JP2007237937A - Steering controller for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering controller for a vehicle capable of quickly starting a steering reaction force in an initial stage of steering causing no occurrence of a rolling reaction, while restraining generation of the unnecessary steering reaction force accompanied by delay of steering control relative to steering. <P>SOLUTION: This steering controller for a vehicle comprises rolling angle estimation means (S4) estimating rolling angles of right and left front wheels as estimated rolling angles Lp*θe based on a target rolling angle θe and a filter Lp indicating a response characteristic of a rolling motor; a rolling angle sensor detecting actual rolling angles θp of the right and left front wheels; and steering reaction force command value setting means (S13) setting a steering reaction force command value T based on a first steering reaction force G*F according to the rolling reaction force given to the rolling motor at least from the right and left front wheels and a second steering reaction force θa according to a deviation between the estimated rolling angle Lp*θe and the actual rolling angle θp. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention belongs to the technical field of a vehicle steering control device that includes a steering actuator that steers steering wheels and a steering reaction force actuator that applies a steering reaction force to an operation unit.

Conventionally, in a steer-by-wire system in which a steering wheel and a steering wheel are mechanically separated, a steering reaction force according to a deviation between a steering force and a turning reaction force (for example, rack axial force) is applied, and Information is fed back to the driver. Furthermore, a steering reaction force corresponding to the deviation between the target turning angle of the steered wheel corresponding to the steering angle and the actual turning angle is applied, and the steering reaction force is quickly established in the initial stage of steering where no turning reaction force is generated. There is known a technique for raising and suppressing deterioration of the steering feeling (see, for example, Patent Document 1).
JP-A-10-217998

  However, since the steering reaction force is generated according to the deviation between the target turning angle and the actual turning angle in the above prior art, the steering reaction force largely depends on the control performance of the turning drive. For this reason, in the case of a system in which the response of the steering control is low and there is always a deviation between the target turning angle and the actual turning angle, the steering reaction according to the deviation between the target turning angle and the actual turning angle. Since the force is always generated, there is a problem that the feeling of viscosity is strong and the steering feeling is deteriorated.

  The present invention has been made to solve the above-described problem, and the object of the present invention is to generate a steering reaction force while suppressing generation of an unnecessary steering reaction force accompanying a delay in the steering control with respect to the steering. An object of the present invention is to provide a vehicle steering control device capable of quickly raising a steering reaction force at the initial stage of steering.

In order to achieve the above object, the present invention provides:
A steering actuator that steers steering wheels;
A steering control means for setting a target turning angle according to the steering state of the operation unit operated by the driver, and driving and controlling the steering actuator so as to coincide with the target turning angle;
A steering reaction force actuator for applying a steering reaction force to the operation unit;
Steering reaction force control means for driving and controlling the steering reaction force actuator based on a steering reaction force command value corresponding to the steering state of the steered wheel;
In a vehicle steering control device comprising:
Based on the target turning angle and the response characteristics of the turning actuator, a turning angle estimation means for estimating the turning angle of the steered wheel as an estimated turning angle;
An actual turning angle detection means for detecting an actual turning angle of the steering wheel;
At least a first steering reaction force according to a steering reaction force applied to the steering actuator from the steered wheel, and a second steering reaction force according to a deviation between the estimated steering angle and the actual steering angle. And a steering reaction force command value setting means for setting the steering reaction force command value,
It is characterized by providing.

  In the vehicle steering control device of the present invention, the estimated turning angle of the steered wheel is estimated based on the target turning angle and the response characteristic of the turning actuator, and is provided from at least the steered wheel to the turning actuator. Based on the first steering reaction force according to the steering reaction force and the second steering reaction force according to the deviation between the estimated turning angle and the actual turning angle, the steering reaction force command value of the steering reaction force actuator is calculated. Is set.

That is, by generating the second steering reaction force according to the deviation between the target turning angle (estimated turning angle) and the actual turning angle, the turning reaction force is not generated and the first steering reaction force is zero or The steering reaction force can be quickly raised at the initial stage of steering, which is a minute value near zero. At this time, the second steering reaction force is generated according to the deviation between the target turning angle (estimated turning angle) and the actual turning angle through a filter equivalent to the time delay of the turning control. Therefore, even when the response delay of the turning control is large, generation of unnecessary steering reaction force due to this response delay is suppressed.
As a result, it is possible to quickly start up the steering reaction force at the initial stage of steering where the steering reaction force is not generated while suppressing generation of unnecessary steering reaction force due to the delay of the steering control with respect to the steering.

