JP2017081250A - Vehicular steering-reactive-force control apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicular steering-reactive-force control apparatus for improving the followability of a steering wheel to a target steering angle without compromising the stability of steering when a driver performs an over-ride steering, in controlling steering reactive force in a vehicle having a drive support device.SOLUTION: A steering-reactive-force control apparatus is used for a vehicle having a drive support device that controls an electric power steering device via a control device so that a steering angle of a steering wheel matches a target steering angle. In a case where the drive support device is in operation (S20), the control device computes target steering attenuation torque Td on the basis of a temporal integration value of a steering angle θor a steering angular velocity dθ that is modified with a target steering angle θt of drive support control (S50, 70). In a case where a magnitude of the steering angular velocity dθ is less than a reference value θdc, the target steering attenuation torque Td is computed so as to be smaller during operation of the drive support device than during non-operation (S70).SELECTED DRAWING: Figure 2

Description

  The present invention relates to a vehicle steering reaction force control device including an electric power steering device and a driving support device.

  BACKGROUND ART A steering reaction force control device for a vehicle such as an automobile reduces a driver's steering burden and improves steering feeling by applying torque to the steering device using an electric power steering device. For example, as described in Patent Document 1 below, in the steering reaction force control device, the target steering reaction force torque is calculated, and the electric power is adjusted so that the actual steering reaction force torque becomes the target steering reaction force torque. The steering device is controlled by PID feedback. The target steering reaction torque includes a target steering spring torque that generates a force to return the steering wheel to the neutral position, and further generates a steering drag proportional to the steering angular velocity to improve the stability of the steering system. Includes steering damping torque.

  By the way, as described in Patent Document 2 below, for example, in a vehicle equipped with a driving support device that performs automatic driving or the like, the control device of the electric power steering device has two modes, a manual steering mode and an automatic steering mode. The operation mode is selected, and the selection of the operation mode is performed by the vehicle occupant operating the switch.

  In both the manual steering mode and the automatic steering mode, the control device of the steering reaction force control device calculates the target steering reaction force torque, and uses the PID feedback so that the actual steering reaction force torque becomes the target steering reaction force torque. To control the electric power steering device.

  In the automatic steering mode, the electric power steering device also functions as an actuator that generates a turning torque for automatically turning the steered wheels. The driving assist device calculates, for example, a target rudder angle of a steered wheel for causing the vehicle to travel along the traveling lane, and the control device performs target steering based on a deviation between the target rudder angle and the actual rudder angle of the steered wheel. Calculate the reaction torque. Further, the control device controls the electric power steering device by PID feedback so that the steering reaction torque becomes the target steering reaction torque, whereby the steering reaction force is controlled and the steered angle of the steered wheels is set to the target rudder. It is controlled to be a corner.

  Specifically, the target steering spring torque is calculated based on the steering angle corrected at the target steering angle corresponding to the target steering angle, and the target steering damping torque is calculated by calculating the time differential value of the steering angle or the corrected steering angle. Calculated based on the time derivative. The higher the ratio of the target steering spring torque to the steering angle or the corrected steering angle, the higher the steering reaction force felt by the driver, resulting in a smaller steering assist torque.

JP 2007-76582 A JP 2013-193490 A

[Problems to be Solved by the Invention]
Generally, the gain when controlling the electric power steering device by the PID feedback in the steering reaction force control device is constant. Therefore, when the gain of feedback control is set to a low value in order to improve the followability of the steered wheels to the target rudder angle in the automatic steering mode by reducing the drag caused by the steering damping torque, the driver overrides it. Steering stability during steering is reduced. Conversely, if the feedback control gain is set to a high value in order to ensure the stability of the steering when the driver performs override steering, the drag caused by the steering damping torque increases, so in the automatic steering mode The followability of the steered wheels to the target rudder angle is reduced.

  Note that if the gain of feedback control is set to a high value in order to improve the followability of the steered wheels to the target rudder angle in the automatic steering mode by increasing the magnitude of the steering spring torque, the driver will perform infeed steering. The steering reaction force felt when doing As a result, the operability of the override steering, that is, the operability that the driver steers over the automatic steering is lowered. Conversely, if the feedback control gain is set to a low value in order to ensure the operability of the override steering by reducing the magnitude of the steering spring torque, the tracking of the steered wheels to the target steering angle in the automatic steering mode will be performed. Sex is reduced.

  The main problem of the present invention is that in the control of the steering reaction force in the vehicle equipped with the driving support device, the steering wheel can be adjusted to the target steering angle without lowering the stability of the steering when the driver performs the override steering. It is to improve the following ability.

[Means for Solving the Problems and Effects of the Invention]
According to the present invention, the electric power steering device, the control device that controls the electric power steering device, and the electric power steering device are controlled via the control device so that the turning angle of the steered wheels becomes the target turning angle. And a control device that obtains a steering index value indicating an actual steering operation amount of the driver and includes a target steering damping force based on a time differential value of the steering index value. There is provided a vehicle steering reaction force control device that calculates a steering reaction force and controls an electric power steering device so that the steering reaction force becomes a target steering reaction force.

