WO2014108955A1

WO2014108955A1 - Steering control device and steering control method

Info

Publication number: WO2014108955A1
Application number: PCT/JP2013/007116
Authority: WO
Inventors: 拓鈴木
Original assignee: 日産自動車株式会社
Priority date: 2013-01-11
Filing date: 2013-12-04
Publication date: 2014-07-17
Also published as: JPWO2014108955A1; JP5867627B2

Abstract

Provided are a steering control device and steering control method which are capable of more appropriately reducing the deviation between a steering command angle and an actual steering angle. When determined that a vehicle is traveling straight, it is then determined that an error between a calculated pinion absolute angle (θp0) and an actual pinion absolute angle has occurred if the absolute value of the calculated pinion absolute angle (θp0) is equal to or greater than an allowable angle (θpth). In addition, the cause of this error is determined on the basis of the pinion absolute angle (θp0) calculated when determined that the vehicle is traveling straight. According to the cause of this error, the calculated pinion absolute angle (θp0) is corrected in the direction which causes the error to become smaller.

Description

Steering control device and steering control method

The present invention relates to a steering control device and a steering control method in which a steering wheel and a steered wheel are mechanically separated and the steered wheel is steered based on a steering state of the steering wheel.

Conventionally, as a technique in which the steering wheel and the steered wheel are mechanically separated and the steering control is performed based on the steering state of the steering wheel, for example, there is a technique described in Patent Document 1. This technique steers a steered wheel based on a steered command angle calculated based on a steering angle of a steering wheel and an estimated steered angle of the steered wheel.

JP 2011-5933 A

However, in the technique described in Patent Document 1, since the steered wheels are steered based on the calculated steered command angle and the estimated steered angle, there is an error in the estimated steered angle. If it is large, the steering wheel cannot be steered properly. That is, in this case, the actual turning angle deviates from the turning command angle.
Therefore, an object of the present invention is to provide a steering control device and a steering control method that can more appropriately reduce the deviation between the steering command angle and the actual steering angle.

In order to solve the above-described problem, an aspect of the present invention includes a resolver that outputs a signal that periodically changes according to a rotation angle of a steered motor that steers a steered wheel, and a signal output by the resolver. A count value indicating which section of the mechanical angle corresponds to the angle indicated by is stored. Further, based on the signal output from the resolver and the stored count value, a pinion absolute angle that is an absolute angle of the rotation angle of the pinion that meshes with the rack gear of the steering rack is calculated. When the absolute value of the pinion absolute angle calculated when it is determined that the host vehicle is traveling straight ahead is greater than or equal to the preset allowable angle, there is an error between the calculated pinion absolute angle and the actual pinion absolute angle. It is determined that the error has occurred, and the cause of the error is determined based on the pinion absolute angle calculated when it is determined that the host vehicle is traveling straight ahead. Then, according to the cause of the error, the calculated pinion absolute angle is corrected so that the error becomes smaller.

According to the present invention, when there is a deviation in the pinion absolute angle calculated based on the output signal of the resolver, correction according to the factor can be performed. Therefore, the deviation between the steering command angle and the actual steering angle can be more appropriately reduced.

1 is an overall configuration diagram of a vehicle 1 to which a vehicle steering device 2 is applied. It is a graph showing the relationship between the electrical angle and mechanical angle of a resolver with 3 pole pairs. 3 is a control block diagram of the vehicle steering device 2. FIG. It is a figure explaining the separation method of an angle shift factor. 4 is a block diagram illustrating a configuration of a pinion absolute angle correction unit 43. FIG. It is a flowchart which shows the correction process execution flag setting process procedure performed in the correction process execution flag setting part 43a. It is a flowchart which shows the correction process procedure performed in the correction process execution part 43b. It is a correction | amendment angular velocity calculation map.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the present embodiment, the present invention is applied to a vehicle steering device 2 for a vehicle 1.
(First embodiment)
(Constitution)
FIG. 1 is an overall configuration diagram of a vehicle 1 to which a vehicle steering device 2 is applied.
As shown in FIG. 1, the vehicle 1 uses the front wheels 3FL and 3FR among the front wheels 3FL and 3FR and the rear wheels 4RL and 4RR as steered wheels for turning. The vehicle steering device 2 is a steer-by-wire system that performs steering control to steer the front wheels 3FL, 3FR based on the steering state of the steering wheel 5 in a state where the steering wheel 5 and the front wheels 3FL, 3FR are mechanically separated. It is. Further, the vehicle steering device 2 variably controls the steering angle ratio, which is the ratio of the steering angle to the steering angle.

The vehicle steering device 2 includes a steering side mechanism 2a, a steering mechanism 2b, a backup mechanism 2c, and a control mechanism 2d.
(Steering side mechanism 2a)
The steering side mechanism 2a includes a steering wheel 5 that is steered by a driver, a steering shaft 6 that is coupled to the steering wheel 5, and a steering absolute angle sensor 7 that detects a steering angle (absolute angle) of the steering wheel 5. . Regarding the steering angle, the direction in which the steering wheel 5 is rotated rightward is defined as a positive direction, and the direction in which the steering wheel 5 is rotated leftward is defined as a negative direction.
Further, the steering side mechanism 2 a includes a steering torque sensor 8 that detects the steering torque of the steering wheel 5. In the steering torque, a direction in which the steering wheel 5 is rotated rightward is a positive direction, and a direction in which the steering wheel 5 is rotated leftward is a negative direction.
Further, the steering side mechanism 2 a includes a reaction force motor 9 that is connected to the steering wheel 5 via the steering shaft 6 and applies a steering reaction force to the steering wheel 5 via the steering shaft 6. Further, the steering side mechanism 2 a includes a reaction force motor rotation angle sensor 10 that detects a rotation angle of the reaction force motor 9. As the reaction force motor rotation angle sensor 10, for example, there is a resolver that outputs an analog signal that periodically changes according to the rotation angle of the reaction force motor 9.

(Steering mechanism 2b)
The steered mechanism 2b includes a steered motor 11 that steers the front wheels 3FL and 3FR, and a steered motor angle sensor 12 that detects a rotation angle of the steered motor 11. As the steered motor angle sensor 12, a resolver that outputs an analog signal that periodically changes according to the rotational angle of the steered motor 11 is used.
The steering mechanism 2 b includes a pinion 14 connected to the end of the motor shaft 13 of the steering motor 11 and a steering rack 16 including a rack gear 15 that meshes with the pinion 14. Furthermore, the steering mechanism 2b includes a tie rod 17 that transmits the axial force input to the steering rack 16 to the front wheels 3FL and 3FR as a steering force. The steering mechanism 2b includes a steering reaction force sensor 18 that detects an axial force input to the steering rack 16 as a steering reaction force acting on the front wheels 3FL and 3FR from the road surface.