  Hereinafter, the best mode for carrying out the present invention will be described based on Examples 1 to 3.

First, the configuration will be described.
[overall structure]
FIG. 1 is a configuration diagram of a steer-by-wire (steer-by-wire) system to which the vehicle steering control device of the first embodiment is applied.

  As shown in FIG. 1, the steer-by-wire system according to the first embodiment includes a steering handle 1 (operation unit), a steering angle sensor 2, a steering torque sensor 3, a steering reaction force motor (steering reaction force actuator) 4, Backup clutch 5, steering motor (steering actuator) 6, steering angle sensor (actual steering angle detection means) 7, steering mechanism 8, left and right front wheels 9, 9 (steering wheels), rack shaft A force sensor 10, a steering reaction force controller (steering reaction force control means) 11, a turning controller (steering control means) 12, and a communication line 13 are provided.

The steered motor 6 is composed of a brushless motor or the like. Further, the steering reaction force motor 4 for applying a steering reaction force to the steering handle 1 is constituted by a brushless motor or the like, similar to the steering motor 6.
The rack axial force sensor 10 detects the axial force applied to the rack of the steering mechanism 8.

  In the steer-by-wire system according to the first embodiment, the steering handle 1 operated by the driver, the steering handle 1 is mechanically separated, the steering mechanism 8 that steers the left and right front wheels 9 and 9, and the steering handle 1 The steering reaction force motor 4 that applies force and the steering motor 6 that applies steering force to the steering mechanism 8 are provided, and there is no mechanical connection between the steering handle 1 and the steering mechanism 8. ing.

  However, a backup clutch 5 is provided as a mechanical backup mechanism, and the steering handle 1 and the steering mechanism 8 can be mechanically coupled. In other words, when any abnormality occurs in the steer-by-wire system, it is possible to travel safely by connecting the backup clutch 5.

  In the first embodiment, the steering angle of the steering handle 1 is detected by the steering angle sensor 2, and the command turning angle is calculated by the steering reaction force controller 11. In the turning controller 12, the drive command value of the turning motor 6 is calculated so that the actual turning angle coincides with the command turning angle, and the turning operation is performed by driving the turning motor 6. .

The current command value calculated by the turning controller 12 is calculated by an angle servo system that performs control calculation so that the actual turning angle follows the command turning angle with a predetermined response characteristic.
The angle servo system of the turning controller 12 is configured by a method using a robust model matching method as shown in the turning angle control block diagram of FIG. 2, for example. In this method, a current command value for realizing a predetermined normative response characteristic is calculated with respect to the command turning angle by a model matching compensator for matching with a desired characteristic given in advance, and a robust compensator is used. A compensation current corresponding to the disturbance component is calculated. As a result, it is possible to realize a control system with excellent disturbance resistance in which the actual turning angle can follow the normal response characteristic even when a disturbance occurs.

  In the steering reaction force controller 11, the actual turning angle (actual turning angle) of the left and right front wheels 9 and 9 obtained from the steering angle of the steering handle 1 and the rotation angle of the turning motor 6 detected by the turning angle sensor 7. And the steering reaction force command value is calculated based on the axial force detected by the rack axial force sensor 10. The steering reaction force controller 11 calculates a drive command value for the steering reaction force motor 4 so that the steering torque detected by the steering torque sensor 3 becomes a value corresponding to the steering reaction force command value. Is driven, a steering reaction force is applied. This steering reaction force is monitored by a steering torque sensor 3 provided between the steering handle 1 and the steering reaction force motor 4.

[Steering reaction force command value setting control process]
FIG. 3 is a flowchart showing the flow of the steering reaction force command value setting control process executed by the steering reaction force controller 11 of the first embodiment. Each step will be described below. This control process is repeatedly executed every predetermined control cycle.

  In step S1, the actual turning angle θp of the left and right front wheels 9, 9 obtained from the steering angle θh detected by the steering angle sensor 2, the rotation angle of the turning motor 6 detected by the turning angle sensor 7, and the rack shaft The axial force F detected by the force sensor 10 is read, and the process proceeds to step S2.

  In step S2, the steering angle θh read in step S1 is time-differentiated to calculate the steering angular velocity dθh / dt, and the process proceeds to step S3.

