Patents by Inventor Takahiro Tsubaki
Takahiro Tsubaki 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).
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Patent number: 9789901Abstract: [Problem] An object of the present invention is to provide an electric power steering apparatus that achieves desired steering feeling by controlling a column angle to follow a value corresponding to a steering angle and vehicle information, and that is not affected by variations in manufacturing, changes due to aging or the like of a vehicle and a steering system. [Means for Solving the Problem] An electric power steering apparatus that calculates a current command value based on at least a steering torque, and assists and controls a steering system by driving a motor based on the current command value, comprises a target column angle calculating section that calculates a target column angle based on a steering angle and vehicle information, and a column angle control section that calculates the current command value based on the target column angle and a detected actual column angle; and performs angle control of making a column angle a value corresponding to the steering angle and the vehicle information.Type: GrantFiled: September 3, 2015Date of Patent: October 17, 2017Assignee: NSK LTD.Inventors: Takahiro Tsubaki, Atsushi Oshima
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Publication number: 20170232997Abstract: [Problem] An object of the present invention is to provide an electric power steering apparatus that achieves desired steering feeling by controlling a column angle to follow a value corresponding to a steering angle and vehicle information, and that is not affected by variations in manufacturing, changes due to aging or the like of a vehicle and a steering system. [Means for Solving the Problem] An electric power steering apparatus that calculates a current command value based on at least a steering torque, and assists and controls a steering system by driving a motor based on the current command value, comprises a target column angle calculating section that calculates a target column angle based on a steering angle and vehicle information, and a column angle control section that calculates the current command value based on the target column angle and a detected actual column angle; and performs angle control of making a column angle a value corresponding to the steering angle and the vehicle information.Type: ApplicationFiled: September 3, 2015Publication date: August 17, 2017Applicant: NSK Ltd.Inventors: Takahiro TSUBAKI, Atsushi OSHIMA
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Publication number: 20170217479Abstract: An electric power steering apparatus that enables implementation of a desired steering torque without being affected by a state of a road surface by controlling a steering torque so as to become a value corresponding a steering angle and a steering angular velocity. The apparatus includes a SAT compensation value calculating section that calculates a SAT compensation value based on a SAT value; and a steering reaction compensation value calculating section that calculates a steering reaction compensation value based on the SAT compensation value, a steering angle and a steering angular velocity, and corrects the current command value by the steering reaction compensation value. Further, an electric power steering apparatus controls a twist angle of a torsion bar so as to follow a value corresponding to a steered angle.Type: ApplicationFiled: August 4, 2015Publication date: August 3, 2017Applicant: NSK LTD.Inventor: Takahiro TSUBAKI
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Patent number: 9701338Abstract: An electric power steering apparatus that suppresses the vibration of the operating member and improves the steering feeling due to the characteristic compensation of the assist map, without a change of a proportional and integral (PI) control gain in the current control section. The electric power steering apparatus includes a first compensating section provided at a front stage of the assist map and a second compensating section provided at a rear stage of the assist map. A current command value is calculated with a characteristic of which sloping increases for an absolute value of the steering torque being input into the first compensating section and being output from the second compensating section. Therefore, vibrations of operating members are suppressed.Type: GrantFiled: August 5, 2015Date of Patent: July 11, 2017Assignee: NSK LTD.Inventor: Takahiro Tsubaki
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Patent number: 9663143Abstract: A control unit for an electric power steering apparatus that controls a motor based on a current command value (2) calculated based on a current command value (1) due to steering torque generated on a steering shaft and a current detection value of the motor providing a steering mechanism with a steering assist force. The apparatus includes an SAT estimating section that inputs a motor angular velocity, a motor angular acceleration, the current command value (1) and the steering torque, and estimates a self-aligning torque (SAT) or measures by a sensor; and a feedback section that processes the estimated SAT value and outputs an SAT compensation value. The feedback section comprises a BPF, a dead band section, a steering torque sensitive gain section and a vehicle velocity sensitive gain section. The current command value (2) is obtained by adding the SAT compensation value to the current command value (1).Type: GrantFiled: August 22, 2014Date of Patent: May 30, 2017Assignee: NSK LTD.Inventor: Takahiro Tsubaki