Here, the resolver used for the steered motor angle sensor 12 will be described.
FIG. 2 is a graph showing the relationship between the electrical angle and mechanical angle of a resolver with 3 pole pairs.
As shown in FIG. 2, the resolver with the number of pole pairs of 3 can detect the range of the mechanical angle of 120 deg within the range of the electrical angle of 360 deg. In FIG. 2, since the electrical angle 0 deg is associated with the mechanical angle 0 deg, the electrical angles 0 deg, 180 deg, 360 deg indicate 0 deg, 60 deg, 120 deg as the detected value (analog signal) of the resolver, respectively.
In addition, since the resolver with the pole pair number of 3 can detect the range of the mechanical angle of 120 deg, for example, the range of the mechanical angle of −720 deg to 720 deg corresponds to 12 cycles in the resolver with the pole pair number of 3. That is, a resolver with a pole pair number of 3 has a mechanical angle of -720 to -600 deg for one cycle, -600 to -480 deg for two cycles, -480 deg to -360 deg for three cycles, -360 deg to -240 deg for four cycles, -240 deg. From -120deg to 5 cycles, from -120deg to 0deg is 6 cycles. Further, the mechanical angle of 0 deg to 120 deg is 7 cycles, 120 deg to 240 deg is 8 cycles, 240 deg to 360 deg is 9 cycles, 360 deg to 480 deg is 10 cycles, 480 deg to 600 deg is 11 cycles, and 600 deg to 720 deg is 12 cycles.

Therefore, for example, when the detected value (analog signal) of the resolver is 60 deg, the mechanical angles are -660 deg, -540 deg, -420 deg, -300 deg, -180 deg, -60 deg, 60 deg, 180 deg, 300 deg, 420 deg, 540 deg, It is only understood that it is either 660deg. That is, a resolver with a pole pair number of 3 can be detected within a mechanical angle range of 120 deg, but sensor values are -660 deg, -540 deg, -420 deg, -300 deg, -180 deg, -60 deg, 60 deg, 180 deg, 300 deg, 420 deg. It cannot be detected which angle is 540 deg or 660 deg. Hereinafter, the mechanical angle within the range of 0 deg to 120 deg represented by the resolver detection value (analog signal) is referred to as a relative angle.

(Backup mechanism 2c)
Returning to FIG. 1, the backup mechanism 2 c includes a clutch 19 that can mechanically fasten and separate the steering wheel 5 and the front wheels 3FL and 3FR, and a pinion shaft 20 that transmits the steering torque of the steering wheel 5 via the clutch 19. . The backup mechanism 2 c includes a pinion 21 that is connected to the end of the pinion shaft 20 and meshes with the rack gear 15 of the steering rack 16.

(Control mechanism 2d)
The control mechanism 2d includes a vehicle speed sensor (vehicle speed detection unit) 22 that detects the vehicle speed, a yaw rate sensor 23 that detects the yaw rate, a reaction force controller 30 that controls the reaction force motor 9 and the clutch 19, a steering motor 11 and a clutch. A steering controller 40 that controls the vehicle 19. The reaction force controller 30 and the steering controller 40 are communicably connected to each other by the communication circuit 24 of the FlexRay system, and are configured to be able to share information input by each. An example of a FlexRay system is an in-vehicle communication network system.
The reaction force controller 30 performs control of the reaction force motor 9, control of the clutch 19, calculation of a steering command angle, calculation of a steering angle (absolute angle) of the steering wheel 5, and the like.
Specifically, the reaction force controller 30 includes the steering angle (absolute angle) detected by the steering absolute angle sensor 7, the rotation angle of the reaction force motor 9 detected by the reaction force motor rotation angle sensor 10, and the steering reaction force. The steering reaction force detected by the sensor 18 is acquired. Further, the reaction force controller 30 acquires the vehicle speed detected by the vehicle speed sensor 22 and the reaction force motor monitor value detected by the reaction force motor 9. Examples of the reaction force motor monitor value include a drive current and a temperature of the reaction force motor 9.

Then, the reaction force controller 30 calculates a steering reaction force (hereinafter also referred to as “steering reaction force command value”) to be applied to the steering wheel 5 based on the steering reaction force detected by the steering reaction force sensor 18. Subsequently, the reaction force controller 30 controls the reaction force motor 9 based on the calculated steering reaction force command value. Thereby, the reaction force controller 30 controls the steering reaction force of the steering wheel 5.
In addition, the reaction force controller 30 is configured to mechanically fasten the steering wheel 5 and the front wheels 3FL and 3FR when the steering control cannot be performed, for example, when the ignition switch is turned off (hereinafter, referred to as “the steering wheel 5”). (Also referred to as “engagement command”) is output to the clutch 19. Further, the reaction force controller 30 mechanically separates the steering wheel 5 and the front wheels 3FL, 3FR when the steering control is started, such as when the ignition switch is turned on (hereinafter, “ Is also output to the clutch 19.

Further, the reaction force controller 30 provides a turning angle (steering command angle) to be given to the pinion 21 based on the steering angle (absolute angle) detected by the steering absolute angle sensor 7 and the vehicle speed detected by the vehicle speed sensor 22. calculate. As a method for calculating the steering command angle, for example, referring to a variable steering angle ratio map, a steering angle ratio corresponding to the vehicle speed V is set, and a multiplication result of the set steering angle ratio and the steering angle (absolute angle) is set. There is a method of using the steering command angle. As the variable steering angle ratio map, for example, there is a map in which the steering angle ratio is maximized when the vehicle speed V is 0, and the steering angle ratio is decreased as the vehicle speed V increases. The reaction force controller 30 outputs the calculated turning command angle to the turning controller 40.

The steered controller 40 performs control of the steered motor 11, control of the clutch 19, calculation of an absolute angle of the rotation angle of the pinion 21 (hereinafter also referred to as “pinion absolute angle”), and the like.
Specifically, the steered controller 40 detects the steering torque of the steering wheel 5 detected by the steering torque sensor 8, the steered motor monitor value detected by the steered motor 11, and the steered motor angle sensor 12. The rotation angle of the rudder motor 11 (hereinafter also referred to as “steering motor angle”) is acquired. Further, the turning controller 40 acquires the steering angle (absolute angle) and the turning command angle calculated by the reaction force controller 30. Examples of the steered motor monitor value include a drive current and temperature of the steered motor 11.

Subsequently, the turning controller 40 calculates the pinion absolute angle based on the turning motor angle (relative angle) detected by the turning motor angle sensor 12, and corrects it as necessary. Subsequently, the steered controller 40 outputs a steered motor drive current corresponding to the deviation between the corrected pinion absolute angle and the steered command angle calculated by the reaction force controller 30 to the steered motor 11. Thereby, the turning controller 40 controls the pinion absolute angle, that is, the turning angle of the front wheels 3FL and 3FR.
Further, the steering controller 40 outputs an engagement command to the clutch 19 when the steering motor monitor value or the reaction force motor monitor value becomes a value representing an abnormality. At that time, the steering controller 40 drives and controls the steering motor 11 so as to assist the driver's steering torque based on the steering torque of the steering wheel 5 detected by the steering torque sensor 8.