  In step S3, the actual turning angle θp read in step S1 is time-differentiated to calculate the actual turning angular velocity dθp / dt, and the process proceeds to step S4.

  In step S4 (steering angle estimation means), the target turning angle θe corresponding to the steering angle θh read in step S1 is calculated, and the control performance of the steering reaction force motor 4 is equivalent to the calculated target turning angle θe. The estimated turning angle Lp · θe is calculated by multiplying the filter Lp, and the process proceeds to step S5.

  In step S5, the target turning angle Lp · θe calculated in step S4 is time-differentiated to calculate the estimated turning angular velocity Lp · dθe / dt, and the process proceeds to step S6.

In step S6, the first steering reaction force is calculated by multiplying the axial force F read in step S1 by a predetermined weight coefficient G, and the process proceeds to step S7.
First steering reaction force = GF

  In step S7, it is determined whether or not the absolute value | Lp · θe | of the estimated turning angle calculated in step S4 is smaller than the absolute value | θp | of the actual turning angle read in step S1. If YES, the process proceeds to step S8, and if NO, the process proceeds to step S9.

  In step S8, both the second steering reaction force θa and the third steering reaction force θv are set to zero, and the process proceeds to step S13.

In step S9, the second steering reaction force θa is calculated by subtracting the actual turning angle θp read in step S1 from the estimated turning angle Lp · θe calculated in step S4, and the process proceeds to step S10.
Second steering reaction force θa = Lp ・ θe−θp

In step S10, the third steering reaction force θv is calculated by subtracting the actual steering angular velocity dθp / dt calculated in step S3 from the estimated steering angular velocity Lp · dθe / dt calculated in step S5, and the process proceeds to step S11. .
Third steering reaction force θv = Lp · dθe / dt−dθp / dt

  In step S11, it is determined whether the axial force F read in step S1 and the sign of the second steering reaction force θa calculated in step S9 are both positive or negative. If YES, the process proceeds to step S13, and if NO, the process proceeds to step S12.

In step S12, the second steering reaction force θa calculated in step S9 and the third steering reaction force θv calculated in step S10 are respectively multiplied by the gain shown in FIG. 4, and the process proceeds to step S13. Here, the gain in FIG. 4 is set according to the axial force F, and is such that the axial force F decreases from zero to the axial force F ₀ near neutral, and decreases beyond that in inverse proportion to the axial force F. Is set to

In step S13 (steering reaction force command value setting means), the first steering reaction force G · F calculated in step S6 and the second steering reaction force calculated in step S8, step S9 and step S10, or step S12. Based on θa and the third steering reaction force θv, the steering reaction force command value T of the steering reaction force motor 4 is calculated, and the process proceeds to return.
T = G ・ F + K ・ θa + C ・ θv
Here, K is a weighting coefficient applied to the second steering reaction force θa, and C is a weighting coefficient applied to the third steering reaction force θv.

Next, the operation will be described.
[Steering reaction force command value setting action considering steering control performance]
Conventionally, as a method of generating a steering reaction force in steer-by-wire, a method of detecting a rack axial force and generating a steering reaction force according to the rack axial force is known. This axial force is detected when the steering is rotationally driven according to the target turning angle corresponding to the steering state of the steering wheel, and as a result, axial force is generated. Therefore, as shown in FIG. 5, since no axial force is generated at the initial stage of steering, the steering reaction force is small. Thereafter, the steering is driven to generate an axial force, and the steering reaction force increases accordingly. As described above, a phase shift (temporal shift) occurs between the steering amount and the steering reaction force, which results in a decrease in the steering feeling of the driver and a feeling of steering discomfort.

  As a method for solving this problem, in addition to the deviation between the steering force and the axial force, as in the steering control device described in JP-A-10-217998, the target turning angle of the steered wheel corresponding to the steering angle and A technique for generating a steering reaction force based on a deviation from an actual turning angle is known. That is, when the actual turning angle is delayed with respect to the target turning angle corresponding to the increase in the steering angle at the initial stage of steering, the deviation increases rapidly as shown in FIG. 6, and the steering reaction force rises greatly at the initial stage. . Thereby, the steering reaction force can be generated from the initial stage of steering where no axial force is generated.

