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公开(公告)号：US20200255055A1
公开(公告)日：2020-08-13
申请号：US16499709
申请日：2018-10-26
Applicant: NSK Ltd.
Inventor： Hiroaki TAKASE , Ryo MINAKI , Takayoshi SUGAWARA , Kouichi NAMPEI
Abstract: A motor control device for performing PWM control of an inverter for driving a three-phase brushless motor on the basis of a current command value, wherein the motor control device is provided with: a voltage command value computation unit for calculating a voltage command value using the current command value, and a motor rotation speed and a motor electric angle acquired for each control cycle from the three-phase brushless motor; an electric angle interpolation unit for estimating an interpolated electric angle from the motor electric angle at division intervals obtained by dividing the control cycle; a conversion unit for calculating a three-phase Duty command value from the voltage command value and the motor electric angle, and calculating a three-phase interpolated Duty command value from the voltage command value and the interpolated electric angle; and an output setting unit for switching between, and outputting, the three-phase Duty command value and the three-phase interpolated Duty command value so as to match the division intervals.
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公开(公告)号：US20190168801A1
公开(公告)日：2019-06-06
申请号：US16320664
申请日：2017-08-16
Applicant: NSK Ltd.
Inventor： Hiroaki TAKASE , Ryo MINAKI , Hideki SAWADA , Takayoshi SUGAWARA
CPC classification number: B62D5/0463 , B62D5/046 , B62D6/00 , H02M1/38 , H02M7/5395 , H02M2001/385 , H02P21/06 , H02P27/08
Abstract: An electric power steering apparatus of vector control system that calculates steering assist command values of dq axes based on at least a steering torque, calculates dq-axes current command values from the steering assist command values, converts the 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 the electric power steering apparatus has plural dead time compensating functions of which efficiencies to respectively perform a dead time compensation of the inverter are different each other, and performs the dead time compensation by gradually shifting from one of the plural dead time compensating functions to an another dead time compensating function while mixing the plural dead time compensating functions.
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公开(公告)号：US20180229764A1
公开(公告)日：2018-08-16
申请号：US15751315
申请日：2016-09-15
Applicant: NSK LTD.
Inventor： Takayoshi SUGAWARA , Hideki SAWADA , Ryo MINAKI
CPC classification number: B62D5/0487 , B62D5/043 , B62D5/0484 , B62D5/049 , B62D6/10 , H02P6/17 , H02P6/18 , H02P25/22 , H02P27/085 , H02P29/028
Abstract: [Problem]An object of the present invention is to provide an electric power steering apparatus that can perform an angle estimating by using a motor regenerative current so as to accurately perform an angle estimating even in a low speed steering.[Means for Solving the Problem]The present invention is the electric power steering apparatus that calculates a current command value based on at least a steering torque, driving-controls a motor, which applies an assist torque to a steering system based on the current command value, by an inverter with respective phase duties of a PWM, and detects an angle of the steering system or the motor, comprising: an angle estimating section to estimate the angle when a detecting system of the angle is failed, wherein the electric power steering apparatus performs an assist-control based on an estimating angle that is estimated at the angle estimating section. The present invention can be also adapted to the control of the motor having multi-system windings.
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公开(公告)号：US20170166243A1
公开(公告)日：2017-06-15
申请号：US15312075
申请日：2015-08-03
Applicant: NSK LTD.
Inventor： Takayoshi SUGAWARA , Masahiro MAEDA
CPC classification number: B62D5/0463 , B62D6/00 , B62D6/02 , B62D6/10
Abstract: 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.
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公开(公告)号：US20190375449A1
公开(公告)日：2019-12-12
申请号：US16479254
申请日：2018-02-13
Applicant: NSK LTD.
Inventor： Hiroaki TAKASE , Ryo MINAKI , Hideki SAWADA , Takayoshi SUGAWARA
Abstract: An electric power steering apparatus of a vector control system that drives and controls a motor by an inverter and applies an assist torque to a steering system of a vehicle, including the first compensation function to perform a dead time (DT) compensation based on respective phase motor terminal voltages and respective phase duty command values, the second compensation function to perform a DT compensation based on steering assist command values, the third compensation function to perform the DT compensation based on dq-axis current command values, and a temperature detecting section to detect temperature of ECU, wherein the correction of the DT compensation is performed based on the temperature, wherein switches of the compensation functions are performed by using a conditional branch due to software and a gradual-changing switch, wherein the dq-axis DT compensation values after the conditional branch and the gradual-changing switch are performed are calculated, and wherein the dq-axis voltage command values are compensated by the dq-axis DT compensation values.
