公开(公告)号：US20170297614A1

公开(公告)日：2017-10-19

申请号：US15516145

申请日：2015-11-30

Applicant: NSK LTD.

Inventor： Ryo MINAKI ,  Takayoshi SUGAWARA ,  Hideki SAWADA

IPC: B62D5/04 ,  B62D6/08 ,  B62D6/04 ,  B62D1/28

CPC classification number: B62D5/0463 ,  B62D1/28 ,  B62D1/286 ,  B62D5/0493 ,  B62D6/007 ,  B62D6/04 ,  B62D6/08 ,  B62D15/025 ,  B62D15/027

Abstract: [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.[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 of a torque system to control a motor output torque and a position/speed control system of a steering angle system to control a steering angle of a steering in accordance with a predetermined switching trigger, wherein each of a steering angle command value and a steering angle speed of the position/speed control system and an assist torque level of the torque control system gradually change sensitive to the steering torque, when shifting from the torque control system to the position/speed control system or vice versa.

公开(公告)号：US20200269905A1

公开(公告)日：2020-08-27

申请号：US16630664

申请日：2019-06-07

Applicant: NSK LTD.

Inventor： Takayoshi SUGAWARA ,  Takuya MASUKO ,  Tomoki FUKUDA ,  Hideki SAWADA

IPC: B62D5/04 ,  B62D5/00 ,  B62D6/00 ,  B62D15/02

Abstract: An electric power steering system is provided that is capable of performing assist control in which a change in a steering feel is reduced. The electric power steering system includes a current command value calculating unit configured to output a current command value Iref1 in accordance with steering torque and a vehicle speed on the basis of an assist map. The current command value calculating unit includes a vibration component reducing section configured to reduce a vibration component resulting from vibrations for warning that have been transmitted to a steering wheel and included in the steering torque.

公开(公告)号：US20190382048A1

公开(公告)日：2019-12-19

申请号：US16479269

申请日：2018-02-19

Applicant: NSK LTD.

Inventor： Hideki SAWADA ,  Yukie FUJIWARA ,  Ryo MINAKI ,  Takayoshi SUGAWARA

IPC: B62D5/04 ,  B62D6/00

Abstract: An electric power steering apparatus that drives and controls a motor which applies an assist orque to a steering system of a vehicle and has a function switching between an assist mode and an automatic mode, including a torsion bar torsional angle calculating section to calculate a torsion bar torsional angle based on a torque information, an output-side column shaft relative angle generating section to output an output-side relative angle from an electrical angle signal of the motor, an actual handle angle calculating section to calculate an actual handle angle based on the torsion bar torsional angle and the output-side relative angle, a resonance filter to obtain an estimated handle angle in a hands-off state from the output-side relative angle, and a hands-on/off judging section to judge a hands-on state when a time that a deviation angle between the actual handle angle and the estimated handle angle is equal to or more than a predetermined angle is continued for the predetermined time or more.

公开(公告)号：US20190252972A1

公开(公告)日：2019-08-15

申请号：US16312682

申请日：2017-07-18

Applicant: NSK LTD.

Inventor： Ryo MINAKI ,  Hiroaki TAKASE ,  Hideki SAWADA ,  Takayoshi SUGAWARA

IPC: H02M1/38 ,  B62D5/04 ,  B62D6/00 ,  H02P21/22 ,  H02P21/13 ,  H02P27/08 ,  H02M7/5387 ,  H02P21/05 ,  H02P21/14

Abstract: [Problem]An object of the present invention is to provide an electric power steering apparatus of a vector control system that compensates a dead time of an inverter, a motor back-EMF and an interference voltage due to a mutual inductance between motor windings, improves a distortion of a current waveform and a responsibility of a current control, and suppresses a noise, vibration and a ripple.[Means for Solving the Problem]The present invention is the electric power steering apparatus that driving-controls a 3-phase brushless motor which applies an assist torque to a steering mechanism of a vehicle by using a current command value calculated based on at least a steering torque, and vector-controls the 3-phase brushless motor, via an inverter, by converting dq-axes command values converted from the current command value into 3-phase values, comprising a dq-axes disturbance observer to compensate respective axes disturbance voltages, which include a dead time of the inverter, for the dq-axes command values, or comprising: a dq-axes disturbance observer to compensate respective axes disturbance voltages, which include a dead time of the inverter, for the dq-axes command values and a spatial vector modulating section.

公开(公告)号：US20180354550A1

公开(公告)日：2018-12-13

申请号：US15780502

申请日：2016-11-04

Applicant: NSK LTD.

