller, an inverter torque command value ?inv* is outputted based on the torque detection value ?det and a corrected torque command value ?r* obtained by adding the low-frequency torque controller output ?dc* to the vibrational torque command value ?pd*. The invention thus provides shaft torque vibrational control of a motor drive system wherein engine vibrational torque command values including distortion components are tracked while entirely removing the influence of resonance, non-periodic disturbances, and periodic disturbances.
    Type: Grant
    Filed: April 7, 2020
    Date of Patent: January 12, 2021
    Assignee: Meidensha Corporation
    Inventors: Yugo Tadano, Takao Akiyama, Takashi Yamaguchi
  • Publication number: 20210003479
    Abstract: This method for controlling an engine bench system is provided with: a speed control step in which speed control of a dynamometer is executed while an engine is maintained in a non-ignition state, and in which the speed control is ended when the rotational speed of the dynamometer has increased to a prescribed speed; a measuring step in which a shaft torque detection signal is acquired during a period from when, as a result of inertia, the rotational speed of the dynamometer is a prescribed measuring start speed until said rotational speed reaches a prescribed measuring end speed; a frequency analyzing step in which the frequency of the signal having the strongest intensity, from among the shaft torque detection signals acquired in the measuring step, is acquired as a resonant frequency; a design step in which a control gain of a dynamometer control device is determined using the acquired resonant frequency.
    Type: Application
    Filed: November 22, 2018
    Publication date: January 7, 2021
    Inventor: Takao AKIYAMA
  • Publication number: 20200408641
    Abstract: A drive train bench system has two dynamometers that are connected in series to a specimen. The mechanical characteristics estimation method has: a first measurement step for measuring a response to a first excitation torque input signal when the first excitation torque input signal overlaps a first torque current command signal while a measurement control circuit controls the two dynamometers; a second measurement step for measuring a response to a second excitation torque input signal when the second excitation torque input signal overlaps a second torque current command signal while the measurement control circuit controls the two dynamometers; and a mechanical characteristics transfer function estimation step for using the results from the first and second measurement steps to estimate a mechanical characteristics transfer function.
    Type: Application
    Filed: November 26, 2018
    Publication date: December 31, 2020
    Inventor: Takao AKIYAMA
  • Publication number: 20200348206
    Abstract: The mechanical characteristic estimating method is a method for estimating a value of a mechanical characteristic parameter of a test piece W provided with a first shaft S1, and a second shaft S2 and a third shaft S3 which are connected to the first shaft S1. The mechanical characteristic estimating method includes: a first measuring step of measuring a resonant frequency ?L of the test piece in a state in which a gear ratio of the transmission TM1 and the differential gear TM2 is set to a first gear ratio gL; a second measuring step of measuring the resonant frequency ?H of the test piece in a state in which the gear ratio is set to a second gear ratio gH; and an estimating step of calculating the resonant frequencies ?L and ?H, the gear ratios gL and gH, and an estimated value of a spring stiffness.
    Type: Application
    Filed: June 14, 2018
    Publication date: November 5, 2020
    Applicant: Meidensha Corporation
    Inventor: Takao AKIYAMA
  • Publication number: 20200304050
    Abstract: A low-frequency torque controller 9 outputs a low-frequency torque controller output ?dc* based on a torque command value ?* and a torque detection value ?det, and a vibrational torque controller 11 outputs a vibrational torque command value ?pd* based on the torque command value ?*, the torque detection value ?det, and a rotational phase detection value ?. Meanwhile, in a high-frequency resonance suppression controller, an inverter torque command value ?inv* is outputted based on the torque detection value ?det and a corrected torque command value ?r* obtained by adding the low-frequency torque controller output ?dc* to the vibrational torque command value ?pd*. The invention thus provides shaft torque vibrational control of a motor drive system wherein engine vibrational torque command values including distortion components are tracked while entirely removing the influence of resonance, non-periodic disturbances, and periodic disturbances.
    Type: Application
    Filed: April 7, 2020
    Publication date: September 24, 2020
    Applicant: Meidensha Corporation
    Inventors: Yugo Tadano, Takao Akiyama, Takashi Yamaguchi
  • Publication number: 20200271539
    Abstract: An input-side control device includes: a feedback controller that generates a first control input signal for eliminating the difference between a model speed signal ?m and a speed detection signal ? by using the signal difference between a higher order torque command signal Tref and an axial torque detection signal Tsh to generate the model speed signal ?m which corresponds to the rotational speed of an inertial body having a set moment of inertia Jset moving under a torque corresponding to the signal difference; a feed-forward controller that generates a second control input signal by multiplying the signal difference by k·Jdy/Jset; and a low-pass filter that generates a torque command signal Tr from a signal obtained by combining the outputs of the controllers and attenuating components at a higher frequency than a cut-off frequency fc set in the vicinity of the resonant frequency.