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Patent number: 9637166Abstract: Although the steering angle control of a steering wheel is performed using automatic steering control, when the steering torque is applied by the steering wheel operation of the driver, the target steering angle is corrected to become the same direction as a direction that the steering torque is applied, and the steering angle control is performed to coincide with that target steering angle. Thereby, in the case of adding together outputs of the steering angle control with respect to the corrected target steering angle and the assist control by the steering torque with a certain ratio, it is possible to make the output direction of the automatic steering control coincide with the output direction of the manual steering control, and the control outputs become hard to interfere with each other. As a result, the uncomfortable feeling given to the driver that occurs in switching the steering mode is reduced.Type: GrantFiled: February 4, 2014Date of Patent: May 2, 2017Assignee: NSK LTD.Inventors: Takahiro Tsubaki, Tetsuya Kitazume, Keita Yoshida
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Patent number: 9623899Abstract: An electric power steering apparatus that detects that a driver has steered the handle by using a steering torque detected by a torque sensor, switches to the manual steering mode due to a capacity (an integrated value) corresponding to a generated torque, and does not provide an uncomfortable feeling to the driver.Type: GrantFiled: January 23, 2014Date of Patent: April 18, 2017Assignee: NSK LTD.Inventors: Takahiro Tsubaki, Tetsuya Kitazume, Yoshiki Ninomiya
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Publication number: 20160318548Abstract: [Problem] An object of the present invention is to provide an electric power steering apparatus that suppresses the vibration of the operating member such as the handle and improves the steering feeling due to the characteristic compensation of the assist map, without of the change of the PI-control gain in the current control section.Type: ApplicationFiled: August 5, 2015Publication date: November 3, 2016Applicant: NSK LTD.Inventor: Takahiro TSUBAKI
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Patent number: 9446789Abstract: An electric power steering apparatus that realizes vibration suppression of response characteristics and has a control performance having resistance properties against disturbances such as a road surface change by using a velocity I-P control (a proportional-lead type PI control) in a vehicle having functions of an automatic steering control and a manual steering control.Type: GrantFiled: February 3, 2014Date of Patent: September 20, 2016Assignee: NSK LTD.Inventors: Takahiro Tsubaki, Tetsuya Kitazume, Keita Yoshida
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Patent number: 9440675Abstract: An electric power steering apparatus that is capable of performing the automatic steering control without using any particular parts in a vehicle having functions of the automatic steering control and the manual steering control, and improves accuracy of the automatic steering by comprising a damping control function and correcting the target steering angle by the calculated actual steering angle.Type: GrantFiled: February 3, 2014Date of Patent: September 13, 2016Assignee: NSK LTD.Inventor: Takahiro Tsubaki
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Publication number: 20160251028Abstract: A control unit for an electric power steering apparatus that controls a motor based on a current command value (2) calculated based on a current command value (1) due to steering torque generated on a steering shaft and a current detection value of the motor providing a steering mechanism with a steering assist force. The apparatus includes an SAT estimating section that inputs a motor angular velocity, a motor angular acceleration, the current command value (1) and the steering torque, and estimates a self-aligning torque (SAT) or measures by a sensor; and a feedback section that processes the estimated SAT value and outputs an SAT compensation value. The feedback section comprises a BPF, a dead band section, a steering torque sensitive gain section and a vehicle velocity sensitive gain section. The current command value (2) is obtained by adding the SAT compensation value to the current command value (1).Type: ApplicationFiled: August 22, 2014Publication date: September 1, 2016Applicant: NSK LTD.Inventor: Takahiro Tsubaki
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Patent number: 9387877Abstract: [Problem] An object of the present invention is to provide an electric power steering apparatus that does not give uncomfortable feeling to a driver by detecting that the driver steers a steering wheel in an automatic steering mode by means of a steering torque from a torque sensor and switching to a manual steering mode by a capacity (an integrated value) corresponding to the occurring torque magnitude.Type: GrantFiled: January 14, 2014Date of Patent: July 12, 2016Assignee: NSK Ltd.Inventor: Takahiro Tsubaki
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Patent number: 9327761Abstract: An electric power steering apparatus including: a steering angle control section that calculates a motor current command value and a switching section that inputs the motor current command value to switch. The steering angle control section has a feedback control section that generates a feedback control current command value; an SAT compensating section that generates an SAT compensation current command value; and an output section that generates the motor current command value from the feedback control current command value and the SAT compensation current command value. The switching section is switched depending on a switching command of an automatic steering mode and a manual steering mode, a motor is drive-controlled based on the motor current command value in the automatic steering mode.Type: GrantFiled: January 29, 2014Date of Patent: May 3, 2016Assignee: NSK LTD.Inventor: Takahiro Tsubaki