(Control block)
Next, a control block of the vehicle steering device 2 will be described.
FIG. 3 is a control block diagram of the vehicle steering device 2. In FIG. 3, the reaction force controller 30 calculates the steering angle (absolute angle) and the steering command angle of the steering wheel 5, and the steering controller 40 describes the control of the steering motor 11 and the calculation and correction of the pinion absolute angle. is doing.
(Reaction force controller 30)
The reaction force controller 30 includes a steering absolute angle calculation unit 31 and a pinion angle command value calculation unit 32.
The steering absolute angle calculation unit 31 executes a steering angle accuracy improvement process. In the steering angle accuracy improving process, the steering angle (absolute angle) θhabs detected by the steering absolute angle sensor 7 and the rotation angle θhmot of the reaction force motor 9 detected by the reaction force motor rotation angle sensor 10 are acquired. In the steering angle accuracy improving process, the steering absolute angle calculating unit 31 calculates the steering angle (absolute angle) θh based on the acquired steering angle (absolute angle) θhabs and the rotation angle θhmot of the reaction force motor 9.

In the present embodiment, the steering angle (absolute angle) θhabs detected by the steering absolute angle sensor 7 and the rotation angle θhmot of the reaction force motor 9 detected by the reaction force motor rotation angle sensor 10 are determined. Although an example of calculating (angle) θh has been shown, other configurations may be employed. For example, when the accuracy of the steering angle (absolute angle) θhabs detected by the steering absolute angle sensor 7 is sufficiently high, the steering angle (absolute angle) θhabs may be directly used as the steering angle (absolute angle) θh.
The pinion angle command value calculation unit 32 executes a steering command angle calculation process. In the turning command angle calculation process, the pinion angle command value calculation unit 32 acquires the vehicle speed V detected by the vehicle speed sensor 22 and the steering angle (absolute angle) θh calculated by the steering absolute angle calculation unit 31. In the turning command angle calculation process, the pinion angle command value calculation unit 32 calculates the turning command angle θpcmd based on the acquired vehicle speed V and the steering angle (absolute angle) θh. The pinion angle command value calculation unit 32 outputs the calculated steering command angle θpcmd to the steering controller 40.

(Steering controller 40)
The turning controller 40 includes an N value storage unit 41, a pinion absolute angle calculation unit 42, a pinion absolute angle correction unit 43, a turning angle control unit 44, a current control driver 45, a backup mode switching unit 46, Is provided.
The N value storage unit 41 includes a nonvolatile memory, and stores “N value” in the nonvolatile memory. Here, the N value is a rotation count value of the resolver sensor indicating which section of the mechanical angle the output value (electrical angle) of the resolver corresponds to. As shown in FIG. 4, the electrical angle is the mechanical angle. N = 0 within the range corresponding to 0 ° to 120 ° (0 ° to 8.89 ° in pinion angle). The electrical angle is within the range corresponding to the mechanical angle of 120 ° to 240 ° (the pinion angle is 8.89 ° to 17.78 °), N = 1, and the electrical angle is the mechanical angle of 240 ° to 360 ° (the pinion angle is N = 3 within a range corresponding to 17.78 ° to 26.67 °.

Regarding the negative direction, N = -1 within the range corresponding to the mechanical angle of −120 ° to 0 ° (the pinion angle is −8.89 ° to 0 °), and the electrical angle is the mechanical angle of −240 ° to − N = -2 within the range corresponding to 120 ° (pinion angle −1.78 ° to −8.89 °), electrical angle mechanical angle −360 ° to −240 ° (pinion angle −26.67 ° N = −3 within a range corresponding to ˜−17.78 °. The N value is counted up every time the electrical angle changes in the positive direction of 360 °, and conversely every time the electrical angle changes in the negative direction of 360 °.
The pinion absolute angle calculation unit 42 acquires the steered motor angle (relative angle) θm within the range of 0 deg to 120 deg detected by the steered motor angle sensor 12 and the N value stored in the N value storage unit 42. And the pinion absolute angle calculation part 42 calculates pinion absolute angle (theta) p0 based on following Formula based on these.
θp0 = {θm + (360 / n × N)} / Gr (1)
Here, n is the number of pole pairs, and in this embodiment, n = 3. Gr is a gear ratio between the pinion 14 and the pinion 21, and Gr = 1.35 in the present embodiment.

The pinion absolute angle correction unit 43 determines whether or not the pinion absolute angle θp0 calculated by the pinion absolute angle calculation unit 42 needs to be corrected. If it is determined that correction is necessary, the pinion absolute angle correction unit 43 corrects the pinion absolute angle θp0. The absolute angle θp is output. Here, as factors that require correction, the N value stored in the N value storage unit 41 is not an accurate value, so-called “N deviation”, and the actual running value and the detected value are slightly shifted. There is a so-called “neutral angle shift”.
When the steering wheel 5 is operated with the clutch 19 engaged while the ignition is off, the steered wheels 3FL and 3FR also move accordingly. However, in this case, the N value may not be an accurate value when the next ignition is turned on. In this way, N shift occurs. On the other hand, the neutral angle deviation is a minute angle deviation caused by a component error, an alignment adjustment error, or the like.

In the pinion absolute angle correction unit 43, when it is determined that the pinion absolute angle θp0 calculated by the pinion absolute angle calculation unit 42 has an error from the actual pinion absolute angle and correction is necessary, the error is Determine which of the above factors has caused the problem. Then, the pinion absolute angle θp0 is corrected according to the error factor, and the pinion absolute angle θp is output. Processing executed by the pinion absolute angle correction unit 43 will be described later.
The turning angle control unit 44 acquires the turning command angle θpcmdco calculated by the pinion angle command value calculation unit 32 and the pinion absolute angle θp calculated by the pinion absolute angle correction unit 43. Then, the turning angle control unit 44 calculates a current command value Ipcmd corresponding to the deviation between the obtained turning command angle θpcmdco and the pinion absolute angle θp.

The current control driver 45 acquires the current command value Ipcmd calculated by the turning angle control unit 44 and the actual driving current Ipreal that is the turning motor monitor value of the turning motor 11. Then, the current control driver 45 controls the drive current Ipdri supplied to the steered motor 11 so that the actual drive current Ipreal matches the acquired current command value Ipcmd.
The backup mode switching unit 46 acquires the pinion absolute angle θp calculated by the pinion absolute angle correction unit 43. When the pinion absolute angle θp cannot be obtained from the pinion absolute angle correction unit 43, the backup mode switching unit 46 outputs a calculation stop command for the current command value Ipcmd to the turning angle control unit 44, and the clutch A fastening command is output to 19.

(Pinion absolute angle correction unit 43)
FIG. 5 is a block diagram showing a specific configuration of the pinion absolute angle correction unit 43.
As shown in FIG. 5, the pinion absolute angle correction unit 43 includes a correction processing execution flag setting unit 43a and a correction processing execution unit 43b. The correction process execution unit 43b includes a correction angle calculation unit 43c and an addition unit 43d.
The correction process execution flag setting unit 43a determines whether or not the N deviation correction process and the neutral angle deviation correction process have been executed, that is, whether or not the N deviation correction process and the neutral angle deviation correction process are to be executed.
FIG. 6 is a flowchart showing a correction processing executed flag setting processing procedure executed by the correction processing executed flag setting unit 43a.
First, in step S1, the correction process execution flag setting unit 43a determines whether or not the host vehicle is traveling straight ahead. Specifically, it is determined whether the vehicle is traveling straight ahead based on the vehicle speed V, the yaw rate γ, and the steering angle (absolute angle) θh. For example, when the vehicle speed V is 40 km / h or more, the absolute value of the yaw rate γ is 0.2 deg / s or less, and the absolute value of the steering angular velocity dθ / dt is 20 deg / s or less, the vehicle is traveling straight ahead. judge. If it is determined that the vehicle is traveling straight, the process proceeds to step S2, and if it is determined that the vehicle is not traveling straight, the correction processing execution flag setting process is terminated.