  However, in the technique described in Japanese Patent Laid-Open No. 10-217998, the steering reaction force is simply generated based on the deviation between the target turning angle and the actual turning angle, so that the control performance of the turning drive is greatly increased. There was a problem of being influenced. For example, in the case of a steer-by-wire system with a low control response as shown in FIG. 7 and a response delay of the actual turning angle with respect to the target turning angle, a steering reaction force is always generated, so it is unnecessary for the steering reaction force. When a reaction force is applied, the feeling of viscosity becomes stronger, and the steering feeling deteriorates.

  On the other hand, when the control gain is increased in order to increase the response of the steering to the steering, the actual turning angle may overshoot the target turning angle as shown in FIG. Therefore, when this overshoot occurs during steering, the sign of the deviation is reversed and the steering reaction force fluctuates, so that the driver feels uncomfortable and the desired steering reaction force may not be obtained.

  On the other hand, in the vehicle steering control apparatus according to the first embodiment, the target turning angle θe is given the filter Lp equivalent to the turning control performance, and the filter Lp is added (estimated turning angle). Lp · θe) and the actual turning angle θp, the second steering reaction force θa is generated, and the target turning angular velocity (estimated turning angular velocity Lp · dθe / dt) and the actual turning angular velocity dθp / dt A third steering reaction force θv is generated based on the deviation.

  That is, the second steering reaction force θa corresponding to the deviation between the estimated turning angle Lp · θe and the actual turning angle θp, and the deviation between the estimated turning angular velocity Lp · dθe / dt and the actual turning angular velocity dθp / dt By adding the corresponding third steering reaction force θv to the steering reaction force command value T, the axial force F is not generated and the first steering reaction force G · F becomes zero or a minute value near zero. The steering reaction force can be quickly raised by the second steering reaction force θa and the third steering reaction force θv.

At this time, as shown in FIG. 9, the second steering reaction force θa and the third steering reaction force θv are calculated based only on the delay in the initial stage of steering, so that the weight gains K and C related to the deviation are large values. Even if it is set to, the influence on the overall steering reaction force such as the above-mentioned overshoot can be suppressed to a small level.
Here, the filter Lp is usually set to be equivalent to the turning angle control, but the magnitude of the steering reaction force can be adjusted by setting the value to a larger value as the vehicle speed V is higher as shown in FIG. It is.

[Overshoot suppression effect]
Normally, in the steering control, it is necessary to improve the followability to disturbance, and therefore, the control gain is designed to be as large as possible.
However, when the steering wheel rotation is decelerated, such as when turning back or turning over, with a large control gain, the steering angle may overshoot the steering angle. In such a situation, the steering reaction force becomes unstable, giving the driver anxiety.

  Therefore, in the first embodiment, when the absolute value | θp | of the actual turning angle is larger than the absolute value | Lp · θe | of the estimated turning angle, the second steering reaction force θa and the third steering reaction force Only the first steering reaction force G · F is given without providing θv. That is, in the flowchart of FIG. 3, if it is determined in step S7 that | the estimated turning angle | <| actual turning angle |, the process proceeds to step S8 where the second steering reaction force θa and the third steering angle are determined. The reaction force θv is both zero. Thereby, reversal of the steering reaction force due to overshoot can be prevented, and the uncomfortable feeling of steering given to the driver can be suppressed.

  Here, since the detected value of the axial force F has hysteresis, the detected value does not appear immediately even if the steering angle passes neutral. On the other hand, the sign in the vicinity of zero of the steering angle is switched, and the second steering reaction force θa and the third steering reaction force θv are generated. The rise of the second steering reaction force θa and the third steering reaction force θv becomes the reaction force change as it is, which makes the steering feel uncomfortable.

  On the other hand, in the first embodiment, the second steering reaction force θa and the third steering reaction force θv are gradually generated as the position approaches neutral. Therefore, in the region where the direction of the axial force F and the direction of the deviation do not match as shown in FIG. 11, the gain shown in FIG. 4 is added. That is, in the flowchart of FIG. 3, when it is determined in step S11 that the signs of the axial force F and the second steering reaction force θa do not match, the process proceeds to step S12, where the second steering reaction force θa, the second steering reaction force The reaction force θv is multiplied by the gain shown in FIG.

  By doing so, it is possible to suppress generation of unnecessary steering reaction force due to overshoot and to smoothly switch the force of the second steering reaction force θa and the third steering reaction force θv when passing through the neutral position, A smooth steering feeling can be obtained when steering left and right across the neutral position.

