Patents by Inventor Takayoshi Sugawara
Takayoshi Sugawara 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: 9796407Abstract: A steering angle detecting apparatus for vehicles includes a vernier calculating section that performs vernier calculation based on a steering shaft angle and a motor angle, a neutral period specifying section that specifies a neutral period including a neutral point based on a reference angle calculated by the vernier calculation in the vernier calculating section, and a neutral point specifying section that specifies the neutral point from the neutral period and a stored neutral point value, and outputs a steering angle the neutral point of which is specified.Type: GrantFiled: February 1, 2016Date of Patent: October 24, 2017Assignee: NSK LTD.Inventors: Takayoshi Sugawara, Ryo Minaki, Hideki Sawada
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Publication number: 20170297614Abstract: [Problem] An object of the present invention is to provide an electric power steering apparatus capable of smoothly switching the control systems without self-steer by gradually changing a control torque of the torque control and a command value of the position/speed control upon fade processing that switches the control systems.Type: ApplicationFiled: November 30, 2015Publication date: October 19, 2017Applicant: NSK LTD.Inventors: Ryo MINAKI, Takayoshi SUGAWARA, Hideki SAWADA
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Publication number: 20170274928Abstract: [Problem] An object of the present invention is to provide an electric power steering apparatus capable of smoothly switching the control systems without self-steer by gradually changing a control torque of the torque control and a command value of the position/speed control upon the fade processing [Means for solving the problem] The present invention is the electric power steering apparatus including a torque sensor to detect a steering torque and a motor control unit to control a motor that applies an assist torque to a steering system of a vehicle, comprising: a function to switch a control system of the motor between a torque control system to control a motor output torque and a position/speed control system to control a steering angle of a steering in accordance with a predetermined switching trigger, wherein a fade processing which switches from the torque control system to the position/speed control system or vice versa.Type: ApplicationFiled: November 30, 2015Publication date: September 28, 2017Applicant: NSK LTD.Inventors: Ryo MINAKI, Takayoshi SUGAWARA, Hideki SAWADA
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Publication number: 20170166243Abstract: An electric power steering apparatus that improves an on-center feeling while improving vehicle response by increasing a steering assist current in a torque range where a steering torque is equal to or less than a static friction torque of a reduction mechanism mainly so as to reduce a static friction uncomfortable feeling in the vicinity of on-center. The apparatus drive-controls a motor for providing a steering mechanism with a steering assist force using a current command value calculated based on at least a steering torque. The apparatus includes: a static friction compensating section that calculates a static friction compensation command value for compensating static friction of the steering mechanism based on the steering torque and a vehicle speed, wherein the current command value is corrected with the static friction compensation command value.Type: ApplicationFiled: August 3, 2015Publication date: June 15, 2017Applicant: NSK LTD.Inventors: Takayoshi SUGAWARA, Masahiro MAEDA
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Patent number: 9667179Abstract: A multi-phase motor control apparatus that reduces the occurrence of the vibrations and the noises by setting the shift amount per time more finely after realizing a reduction in processing ability of a CPU by using a one-shunt type current detection circuit and an electric power steering apparatus using the same. The apparatus includes a PWM-signal generating section that generates plural second each-phase PWM-signals within two control periods based on the current estimation value and the carrier signal, and in a case that a phase shift amount of a predetermined phase in a just before control period is zero and a phase shift amount of a predetermined phase in a present control period is not zero, the phase shift control section gradually increases the phase shift amount from zero in the present control period and a next control period, and uses the second each-phase PWM-signals in the next control period.Type: GrantFiled: May 4, 2016Date of Patent: May 30, 2017Assignee: NSK LTD.Inventors: Takayoshi Sugawara, Yousuke Imamura, Hiroyasu Kumagai