In step S2, the correction processing execution flag setting unit 43a acquires the pinion absolute angle θp0 calculated by the pinion absolute angle calculation unit 42. Then, it is determined whether or not the absolute value of the pinion absolute angle θp0 exceeds an allowable angle θpth (for example, 1 deg). At this time, if | θp0 | ≦ θpth, it is determined that there is no deviation in the pinion absolute angle θp0, and the process proceeds to step S3. If | θp0 |> θpth, the pinion absolute angle θp0 is obtained. It is determined that a deviation has occurred, and the process proceeds to step S4 described later.
In step S3, the correction processing execution flag setting unit 43a sets the correction processing execution flag Flg to “0” indicating that the N deviation correction processing and the neutral angle deviation correction processing have been executed, and the correction processing is performed as it is. The executed flag setting process is terminated.

In step S4, the correction processing execution flag setting unit 43a determines whether or not the deviation of the pinion absolute angle θp0 is due to N deviation. Specifically, when the pinion absolute angle θp0 during straight running is outside the neutral angle deviation range, it is determined that the deviation of the pinion absolute angle θp is due to N deviation. Here, the neutral angle deviation range is a minute angle range over 0 deg, for example, a range of −6 deg to 6 deg. This neutral angle deviation range is a range that the pinion absolute angle θp0 can take when traveling straight in a state where only the neutral angle deviation occurs.
If the pinion absolute angle θp0 acquired in step S2 is outside the range of ± 6 deg, it is determined that N deviation has occurred, and the process proceeds to step S5. On the other hand, when the pinion absolute angle θp0 acquired in step S2 is within the range of ± 6 deg, it is determined that no N deviation has occurred (only a neutral angle deviation has occurred), and will be described later in step S7. Migrate to

In step S5, the correction process execution flag setting unit 43a sets the correction process execution flag Flg to “2” indicating that the N deviation correction process and the neutral angle deviation correction process have not been executed, and the process proceeds to step S6. Transition.
In step S6, the correction process execution flag setting unit 43a stores the pinion absolute angle θp0 acquired in step S2 as the shift angle Δθp to be corrected, and ends the correction process execution flag setting process.
In step S7, the correction processing execution flag setting unit 43a sets the correction processing execution flag Flg to “1” indicating that only the N deviation correction processing has been executed (only the neutral angle deviation correction processing has not been executed). Then, the process proceeds to step S6.

Returning to FIG. 5, the correction processing execution unit 43b corrects the pinion absolute angle θp0 as necessary based on the correction processing execution flag Flg set by the correction processing execution flag setting unit 43a, and obtains the final pinion. The absolute angle θp is output.
That is, the correction processing execution unit 43b calculates the correction angle θcor for correcting the deviation of the pinion absolute angle θp0 by the correction angle calculation unit 43c, and adds this to the pinion absolute angle θp0 by the addition unit 43d. In this way, the corrected pinion absolute angle θp is output.

FIG. 7 is a flowchart showing a correction processing procedure executed by the correction processing execution unit 43b.
First, in step S11, the correction process execution unit 43b determines whether or not the correction process execution flag Flg is “2”. If Flg = 2, the process proceeds to step S12. If Flg ≠ 2, the process proceeds to step S16 described later.
In step S12, the correction processing execution unit 43b sets the amount of change in the N shift correction angle per unit time (N shift correction angular velocity) Δθcorn. The N deviation correction angular velocity Δθcorn is a constant value set in advance when the vehicle is traveling straight ahead. When the vehicle is turning, the N deviation correction angular velocity Δθcorn is calculated based on the correction angular velocity calculation map of FIG. 8 based on the vehicle speed V and the steering angular velocity dθh / dt.

The horizontal axis in FIG. 8 is the absolute value of the steering angular velocity dθ / dt, and the vertical axis is the absolute value of the N deviation correction angular velocity Δθcorn. Thus, the absolute value of the N deviation correction angular velocity Δθcorn is increased as the absolute value of the steering angular velocity dθ / dt is increased. Further, the absolute value of the N deviation correction angular velocity Δθcorn is reduced as the vehicle speed V increases. Here, when the vehicle speed V is in a high speed region (for example, 120 km / h), the N deviation correction angular velocity Δθcorn is set to zero. An upper limit value may be provided for the absolute value of the N deviation correction angular velocity Δθcorn.
After calculating the absolute value of the N deviation correction angular velocity Δθcorn based on FIG. 8, the final value is calculated based on the sign of the deviation angle Δθp of the pinion absolute angle θp0 stored in the correction processing execution flag setting unit 43a. N deviation correction angular velocity Δθcorn is calculated. Specifically, when the deviation angle Δθp of the pinion absolute angle θp0 stored in the correction processing execution flag setting unit 43a is a positive value, the absolute value of the N deviation correction angular velocity Δθcorn is multiplied by −1. A final N deviation correction angular velocity Δθcorn is assumed. When the deviation angle Δθp of the pinion absolute angle θp0 stored in the correction processing execution flag setting unit 43a is a negative value, a value obtained by multiplying the absolute value of the N deviation correction angular velocity Δθcorn by +1 is the final N The deviation correction angular velocity is Δθcorn.

Next, in step S13, the correction processing execution unit 43b corrects the pinion absolute angle θp0 with the N deviation correction angular velocity Δθcorn set in step S12, and outputs the result as the pinion absolute angle θp. Specifically, the N deviation correction angular velocity Δθcorn is added to the N deviation correction angle θcorn (initial value is 0), and this is set as a new N deviation correction angle θcorn. Then, the N deviation correction angle θcorn is output as the correction angle θcor. In this process, the N deviation correction angle θcorn is converted into a pinion angle converted value for one period of the resolver electrical angle, that is, an upper limit value of the converted value obtained by converting the signal output from the resolver into the pinion rotation angle (360 / number of pole pairs / gear ratio). Repeat until In this embodiment, since the number of pole pairs = 3 and the gear ratio = 13.5, the process is repeated until the correction angle θcorn = 8.89 deg.

Next, in step S14, the correction process execution unit 43b updates the N value stored in the N value storage unit 41, and proceeds to step S15. In this step S14, when the deviation angle Δθp of the pinion absolute angle θp0 is a positive value, the N value is corrected by −1, and when the deviation angle Δθp of the pinion absolute angle θp0 is a negative value, the N value is increased by +1. Only correct. In step S14, the correction processing execution unit 43b initializes the N deviation correction angle θcorn and the correction angle θcor to zero.
In step S15, the correction process execution unit 43b determines whether the N deviation correction process is completed. Specifically, the total angle (8.89 × (N-value update count)) corrected by the N deviation correction process is subtracted from the deviation angle Δθp of the pinion absolute angle θp0 stored in the correction processing execution flag setting unit 43a. It is determined whether the result (remaining deviation angle Δθp) is within the neutral angle deviation range (± 6 deg). If it is outside ± 6 deg, it is determined that the N deviation correction process has not been completed, and the process proceeds to step S12. If it is within ± 6 deg, it is determined that the N deviation correction process has been completed, and the remainder of the deviation angle Δθp is stored as a new deviation angle Δθp to be subjected to the neutral angle deviation correction process, and will be described later. The process proceeds to S17.

