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: 11879807
    Abstract: This system identification method includes: a step (S1) for measuring frequency responses (?, HR1), (?, HR2) . . . , and (?, HRn) in a real system under n sets of disturbances of different magnitudes; a step (S3) for calculating frequency responses (?, HM1), (?, HM2) . . . , (?, HMn) from input to output in n sets of mechanical models M1 to Mn including i sets (i is an integer of 1 or greater) of common parameters that do not change due to disturbance and j sets of disturbance variable parameters that do change due to disturbance; a step (S4) for calculating the values of a total of n sets of evaluation functions F (HRk, HMk) and the sum ?F thereof, and steps (S3 to S6) for searching for the values of i sets of common parameters and j×n sets of disturbance variable parameters for which the sum ?F would meet convergence conditions.
    Type: Grant
    Filed: March 18, 2020
    Date of Patent: January 23, 2024
    Assignee: MEIDENSHA CORPORATION
    Inventor: Takao Akiyama
  • Patent number: 11733671
    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: Grant
    Filed: December 19, 2018
    Date of Patent: August 22, 2023
    Assignee: MEIDENSHA CORPORATION
    Inventors: Masayasu Kanke, Takao Akiyama
  • Publication number: 20220349779
    Abstract: This system identification method includes: a step (S1) for measuring frequency responses (?, HR1), (?, HR2) . . . , and (?, HRn) in a real system under n sets of disturbances of different magnitudes; a step (S3) for calculating frequency responses (?, HM1), (?, HM2) . . . , (?, HMn) from input to output in n sets of mechanical models M1 to Mn including i sets (i is an integer of 1 or greater) of common parameters that do not change due to disturbance and j sets of disturbance variable parameters that do change due to disturbance; a step (S4) for calculating the values of a total of n sets of evaluation functions F (HRk, HMk) and the sum ?F thereof, and steps (S3 to S6) for searching for the values of i sets of common parameters and j×n sets of disturbance variable parameters for which the sum ?F would meet convergence conditions.
    Type: Application
    Filed: March 18, 2020
    Publication date: November 3, 2022
    Inventor: Takao AKIYAMA
  • Patent number: 11441971
    Abstract: This testing system is provided with: an input side control device 5 for controlling an input side dynamometer to eliminate a deviation between a speed command signal w1ref and a speed detected signal w1; and an output side control device 6 for controlling output side dynamometer to eliminate a deviation between a torque command signal Tk1 ref and a torque detected signal Tk1. A control gain of the control device 5 is set such that the real part of a pole of a transfer function (w1/w1 ref) becomes greater toward the negative side than a value obtained by multiplying a resonant frequency by the negative sign, and a control gain of the control device 6 is set such that the real part of a pole of a transfer function (Tk1/Tk1 ref) becomes smaller toward the negative side than the real part of the pole of speed control system closed loop transfer function.
    Type: Grant
    Filed: March 18, 2020
    Date of Patent: September 13, 2022
    Assignee: MEIDENSHA CORPORATION
    Inventor: Takao Akiyama
  • Publication number: 20220205869
    Abstract: This testing system is provided with: an input side control device 5 for controlling an input side dynamometer to eliminate a deviation between a speed command signal w1ref and a speed detected signal w1; and an output side control device 6 for controlling output side dynamometer to eliminate a deviation between a torque command signal Tk1 ref and a torque detected signal Tk1. A control gain of the control device 5 is set such that the real part of a pole of a transfer function (w1/w1 ref) becomes greater toward the negative side than a value obtained by multiplying a resonant frequency by the negative sign, and a control gain of the control device 6 is set such that the real part of a pole of a transfer function (Tk1/Tk1 ref) becomes smaller toward the negative side than the real part of the pole of speed control system closed loop transfer function.