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Publication number: 20160107680Abstract: [Problem] An object of the present invention is to provide an electric power steering control unit that detects the vibration components of the vibration compressing object such as the handle and current command value based on an expression of Fourier series of which calculation capacity is small, changes a gain of the PI control section at only a time when the vibration of the predetermined frequency continues during the predetermined time or more and compresses the vibration, and improves the steering feeling.Type: ApplicationFiled: July 3, 2014Publication date: April 21, 2016Applicant: NSK LTD.Inventors: Takahiro TSUBAKI, Tetsuya KITAZUME, Satoshi SHIMOKAWABE
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Publication number: 20160059885Abstract: [Problem] An object of the present invention is to provide an electric power steering apparatus that suppresses a handle vibration (noisy sound) being caused by a handle inertia and a spring nature of a torsion bar and improves a steering feeling, without changing of the gain of the PI control. [Means for solving the problem] The present invention is an electric power steering apparatus that assist-controls a steering by driving a motor with a current command value calculated based on at least a steering torque, comprising a vibration-damping compensating section that calculates a vibration-damping compensation command value for suppressing a vibration of a handle based on a motor velocity of the motor, wherein the current command value is corrected by the vibration-damping compensation command value.Type: ApplicationFiled: April 7, 2014Publication date: March 3, 2016Applicant: NSK LTD.Inventors: Takahiro TSUBAKI, Tamotsu OUMI
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Publication number: 20160016606Abstract: An electric power steering apparatus that is capable of performing the automatic steering control without using any particular parts in a vehicle having functions of the automatic steering control and the manual steering control, and improves accuracy of the automatic steering by comprising a damping control function and correcting the target steering angle by the calculated actual steering angle.Type: ApplicationFiled: February 3, 2014Publication date: January 21, 2016Applicant: NSK LTD.Inventor: Takahiro TSUBAKI
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Publication number: 20160001810Abstract: An electric power steering apparatus including: a steering angle control section that calculates a motor current command value and a switching section that inputs the motor current command value to switch. The steering angle control section has a feedback control section that generates a feedback control current command value; an SAT compensating section that generates an SAT compensation current command value; and an output section that generates the motor current command value from the feedback control current command value and the SAT compensation current command value. The switching section is switched depending on a switching command of an automatic steering mode and a manual steering mode, a motor is drive-controlled based on the motor current command value in the automatic steering mode.Type: ApplicationFiled: January 29, 2014Publication date: January 7, 2016Applicant: NSK LTD.Inventor: Takahiro TSUBAKI
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Publication number: 20150353125Abstract: [Problem] An object of the present invention is to provide an electric power steering apparatus that does not give uncomfortable feeling to a driver by detecting that the driver steers a steering wheel in an automatic steering mode by means of a steering torque from a torque sensor and switching to a manual steering mode by a capacity (an integrated value) corresponding to the occurring torque magnitude.Type: ApplicationFiled: January 14, 2014Publication date: December 10, 2015Applicant: NSK LTD.Inventor: Takahiro TSUBAKI
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Publication number: 20150344066Abstract: An electric power steering apparatus that detects that a driver has steered the handle by using a steering torque detected by a torque sensor, switches to the manual steering mode due to a capacity (an integrated value) corresponding to a generated torque, and does not provide an uncomfortable feeling to the driver.Type: ApplicationFiled: January 23, 2014Publication date: December 3, 2015Applicant: NSK LTD.Inventors: Takahiro TSUBAKI, Tetsuya KITAZUME, Yoshiki NINOMIYA
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Publication number: 20150191200Abstract: An electric power steering apparatus that realizes vibration suppression of response characteristics and has a control performance having resistance properties against disturbances such as a road surface change by using a velocity I-P control (a proportional-lead type PI control) in a vehicle having functions of an automatic steering control and a manual steering control.Type: ApplicationFiled: February 3, 2014Publication date: July 9, 2015Applicant: NSK LTD.Inventors: Takahiro Tsubaki, Tetsuya Kitazume, Keita Yoshida