That is, in this step S15, the correction processing execution unit 43b is an integer of the upper limit (8.89deg) of the conversion value obtained by converting the signal output from the resolver into the rotation angle of the pinion as the correction angle for correcting the N deviation. Set to double. In addition, the correction processing execution unit 43b sets the correction angle for correcting the neutral angle deviation to the pinion absolute angle θp0 when the vehicle travels straight in a state where no N deviation occurs.
In step S16, the correction processing execution unit 43b determines whether or not the correction processing execution flag Flg is “1”. If Flg = 1, the process proceeds to step S17, and if Flg ≠ 1, the correction process is terminated as it is.

In step S17, the correction processing execution unit 43b initializes the neutral angle deviation correction angle θcorc to 0. In step S17, the correction processing execution unit 43b sets a change amount (neutral angle deviation correction angular velocity) Δθcorc of the neutral angle deviation correction angle per unit time. The neutral angle deviation correction angular velocity Δθcorc is set to a predetermined constant value when traveling straight ahead, and is calculated based on the correction angular velocity calculation map of FIG. 8 during cornering, similarly to the processing of step S12 described above. .
At this time, if the stored deviation angle Δθp is a positive value, the absolute value of the neutral angle deviation correction angular velocity Δθcorc calculated based on FIG. 8 is multiplied by −1 to obtain the final neutral angle deviation correction. The angular velocity is Δθcorc. When the stored deviation angle Δθp is a negative value, the absolute value of the neutral angle deviation correction angular velocity Δθcorc calculated based on FIG. 8 is multiplied by +1 to obtain the final neutral angle deviation correction angular velocity Δθcorc. And

In step S18, the correction processing execution unit 43b corrects the pinion absolute angle θp0 with the neutral angle deviation correction angular velocity Δθcorc set in step S17, and outputs the result as the pinion absolute angle θp. To do. Specifically, the neutral angle deviation correction angular velocity Δθcorc is added to the neutral angle deviation correction angle θcorc (initial value is 0), and this is set as a new neutral angle deviation correction angle θcorc. Then, the neutral angle deviation correction angle θcorc is output as the correction angle θcor. This process is repeated until the neutral angle deviation correction angle θcorc becomes the deviation angle Δθp of the pinion absolute angle θp.
Next, in step S19, the correction processing execution flag Flg is set to “0”, and the correction processing ends.

(Operation)
Next, the operation of the first embodiment will be described.
Assume that the driver turns the ignition switch on when the ignition switch is off, that is, when the clutch 19 is engaged. Then, the reaction force controller 30 outputs a release command to the clutch 19 to place the clutch 19 in a released state. As a result, the SBW control can be executed.
When the driver performs a steering operation during the SBW control, the reaction force controller 30 calculates the steering angle θh input by the driver, and calculates the steering command angle θpcmd corresponding to the vehicle speed V and the steering angle θh. Then, the turning controller 40 drives and controls the turning motor 11 so that the actual turning angle becomes the turning command angle θpcmd. Thereby, the steered wheels 3FL and 3FR are steered.
Further, road surface reaction force is input from the road surface to the steered wheels 3FL and 3FR by turning the steered wheels 3FL and 3FR. Therefore, the reaction force controller 30 drives and controls the reaction force motor 9 and applies a steering reaction force corresponding to the actual road surface reaction force to the steering wheel 5. In this way, SBW control is performed.

At this time, if the vehicle travels straight at 40 km / h or more and the yaw rate | γ | ≦ 0.2 deg / s and the steering angular velocity | dθ / dt | ≦ 20 deg / s (Yes in step S1 in FIG. 6), the vehicle rolls. The rudder controller 40 determines whether or not there is a deviation in the pinion absolute angle θp0 calculated by the pinion absolute angle calculation unit 42. During straight traveling where γ ≦ 0.2 deg / s, the pinion absolute angle θp0 is ideally 1 deg or less. Therefore, when the absolute value of the pinion absolute angle θp0 exceeds the allowable angle θpth (1 deg), it is determined that a deviation occurs in the calculated pinion absolute angle θp0.

Here, it is assumed that when the ignition switch is in the OFF state, the driver steers the steering wheel 5 and steers the front wheels 3FL and 3FR. Assuming that N deviation occurs at this time, if there is no neutral angle deviation, the deviation angle Δθp of the pinion absolute angle θp0 is 8.89 deg which is a pinion angle conversion value for one period of the resolver electrical angle. It is an integer multiple.
That is, during straight traveling, N = 0 and the pinion absolute angle θp0 should be 1 deg or less, but N deviation occurs, and if N = 2 by mistake, the calculated pinion absolute angle θp0 is 8 .89 × 2 = 17.78 deg.

In this case, since the pinion absolute angle θp0 during straight traveling is outside the neutral angle deviation range (± 6 deg), the steering controller 40 determines that N deviation has occurred (Yes in step S4). Then, the correction processing completion flag Flg is set to “2” indicating that both N deviation correction and neutral angle deviation correction have not been performed (step S5). Therefore, the turning controller 40 sets the pinion absolute angle θp0 calculated during the straight traveling as the deviation angle Δθp of the pinion absolute angle θp0 to be corrected (step S6), and corrects the pinion absolute angle θp0 by the deviation angle Δθp. Deviation correction processing is performed.

Specifically, in the N deviation correction processing, the pinion absolute angle θp0 is gradually corrected by the deviation angle Δθp with the N deviation correction angular velocity Δθcorn corresponding to the steering angular velocity | dθh / dt | and the vehicle speed V. When the vehicle is traveling straight ahead, the steering controller 40 sets the absolute value of the N deviation correction angular velocity Δθcorn to a constant value. When the vehicle is traveling around, the steering controller 40 The absolute value of the N deviation correction angular velocity Δθcorn is calculated with reference to the correction angular velocity calculation map shown. At this time, since the deviation angle Δθp = 17.78 deg (positive value), the absolute value of the calculated N deviation correction angular velocity Δθcorn multiplied by −1 is used as the final N deviation correction angular velocity Δθcorn (FIG. 7). Step S12).

Here, the N deviation correction process when the vehicle continues running straight will be described. The steered controller 40 first adds the N deviation correction angular velocity Δθcorn (<0) to the N deviation correction angle θcorn (initial value 0). Subsequently, the steered controller 40 sets the calculated N deviation correction angle θcorn (= Δθcorn) as the correction angle θcor, adds it to the pinion absolute angle θp0, and outputs the corrected pinion absolute angle θp (step S13). . That is, the pinion absolute angle θp is smaller by | Δθcorn | than the pinion absolute angle θp0, and the difference between the pinion absolute angle θp and the actual pinion absolute angle is reduced. This process is repeated until the pinion absolute angle θp0 is corrected by 8.89 deg.