    Type: Application
    Filed: June 14, 2018
    Publication date: August 27, 2020
    Inventor: Takao AKIYAMA
  • Publication number: 20200264072
    Abstract: The input/output characteristic estimation method for testing system comprises; first excitation measurement steps (S3-S5) in which an input obtained by superimposing an excitation input d2 onto a second torque control input ib2 is input to a second dynamometer, and the frequency response i2d2 with respect to the excitation input d2 is measured; second excitation measurement steps (S7-S9) in which input obtained by superimposing excitation input d3 on third torque control input ib3 is input to a third dynamometer, and frequency response i2d3 with respect to the excitation input d3 and the like are measured; and mechanical characteristic estimation steps (S11 and S12) in which the response measured in the first and second excitation measurement steps are used to estimate the transfer function Gt2_i2 and the like from the second or third torque current command signals (i2, i3) to the first or second axial torque detection signals (t2 or t3).
    Type: Application
    Filed: March 9, 2018
    Publication date: August 20, 2020
    Inventor: Takao AKIYAMA
  • Publication number: 20200103296
    Abstract: An electric inertia control device 5A simulates the behavior of an inertial body having a predetermined set moment of inertia Jset by means of a dynamometer, and is provided with: an inertia compensator 51A which generates a torque signal by multiplying a signal obtained by subtracting a shaft torque detection signal T12 from a higher-level command torque signal T* by the ratio of a moment of inertia J1 of the dynamometer to the set moment of inertia Jset, and generates an inertia compensation torque signal Tref by summing the torque signal and the shaft torque detection signal J1; and a resonance suppression control circuit 53A which uses the inertia compensation torque signal Tref and the shaft torque detection signal T12 to generate a torque current command signal T1 in such a way as to suppress resonance in a mechanical system including a test piece and the dynamometer.
    Type: Application
    Filed: April 9, 2018
    Publication date: April 2, 2020
    Inventors: Takashi YAMAGUCHI, Takao AKIYAMA
  • Patent number: 10605689
    Abstract: A test piece characteristic estimation method includes estimating a moment of inertia of a test piece. A first transfer function G1 from a torque current command for a dynamometer to output from a shaft torque sensor is measured by vibrationally operating the dynamometer. A second transfer function G2 from the torque current command to the output of a dynamo rotation speed sensor is measured by vibrationally operating the dynamometer. A real part and an imaginary part of a ratio obtained by dividing the second transfer function G2 by the first transfer function G1 at a prescribed measurement frequency ?k are calculated. A moment of inertia Jeg and a rotational friction Ceg are estimated by using the real part and the imaginary part of the ratio.
    Type: Grant
    Filed: December 13, 2016
    Date of Patent: March 31, 2020
    Assignee: MEIDENSHA CORPORATION
    Inventor: Takao Akiyama
  • Patent number: 10558179
    Abstract: A shaft torque control device executes highly responsive shaft-torque control even when spring rigidity of a connection shaft connecting an engine and dynamometer varies, and has a feedback control system including a nominal plant imitating input-output characteristics of a test system, generalized plant having nominal plant; controller providing an input with use of outputs and variation term causing variation in the nominal plant on the basis of a variation transfer function. In the controller, setting is made to satisfy a design condition. Nominal plant is structured with a two-inertia system configured by connecting two inertia bodies via a shaft having spring rigidity equal to a predetermined nominal value set to be a lower limit value in an assumed variation range of spring rigidity of the connection shaft. The variation transfer function is a positive real function. Spring rigidity in the nominal plant Na increases from the nominal value.
    Type: Grant
    Filed: July 21, 2017
    Date of Patent: February 11, 2020
    Assignee: National University Corporation Chiba University
    Inventors: Takao Akiyama, Takashi Yamaguchi, Kang-Zhi Liu, Sho Shimonomura
  • Patent number: 10444117
    Abstract: A resonance suppression control circuit provides operation stable for variations with a low order mode of vibration and suppressing spill-over due to high order mode of vibration. This circuit controls a physical system having two or more modes of vibration, and suppresses resonance in a lowest order mode of vibration from among the plurality of modes. The circuit has a controller designed by a ? design method, using a generalized plant with nominal model, and structured perturbation to the generalized plant. The nominal model is represented by the product of a low order vibration mode transfer function having the low order mode of vibration to be suppressed, and a high order vibration mode transfer function having a high order mode of vibration. The structured perturbation includes a first parameter perturbation term which imparts a multiplicative error to a spring constant included in the vibration mode transfer function being suppressed.