    Type: Application
    Filed: March 18, 2020
    Publication date: June 30, 2022
    Inventor: Takao AKIYAMA
  • Patent number: 11371912
    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: Grant
    Filed: November 26, 2018
    Date of Patent: June 28, 2022
    Assignee: MEIDENSHA CORPORATION
    Inventor: Takao Akiyama
  • Patent number: 11313762
    Abstract: An input-side control device includes a first input signal generation unit for generating a first input signal on the basis of the deviation between an engine torque command signal and an input-side shaft torque detection signal; a second input signal generation unit for generating a second input signal on the basis of an input-side speed detection signal weighted according to a prescribed weighting signal; and a torque command signal generation unit for generating a torque command signal on the basis of the first and second input signals. If the value of a filtered signal obtained from the input-side speed detection signal is less than a prescribed threshold, the second input signal generation unit makes the value of the weighting signal lower than if the value of the filtered signal were greater than or equal to the threshold.
    Type: Grant
    Filed: December 13, 2019
    Date of Patent: April 26, 2022
    Assignee: MEIDENSHA CORPORATION
    Inventor: Takao Akiyama
  • Patent number: 11313761
    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: Grant
    Filed: April 25, 2017
    Date of Patent: April 26, 2022
    Assignee: MEDENSHA CORPORATION
    Inventor: Takao Akiyama
  • Patent number: 11280702
    Abstract: A shaft torque control device includes a feedback control system having: a generalized plant P including a nominal plant model N representing the input/output characteristic of a test system including a tandem dynamometer system; and a controller K for applying a first and second control inputs u1, u2 to the generalized plant P on the basis of a first observed output y1 and second observed output y2. The controller K has been designed using a computer so as to satisfy a prescribed design condition. For the generalized plant P, defined are: a first control amount output z1 resulting from weighting the first observed output y1 using a weighting function Ge(s); a second control amount output z2 resulting from weighting a front transmission torque t1 using a weighting function Gt1(s); and a third control amount output z3 resulting from weighting a rear transmission torque t2 using a weighting function Gt2(s).
    Type: Grant
    Filed: August 20, 2019
    Date of Patent: March 22, 2022
    Assignee: MEIDENSHA CORPORATION
    Inventor: Takao Akiyama
  • Publication number: 20220065750
    Abstract: An input-side control device includes a first input signal generation unit for generating a first input signal on the basis of the deviation between an engine torque command signal and an input-side shaft torque detection signal; a second input signal generation unit for generating a second input signal on the basis of an input-side speed detection signal weighted according to a prescribed weighting signal; and a torque command signal generation unit for generating a torque command signal on the basis of the first and second input signals. If the value of a filtered signal obtained from the input-side speed detection signal is less than a prescribed threshold, the second input signal generation unit makes the value of the weighting signal lower than if the value of the filtered signal were greater than or equal to the threshold.
    Type: Application
    Filed: December 13, 2019
    Publication date: March 3, 2022
    Inventor: Takao AKIYAMA
  • Patent number: 11262274
    Abstract: This design method is provided with a design process for a computer to design a ? controller satisfying a prescribed design condition in a feedback control system provided with the ? controller and a generalized plant. Set in the design process are: an integration operation amount calculation unit which calculates an integration operation amount; a summing unit which sums the output from the ? controller and the integration operation amount and generates an input to a nominal plant; a first control amount output port which outputs, as a first control amount output, an output obtained by multiplying the deviation input by a weight function Ge(s); and a second control amount output port which outputs, as a second control amount output, an output obtained by multiplying the output from the ? controller by a weight function Gip(s).
    Type: Grant
    Filed: September 11, 2019
    Date of Patent: March 1, 2022
    Assignee: MEIDENSHA CORPORATION
    Inventor: Takao Akiyama
  • Publication number: 20210356360
    Abstract: This design method is provided with a design process for a computer to design a ? controller satisfying a prescribed design condition in a feedback control system provided with the ? controller and a generalized plant. Set in the design process are: an integration operation amount calculation unit which calculates an integration operation amount; a summing unit which sums the output from the ? controller and the integration operation amount and generates an input to a nominal plant; a first control amount output port which outputs, as a first control amount output, an output obtained by multiplying the deviation input by a weight function Ge(s); and a second control amount output port which outputs, as a second control amount output, an output obtained by multiplying the output from the ? controller by a weight function Gip(s).