That is, the turning controller 40 adds the N deviation correction angular velocity Δθcorn (<0) to the N deviation correction angle θcorn (= Δθcorn). Subsequently, the turning controller 40 sets the calculated N deviation correction angle θcorn (= Δθcorn + Δθcorn) as the correction angle θcor, adds it to the pinion absolute angle θp0, and outputs the corrected pinion absolute angle θp. As a result, the pinion absolute angle θp is smaller by | Δθcorn + Δθcorn | than the pinion absolute angle θp0, and the difference between the pinion absolute angle θp and the actual pinion absolute angle is further reduced.
Thus, the turning controller 40 gradually corrects the pinion absolute angle θp0 by N deviation correction angular velocities Δθcorn. When the pinion absolute angle θp0 is corrected by 8.89 deg, the steering controller 40 decreases the N value stored in the N value storage unit 41 by 1 and updates it to N = 1 (step S14). At this time, the N deviation correction angle θcorn and the correction angle θcor are initialized to zero.

Subsequently, the steering controller 40 determines whether or not the N deviation correction process is completed. At this time, the result of subtracting the total angle (8.89 deg) corrected by the N shift correction process from the shift angle Δθp of the pinion absolute angle θp0 (remaining shift angle Δθp) is 8.89 deg. Thus, since the remainder of the deviation angle Δθp is outside the neutral angle deviation range (± 6 deg), the steered controller 40 performs the N deviation correction process again.
That is, the turning controller 40 adds the N deviation correction angular velocity Δθcorn (<0) to the N deviation correction angle θcorn (initial value 0). Subsequently, the steering controller 40 adds the calculated N deviation correction angle θcorn (= Δθcorn) to the pinion absolute angle θp0, and outputs the corrected pinion absolute angle θp (step S13). And after repeating this process until pinion absolute angle (theta) p0 is correct | amended by 8.89 deg, the steering controller 40 reduces N value memorize | stored in N value memory | storage part 41, and updates it to N = 0 (step). S14). In this way, the deviation angle Δθp = 17.78 deg is corrected, and the N deviation correction process is completed (Yes in step S15).

As a result of performing the N deviation correction process, the N value stored in the N value storage unit 41 is N = 0, and the absolute value of the pinion absolute angle θp0 during straight traveling is equal to or less than the allowable angle (1 deg). In this way, the pinion absolute angle θp0 can be in a state where there is no deviation.
In this embodiment, when correcting the deviation of the pinion absolute angle θp0, the amount of change of the correction angle per unit time is set, and the pinion absolute angle θp0 is gradually changed to an angle without deviation based on the set correction angular velocity. . When traveling straight as described above, the steering angles 3FL and 3FR are straight and the steering wheel 5 is deviated from the neutral position before the correction of the pinion absolute angle θp0. If the pinion absolute angle θp0 is gradually changed from this state and the process of correcting the deviation is performed, the steering wheel 5 gradually returns to the neutral position while the turning angles 3FL and 3FR are kept straight. Therefore, by appropriately setting the correction angular velocity, the pinion absolute angle θp0 can be corrected without causing the driver to feel uncomfortable.

After the correction of the pinion absolute angle θp0 is completed, the calculated pinion absolute angle θp0 is output as it is as the pinion absolute angle θp without performing the N deviation correction process and the neutral angle deviation correction process.
Therefore, when the driver operates the steering wheel 5, the reaction force controller 30 calculates a steering command angle θpcmd corresponding to the steering angle θh. Then, the steering controller 40 calculates a current command value Ipcmd corresponding to the deviation between the pinion absolute angle θp and the steering command angle θpcmd, and turns the steering so that the actual driving current Ipreal matches the current command value Ipcmd. The motor 11 is controlled. At this time, there is no difference between the steering command angle θpcmd and the actual steering angle, and the steering can be appropriately performed according to the steering operation of the driver.

When a neutral angle deviation occurs in addition to the N deviation, the neutral angle deviation correction process is performed after the N deviation correction process. In this case, when the N deviation correction process is completed, a deviation angle Δθp of the pinion absolute angle θp0 to be subjected to neutral angle deviation correction is obtained. Similar to the N deviation correction process, the pinion absolute angle θp0 is gradually corrected by the deviation angle Δθp with the neutral angle deviation correction angular speed Δθcorc corresponding to the steering angular velocity | dθh / dt | and the vehicle speed V (step S17). , S18).
When the pinion absolute angle θp0 is corrected by the shift angle Δθp, the neutral angle shift correction process is completed. When the neutral angle deviation correction processing is completed, the correction angle θcor is equal to the deviation angle Δθp that should be subjected to neutral angle deviation correction. Therefore, thereafter, the pinion absolute angle θp0 can be corrected with the correction angle θcor, and the accurate pinion absolute angle θp can be output.

Thus, in the present embodiment, it is determined whether or not there is an error between the pinion absolute angle θp0 and the actual pinion absolute angle based on the pinion absolute angle θp0 calculated during the straight traveling. Further, when an error has occurred, the cause of the error is determined based on the pinion absolute angle θp0 calculated during the straight traveling. More specifically, two factors, N deviation and neutral angle deviation, are discriminated as error factors. Therefore, an appropriate correction process according to the error factor can be performed, and the deviation between the turning command angle θpcmd and the actual turning angle during the SBW control can be surely reduced.

At this time, it is determined whether or not N deviation has occurred depending on whether or not the pinion absolute angle θp0 calculated during straight traveling is within the neutral angle deviation range (± 6 deg). Here, the neutral angle deviation range is set based on a pinion angle conversion value (8.89 deg) for one period of the resolver electrical angle determined from the number of pole pairs of the resolver. That is, considering that the deviation angle Δθp generated when the N value is shifted by 1 is 8.89 deg, the neutral angle deviation range is set so that the deviation below this is caused by the neutral angle deviation. To do. Thereby, it is possible to appropriately discriminate and discriminate between two error factors.
Further, when both the N shift and the neutral angle shift occur, the N shift correction process is preferentially performed. Therefore, it is possible to deal with a large error that should be corrected quickly and to perform appropriate correction processing.

Furthermore, since the correction method is changed depending on whether the vehicle is traveling straight or turning, an appropriate correction process according to the traveling state can be performed. For example, when the correction angular velocity is calculated using the correction angular velocity calculation map of FIG. 8 even during straight traveling, the correction angular velocity remains 0 when traveling at high speed, and the pinion absolute angle θp0 Cannot be corrected. In the present embodiment, the correction angular velocity is set to a value other than 0, assuming that stable traveling can be maintained even if correction of the pinion absolute angle θp0 is performed in the case of straight traveling even at high speed. In this way, the pinion absolute angle θp0 can be corrected while ensuring stable running.

In FIG. 3, the N value storage unit 41 corresponds to the storage unit, the pinion absolute angle calculation unit 42 corresponds to the rotation angle calculation unit, and the pinion absolute angle correction unit 43 corresponds to the rotation angle correction unit. Further, step S1 in FIG. 6 corresponds to the running state determination unit, step S2 corresponds to the error occurrence determination unit, and step S4 corresponds to the error factor determination unit. Further, steps S12 and S17 in FIG. 7 correspond to the correction angular velocity setting unit, step S14 corresponds to the count value correction unit, and step S15 corresponds to the correction angle setting unit.