  Note that the steering angle θh is used as a parameter instead of the axial force F, and while the steering angular velocity dθh / dt is determined as the return direction, the second steering reaction force θa, The gain may be set with the horizontal axis in FIG. 4 as the steering angle θh so that the three steering reaction force θv is gradually generated.

Next, the effect will be described.
The vehicle steering control apparatus according to the first embodiment has the following effects.

  (1) A target turning angle θe corresponding to the steering state of the steering motor 6 that steers the left and right front wheels 9 and 9 and the steering handle 1 operated by the driver is set and coincides with the target turning angle θe. The steering controller 12 that drives and controls the steering motor 6, the steering reaction motor 4 that applies a steering reaction force to the steering handle 1, and the steering reaction force command value corresponding to the steering state of the left and right front wheels 9 and 9. In a vehicle steering control device including a steering reaction force controller 11 that drives and controls the steering reaction force motor 4 based on T, a target turning angle θe and a filter Lp that represents the response characteristic of the turning motor 6 are used. Based on the turning angle estimating means (step S4) for estimating the turning angle of the left and right front wheels 9, 9 as the estimated turning angle Lp · θe, and the turning for detecting the actual turning angle θp of the left and right front wheels 9, 9. The angle sensor 7 and at least the left and right front wheels 9, 9 are applied to the steered motor 6. Based on the first steering reaction force G · F corresponding to the steering reaction force and the second steering reaction force θa corresponding to the deviation between the estimated turning angle Lp · θe and the actual turning angle θp, the steering reaction force command Steering reaction force command value setting means (step S13) for setting the value T. As a result, it is possible to quickly start up the steering reaction force at the initial stage of steering when the steering reaction force is not generated while suppressing the generation of unnecessary steering reaction force due to the delay in the steering control with respect to the steering.

  (2) The steering reaction force command value setting means (step S13) is a third steering reaction force according to the deviation between the estimated turning angular velocity Lp · dθe / dt of the left and right front wheels 9, 9 and the actual turning angular velocity dθp / dt. A steering reaction force command value T is set based on θv. That is, according to the deviation between the target turning angular velocity (estimated turning angular velocity Lp · dθe / dt) and the actual turning angular velocity dθp / dt through the filter Lp equivalent to the turning control performance (time delay). By applying the steering reaction force, generation of unnecessary steering reaction force due to a delay in the steering control performance can be suppressed to a small level.

The second embodiment is an example in which the magnitudes of the second steering reaction force and the third steering reaction force are changed according to the vehicle speed.
The overall configuration of the steer-by-wire system to which the vehicle steering control device of the second embodiment is applied is the same as the configuration of the first embodiment shown in FIG.

[Steering reaction force command value setting control process]
FIG. 12 is a flowchart showing the flow of the steering reaction force command value setting control process executed by the steering reaction force controller 11 of the second embodiment. Each step will be described below. In addition, the same step number is attached | subjected to the step which performs the process same as Example 1 shown in FIG. 3, and description is abbreviate | omitted.

  In step S21, the steering angle θh, the actual turning angle θp, the axial force F, and the vehicle speed V are read, and the process proceeds to step S2.

In step S22, the second weight gain K is set from the vehicle speed V read in step S21 with reference to the map of FIG. 13, and the process proceeds to step S9. FIG. 13 is a setting map of the weight gains K and C corresponding to the vehicle speed V. The weight gains K and C are zero in the extremely low speed range where the vehicle speed V is equal to or less than the predetermined value V ₀ , and the vehicle speed is the predetermined value V _0. Is set to increase in proportion to the vehicle speed V.

  In step S23, the weight gain C is set from the vehicle speed V read in step S21 with reference to the map of FIG. 13, and the process proceeds to step S10.

Next, the operation will be described.
[Weight gain setting function according to vehicle speed]
In the vehicle steering control apparatus of the second embodiment, the weight gains K and C applied to the second steering reaction force θa and the third steering reaction force θv are changed according to the vehicle speed V as shown in FIG. For example, when driving at extremely low speeds such as in a garage, it is easier for the driver to handle the steering wheel 1 with as little force as possible.

Therefore, in the second embodiment, in the extremely low speed range where the vehicle speed V is equal to or lower than the predetermined value V ₀ , the weight gains K and C of the second steering reaction force θa and the third steering reaction force θv are both set low, Reduce reaction force generation. As a result, the steering reaction force at the start of cutting is reduced, and the driver's steering burden can be reduced when entering the garage.