    Type: Application
    Filed: September 11, 2019
    Publication date: November 18, 2021
    Inventor: Takao AKIYAMA
  • Patent number: 11150150
    Abstract: In the present invention, an input-side control device generates an input-side torque command signal Tr using an engine torque command signal, an input-side velocity detection signal ?, and an input-side shaft torque detection signal Tsh, and is provided with: a shaft torque controller that generates a torque command signal on the basis of the engine torque command signal and an input shaft torque detection signal; and an inertia compensator that feeds back an inertia compensation signal generated by multiplying a set inertia value Jset by the input-side velocity detection signal. The shaft torque controller is provided with a first low-pass filter that, from the engine torque command signal, allows a high-frequency component to decay; and the inertia compensator is provided with a second low-pass filter that, from the input-side velocity detection signal, allows a high-frequency component to decay.
    Type: Grant
    Filed: June 28, 2019
    Date of Patent: October 19, 2021
    Assignee: MEIDENSHA CORPORATION
    Inventor: Takao Akiyama
  • Publication number: 20210318205
    Abstract: A shaft torque control device includes a feedback control system having: a generalized plant P including a nominal plant model N representing the input/output characteristic of a test system including a tandem dynamometer system; and a controller K for applying a first and second control inputs u1, u2 to the generalized plant P on the basis of a first observed output y1 and second observed output y2. The controller K has been designed using a computer so as to satisfy a prescribed design condition. For the generalized plant P, defined are: a first control amount output z1 resulting from weighting the first observed output y1 using a weighting function Ge(s); a second control amount output z2 resulting from weighting a front transmission torque t1 using a weighting function Gt1(s); and a third control amount output z3 resulting from weighting a rear transmission torque t2 using a weighting function Gt2(s).
    Type: Application
    Filed: August 20, 2019
    Publication date: October 14, 2021
    Inventor: Takao AKIYAMA
  • Patent number: 11105701
    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: Grant
    Filed: June 14, 2018
    Date of Patent: August 31, 2021
    Assignee: Meidensha Corporation
    Inventor: Takao Akiyama
  • Publication number: 20210247251
    Abstract: In the present invention, an input-side control device generates an input-side torque command signal Tr using an engine torque command signal, an input-side velocity detection signal ?, and an input-side shaft torque detection signal Tsh, and is provided with: a shaft torque controller that generates a torque command signal on the basis of the engine torque command signal and an input shaft torque detection signal; and an inertia compensator that feeds back an inertia compensation signal generated by multiplying a set inertia value Jset by the input-side velocity detection signal. The shaft torque controller is provided with a first low-pass filter that, from the engine torque command signal, allows a high-frequency component to decay; and the inertia compensator is provided with a second low-pass filter that, from the input-side velocity detection signal, allows a high-frequency component to decay.
    Type: Application
    Filed: June 28, 2019
    Publication date: August 12, 2021
    Inventor: Takao AKIYAMA
  • Patent number: 11085851
    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: Grant
    Filed: June 14, 2018
    Date of Patent: August 10, 2021
    Assignee: MEIDENSHA CORPORATION
    Inventor: Takao Akiyama
  • Patent number: 11029233
    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: Grant
    Filed: March 9, 2018
    Date of Patent: June 8, 2021
    Assignee: Meidensha Corporation
    Inventor: Takao Akiyama
  • Patent number: 10948383
    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: Grant
    Filed: November 22, 2018
    Date of Patent: March 16, 2021
    Assignee: Meidensha Corporation
    Inventor: Takao Akiyama
  • Patent number: 10942091
    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: Grant
    Filed: December 11, 2018
    Date of Patent: March 9, 2021
    Assignee: MEIDENSHA CORPORATION
    Inventors: Takao Akiyama, Tomoaki Kimura