Inventor： Hideki SAWADA ,  Takayoshi SUGAWARA ,  Ryo MINAKI

IPC: B62D5/04 ,  H02P21/22 ,  B62D6/02 ,  B62D6/00

CPC classification number: B62D5/0463 ,  B62D5/0481 ,  B62D6/00 ,  B62D6/002 ,  B62D6/02 ,  H02P21/00 ,  H02P21/22

Abstract: [Problem]An object of the present invention is to provide a control method and a control unit of an electric power steering apparatus that simplifies a calculation of a transformation from a two-phase command value to a three-phase command value performed in the case of driving and controlling a motor mounted on the electric power steering apparatus, reduces a load of the calculation, and enables installation to a microcomputer.[Means for solving the problem]A control method comprises a transformation step of transforming a two-phase command value calculated from the current command value into a three-phase command value; the transformation step separates a region for a vector consisting of the two-phase command value into six sectors, and transforms the two-phase command value into the three-phase command value in accordance with a calculation method that is predefined in each sector and is simplified; and the electric power steering apparatus drives the motor in accordance with the three-phase command value.

公开(公告)号：US20180170421A1

公开(公告)日：2018-06-21

申请号：US15897928

申请日：2018-02-15

Applicant: NSK LTD.

Inventor： Ryo MINAKI ,  Takayoshi SUGAWARA ,  Hideki SAWADA

IPC: B62D5/04 ,  B62D15/02

CPC classification number: B62D5/0463 ,  B62D1/286 ,  B62D5/04 ,  B62D15/02 ,  B62D15/021 ,  B62D15/0285

Abstract: An 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, including 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, such that a fade processing switches from the torque control system to the position/speed control system or vice versa.

公开(公告)号：US20180009472A1

公开(公告)日：2018-01-11

申请号：US15545539

申请日：2016-02-02

Applicant: NSK LTD.

Inventor： Hideki SAWADA ,  Takayoshi SUGAWARA ,  Ryo MINAKI

IPC: B62D6/00 ,  B62D5/04 ,  B62D15/02

CPC classification number: B62D6/002 ,  B62D5/0409 ,  B62D5/0463 ,  B62D15/0215

Abstract: A steering holding judging apparatus for the vehicle including: at least two steering angle sensors to detect a steering angle; and a steering state judging section to calculate a hysteresis central value by using a hysteresis signal that sets a hysteresis width to the two steering angle sensor, judge a steering state using the hysteresis central value, and output provisional steering information, wherein a steering holding state is detected based on the provisional steering information, and the electric power steering apparatus equipped with the steering holding judging apparatus for the vehicle.

公开(公告)号：US20190337553A1

公开(公告)日：2019-11-07

申请号：US16311856

申请日：2017-07-14

Applicant: NSK LTD.

Inventor： Ryo MINAKI ,  Hiroaki TAKASE ,  Hideki SAWADA ,  Takayoshi SUGAWARA

IPC: B62D5/04 ,  H02P21/05 ,  H02P21/13 ,  H02P6/10

Abstract: A vector control type electric power steering apparatus that compensates a dead time of an inverter, a motor back-EMF and an interference voltage by means of a mutual inductance between motor windings, improves a distortion of a current waveform and a responsibility of a current control, and suppresses a noisy sound, vibration and a ripple. The apparatus driving-controls a three-phase brushless motor which applies an assist torque to a steering mechanism of a vehicle by using a current command value calculated based on at least a steering torque, and vector-controls the three-phase brushless motor by using dq-axis command values that are converted from the current command value via an inverter, including: a 3-phase disturbance observer to compensate respective phase disturbance voltages, which include a dead time of the inverter, for 3-phase voltage command values.

公开(公告)号：US20190256128A1

公开(公告)日：2019-08-22

申请号：US16312723

申请日：2017-07-07

Applicant: NSK LTD.

Inventor： Hiroaki TAKASE ,  Ryo MINAKI ,  Hideki SAWADA ,  Takayoshi SUGAWARA

IPC: B62D5/04 ,  H02P6/08 ,  H02P27/08

Abstract: An electric power steering apparatus of a vector control system converts calculated dq-axes current command values into 3-phase duty command values, driving-controls a 3-phase brushless motor by an inverter of a PWM control, and applies an assist torque to a steering system of a vehicle, wherein compensation signs of 3-phase current model command values in which the dq-axes current command values are converted into a 3-phase current command value model are estimated, wherein a dead time compensation amount is calculated based on an inverter-applying voltage, and wherein dead time compensation is performed by adding dead time compensation values that are 2-phase values converted from 3-phase values in which the compensation signs are multiplied with the dead time compensation amount, to dq-axes voltage command values, or by adding 3-phase dead time compensation values to 3-phase voltage command values.

公开(公告)号：US20190023312A1

公开(公告)日：2019-01-24

申请号：US16140026

申请日：2018-09-24

Applicant: NSK LTD.

Inventor： Ryo MINAKI ,  Takayoshi SUGAWARA ,  Hideki SAWADA

IPC: B62D5/04 ,  B62D1/28 ,  B62D6/00 ,  B62D15/02

Abstract: An 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, including: 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. The fade processing time from the torque control system to the position/speed control system and the fade processing time from the position/speed control system to the torque control system are individually set.