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Patent number: 9586616Abstract: An electric power steering device includes a torque detector including an input shaft rotational angle detector and an output shaft rotational angle detector configured to respectively detect rotational angles of an input shaft and an output shaft coupled by a torsion bar arranged in a steering system of a vehicle; an electric motor configured to be controlled based on a torque detection value detected by the torque detector, and to generate a steering assistance force to be exerted on the output shaft; a motor rotational angle detector configured to detect a motor rotational angle of the electric motor; and a noise suppression unit configured to reduce a noise in a signal of the rotational angle of the output shaft detected by the output shaft rotational angle detector, by using the motor rotational angle detected by the motor rotational angle detector.Type: GrantFiled: February 23, 2015Date of Patent: March 7, 2017Assignee: NSK Ltd.Inventors: Takayoshi Sugawara, Yousuke Imamura, Masahiro Maeda
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Publication number: 20160362128Abstract: A steering angle detecting apparatus for vehicles includes a vernier calculating section that performs vernier calculation based on a steering shaft angle and a motor angle, a neutral period specifying section that specifies a neutral period including a neutral point based on a reference angle calculated by the vernier calculation in the vernier calculating section, and a neutral point specifying section that specifies the neutral point from the neutral period and a stored neutral point value, and outputs a steering angle the neutral point of which is specified.Type: ApplicationFiled: February 1, 2016Publication date: December 15, 2016Applicant: NSK LTD.Inventors: Takayoshi SUGAWARA, Ryo MINAKI, Hideki SAWADA
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Publication number: 20160304119Abstract: An electric power steering device includes a torque detector including an input shaft rotational angle detector and an output shaft rotational angle detector configured to respectively detect rotational angles of an input shaft and an output shaft coupled by a torsion bar arranged in a steering system of a vehicle; an electric motor configured to be controlled based on a torque detection value detected by the torque detector, and to generate a steering assistance force to be exerted on the output shaft; a motor rotational angle detector configured to detect a motor rotational angle of the electric motor; and a noise suppression unit configured to reduce a noise in a signal of the rotational angle of the output shaft detected by the output shaft rotational angle detector, by using the motor rotational angle detected by the motor rotational angle detector.Type: ApplicationFiled: February 23, 2015Publication date: October 20, 2016Inventors: Takayoshi SUGAWARA, Yousuke IMAMURA, Masahiro MAEDA
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Publication number: 20160248351Abstract: A multi-phase motor control apparatus that reduces the occurrence of the vibrations and the noises by setting the shift amount per time more finely after realizing a reduction in processing ability of a CPU by using a one-shunt type current detection circuit and an electric power steering apparatus using the same. The apparatus includes a PWM-signal generating section that generates plural second each-phase PWM-signals within two control periods based on the current estimation value and the carrier signal, and in a case that a phase shift amount of a predetermined phase in a just before control period is zero and a phase shift amount of a predetermined phase in a present control period is not zero, the phase shift control section gradually increases the phase shift amount from zero in the present control period and a next control period, and uses the second each-phase PWM-signals in the next control period.Type: ApplicationFiled: May 4, 2016Publication date: August 25, 2016Applicant: NSK LTD.Inventors: Takayoshi SUGAWARA, Yousuke IMAMURA, Hiroyasu KUMAGAI
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Patent number: 9362860Abstract: A control device for a multiple motor comprises: a drive unit constituted by a pair of upper and lower arm switching elements for driving the multiphase motor; a single current detection circuit for detecting a current value; a PWM signal generation unit for generating a plurality of first phase PWM signals within two control cycles on the basis of the current value and a carrier signal; a phase shift control unit for shifting a first PWM signal with a prescribed phase generated by the PWM signal generation unit by gradually changing the amount of phase shift within the two control cycles, and outputting the shifted first PWM signal to the drive unit; and a current detection observer for estimating a current value for the multiphase motor on the basis of the current value. The PWM signal generation unit generates a plurality of second phase PWM signals within two control cycles on the basis of the estimated current value and carrier signal.Type: GrantFiled: October 11, 2013Date of Patent: June 7, 2016Assignee: NSK LTDInventors: Takayoshi Sugawara, Yousuke Imamura, Hiroyasu Kumagai