Further, in the second embodiment, the weight gains K and C are gradually increased as the vehicle speed V increases in the normal vehicle speed range where the vehicle speed V exceeds the predetermined value V ₀ . As a result, the higher the vehicle speed V is, the larger the steering reaction force is obtained at the initial stage of steering, and a firm feeling can be given to the steering. As a result, as the vehicle speed V is higher, the wobbling of the steering handle 1 at the initial stage of steering is further suppressed, so that it is possible to ensure straight running stability during high speed traveling.

Next, the effect will be described.
In addition to the effects (1) and (2) of the first embodiment, the vehicle steering apparatus of the second embodiment has the following effects.

  (3) The steering reaction force command value setting means (step S13) decreases the second steering reaction force θa as the vehicle speed V decreases. In other words, by not providing the second steering reaction force θa in the extremely low speed region where the steering burden is greatest, it is possible to suppress the generation of unnecessary reaction force and reduce the driver's steering burden.

  (4) The steering reaction force command value setting means (step S13) decreases the third steering reaction force θv as the vehicle speed decreases. That is, by not providing the third steering reaction force θv in the extremely low speed range where the turning burden is greatest, it is possible to suppress the generation of unnecessary reaction force and reduce the driver's steering burden.

The third embodiment is an example in which the magnitudes of the second steering reaction force and the third steering reaction force are changed according to the yaw rate of the vehicle.
The overall configuration of the steer-by-wire system to which the vehicle steering control device of the third embodiment is applied is the same as the configuration of the first embodiment shown in FIG.

[Steering reaction force command value setting control process]
The flow of the steering reaction force command value setting control process executed by the steering reaction force controller 11 of the third embodiment is different from the second embodiment because the vehicle speed V of the second embodiment is replaced by the yaw rate φ of the vehicle. Only the step of performing will be described with reference to the flowchart of FIG.

  In step S21, the steering angle θh, the actual turning angle θp, the axial force F, and the yaw rate φ of the vehicle are read, and the process proceeds to step S2.

  In step S22, the weight gain K applied to the second steering reaction force θa is set from the yaw rate φ read in step S21 with reference to the map of FIG. 14, and the process proceeds to step S9. FIG. 14 is a setting map of the weight gains K and C corresponding to the yaw rate φ, and the weight gains K and C are set to have characteristics that increase in proportion to the yaw rate φ.

  In step S23, the weight gain C applied to the third steering reaction force θv is set from the yaw rate φ read in step S21 with reference to the map of FIG. 14, and the process proceeds to step S10.

Next, the operation will be described.
[Weight gain setting function according to yaw rate]
In the vehicle steering control apparatus of the third embodiment, as shown in FIG. 14, the weight gains K and C applied to the second steering reaction force θa and the third steering reaction force θv are changed by the yaw rate φ of the vehicle. That is, by increasing the weight gains K and C as the vehicle behavior change increases, the steering reaction force command value T increases, so that the driver can recognize the vehicle behavior change as the steering reaction force. it can.

Next, the effect will be described.
The vehicle steering control apparatus according to the third embodiment has the following effects in addition to the effects (1) and (2) of the first embodiment.

  (5) Since the steering reaction force command value setting means (step S13) changes the magnitude of the second steering reaction force θa according to the yaw rate φ of the vehicle, the driver recognizes the change in the vehicle behavior as the steering reaction force. Can be made.

  (6) Since the steering reaction force command value setting means (step S13) changes the magnitude of the third steering reaction force θv according to the yaw rate φ of the vehicle, the driver recognizes the change in the vehicle behavior as the steering reaction force. Can be made.

  In the first to third embodiments, an example of application to a steer-by-wire system including a backup clutch as a backup mechanism has been shown. However, for example, there is no backup clutch, and the steer-by-wire in which the operation unit and the steering wheel are completely separated mechanically. Even a system can be applied. In short, the operation unit and the steered wheel are mechanically separated, and a control command for driving the steered actuator to output the steered angle according to the operation state of the operation unit is output, and the steered wheel is turned to the steered state Any vehicle steering control device that executes steer-by-wire control that outputs a control command for driving a reaction force actuator so as to apply a corresponding steering reaction force can be applied.