(effect)
In the first embodiment, the following effects can be obtained.
(1) The steered controller 40 has an N value storage unit for indicating a count value (N value) indicating which section of the mechanical angle corresponds to the angle indicated by the signal output from the resolver used for the steered motor angle sensor 12. 41. Further, the turning controller 40 calculates the pinion absolute angle θp0 based on the signal output from the resolver used for the turning motor angle sensor 12 and the N value stored in the N value storage unit 41. When the absolute value of the pinion absolute angle θp0 when the steering controller 40 determines that the host vehicle is traveling straight ahead is equal to or greater than the allowable angle θpth, the steering controller 40 determines that the pinion absolute angle θp0 is between the actual pinion absolute angle and the actual pinion absolute angle. It is determined that there is an error in At this time, the steering controller 40 determines a factor of error based on the pinion absolute angle θp0 when it is determined that the host vehicle is traveling straight ahead, and the error of the pinion absolute angle θp0 is reduced according to the factor. Correct in the direction.

In this way, utilizing the fact that the pinion absolute angle during straight traveling is substantially 0, when the absolute value of the pinion absolute angle θp0 calculated during straight traveling is greater than or equal to the allowable angle θpth, a deviation occurs in the pinion absolute angle θp0. Judge that Therefore, a deviation occurs in the pinion absolute angle θp0, and it can be appropriately recognized that the actual turning angle is deviated from the turning command angle. In addition, since the correction method can be changed according to the cause of the deviation of the pinion absolute angle θp0, more appropriate correction can be performed. As a result, the deviation between the steering command angle and the actual steering angle can be reduced more appropriately.

(2) When the turning controller 40 determines that the pinion absolute angle θp0 when it is determined that the host vehicle is traveling straight ahead is within a minute angle range (neutral angle deviation range) crossing 0 degrees, an error factor is generated. It is determined that the error is due to a component error, and when it is outside the minute angle range (neutral angle deviation range), it is determined that the cause of the error is an N value error.
When the ignition switch is turned off and the clutch is engaged (steering wheel and steered wheel are mechanically connected), if the driver steers the steered wheel by operating the steering wheel, the ignition switch is turned on. The N value may be shifted. That is, there is a case where the N value last stored in the N value storage unit 41 while the previous ignition switch is turned on does not match the actual N value when the current ignition switch is turned on. In the case of a neutral angle deviation in which the pinion absolute angle deviates due to component error, alignment adjustment error, etc., the deviation angle becomes a minute angle, but in the case of N deviation in which the pinion absolute angle deviates due to the deviation of the N value as described above, The deviation angle is relatively large. Therefore, the deviation factor can be determined by monitoring the deviation angle of the calculated pinion absolute angle θp0.

(3) The steering controller 40 sets a correction angle for correcting the pinion absolute angle θp0 according to the cause of the error. Further, the turning controller 40 sets a change amount of the correction angle per unit time. Then, the turning controller 40 corrects the pinion absolute angle θp0 by the set change amount by the set correction angle.
Thereby, the deviation of the pinion absolute angle θp0 can be corrected gradually. Therefore, it is possible to make it difficult for the driver to notice the change in the turning angle caused by correcting the pinion absolute angle θp0.

(4) When the cause of the error is due to the error of the N value, the steered controller 20 converts the signal output from the resolver into the rotation angle of the pinion (360 / number of pole pairs / gear ratio = An integer multiple of 8.89 deg) is set as the correction angle of the pinion absolute angle θp0. Further, the steering controller 20 corrects the N value stored in the N value storage unit 41 each time the pinion absolute angle θp0 is corrected by the above upper limit while correcting the pinion absolute angle θp0 by the set correction angle with a small error. Correct in the direction.
When the N value is shifted by “1”, the pinion absolute angle θp0 deviates from the actual pinion absolute angle by a converted pinion angle value (8.89 deg) for one period of the resolver electrical angle. Therefore, if an integer multiple of 8.89 deg is set as the correction angle of the pinion absolute angle θp0, the N deviation can be corrected reliably. In addition, when correcting the N deviation, the N value stored in the N value storage unit 41 is corrected every time the pinion absolute angle θp0 is corrected by 8.89 deg. Therefore, after the N deviation correction is completed, the correct pinion absolute value is correct. The angle θp0 can be calculated.

(5) The steering controller 40 sets the pinion absolute angle θp0 when it is determined that the host vehicle is traveling straight when the error is caused by a component error as the correction angle of the pinion absolute angle θp0. . Thereby, when the correction of the pinion absolute angle θp0 is completed, the pinion absolute angle θp0 calculated during the straight traveling can be set to an ideal value (0).
(6) When the turning controller 40 determines that the host vehicle is turning, the turning controller 40 sets a larger amount of change in the correction angle per unit time as the steering angular velocity is faster. As a result, when fast steering is being performed, the correction angular velocity of the pinion absolute angle θp0 can be increased because the driver is less likely to notice a change in the turning angle due to the correction of the pinion absolute angle θp0. Therefore, the pinion absolute angle θp0 can be corrected quickly.

(7) When the turning controller 40 determines that the host vehicle is turning, the turning controller 40 sets a smaller change amount of the correction angle per unit time as the vehicle speed is higher. Thereby, when traveling at high speed, the correction angular velocity of the pinion absolute angle θp0 can be made smaller than when traveling at low speed. Therefore, the pinion absolute angle θp0 can be corrected while ensuring stable running.
(8) When the turning controller 40 determines that the host vehicle is traveling straight ahead, the turning controller 40 sets the amount of change in the correction angle per unit time to a predetermined constant value. As a result, when the vehicle is traveling straight ahead, the corrected angular velocity of the pinion absolute angle θp0 can be made relatively large so that the driver is less likely to notice the change in the turning angle due to the correction of the pinion absolute angle θp0. Therefore, the pinion absolute angle θp0 can be corrected more appropriately.

(9) The minute angle range (neutral angle deviation range) is determined based on the number of pole pairs of the resolver used for the steered motor angle sensor 12, and is the upper limit of a conversion value obtained by converting the signal output by the resolver into the rotation angle of the pinion. Set based on the value.
That is, when N deviation occurs, the pinion absolute angle θp0 is considered to be shifted by an upper limit value of the converted value obtained by converting the signal output from the resolver into the rotation angle of the pinion at least. Set. Accordingly, it is possible to appropriately determine the deviation factor of the pinion absolute angle θp0.

(10) Indicates which section of the mechanical angle corresponds to the angle indicated by the signal output by the resolver that outputs a signal that periodically changes according to the rotation angle of the steered motor that steers the steered wheels. Store the count value. Further, based on the signal output from the resolver and the stored count value, a pinion absolute angle that is an absolute angle of the rotation angle of the pinion that meshes with the rack gear of the steering rack is calculated. When the absolute value of the pinion absolute angle calculated when it is determined that the host vehicle is traveling straight ahead is greater than or equal to the preset allowable angle, the calculated pinion absolute angle is between the actual pinion absolute angle and Judge that an error has occurred. At this time, after determining the cause of the error based on the pinion absolute angle calculated when it is determined that the host vehicle is traveling straight ahead, the calculated pinion absolute angle is determined according to the error factor. Correction is performed in a direction that reduces the error.