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Publication number: 20160072421Abstract: A multi-phase motor control apparatus that reduces the occurrence of the vibrations and the noises by setting the shift amount per time more finely after realizing a reduction in processing ability of a CPU by using a one-shunt type current detection circuit and an electric power steering apparatus using the same. The apparatus includes a PWM-signal generating section that generates plural second each-phase PWM-signals within two control periods based on the current estimation value and the carrier signal, and in a case that a phase shift amount of a predetermined phase in a just before control period is zero and a phase shift amount of a predetermined phase in a present control period is not zero, the phase shift control section gradually increases the phase shift amount from zero in the present control period and a next control period, and uses the second each-phase PWM-signals in the next control period.Type: ApplicationFiled: October 11, 2013Publication date: March 10, 2016Applicant: NSK LTD.Inventor: Takayoshi SUGAWARA
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Patent number: 9254863Abstract: There is provided a torque detecting device for providing a highly accurate torque signal, and an electric power steering device using the torque detecting device. A torque sensor is provided with a first coil pair and a second coil pair, which detect a relative displacement between an input shaft and an output shaft by corresponding the relative displacement to a change in impedance. Magnetization signal generating units supply exciting currents with different magnetization frequencies to the first coil pair and a second coil pair, respectively. The magnetization frequency difference is set to 3.5 kHz or higher. Moreover, low-pass filters for intercepting passage of a frequency equivalent to the magnetization frequency difference are deployed in signal processing circuits respectively.Type: GrantFiled: March 21, 2012Date of Patent: February 9, 2016Assignee: NSK Ltd.Inventors: Masaki Kuwahara, Takayuki Kobayashi, Kazuhiro Yoshida, Toshiyuki Onizuka, Takayoshi Sugawara, Nobuhiko Andou
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Patent number: 9248853Abstract: An abnormality diagnosing method is provided for a torque detecting device and an electric power steering device is provided using the torque detecting device. Immediately after the power supply is turned on and before steering auxiliary control is started, initial diagnosis is performed to determine that each monitoring block for monitoring an abnormality of a signal processing circuit constituting a torque detecting device operates normally. The initial diagnosis determines that a monitoring block is operating normally, by inputting a normal signal and an abnormal signal to the monitoring block alternately, and finding that the monitoring block carries out normal diagnosis when it receives the normal signal and that it carries out abnormal diagnosis when it receives the abnormal signal. Once all of the monitoring blocks are determined as normal, the steering auxiliary control based on a steering torque detected by the torque detecting device is started.Type: GrantFiled: March 21, 2012Date of Patent: February 2, 2016Assignee: NSK, Ltd.Inventors: Masaki Kuwahara, Takayuki Kobayashi, Kazuhiro Yoshida, Toshiyuki Onizuka, Takayoshi Sugawara, Nobuhiko Andou
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Patent number: 9056626Abstract: An electric power steering apparatus that is capable of efficiently suppressing vibrations and simultaneously minimizing steering performance degradation such as an increase in a steering wheel's viscous feeling by extracting a vibration component having an arbitrary amplitude and an arbitrary frequency range depending on an electric power steering state parameter and feeding back a vibration suppression compensation value determined depending on the extracted vibration component to a current command value.Type: GrantFiled: April 24, 2013Date of Patent: June 16, 2015Assignee: NSK LTD.Inventors: Yousuke Imamura, Takayoshi Sugawara, Masahiro Maeda
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Publication number: 20150088381Abstract: An electric power steering apparatus that is capable of efficiently suppressing vibrations and simultaneously minimizing steering performance degradation such as an increase in a steering wheel's viscous feeling by extracting a vibration component having an arbitrary amplitude and an arbitrary frequency range depending on an electric power steering state parameter and feeding back a vibration suppression compensation value determined depending on the extracted vibration component to a current command value.Type: ApplicationFiled: April 24, 2013Publication date: March 26, 2015Applicant: NSK LTD.Inventors: Yousuke Imamura, Takayoshi Sugawara, Masahiro Maeda