1 is a configuration diagram of a steer-by-wire system to which a vehicle steering control device of Embodiment 1 is applied. It is a turning angle control block diagram of Example 1. 3 is a flowchart illustrating a flow of a steering reaction force command value setting control process executed by a steering reaction force controller 11 according to the first embodiment. 7 is a gain setting map for multiplying the second steering reaction force θa and the third steering reaction force θv in accordance with the axial force F of the first embodiment. It is an axial force characteristic view at the start of steering. It is a deviation characteristic figure of the target turning angle at the time of steering start, and an actual turning angle. It is the figure which showed the deviation of the target turning angle and actual turning angle in a steer-by-wire system with low turning responsiveness in time series. It is a figure which shows the overshoot of the actual turning angle with respect to the target turning angle at the time of improving control responsiveness. It is a figure which shows the steering reaction force command value setting effect | action according to the steering control performance of Example 1. FIG. FIG. 6 is a diagram illustrating a setting operation of a filter Lp according to the vehicle speed V of the first embodiment. It is a figure which shows the relationship between axial force F and 2nd steering reaction force (theta) a. 7 is a flowchart illustrating a flow of a steering reaction force command value setting control process executed by a steering reaction force controller 11 according to the second embodiment. 6 is a setting map of weight gains K and C according to the vehicle speed V of the second embodiment. 7 is a setting map of weight gains K and C corresponding to the yaw rate φ of the second embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steering handle 2 Steering angle sensor 3 Steering torque sensor 4 Steering reaction force motor 5 Backup clutch 6 Steering motor 7 Steering angle sensor 8 Steering mechanism 9, 9 Left and right front wheel 10 Rack axial force sensor 11 Steering reaction force controller 12 Steering controller 13 Communication line

Claims (7)

A steering actuator that steers steering wheels;
A steering control means for setting a target turning angle according to the steering state of the operation unit operated by the driver, and driving and controlling the steering actuator so as to coincide with the target turning angle;
A steering reaction force actuator for applying a steering reaction force to the operation unit;
Steering reaction force control means for driving and controlling the steering reaction force actuator based on a steering reaction force command value corresponding to the steering state of the steered wheel;
In a vehicle steering control device comprising:
Based on the target turning angle and the response characteristics of the turning actuator, a turning angle estimation means for estimating the turning angle of the steered wheel as an estimated turning angle;
An actual turning angle detection means for detecting an actual turning angle of the steering wheel;
At least a first steering reaction force according to a steering reaction force applied to the steering actuator from the steered wheel, and a second steering reaction force according to a deviation between the estimated steering angle and the actual steering angle. And a steering reaction force command value setting means for setting the steering reaction force command value,
A vehicle steering control device comprising: The vehicle steering control device according to claim 1,
The steering control device for a vehicle, wherein the steering reaction force command value setting means changes the magnitude of the second steering reaction force according to the yaw rate of the vehicle. The vehicle steering control device according to claim 1 or 2,
The steering control device for a vehicle, wherein the steering reaction force command value setting means decreases the second steering reaction force as the vehicle speed decreases. The vehicle steering control device according to any one of claims 1 to 3,
The steering reaction force command value setting means sets the steering reaction force command value based on a third steering reaction force according to a deviation between an estimated steering angular velocity of the steered wheels and an actual steering angular velocity. A vehicle steering control device. The vehicle steering control device according to claim 4,
The vehicle steering control device, wherein the steering reaction force command value setting means changes the magnitude of the third steering reaction force according to the yaw rate of the vehicle. In the vehicle steering control device according to claim 4 or 5,
The steering control device for a vehicle, wherein the steering reaction force command value setting means decreases the third steering reaction force as the vehicle speed decreases. Based on the target turning angle of the steered wheel according to the steering state of the operation unit operated by the driver and the response characteristic of the steered actuator that steers the steered wheel, the steered angle of the steered wheel Is estimated as the estimated turning angle,
Calculating a first steering reaction force corresponding to a steering reaction force applied to the steering actuator from at least the steered wheel;
Calculating a second steering reaction force according to a deviation between the estimated turning angle and an actual turning angle that is an actual turning angle of the steered wheel;
A vehicle steering control characterized in that a steering reaction force command value of a steering reaction force actuator that applies a steering reaction force to the operation unit is set based on the first steering reaction force and the second steering reaction force. apparatus.

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