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Patent Agency Ranking
公开(公告)号：US20190241208A1
公开(公告)日：2019-08-08
申请号：US16312443
申请日：2017-07-20
Applicant: NSK LTD.
Inventor： Hiroaki TAKASE , Ryo MINAKI , Hideki SAWADA , Takayoshi SUGAWARA
Abstract: An electric power steering apparatus of a vector control system that compensates a dead time of an inverter without tuning operation, improves a distortion of a current waveform and a responsibility of a current control, and suppresses a steering sound, a vibration and a ripple. The apparatus converts dq-axes current command values calculated based on at least a steering torque into 3-phase voltage command values, converts the 3-phase voltage command values into 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 3-phase detection voltages are estimated based on 3-phase motor terminal voltages, wherein loss voltages due to a dead time of the inverter are estimated from differences between 3-phase command voltages calculated from the duty command values and the 3-phase detection voltages, and wherein a dead time compensation of the inverter is performed by feeding-back dead time compensation values obtained by compensating the loss voltages to the 3-phase voltage command values.
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公开(公告)号：US20180178832A1
公开(公告)日：2018-06-28
申请号：US15738964
申请日：2016-07-07
Applicant: NSK LTD.
Inventor： Ryo MINAKI , Takayoshi SUGAWARA , Hideki SAWADA
CPC classification number: B62D5/049 , B62D5/04 , B62D5/0463 , B62D6/00 , B62D15/0215 , B62D15/0235 , G07C5/0808 , H02P23/00 , H02P23/0004
Abstract: [Problem]An object of the present invention is to provide an electric power steering apparatus with high quality and reasonable price that estimates a motor shaft angle and a steering shaft angle with high accuracy by learning nonlinear elements of a mechanism system and a steering system, and can back up the both angle sensors by utilizing the estimating angles of the angle sensors.[Means for solving the problem]The present invention is the electric power steering apparatus that a motor to assist-control a steering system of a vehicle is connected to a steering shaft via a reduction mechanism, and comprises a first angle sensor to detect a steering shaft angle of the steering shaft and a second angle sensor to detect a motor shaft angle of the motor, comprising: a function that obtains compensation value maps by iteratively learning characteristics of nonlinear elements including the reduction mechanism based on an actual measuring angle of the first angle sensor, an actual measuring angle of the second angle sensor, a motor torque and a motor angular speed, and estimates the steering shaft angle and the motor shaft angle by using the compensation value maps.
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公开(公告)号：US20170305459A1
公开(公告)日：2017-10-26
申请号：US15512729
申请日：2015-11-30
Applicant: NSK LTD.
Inventor： Ryo MINAKI , Takayoshi SUGAWARA , Hideki SAWADA
CPC classification number: B62D5/0463 , B62D1/28 , B62D1/286 , B62D6/00 , 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. 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.
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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
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.
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公开(公告)号：US20200180682A1
公开(公告)日：2020-06-11
申请号：US16613831
申请日：2018-06-12
Applicant: NSK Ltd.
Inventor： Hiroaki TAKASE , Ryo MINAKI , Hideki SAWADA , Takayoshi SUGAWARA
Abstract: A vector-control type motor control unit that calculates dq-axes control assist command values, calculates dq-axes current command values from the dq-axes control assist command values, converts the dq-axes current command values into 3-phase duty command values, and drives and controls a 3-phase brushless motor by an inverter of a PWM control, wherein a dead time compensation of the inverter is performed by calculating 3-phase dead time reference compensation values based on a motor rotational angle which is phase-corrected by using the dq-axes current command values, calculating dead time compensation values by processing the 3-phase dead time reference compensation values by a gain and a sign, and adding the dead time compensation values to dq-axes voltage command values or 3-phase voltage command values.
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