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Patent number: 8825301Abstract: An electric power steering apparatus that compensates both a static friction and a dynamic friction, performs the switching between a static friction compensation and a dynamic friction compensation smoothly and without unpleasant sensation in order to achieve a natural comfortable steering feeling. In an electric power steering apparatus wherein a current command value is calculated based on at least a steering torque, and a motor is controlled by a current control value calculated based on said current command value to provide a steering assist force to a steering mechanism, wherein: there is provided a friction compensator calculating a friction compensation value for compensating friction to said steering mechanism on the basis of said steering torque, and said current command value is corrected by said friction compensation value.Type: GrantFiled: January 25, 2010Date of Patent: September 2, 2014Assignee: NSK Ltd.Inventors: Takayoshi Sugawara, Masahiro Maeda, Yong Wei
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Publication number: 20140195117Abstract: There is provided a torque detecting device for providing a highly accurate torque signal, and an electric power steering device using the torque detecting device. A torque sensor is provided with a first coil pair and a second coil pair, which detect a relative displacement between an input shaft and an output shaft by corresponding the relative displacement to a change in impedance. Magnetization signal generating units supply exciting currents with different magnetization frequencies to the first coil pair and a second coil pair, respectively. The magnetization frequency difference is set to 3.5 kHz or higher. Moreover, low-pass filters for intercepting passage of a frequency equivalent to the magnetization frequency difference are deployed in signal processing circuits respectively.Type: ApplicationFiled: March 21, 2012Publication date: July 10, 2014Applicant: NSK Ltd.Inventors: Masaki Kuwahara, Takayuki Kobayashi, Kazuhiro Yoshida, Toshiyuki Onizuka, Takayoshi Sugawara, Nobuhiko Andou
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Publication number: 20140102219Abstract: An abnormality diagnosing method is provided for a torque detecting device and an electric power steering device is provided using the torque detecting device. Immediately after the power supply is turned on and before steering auxiliary control is started, initial diagnosis is performed to determine that each monitoring block for monitoring an abnormality of a signal processing circuit constituting a torque detecting device operates normally. The initial diagnosis determines that a monitoring block is operating normally, by inputting a normal signal and an abnormal signal to the monitoring block alternately, and finding that the monitoring block carries out normal diagnosis when it receives the normal signal and that it carries out abnormal diagnosis when it receives the abnormal signal. Once all of the monitoring blocks are determined as normal, the steering auxiliary control based on a steering torque detected by the torque detecting device is started.Type: ApplicationFiled: March 21, 2012Publication date: April 17, 2014Applicant: NSK Ltd.Inventors: Masaki Kuwahara, Takayuki Kobayashi, Kazuhiro Yoshida, Toshiyuki Onizuka, Takayoshi Sugawara, Nobuhiko Andou
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Publication number: 20110276229Abstract: [Problem] An object is to provide an electric power steering apparatus that compensates both a static friction and a dynamic friction, performs the switching between a static friction compensation and a dynamic friction compensation smoothly and without unpleasant sensation in order to achieve a natural comfortable steering feeling. [Means for Solving] In an electric power steering apparatus wherein a current command value is calculated based on at least a steering torque, and a motor is controlled by a current control value calculated based on said current command value to provide a steering assist force to a steering mechanism, wherein: there is provided a friction compensator calculating a friction compensation value for compensating friction to said steering mechanism on the basis of said steering torque, and said current command value is corrected by said friction compensation value.Type: ApplicationFiled: January 25, 2010Publication date: November 10, 2011Applicant: NSK LTD.Inventors: Takayoshi Sugawara, Masahiro Maeda, Yong Wei