    Type: Grant
    Filed: June 19, 2017
    Date of Patent: October 15, 2019
    Assignee: MEIDENSHA CORPORATION
    Inventor: Takao Akiyama
  • Publication number: 20190278237
    Abstract: A shaft torque control device executes highly responsive shaft-torque control even when spring rigidity of a connection shaft connecting an engine and dynamometer varies, and has a feedback control system including a nominal plant imitating input-output characteristics of a test system, generalized plant having nominal plant; controller providing an input with use of outputs and variation term causing variation in the nominal plant on the basis of a variation transfer function. In the controller, setting is made to satisfy a design condition. Nominal plant is structured with a two-inertia system configured by connecting two inertia bodies via a shaft having spring rigidity equal to a predetermined nominal value set to be a lower limit value in an assumed variation range of spring rigidity of the connection shaft. The variation transfer function is a positive real function. Spring rigidity in the nominal plant Na increases from the nominal value.
    Type: Application
    Filed: July 21, 2017
    Publication date: September 12, 2019
    Inventors: Takao AKIYAMA, Takashi YAMAGUCHI, Kang-Zhi LIU, Sho SHIMONOMURA
  • Patent number: 10371589
    Abstract: The purpose of the present invention is to provide a control device for a dynamometer system, with which, by a simple method, an unloaded state can be reproduced highly accurately when a test piece is started. A dynamo control device 6 is provided with: an integral control input computation unit 611 for computing the integral value of axle torque deviation, and multiplying the sum thereof and a correction value by an integral gain to compute an integral control input; a correction value computation unit 612 for multiplying an inertia compensation quantity Jcmp by the dynamo rotation frequency to compute a correction value; a non-integral control input computation unit 613 for designating, as a non-integral control input, the output of a prescribed transmission function Ge0(s) having axle torque deviation as input; and a totaling unit 614 for totaling the integral control input and the non-integral control input in order to generate a torque current command signal to the dynamometer.
    Type: Grant
    Filed: January 8, 2016
    Date of Patent: August 6, 2019
    Assignee: Meidensha Corporation
    Inventors: Takao Akiyama, Nobuhiko Asakura
  • Publication number: 20190229659
    Abstract: A low-frequency torque controller 9 outputs a low-frequency torque controller output ?dc* based on a torque command value ?* and a torque detection value ?det, and a vibrational torque controller 11 outputs a vibrational torque command value ?pd* based on the torque command value ?*, the torque detection value ?det, and a rotational phase detection value ?. Meanwhile, in a high-frequency resonance suppression controller, an inverter torque command value ?inv* is outputted based on the torque detection value ?det and a corrected torque command value ?r* obtained by adding the low-frequency torque controller output ?dc* to the vibrational torque command value ?pd*. The invention thus provides shaft torque vibrational control of a motor drive system wherein engine vibrational torque command values including distortion components are tracked while entirely removing the influence of resonance, non-periodic disturbances, and periodic disturbances.
    Type: Application
    Filed: March 15, 2017
    Publication date: July 25, 2019
    Applicant: Meidensha Corporation
    Inventors: Yugo TADANO, Takao AKIYAMA, Takashi YAMAGUCHI
  • Publication number: 20190219481
    Abstract: A resonance suppression control circuit provides operation stable for variations with a low order mode of vibration and suppressing spill-over due to high order mode of vibration. This circuit controls a physical system having two or more modes of vibration, and suppresses resonance in a lowest order mode of vibration from among the plurality of modes. The circuit has a controller designed by a ? design method, using a generalized plant with nominal model, and structured perturbation to the generalized plant. The nominal model is represented by the product of a low order vibration mode transfer function having the low order mode of vibration to be suppressed, and a high order vibration mode transfer function having a high order mode of vibration. The structured perturbation includes a first parameter perturbation term which imparts a multiplicative error to a spring constant included in the vibration mode transfer function being suppressed.
    Type: Application
    Filed: June 19, 2017
    Publication date: July 18, 2019
    Inventor: Takao AKIYAMA
  • Publication number: 20190137361
    Abstract: The purpose of the present invention is to provide a device for controlling a dynamometer of a test system, wherein the device is capable of controlling shaft torque to a prescribed target torque while minimizing low-frequency-range resonance caused by viscous drag of a test piece. This test system is provided with a dynamometer joined to an engine via a coupling shaft, an inverter for supplying electric power to the dynamometer, a shaft torque meter for detecting the shaft torque produced in the coupling shaft, and a dynamometer-controlling device 6 for generating a torque-current command signal T2 that is sent to the inverter and is generated on the basis of a shaft torque detection signal T12 from the shaft torque meter.
    Type: Application
    Filed: April 25, 2017
    Publication date: May 9, 2019
    Inventor: Takao AKIYAMA
  • Patent number: 10190944
    Abstract: Provided is a dynamometer-system dynamo control device that can appropriately suppress the occurrence of resonance phenomena and can realize a no-load state, even in a case where an engine the inertia of which is unknown is connected. The dynamometer system comprises a dynamometer and a shaft torque meter. A dynamo control device 6 in the dynamometer system generates a torque current command signal on the basis of a torque detection signal and a torque command signal.
    Type: Grant
    Filed: November 2, 2016
    Date of Patent: January 29, 2019
    Assignee: MEIDENSHA CORPORATION
    Inventor: Takao Akiyama