In this way, utilizing the fact that the pinion absolute angle during straight traveling is substantially 0, when the absolute value of the pinion absolute angle θp0 calculated during straight traveling is equal to or larger than the allowable angle θpth, the pinion absolute angle θp0 is shifted. Judge that Therefore, a deviation occurs in the pinion absolute angle θp0, and it can be appropriately recognized that the actual turning angle is deviated from the turning command angle. In addition, since the correction method can be changed according to the cause of the deviation of the pinion absolute angle θp0, more appropriate correction can be performed. As a result, the deviation between the steering command angle and the actual steering angle can be reduced more appropriately.

(Modification)
(1) In the above embodiment, the case where the number of pole pairs is 3 has been described, but a value other than 3 may be used. However, if the number of pole pairs is too large, the deviation angle of the minimum pinion absolute angle θp0 when the N deviation occurs is larger than the deviation angle of the maximum pinion absolute angle θp0 when the neutral angle deviation occurs. As a result, the deviation factor of the pinion absolute angle θp0 cannot be determined. Therefore, the number of pole pairs capable of separating the deviation factors is adopted.
(2) In the above embodiment, the neutral angle deviation correction is realized by correcting the pinion absolute angle θp0. However, the neutral angle deviation correction can also be performed by correcting the steering command angle θpcmd. Also in this case, the deviation between the steering command angle and the actual steering angle can be reduced appropriately.

Industrial applicability

According to the steering control device according to the present invention, when there is a shift in the pinion absolute angle calculated based on the output signal of the resolver, correction according to the factor can be performed. Therefore, the deviation between the steering command angle and the actual steering angle can be more appropriately reduced, which is useful.

3FL, 3FR: Front wheels (steering wheels), 5 ... Steering wheel, 7 ... Steering absolute angle sensor, 9 ... Reaction force motor, 11 ... Steering motor, 12 ... Steering motor angle sensor, 15 ... Rack gear, 16 ... Steering rack , 19 ... Clutch, 21 ... Pinion, 30 ... Reaction force controller, 31 ... Steering absolute angle calculation unit, 32 ... Pinion angle command value calculation unit, 40 ... Steering controller, 41 ... N value storage unit, 42 ... Pinion absolute angle Calculation unit, 43 ... Pinion absolute angle correction unit, 44 ... Steering angle control unit, 45 ... Current control driver, 46 ... Backup mode switching unit

Claims

A steering control device that mechanically separates a steering wheel and a steered wheel and steers the steered wheel based on a steering state of the steering wheel,
A steered motor that steers the steered wheels;
A resolver that outputs a signal that periodically changes according to a rotation angle of the steering motor;
A non-volatile storage unit that stores a count value indicating which section of the mechanical angle the angle indicated by the signal output from the resolver corresponds to;
A rotation angle calculation unit that calculates a pinion absolute angle that is an absolute angle of the rotation angle of the pinion that meshes with the rack gear of the steering rack, based on the signal output from the resolver and the count value stored in the storage unit;
A traveling state determination unit that determines whether the host vehicle is traveling straight or turning.
When the absolute value of the pinion absolute angle calculated by the rotation angle calculation unit when the traveling state determination unit determines that the host vehicle is traveling straight ahead is greater than or equal to a preset allowable angle, the rotation angle calculation unit An error occurrence determination unit that determines that an error has occurred between the pinion absolute angle calculated in step 1 and the actual pinion absolute angle;
Based on the pinion absolute angle calculated by the rotation angle calculation unit when the driving state determination unit determines that the vehicle is traveling straight when the error generation determination unit determines that the error has occurred. , An error factor determination unit for determining the error factor;
A rotation angle correction unit that corrects the pinion absolute angle calculated by the rotation angle calculation unit in a direction in which the error decreases according to the error factor determined by the error factor determination unit. Steering control device.
When the error factor determining unit determines that the traveling state determining unit determines that the host vehicle is traveling straight ahead, the pinion absolute angle calculated by the rotation angle calculating unit is within a minute angle range over 0 degrees. The error factor is determined to be due to a component error, and when the error factor is outside the minute angle range, the error factor is determined to be due to the error of the count value. The steering control device described in 1.
The rotation angle correction unit
A correction angle setting unit for setting a correction angle for correcting the pinion absolute angle calculated by the rotation angle calculation unit according to the error factor determined by the error factor determination unit;
A correction angular velocity setting unit for setting a change amount of the correction angle per unit time,
3. The pinion absolute angle calculated by the rotation angle calculation unit is corrected by a correction angle set by the correction angle setting unit with a change amount set by the correction angular velocity setting unit. Steering control device.
When the error factor determination unit determines that the error factor is due to the error of the count value, the correction angle setting unit converts the signal output from the resolver into a rotation angle of the pinion. Set an integer multiple of the upper limit as the correction angle,
The rotation angle correction unit corrects the pinion absolute angle calculated by the rotation angle calculation unit by the correction angle set by the correction angle setting unit, and stores the memory every time the pinion absolute angle is corrected by the upper limit value. The steering control device according to claim 3, further comprising a count value correction unit that corrects the count value stored in the unit in a direction in which the error decreases.
The correction angle setting unit performs the rotation when the error factor determination unit determines that the error factor is due to a component error, and when the traveling state determination unit determines that the host vehicle is traveling straight ahead. The turning control device according to claim 3 or 4, wherein the pinion absolute angle calculated by the angle calculation unit is set as the correction angle.
The correction angular velocity setting unit sets a larger change amount of the correction angle per unit time as the steering angular velocity is faster when the traveling state determination unit determines that the host vehicle is turning. The turning control device according to any one of claims 3 to 5.
It has a vehicle speed detector that detects the vehicle speed,
The correction angular velocity setting unit sets a smaller change amount of the correction angle per unit time as the vehicle speed detected by the vehicle speed detection unit is faster when the traveling state determination unit determines that the host vehicle is turning. The turning control device according to any one of claims 3 to 6, characterized in that:
The correction angular velocity setting unit sets a change amount of the correction angle per unit time to a predetermined constant value when the traveling state determination unit determines that the host vehicle is traveling straight ahead. The turning control device according to any one of claims 3 to 7.
The minute angle range is set based on an upper limit value of a conversion value determined based on the number of pole pairs of the resolver, and a signal output from the resolver converted into a rotation angle of the pinion. 9. The steering control device according to any one of 2 to 8.
A steering control method in which a steering wheel and a steered wheel are mechanically separated, and the steered wheel is steered based on a steering state of the steering wheel,
A count value indicating which section of the mechanical angle corresponds to the angle indicated by the signal output by the resolver that outputs a signal that periodically changes in accordance with the rotation angle of the steering motor that steers the steered wheel. Remember
Based on the signal output from the resolver and the stored count value, the pinion absolute angle, which is the absolute rotation angle of the pinion meshing with the rack gear of the steering rack, is calculated, and it is determined that the host vehicle is traveling straight ahead. When the absolute value of the calculated pinion absolute angle is greater than or equal to the preset allowable angle, it is determined that there is an error between the calculated pinion absolute angle and the actual pinion absolute angle, and the cause of the error Is determined based on the pinion absolute angle calculated when it is determined that the host vehicle is traveling straight ahead, and the calculated pinion absolute angle is corrected in a direction that reduces the error according to the cause of the error. A steering control method characterized by: