CN112770960B - Steering control device and power steering device - Google Patents
Steering control device and power steering device Download PDFInfo
- Publication number
- CN112770960B CN112770960B CN201980063210.6A CN201980063210A CN112770960B CN 112770960 B CN112770960 B CN 112770960B CN 201980063210 A CN201980063210 A CN 201980063210A CN 112770960 B CN112770960 B CN 112770960B
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- steering
- torque
- angle
- motor
- rudder angle
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D6/00—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits
- B62D6/002—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits computing target steering angles for front or rear wheels
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D6/00—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits
- B62D6/008—Control of feed-back to the steering input member, e.g. simulating road feel in steer-by-wire applications
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Mathematical Physics (AREA)
- Steering Control In Accordance With Driving Conditions (AREA)
- Power Steering Mechanism (AREA)
Abstract
A steering control device and a power steering device are provided. One aspect of the steering control device is a steering control device that controls a rotation angle of a motor that drives a steering mechanism based on a rotation angle of a steering wheel, the steering control device including: an external disturbance observer that calculates steering reaction torque that occurs when a steering angle is changed by the steering mechanism; and a motor control unit that reduces a difference between a target rudder angle and a rudder angle in the steering mechanism by driving the motor with a rotation angle of the steering wheel and the steering reaction torque as command values.
Description
Technical Field
The present invention relates to a steering control device and a power steering device.
Background
A steering control device that controls steering of a power steering device has been known. The conventional steering control is mainly assist control.
For example, the control device disclosed in patent document 1 calculates a current command value as a control target of the motor based on the steering torque detected by the torque sensor, and defines a steering reaction force based on the self-adjustment torque estimated by the disturbance observer to feed back the steering torque.
Prior art literature
Patent literature
Patent document 1: japanese patent laid-open publication No. 2003-200844
Disclosure of Invention
Technical problem to be solved by the invention
In the control device disclosed in patent document 1, the degree of freedom in design of the controller is increased by providing a torque feedback loop, and stability of the system and processing of road surface information and external disturbance information are realized.
However, the follow-up property to the target torque is affected by the torque loss and torque pulsation of the motor due to the torque feedback. Therefore, in suppressing such an influence, a complicated compensation process is required. In addition, the design of the compensator is not easy due to the influence of manufacturing variations and aged variations of the motor. Therefore, an object of the present invention is to perform steering control with less influence of torque pulsation.
Technical proposal adopted for solving the technical problems
One aspect of the steering control device of the present invention is a steering control device for controlling a rotation angle of a motor for driving a steering mechanism according to a rotation angle of a steering wheel, the steering control device including: an external disturbance observer that calculates steering reaction torque that occurs when a steering angle is changed by the steering mechanism; and a motor control unit that reduces a difference between a target rudder angle and a rudder angle in the steering mechanism by driving the motor with a rotation angle of the steering wheel and the steering reaction torque as command values.
Further, an aspect of the power steering apparatus of the present invention includes: the steering control device; a motor controlled by the steering control device; and a power steering mechanism driven by the motor.
Effects of the invention
According to the present invention, steering control with less influence of torque pulsation can be performed.
Drawings
Fig. 1 is a schematic view showing an embodiment of a power steering apparatus according to the present invention.
Fig. 2 is a block diagram showing a structure of the electric power steering apparatus.
Fig. 3 is a diagram showing a modification of the steering control apparatus.
Fig. 4 is a view showing another modification of the steering control apparatus.
Fig. 5 is a diagram showing a modification of the electric power steering apparatus.
Detailed Description
Embodiments of a steering control device and a power steering device of the present disclosure are described in detail below with reference to the accompanying drawings. However, in the following description, in order to avoid unnecessary redundancy, those skilled in the art will readily understand that detailed descriptions other than those necessary may be omitted. For example, a detailed description of known matters and a repeated description of substantially the same configuration may be omitted. Fig. 1 is a schematic view showing an embodiment of a power steering apparatus according to the present invention.
As shown in fig. 1, this embodiment exemplifies a column type electric power steering apparatus. The electric power steering device 9 is mounted on a steering mechanism of a wheel of an automobile. The electric power steering device 9 is a column power steering device in which steering force is directly reduced by power of the steering control device 1 incorporating a motor. The electric power steering device 9 includes a steering control device 1, a steering shaft 914, and an axle 913.
The steering shaft 914 transmits the input torque transmitted from the steering wheel 911 via the torsion bar 915 to the axle 913 having the wheels 912. In other words, the steering wheel 911 applies torque to a steering mechanism including the wheels 912, the axle 913, and the steering shaft 914 via the torsion bar 915.
The power of the steering control device 1 is transmitted to the steering shaft 914 via gears or the like. The motor used in the column type electric power steering apparatus 9 is provided inside an engine compartment (not shown). Further, the electric power steering device 9 shown in fig. 1 is a column type, for example, but the power steering device of the present invention may be a rack type.
The steering angle θh, which is the rotation angle of the steering wheel 911, is detected by an angle sensor 916. The detection value detected by the angle sensor 916 is input to the steering control apparatus 1, and is used to calculate a target output of the steering control apparatus 1. Further, the torque transmitted from the torsion bar 915 to the steering shaft 914 is detected by a torque sensor 917. The detection value detected by the torque sensor 917 is input to the steering control apparatus 1 for calculating a target output of the steering control apparatus 1.
The steering shaft 914 is applied with a steering torque transmitted from the steering wheel 911 via the torsion bar 915 and an assist torque generated by power of the steering control apparatus 1, thereby generating a steering angle θs, which is a rotation angle of the steering shaft 914. Fig. 2 is a block diagram showing the structure of the electric power steering apparatus 9. In FIG. 2, θh represents a steering angle, θs represents a steering angle, K tor The torsion coefficient of the torsion bar 915 is shown, and STG(s) indicates steering characteristics.
The torsion bar 915 is twisted by a difference between a steering angle θh and a steering angle θs of the steering wheel 911 to generate torque. The steering angle θh is detected by the angle sensor 916 and input to the steering control device 1. Further, the torque generated by the torsion bar 915 is detected by a torque sensor 917 and input to the steering control apparatus 1.
The steering control apparatus 1 includes a motor 10. The motor 10 is a so-called electromechanical integrated motor, and receives input of a command value indicating a target output torque and outputs the output torque. The steering control device 1 corresponds to one embodiment of a steering control device that controls the rotation angle of a motor 10 that drives a steering mechanism based on the rotation angle of a steering wheel 911.
The torque generated by the torsion bar 915, the output torque of the motor 10, and the torque of the external disturbance D(s) are applied to a steering mechanism including the wheels 912 to the steering shaft 914 and representing the steering characteristic STG(s), and the steering angle θs is generated by the combination of these torques. The external disturbance D(s) applied to the steering mechanism is mainly a steering reaction torque generated in response to a change in the steering angle (steering angle θs) of the steering mechanism, a torque applied to the wheels 912 such as irregularities of the ground, and the like, and acts in a direction opposite to the steering force and the torque of the motor 10. Further, the steering reaction torque includes self-adjusting torque (SAT), torque accompanying friction force of the wheels 912 with the ground. The steering control device 1 drives the motor 10 based on the steering angle θh so that the steering angle θs approaches the steering angle θh.
The steering control apparatus 1 includes an angle feedback unit 21, a target steering angle estimation unit 22, a steering reaction torque estimation unit 23, and an external disturbance observer 30. The disturbance observer 30 includes a motor torque calculation section 31, a steering torque estimation section 32, and a filter 33.
The external disturbance observer 30 inputs the driving current value Imotor of the motor 10, the detection value of the torque sensor 917, and the steering angle θs. Here, the steering angle θs is obtained from the rotational speed of the motor 10 detected by a rotation sensor included in the motor 10.
The rotation shaft (output shaft) of the motor 10 and the steering shaft 914 are coupled to each other via a reduction gear or the like. Therefore, the motor 10 and the steering shaft 914 always rotate together, regardless of whether the torque that rotates the steering shaft 914 is the torque generated by the motor 10 or another torque. Therefore, the steering angle θs can be calculated from the rotation speed of the motor 10 and based on the gear ratio or the like.
The motor torque calculation section 31 of the external disturbance observer 30 inputs the driving current value Imotor of the motor 10 to the characteristic K of the motor 10 to calculate the output torque of the motor 10. The torque calculated by the motor torque calculation unit 31 is a torque used for steering among the output torques of the motor 10.
The steering torque estimating unit 32 of the disturbance observer 30 calculates the total torque applied to the steering system by inputting the steering angle θs to the inverse characteristic of the steering characteristic STG(s).
The calculated value of the external disturbance D(s) is obtained by adding the calculated value of the motor torque calculation unit 31 to the detected value of the torque sensor 917 and subtracting the calculated value of the steering torque estimation unit 32. Since the above-described estimated value includes various disturbance components, the disturbance observer 30 calculates a self-adjusting torque (SAT) among the steering reaction torques by the filtering process of the filter 33.
The self-adjustment torque (SAT) calculated by the disturbance observer 30 is input to the steering reaction force torque estimating unit 23, and is converted into the steering reaction force torque Tk generated by the steering wheel 911 based on a specific conversion characteristic.
The component of the disturbance observer 30 shown in fig. 2 combined with the steering reaction torque estimation unit 23 corresponds to an example of the disturbance observer according to the present invention. In the present embodiment, the steering reaction torque Tk is calculated using a detection value of the torque sensor 917 corresponding to a measurement value of torque applied to the steering mechanism by rotation of the steering wheel 911. Therefore, the steering reaction torque Tk is calculated with high accuracy.
The target rudder angle estimating device 22 estimates a target rudder angle θs0 based on the steering reaction torque Tk obtained by the steering reaction torque estimating device 23 and the rudder angle θh detected by the angle sensor 916. The target rudder angle θs0 is estimated by the following equations (1) and (2).
Δθ×K tor ＝Tk……(1)
θs0＝θh+Δθ……(2)
The difference between the target rudder angle θs0 thus estimated and the steering angle θs is input to the angle feedback unit 21, and a torque that is larger as the difference is larger is calculated. The assist torque is generated by inputting a command value representing the torque thus calculated to the motor 10.
The angle component Δθ added to the steering angle θh in (2) above is an angle component Δθ added to maintain the current steering angle θh against the steering reaction torque Tk, and therefore, in the steering control device
In the above, the angle control is performed to reduce the difference between the steering angle θs and the steering angle θh. In addition, since the torsion coefficient K including the torsion bar 915 is used tor Since the target rudder angle θs0 is estimated by the above equation (1), the torsion amount of the torsion bar 915 can be suppressed as a result of the angle control.
The combination of the angle feedback unit 21 and the target rudder angle estimation unit 22 corresponds to an example of a rudder angle control unit that reduces the difference between the target rudder angle θs0 and the rudder angle (steering angle θs) in the steering mechanism by driving the motor 10 with the rotation angle (steering angle θh) of the steering wheel 911 and the steering reaction torque Tk as command values.
Since the steering control device 1 performs the angle control in this way, the influence of the cogging torque depending on the rotation angle of the motor 10 is smaller than that of the torque control. In addition, under angle control, torque ripple compensation is easier than torque control. Therefore, in the steering control apparatus 1 of the present embodiment, the influence of torque pulsation in steering control is small. Further, in the electric power steering device 9 of the present embodiment, smooth assist can be achieved. Next, a modification of the electric power steering apparatus 9 and the steering control apparatus 1 will be described. Fig. 3 is a diagram showing a modification of the steering control apparatus 1.
In the modification shown in fig. 3, a speed circuit 24 is provided between the motor 10 and the angle feedback unit 21 of the steering control device 1. The speed circuit unit 24 calculates a loss torque generated depending on the rotational speed of the motor 10, such as friction, and inputs a compensation value for compensating the loss torque to the feedforward control of the motor 10.
The motor 10 outputs the total torque of the torque indicated by the command value input from the angle feedback unit 21 and the torque indicated by the compensation value input from the speed circuit unit 24. Thereby, assist assistance is achieved in which loss torque due to friction or the like is compensated. Fig. 4 is a diagram showing another modification of the steering control apparatus 1.
In the modification shown in fig. 4, the disturbance observer 30 of the steering control device 1 includes a torque estimating unit 34. The torque estimating unit 34 is configured to calculate a steering angle θs based on the rotation speed of the motor 10, a steering angle θh detected by the angle sensor 916, and a torsion coefficient K of the torsion bar 915 tor To estimate the torque applied to the steering mechanism by rotation of the steering wheel 911 via the torsion bar 915. By estimating the torque in this way, a torque sensor is not required, and the structure of the steering periphery is simple. Fig. 5 is a diagram showing a modification of the electric power steering device 9.
The modified example shown in fig. 5 is an electric power steering device 9 called steer-by-wire, which is a so-called steer-by-wire, in which a steering wheel 911 is physically separated from a steering shaft 914. That is, the steering wheel 911 is in a state where the physical transmission path of the torque is isolated from the steering mechanism. Therefore, no physical torque transmission from the steering wheel 911 to the steering mechanism occurs.
The steering angle θh of the steering wheel 911 is detected by an angle sensor 916 and input to the steering control device 1. In the modification shown in fig. 5, steering torque for the steering shaft 914 is generated by the motor 10 in the steering control device 1. In order to make the operator respond to the steering operation, a motor, not shown, generates a torque corresponding to the steering reaction torque estimated by the steering reaction torque estimating unit 23, and applies the generated torque to the steering wheel 911.
The steering control device 1 included in the electric power steering device 9 according to the modification shown in fig. 5 is preferably the steering control device 1 having feedforward control as shown in fig. 4. By performing the feedforward control, the steering mechanism exhibits a natural response to the operation of the steering wheel 911.
In such a steer-by-wire electric power steering device 9, since there is no torsion bar and no torque is generated as a control target for torque control, the angle control is more useful than torque control.
In the above description, the example in which the motor 10 is incorporated in the steering control device 1 has been shown, but the steering control device of the present invention may be a control-side-only device in which no motor is incorporated.
It should be understood that the above-described embodiments and variations are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims rather than by the above-described embodiments, and all changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein.
(symbol description)
1. A steering control device;
9. an electric power steering device;
911. a steering wheel;
912. a wheel;
913. an axle;
914. a steering shaft;
915. a torsion bar;
916. an angle sensor;
917. a torque sensor;
10. a motor;
21. an angle feedback unit;
22. a target rudder angle estimating unit;
23. a steering reaction force torque estimation unit;
24. a speed loop section;
30. an external disturbance observer;
31. a motor torque calculation unit;
32. a steering torque estimating unit;
33. a filter;
34. a torque estimating unit.
Claims (7)
1. A steering control device for controlling the rotation angle of a motor for driving a steering mechanism according to the rotation angle of a steering wheel, comprising:
an external disturbance observer that calculates a self-adjusting torque using a total torque calculated by inputting a rudder angle in the steering mechanism to the inverse characteristic of steering characteristics and applied to a steering system, a torque of the motor, and a torque generated by rotation of the steering wheel;
a steering reaction force torque estimating unit that estimates a steering reaction force torque generated in the steering wheel as the steering angle is changed by the steering mechanism, based on the self-adjustment torque; and
a steering angle control unit that reduces a difference between a target steering angle and a steering angle in the steering mechanism by driving the motor with a rotation angle of the steering wheel and the steering reaction torque as command values,
the rudder angle in the steering mechanism is a rotation angle of a shaft transmitting an input torque from the steering wheel to an axle,
the rudder angle control unit has:
a target rudder angle estimating unit that estimates the target rudder angle based on a rotation angle of the steering wheel and the steering reaction torque; and
an angle feedback section that drives the motor based on the target rudder angle and a rudder angle in the steering mechanism,
the target rudder angle estimating device estimates a target rudder angle based on a sum of a rotation angle of the steering wheel and an angle component added to maintain a current rudder angle in the steering mechanism against the steering reaction torque.
2. The steering control apparatus according to claim 1, wherein,
the steering control device further includes a feedforward control portion that performs feedforward control of the motor by a control amount that depends on a rotational speed of the motor.
3. The steering control apparatus according to claim 1 or 2, wherein,
the steering wheel applies torque to the steering mechanism via a torsion bar,
the target rudder angle calculating section calculates the target rudder angle using a torsion coefficient of the torsion bar.
4. The steering control apparatus according to claim 3, wherein,
the disturbance observer calculates the self-adjusting torque using a measurement of torque applied to the steering mechanism by rotation of the steering wheel.
5. The steering control apparatus according to claim 3, wherein,
the disturbance observer calculates the self-adjusting torque using an estimated value of torque applied to the steering mechanism by rotation of the steering wheel.
6. The steering control apparatus according to claim 2, wherein,
the physical transmission path of the torque of the steering wheel is isolated with respect to the steering mechanism.
7. A power steering apparatus, comprising:
the steering control apparatus according to any one of claims 1 to 6;
controlling a driven motor by the steering control device; and
a steering mechanism driven by the motor.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2018-180490 | 2018-09-26 | ||
| JP2018180490 | 2018-09-26 | ||
| PCT/JP2019/025351 WO2020066183A1 (en) | 2018-09-26 | 2019-06-26 | Steering control device and power steering device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112770960A CN112770960A (en) | 2021-05-07 |
| CN112770960B true CN112770960B (en) | 2023-10-10 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201980063210.6A Active CN112770960B (en) | 2018-09-26 | 2019-06-26 | Steering control device and power steering device |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JP7342876B2 (en) |
| CN (1) | CN112770960B (en) |
| DE (1) | DE112019004813T5 (en) |
| WO (1) | WO2020066183A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113665664B (en) * | 2021-08-06 | 2022-08-19 | 上海汽车工业(集团)总公司 | SBW angle following feedforward control method, storage medium and control system |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005306205A (en) * | 2004-04-21 | 2005-11-04 | Nissan Motor Co Ltd | Power steering device |
| JP2006130940A (en) * | 2004-11-02 | 2006-05-25 | Toyoda Mach Works Ltd | Steer-by-wire system |
| CN102066182A (en) * | 2008-07-30 | 2011-05-18 | 三菱电机株式会社 | Motor-driven power steering control device |
| WO2016088718A1 (en) * | 2014-12-02 | 2016-06-09 | 日本精工株式会社 | Electric power steering device |
| WO2017014228A1 (en) * | 2015-07-22 | 2017-01-26 | 日本精工株式会社 | Control device for electric power steering device |
| CN106364549A (en) * | 2015-07-24 | 2017-02-01 | 株式会社捷太格特 | Steering control device |
| CN107848571A (en) * | 2015-06-26 | 2018-03-27 | 日本精工株式会社 | The driving support control apparatus of electric booster turning mechanism is used |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3826286B2 (en) | 2002-06-28 | 2006-09-27 | 三菱自動車工業株式会社 | Electric power steering device |
| JP4340118B2 (en) | 2003-09-12 | 2009-10-07 | 株式会社豊田中央研究所 | Vehicle steering system |
| JP5223718B2 (en) * | 2009-02-17 | 2013-06-26 | 株式会社デンソー | Steering load estimation device and electric power steering device |
-
2019
- 2019-06-26 CN CN201980063210.6A patent/CN112770960B/en active Active
- 2019-06-26 JP JP2020547993A patent/JP7342876B2/en active Active
- 2019-06-26 WO PCT/JP2019/025351 patent/WO2020066183A1/en active Application Filing
- 2019-06-26 DE DE112019004813.9T patent/DE112019004813T5/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005306205A (en) * | 2004-04-21 | 2005-11-04 | Nissan Motor Co Ltd | Power steering device |
| JP2006130940A (en) * | 2004-11-02 | 2006-05-25 | Toyoda Mach Works Ltd | Steer-by-wire system |
| CN102066182A (en) * | 2008-07-30 | 2011-05-18 | 三菱电机株式会社 | Motor-driven power steering control device |
| WO2016088718A1 (en) * | 2014-12-02 | 2016-06-09 | 日本精工株式会社 | Electric power steering device |
| CN107848571A (en) * | 2015-06-26 | 2018-03-27 | 日本精工株式会社 | The driving support control apparatus of electric booster turning mechanism is used |
| WO2017014228A1 (en) * | 2015-07-22 | 2017-01-26 | 日本精工株式会社 | Control device for electric power steering device |
| CN106364549A (en) * | 2015-07-24 | 2017-02-01 | 株式会社捷太格特 | Steering control device |
Also Published As
| Publication number | Publication date |
|---|---|
| JP7342876B2 (en) | 2023-09-12 |
| JPWO2020066183A1 (en) | 2021-08-30 |
| CN112770960A (en) | 2021-05-07 |
| DE112019004813T5 (en) | 2021-06-10 |
| WO2020066183A1 (en) | 2020-04-02 |
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