  The control device calculates the target steering damping force based on the time differential value of the steering index value when the driving support device is not operating, and when the driving support device is operating, the time differential value of the steering index value and The target steering damping force is calculated based on one of the time differential values of the corrected steering index value obtained by correcting the steering index value with the target steering index value corresponding to the target steering angle.

  Further, the control device, when the magnitude of the time differential value of the one steering index value is less than the reference value, is greater when the driving support device is operating than when the driving support device is not operating. The target steering damping force is calculated so that the magnitude is reduced.

  In general, the change range of the change speed of the turning angle of the steered wheels in the driving support control such as automatic driving is smaller than the change range of the change speed of the steered wheels by the steering operation of the normal driver. Therefore, since the magnitude of the change speed of the turning angle of the steered wheels in the driving support control does not become a large value, the target steering corresponding to the time differential value of the steering index value used for calculating the target damping force and the steering angle. One of the time differential values of the steering index value corrected by the index value does not become a large value.

  According to the above configuration, the target steering damping force is activated when the driving assist device is operating when the magnitude of the time differential value of the one steering index value is less than the reference value. It is calculated so that the size is smaller than when it is not. The steering damping force based on the target steering damping force when the driving support device is operating acts as a resistance against bringing the actual steering angle of the steered wheels closer to the target steering angle. Accordingly, it is possible to reduce the drag force against the turning of the steered wheels by driving assistance and improve the followability to the target rudder angle of the steered wheels when the driving assistance device is operating.

  When the magnitude of the time differential value of the one steering index value is greater than or equal to the reference value, the target steering damping force is obtained when the driving support device is not operating when the driving support device is operating. It is not necessary to calculate so that the size is smaller. Therefore, since the magnitude of the steering damping force does not decrease, the stability of the steering when the override steering is performed in the automatic steering mode does not decrease.

  The “steering index value indicating the actual steering operation amount of the driver” is a value indicating the actual steering operation amount of the driver, and may be any value that can be detected or estimated. For example, the steering index value includes the steering angle that is the rotation angle of the steering shaft, the rotation angle of the electric motor of the electric power steering device, the turning angle of the steered wheels, the yaw rate of the vehicle, the lateral acceleration of the vehicle, and the steering device is a rack and pinion type In this case, either the rotation angle of the pinion shaft or the stroke of the rack bar may be used. Further, the “target steering index value” is a target value of the steering index value. For example, when the steering index value is a steering angle, it is a target steering angle.

[Aspect of the Invention]
In one aspect of the present invention, the control device, when the time derivative value of the one steering index value is larger than the reference value, the drive support device is operated when the drive support device is operating. The target steering damping force is calculated so as to be larger than when not operating.

  As described above, the steering damping force based on the target steering damping force when the driving assistance device is operating acts as a drag against bringing the actual steering angle of the steered wheels closer to the target steering angle, while the driver Acts to improve the stability of steering when performing override steering. In addition, as described above, the change range of the change speed of the steered wheels by the steering operation of the normal driver is more than the change range of the change speed of the steered wheels in the driving support control such as automatic driving. Is also big. Therefore, when the magnitude of the time differential value of the one steering index value is larger than the reference value, it is preferable to enhance the effect of improving the steering stability.

  According to the above aspect, when the magnitude of the time differential value of the one steering index value is larger than the reference value, the driving assist device operates when the driving assist device is operating. It is calculated so that the size is larger than when it is not. Therefore, by increasing the magnitude of the steering damping force, the effect of improving the steering stability is enhanced. Therefore, it is possible to improve the stability of steering when the driver performs the override steering in a situation where the driving support device is operating.

  In one aspect of the present invention, the difference between the target steering damping force when the driving support device is operating and the target steering damping force when the driving support device is not operating is the difference between the one steering index value. 0 when the magnitude of the time differential value is the reference value, and gradually increases as the magnitude of the difference between the time differential value of the one steering index value and the reference value increases within a predetermined value or less. To do.

  According to the above aspect, the difference between the time differential value of the one steering index value and the reference value increases gradually from 0 as the difference between the reference value and the reference value increases. Therefore, when the magnitude of the time differential value of the one steering index value exceeds or exceeds the reference value, it is possible to prevent the magnitude of the target steering damping force from changing suddenly.

1 is a schematic configuration diagram showing an embodiment of a steering reaction force control device for a vehicle according to the present invention. It is a flowchart which shows the steering reaction force torque control routine in embodiment. It is a flowchart which shows the driving assistance control routine in embodiment. 6 is a map showing a relationship between a steering angle θ and a target steering spring torque Tp in the embodiment. FIG. 5 is an enlarged view showing the relationship shown in FIG. 4 together with Comparative Example 1 (one-dot chain line) and Comparative Example 2 (two-dot chain line) in a range where the steering angle θ is positively small. 6 is a map showing a relationship between a steering angular velocity θd and a target steering damping torque Td in the embodiment. FIG. 7 is an enlarged view showing the relationship shown in FIG. 6 together with Comparative Example 1 (one-dot chain line) and Comparative Example 2 (two-dot chain line) in a range where the steering angular velocity θd is positively small. It is a graph which shows the relationship between steering angle (theta) and the correction coefficient Kp in a 1st modification example. It is a graph which shows the relationship between steering angular velocity (theta) d and the correction coefficient Kd in a 2nd modification example. FIG. 5 is an enlarged view showing a correction example of the relationship shown in FIG. 4 in a range where the steering angle θ is positively small. It is a figure which expands and shows the example of correction of the relationship shown by FIG. 6 about the range with small steering angular velocity (theta) d.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic configuration diagram showing a steering reaction force control device 10 according to an embodiment of the present invention. The steering reaction force control device 10 is an electric power steering (EPS) device 12 and a control device for controlling the same. The present invention is applied to a vehicle 18 provided with an EPS control device 14 and a driving support control device 16.

  As shown in FIG. 1, the vehicle 18 has left and right front wheels 20FL and 20FR that are steered wheels and left and right rear wheels 20RL and 20RR that are non-steered wheels. The front wheels 20FL and 20FR are steered via the rack bar 24 and the tie rods 26L and 26R by the electric power steering device 12 driven in response to the operation of the steering wheel 22 by the driver. The steering wheel 22 is connected to a pinion shaft 34 of the power steering apparatus 12 via a steering shaft 28 and a universal joint 32.

  In the embodiment, the electric power steering device 12 is a rack coaxial type electric power steering device, and converts the rotational torque of the electric motor 36 and the electric motor 36 into a force in the reciprocating direction of the rack bar 24, for example, a ball screw type. A conversion mechanism 38. The electric power steering device 12 generates a driving force for driving the rack bar 24 with respect to the housing 40, thereby reducing the steering burden on the driver and driving torque for automatically turning the front wheels 20FL and 20FR. Occur. The control of the electric power steering device 12 by the EPS control device 14 will be described in detail later.

  As can be understood from the above description, the steering shaft 28, the universal joint 32, the electric power steering device 12, the rack bar 24, the tie rods 26L and 26R, and the like form a steering device. Although the electric power steering device 12 applies torque to the steering device by applying a driving force to the rack bar 24, the electric power steering device 12 may apply torque to the steering shaft 28.

  In the embodiment, the steering shaft 28 is provided with a steering angle sensor 50 that detects the rotation angle of the steering shaft as the steering angle θ. The pinion shaft 34 is provided with a steering torque sensor 52 that detects the steering torque T. The steering torque sensor 52 may be provided on the steering shaft 28. A signal indicating the steering angle θ and a signal indicating the steering torque T are input to the EPS control device 14. The vehicle 18 is provided with a vehicle speed sensor 54 that detects the vehicle speed V, and a signal indicating the vehicle speed V is also input to the EPS control device 14.

  Further, the vehicle 18 is used to select whether or not to perform a CCD camera 60 for photographing the front of the vehicle and trajectory control (also referred to as “LKA (lane keeping assist) control) for causing the vehicle to travel along the lane”. A selection switch 62 is provided. The selection switch 62 is operated by an occupant of the vehicle and operates the driving support control device 16 to execute the trajectory control as the driving support control (on), and the non-operating position (does not operate the driving support control device 16). Off). A signal indicating image information in front of the vehicle photographed by the CCD camera 60 and a signal indicating the position (on or off) of the selection switch 62 are input to the driving support control device 16.

  The driving support control device 16 also receives from the motion state detection device 64 a signal indicating the vehicle motion state amount necessary for driving support control of the vehicle 18 such as the yaw rate, longitudinal acceleration, and lateral acceleration of the vehicle 18. Note that the image information in front of the vehicle and the information on the traveling lane may be acquired by means other than the CCD camera 60, or may be acquired by a combination of the CCD camera 60 and other means.

  The EPS control device 14 and the driving support control device 16 each have a CPU, a ROM, a RAM, and an input / output port device, and include microcomputers that are connected to each other by a bidirectional common bus. The EPS control device 14 and the driving support control device 16 exchange information with each other by communication as necessary. The steering angle sensor 50 and the steering torque sensor 52 detect the steering angle θ and the steering torque T, respectively, with the case of steering or turning in the left turning direction of the vehicle as positive.

  As will be described in detail later, the EPS control device 14 performs steering reaction force torque control by controlling the electric power steering device 12 according to the flowchart shown in FIG. The driving support control device 16 performs driving support control according to the flowchart shown in FIG. As shown in FIGS. 2 and 3, the “steering index value indicating the actual steering operation amount of the driver” and the “target steering index value” are the steering angle θ and the target steering angle θt, respectively.

  Note that the LKA control as the driving support control may be either a control in which a target locus is set and the vehicle travels along the target locus or a control that prevents the vehicle from deviating from the traveling lane. The LKA control as the driving support control is performed when the selection switch 62 is on. Even when the selection switch 62 is off, for example, the vehicle 18 travels around an obstacle in front of the selection switch 62. Automatic steering for emergency avoidance (emergency avoidance steering) may be performed as driving support control.

<Steering reaction force torque control>
Next, the steering reaction torque control routine in the embodiment will be described with reference to the flowchart shown in FIG. Note that the control according to the flowchart shown in FIG. 2 is repeatedly executed by the EPS controller 14 every predetermined time when an ignition switch not shown in FIG. 1 is on.

  First, in step 10, a signal indicating the steering angle θ detected by the steering angle sensor 50 is read.

  In step 20, it is determined whether or not the driving support control by the driving support control device 16 is being performed, for example, by determining whether or not the selection switch 62 is on. When an affirmative determination is made, the steering reaction force torque control proceeds to step 50, and when a negative determination is made, the steering reaction force torque control proceeds to step 30.

  In step 30, the target steering spring torque Tp corresponding to the target steering spring force is calculated by referring to the map indicated by the broken line in FIG. 4 based on the steering angle θ. As shown in FIG. 4, the magnitude of the target steering spring torque Tp increases as the magnitude of the steering angle θ increases, but the magnitude of the target steering spring torque Tp with respect to the increase amount of the steering angle θ. The ratio of the increase amount decreases as the steering angle θ increases. The relationship between the steering angle θ and the target steering spring torque Tp shown in FIG. 4 is an exemplary relationship.

  In step 40, the time differential value of the steering angle θ is calculated as the steering angular velocity θd, and the target steering damping force is dealt with by referring to the map shown by the broken line in FIG. 6 based on the steering angular velocity θd. The target steering damping torque Td to be calculated is calculated. As shown in FIG. 6, the magnitude of the target steering damping torque Td increases as the steering angular speed θd increases, and the ratio of the target steering damping torque Td to the steering angular speed θd is the magnitude of the steering angular speed θd. Is substantially constant regardless of The relationship between the steering angular velocity θd and the target steering damping torque Td shown in FIG. 6 is an exemplary relationship.

  In step 50, a corrected steering angle θ is calculated by subtracting a target steering angle θt calculated by the driving support device 16 described later from the steering angle θ.

  In step 60, the target steering spring torque Tp corresponding to the target steering spring force is calculated by referring to the map indicated by the solid line in FIG. 4 based on the corrected steering angle θ. As shown in FIGS. 4 and 5, when the magnitude of the steering angle θ is less than the reference value θpc (positive constant), the target steering spring torque Tp when the driving support control is being performed. Is larger than the target steering spring torque Tp when the driving support control is not performed. On the other hand, when the magnitude of the steering angle θ is larger than the reference value θpc, the magnitude of the target steering spring torque Tp when the driving assistance control is being performed is the same as when the driving assistance control is not being carried out. It is smaller than the magnitude of the target steering spring torque Tp.

  Furthermore, when the magnitude of the steering angle θ is the reference value θpc, the magnitude of the target steering spring torque Tp when the driving support control is being performed is the target steering when the driving support control is not being performed. It is the same as the magnitude of the spring torque Tp. Therefore, the target steering spring torque difference ΔTp, which is a value obtained by subtracting the latter target steering spring torque Tp from the former target steering spring torque Tp, is zero. Let Δθpc be a positive constant that is 1/2 to ３ of θpc, and a range of steering angles θpc−Δθpc to θpc + Δθpc is a predetermined range of steering angles. When the magnitude of the steering angle θ is a value within a predetermined steering angle range, the magnitude of the target steering spring torque difference ΔTp is the magnitude of the steering angle θ used for calculating the target steering spring torque Tp. And the reference value θpc increase gradually as the difference increases.

  The target steering spring torque Tp when the driving support control is being performed may be calculated in the following manner (first modification example). First, the target steering spring torque Tp is provisionally calculated by referring to the map indicated by the broken line in FIG. 4 based on the corrected steering angle θ. Next, the correction coefficient Kp is calculated by referring to the map shown in FIG. 8 based on the corrected steering angle θ. Further, the target steering spring torque Tp when the driving support control is being performed is calculated as the product of the provisionally calculated target steering spring torque Tp and the correction coefficient Kp.

  In step 70, the time differential value of the steering angle θ or the corrected time differential value of the steering angle θ is calculated as the steering angular velocity θd, and a map indicated by a solid line in FIG. 6 is calculated based on the steering angular velocity θd. By referencing, the target steering damping torque Td corresponding to the target steering damping force is calculated. As shown in FIGS. 6 and 7, when the magnitude of the steering angular velocity θd is less than the reference value θdc (positive constant), the target steering damping torque Td when the driving support control is being performed. Is smaller than the target steering damping torque Td when the driving support control is not performed. Conversely, when the magnitude of the steering angular velocity θd is larger than the reference value θdc, the magnitude of the target steering damping torque Td when the driving assistance control is being performed is the same as when the driving assistance control is not being carried out. It is larger than the target steering damping torque Td.

  Further, when the magnitude of the steering angular velocity θd is the reference value θdc, the magnitude of the target steering damping torque Td when the driving assistance control is being performed is the target steering when the driving assistance control is not being carried out. It is the same as the magnitude of the damping torque Td. Therefore, the target steering damping torque difference ΔTd, which is a value obtained by subtracting the latter target steering damping torque Td from the former target steering damping torque Td, is zero. Let Δθdc be a positive constant that is 1/2 to 1/3 of θdc, and a range of steering angular velocities θdc−Δθdc to θdc + Δθdc be a predetermined range of steering angular velocities. In the case where the magnitude of the steering angular velocity θd is a value within a predetermined steering angular velocity range, the magnitude of the target steering damping torque difference ΔTd is the magnitude of the steering angular velocity θd used for calculating the target steering damping torque Td. And the reference value θdc increase gradually as the difference increases.

  The target steering damping torque Td when the driving support control is being performed may be calculated in the following manner (second modification example). First, the target steering damping torque Td is provisionally calculated by referring to the map indicated by the broken line in FIG. 6 based on the steering angular velocity θd. Next, the correction coefficient Kd is calculated by referring to the map shown in FIG. 9 based on the steering angular velocity θd. Further, the target steering damping torque Td when the driving support control is being performed is calculated as the product of the provisionally calculated target steering damping torque Td and the correction coefficient Kd.

  When step 40 or 70 is completed, the steering reaction torque control proceeds to step 80. In step 80, the sum Tp + Td of the target steering spring torque Tp and the target steering damping torque Td is calculated as the target steering reaction torque Tat.

  In step 90, the command current Iepst to the electric power steering device 12 for changing the steering torque T to the target steering reaction torque Tat by the PID feedback control becomes a deviation between the steering torque T and the target steering reaction torque Tat. Calculated based on

  In step 100, the electric power steering device 12 is controlled so that the steering reaction force Ta becomes the target steering reaction force torque Tat by applying the command current Iepst to the electric motor 36 of the electric power steering device 12.

<Drive support control>
Next, the driving support control routine in the embodiment will be described with reference to the flowchart shown in FIG.

  First, in step 210, a signal indicating image information in front of the vehicle photographed by the CCD camera 60 and a signal indicating the position of the selection switch 62 are read.

  In step 220, it is determined whether or not the selection switch 62 is on, that is, whether or not the LKA control is being executed. When a negative determination is made, the driving support control proceeds to step 250, and when an affirmative determination is made, the driving support control proceeds to step 230.

  In step 230, the traveling lane ahead of the vehicle 18 is specified based on the information ahead of the vehicle photographed by the CCD camera 60. In step 240, the target steering angle θt of LKA control, that is, the vehicle 18 is determined. A target steering angle θt for traveling along the traveling lane is calculated. Note that the specification of the traveling lane and the calculation of the target steering angle θt do not constitute the present invention, and are executed in any manner known in the art, for example, as described in Japanese Patent No. 5737197. It's okay.

  In step 250, the target steering angle θt for LKA control is set to zero. When step 240 or 250 is completed, the driving support control proceeds to step 260.

  In step 260, a signal indicating the target steering angle θt is output from the driving support control device 16 to the EPS control device 14.

  As can be understood from the above description, when the selection switch 62 is in the operating position (ON), the EPS control device 14 and the driving support control device 16 operate as described above. That is, when the driving assistance control is performed according to the flowchart shown in FIG. 3 by the driving assistance control device 16, the target steering angle θt of the front wheels 20FL and 20FR for causing the vehicle 18 to travel along a predetermined traveling lane is calculated. Is done. By controlling the steering reaction torque according to the flowchart shown in FIG. 2 by the EPS control device 14, the steering reaction force felt by the driver is controlled, and the steering angles of the front wheels 20FL and 20FR are set to the target steering angle θt. Control is performed so that the corresponding steering angle is obtained.

  In particular, as shown in FIG. 2, the target steering reaction torque Tat varies depending on whether or not driving support control is being performed, that is, whether or not the driving support control device 16 is operating.

<When not driving support control>
In Step 20 of FIG. 2, a negative determination is made. In Step 30, the target steering spring torque Tp is calculated based on the steering angle θ, and in Step 40, the target steering damping torque Td is calculated based on the steering angular velocity θd. In step 80, the sum Tp + Td of the target steering spring torque Tp and the target steering damping torque Td is calculated as the target steering reaction torque Tat. Further, in steps 90 and 100, the electric power steering device 12 is controlled by PID feedback control so that the steering torque T becomes the target steering reaction torque Tat.

<During driving support control>
An affirmative determination is made in step 20 of FIG. 2, and the corrected steering angle θ is calculated by subtracting the target steering angle θt from the steering angle θ in step 50. In step 60, the target steering spring torque Tp is calculated based on the corrected steering angle θ, and in step 70, based on the steering angular velocity θd that is the time differential value of the steering angle θ or the time differential value of the corrected steering angle θ. A target steering damping torque Td is calculated. In step 80, the target steering reaction torque Tat is calculated as in the case where the driving support control is not being performed. Further, in steps 90 and 100, the electric power steering device 12 is controlled by PID feedback control so that the steering torque T becomes the target steering reaction torque Tat.

  In both cases where the driving support control is not being performed and the driving support control is being performed, the steering spring torque and the steering damping torque are controlled to be the target steering spring torque Tp and the target steering damping torque Td, respectively. Therefore, the steering spring torque and the steering damping torque, which are steering reaction force torques, can be controlled in accordance with the driver's steering operation.

  When the driving assistance control is being performed, the target steering spring torque Tp is calculated based on the corrected steering angle θ calculated by subtracting the target steering angle θt from the steering angle θ. Therefore, the target steering spring torque Tp acts as a target torque for making the steering spring torque the target steering spring torque and making the steering angle θ close to the target steering angle θt. Therefore, the steering angles of the front wheels 20FL and 20FR can be controlled so as to be the steering angles for the vehicle 18 to travel along the traveling lane.

  In particular, when the magnitude of the corrected steering angle θ is less than the reference value θpc, the target steering spring torque Tp is compared with that when the driving support device is operating and driving support control is not being performed. Thus, the size is calculated so as to increase. Therefore, even during the driving support control, the magnitude of the torque that brings the steering angle θ closer to the target steering angle θt can be made larger than when the magnitude of the target steering spring torque Tp is not increased. Accordingly, it is possible to improve the followability of the front wheels 20FL and 20FR to the target rudder angle during the driving support control.

  On the other hand, when the corrected steering angle θ is larger than the reference value θpc, the target steering spring torque Tp indicates that the driving support device is operating when the driving support device is operating and driving support control is being performed. It is calculated so that the size is smaller than when there is not. Therefore, the magnitude of the torque that brings the actual steering angle of the front wheels 20FL and 20FR closer to the target steering angle is reduced. Therefore, when the driver steers the actual steering angle of the front wheels 20FL and 20FR away from the target steering angle with a large operation amount, the possibility that the steering spring torque hinders the driver's steering operation is reduced. In addition, the operability of the override steering can be improved.

  The difference between the target steering spring torque ΔTp, that is, the difference between the target steering spring torque Tp when the driving support control is being performed and the target steering spring torque Tp when the driving support control is not being performed is the magnitude of the corrected steering angle θ. It is 0 when it is the reference value θpc. Furthermore, the difference ΔTp in the target steering spring torque gradually increases as the difference between the corrected steering angle θ and the reference value θpc increases within a predetermined steering angle range θpc−Δθpc to θpc + Δθpc. . Therefore, as the magnitude of the difference between the corrected steering angle θ and the reference value θpc increases within a predetermined steering angle range from the reference value, it gradually increases from zero. Therefore, when the corrected steering angle θ increases or decreases beyond the reference value θpc, it is possible to prevent the target steering spring torque difference ΔTp from changing suddenly.

  Here, referring to FIG. 5, when driving support control is performed, Comparative Examples 1 and 2 in which the target steering spring torque Tp is corrected to increase or decrease from the value when the driving support control is not performed. This will be described in comparison with the embodiment.

  In FIG. 5, the target steering spring torque Tp of Comparative Example 1 is indicated by a one-dot chain line. In Comparative Example 1, when the magnitude of the corrected steering angle θ is less than the reference value θpc, the target steering spring torque Tp is multiplied by the first correction coefficient that is a constant larger than 1. The target steering spring torque Tp is corrected to increase. Further, when the corrected steering angle θ is larger than the reference value θpc, the target steering spring torque Tp is multiplied by the second correction coefficient, which is a positive constant smaller than 1, so that the target steering spring torque Tp is multiplied. The steering spring torque Tp is corrected to be reduced.

  In FIG. 5, the target steering spring torque Tp of Comparative Example 2 is indicated by a two-dot chain line. In Comparative Example 2, when the magnitude of the corrected steering angle θ is less than the reference value θpc, the first correction amount (positive constant) is added to the target steering spring torque Tp, so that the target The steering spring torque Tp is corrected to increase. Further, when the corrected steering angle θ is larger than the reference value θpc, the target steering spring torque Tp is obtained by subtracting the second correction amount (positive constant) from the target steering spring torque Tp. Is reduced and corrected.

  As shown in FIG. 5, also in Comparative Examples 1 and 2, when the corrected steering angle θ is less than the reference value θpc, driving is performed when driving support control is being performed. The magnitude of the target steering spring torque Tp can be increased compared to when the assist control is not performed. Conversely, when the corrected steering angle θ is larger than the reference value θpc, the target steering spring torque Tp is greater when the driving support control is being performed than when the driving support control is not being performed. Can be reduced in size.

  However, in both cases of Comparative Examples 1 and 2, the correction coefficient and the correction amount are constants, respectively. Therefore, as shown by the one-dot chain line and the two-dot chain line in FIG. 5, when the magnitude of the corrected steering angle θ increases or decreases beyond the reference value θpc, the magnitude of the target steering spring torque Tp is A sudden change is inevitable.

  On the other hand, according to the embodiment, as shown by a solid line in FIG. 5, even when the corrected steering angle θ increases or decreases beyond the reference value θpc, the target steering spring torque Tp It is possible to effectively prevent a sudden change in the size of.

  In addition, when the magnitude of the steering angular velocity θd, which is the time differential value of the steering angle θ or the time differential value of the corrected steering angle θ, is less than the reference value θdc, the target steering damping torque Td is calculated by the driving support device. When it is operating and driving support control is being performed, the size is calculated to be smaller than when driving support control is not being performed. Therefore, even during the driving support control, the magnitude of the drag torque against bringing the steering angle θ closer to the target steering angle θt is smaller than when the magnitude of the target steering damping torque Td is not reduced. Can do. Accordingly, it is possible to improve the followability of the front wheels 20FL and 20FR to the target rudder angle during the driving support control.

  On the other hand, when the magnitude of the steering angular velocity θd is larger than the reference value θdc, the target steering damping torque Td is set when the driving support device is not operating when the driving support device is operating and driving support control is being performed. In comparison, the calculation is performed to increase the size. Therefore, the magnitude of the drag torque against changing the actual steering angle of the front wheels 20FL and 20FR is increased. Accordingly, when the driver steers at a steering speed having a large magnitude so as to change the actual steering angle of the front wheels 20FL and 20FR, the magnitude of the steering damping torque becomes large, and the stability of the override steering is improved. Can do.

  The difference between the target steering damping torque ΔTd, that is, the difference between the target steering damping torque Td when the driving support control is being performed and the target steering damping torque Td when the driving support control is not being performed is that the magnitude of the steering angular velocity θd is the reference value θdc. When it is, it is 0. Further, the difference ΔTd in the target steering damping torque gradually increases as the difference between the steering angular velocity θd and the reference value θdc increases within a predetermined steering angular velocity range θdc−Δθdc to θdc + Δθdc. Therefore, as the magnitude of the difference between the steering angular velocity θd and the reference value θdc increases within the predetermined steering angular velocity from the reference value θdc, it gradually increases from zero. Therefore, when the magnitude of the steering angular velocity θd increases or decreases beyond the reference value θdc, it is possible to prevent the magnitude of the difference ΔTd in the target steering damping torque from changing suddenly.

  Here, referring to FIG. 7, when driving support control is performed, Comparative Examples 1 and 2 in which the target steering damping torque Td is corrected to increase or decrease from the value when the driving support control is not performed. This will be described in comparison with the embodiment.

  In FIG. 7, the target steering damping torque Td of Comparative Example 1 is indicated by a one-dot chain line. In Comparative Example 1, when the magnitude of the steering angular velocity θd is less than the reference value θdpc, the target steering damping torque Td is multiplied by a first correction coefficient that is a positive constant smaller than 1, The target steering damping torque Td is corrected for reduction. Furthermore, when the magnitude of the steering angular velocity θd is larger than the reference value θdc, the target steering damping torque Td is obtained by multiplying the target steering damping torque Td by a second correction coefficient that is a constant larger than 1. Increase correction.

  In FIG. 7, the target steering damping torque Td of Comparative Example 2 is indicated by a two-dot chain line. In Comparative Example 2, when the magnitude of the steering angular velocity θd is less than the reference value θdc, the target steering damping torque is obtained by subtracting the first correction amount (positive constant) from the target steering damping torque Td. Td is corrected for reduction. Further, when the steering angular velocity θd is larger than the reference value θdc, the second correction amount (positive constant) is added to the target steering damping torque Td, whereby the target steering damping torque Td is corrected to increase. Is done.

  As shown in FIG. 7, also in Comparative Examples 1 and 2, when the magnitude of the steering angular velocity θd is less than the reference value θdc, the driving support control is performed when the driving support control is being performed. The magnitude of the target steering damping torque Td can be made smaller than when it is not performed. On the contrary, when the steering angular velocity θd is larger than the reference value θdc, the target steering damping torque Td is larger when the driving support control is being performed than when the driving support control is not being performed. Can be increased.

  However, in both cases of Comparative Examples 1 and 2, the correction coefficient and the correction amount are constants, respectively. Therefore, as shown by the one-dot chain line and the two-dot chain line in FIG. 7, when the magnitude of the steering angular velocity θd increases or decreases beyond the reference value θdc, the magnitude of the target steering damping torque Td changes suddenly. Is inevitable.

  On the other hand, according to the embodiment, as shown by a solid line in FIG. 7, even when the magnitude of the steering angular velocity θd increases or decreases beyond the reference value θdc, the magnitude of the target steering damping torque Td. Can be effectively prevented from changing suddenly.

  Although the present invention has been described in detail with reference to specific embodiments, the present invention is not limited to the above-described embodiments, and various other embodiments are possible within the scope of the present invention. Will be apparent to those skilled in the art.

  For example, in the above-described embodiment, as shown in FIGS. 4 and 5, when the steering angle θ is larger than the reference value θpc, the target when the driving support control is performed is shown. The magnitude of the steering spring torque Tp is smaller than the magnitude of the target steering spring torque Tp when the driving support control is not performed. However, the magnitude of the target steering spring torque Tp when the driving assistance control is being performed may be the same as the magnitude of the target steering spring torque Tp when the driving assistance control is not being carried out.

  Similarly, in the above-described embodiment, as shown in FIGS. 6 and 7, when the magnitude of the steering angular velocity θd is larger than the reference value θdc, the driving assistance control is performed. The magnitude of the target steering damping torque Td is larger than the magnitude of the target steering damping torque Td when the driving support control is not performed. However, the magnitude of the target steering damping torque Td when the driving assistance control is being performed may be the same as the magnitude of the target steering damping torque Td when the driving assistance control is not being conducted.

  In the above-described embodiment, the difference ΔTp between the target steering spring torque Tp when the driving support control is performed and the target steering spring torque Tp when the driving support control is not performed is the corrected steering. It is 0 when the magnitude of the angle θ is the reference value θpc. However, as shown in FIG. 10, the difference ΔTp in the target steering spring torque is such that the magnitude of the corrected steering angle θ is changed from the first reference value θpc1 (positive constant) to the second reference value θpc2 (positive constant). It may be modified to be 0 when it is within a range up to a positive constant larger than θpc1.

  Similarly, in the above-described embodiment, the difference ΔTd between the target steering damping torque Td when the driving assistance control is performed and the target steering damping torque Td when the driving assistance control is not performed is the steering angular velocity θd. Is 0 when the magnitude of is the reference value θdc. However, as shown in FIG. 11, the difference ΔTd in the target steering damping torque indicates that the magnitude of the steering angular velocity θd is larger than the third reference value θdc1 (positive constant) to the fourth reference value θdc2 (θdc1). It may be modified to be 0 when in the range up to (a large positive constant).

  In the embodiment, the relationship between the steering angle θ and the target steering spring torque Tp and the relationship between the steering angular velocity θd and the target steering damping torque Td are constant regardless of the traveling state of the vehicle 18 such as the vehicle speed V. However, at least one of these relationships may be variably set according to the traveling state of the vehicle 18. Further, although the reference values θpc and θdc are constant, at least one of these reference values may be variably set according to the traveling state of the vehicle 18 such as the vehicle speed V, for example.

  In the embodiment, the target steering reaction torque corresponding to the target steering reaction force is the target steering spring torque Tp corresponding to the target steering spring force and the target steering damping torque Td corresponding to the target steering damping force. However, the target steering reaction torque may not include the target steering spring torque Tp corresponding to the target steering spring force. Conversely, in addition to the target steering spring torque Tp and the target steering damping torque Td, the target steering friction torque A target steering friction torque corresponding to the force may be included.

  In the above-described embodiment, the steering device is not provided with a steering transmission ratio variable device that rotates the steering shaft on the pinion shaft 34 relative to the steering shaft on the steering wheel 22 side. However, the steering reaction force control device of the present invention may be applied to a vehicle in which a steering transmission ratio variable device is provided in the steering device. In that case, the target angle θpt of the pinion shaft 34 may be calculated as the target value of the driving support control by the driving support control device 16. Further, the relative steering angle of the steering shaft on the pinion shaft 34 side with respect to the steering shaft on the tearing wheel 22 side by the steering transmission variable device may be calculated as Δθr, and the target steering angle θt may be calculated as θpt−Δθr.

  Further, in the above-described embodiment, the “steering index value” is the steering angle θ, but the rotation angle of the electric motor of the electric power steering device, the turning angle of the steered wheels, the yaw rate of the vehicle, the lateral acceleration of the vehicle, the steering When the apparatus is a rack and pinion type apparatus, either the rotation angle of the pinion shaft or the stroke of the rack bar may be used.

DESCRIPTION OF SYMBOLS 10 ... Steering reaction force control apparatus, 12 ... Electric power steering (EPS) apparatus, 14 ... EPS control apparatus, 16 ... Driving assistance control apparatus, 18 ... Vehicle, 20FL-20RR ... Wheel, 50 ... Steering angle sensor, 52 ... Torque Sensor 54 ... Vehicle speed sensor 60 ... CCD camera 62 ... Selection switch

Claims (3)

Electric power steering device, control device for controlling the electric power steering device, and driving support for controlling the electric power steering device via the control device so that the turning angle of the steered wheels becomes a target turning angle And the control device acquires a steering index value indicating an actual steering operation amount of the driver, and includes a target steering damping force based on a time differential value of the steering index value. A steering reaction force control device for a vehicle that calculates a steering reaction force and controls the electric power steering device so that the steering reaction force becomes the target steering reaction force. The control device is operated by the driving support device. If not, the target steering damping force is calculated based on the time differential value of the steering index value. When the driving support device is operating, the time differential value of the steering index value and the previous In the steering reaction force control apparatus for a vehicle that calculates a target steering damping force based on the one of the time differential value of the steering index value after correction obtained by correcting by the target steering index value corresponding to the target steering angle,
When the magnitude of the time differential value of the one steering index value is less than a reference value, the control device is compared with when the driving support device is not operating when the driving support device is operating. Then, the vehicle steering reaction force control device that calculates the target steering damping force so as to reduce the size.   2. The vehicle steering reaction force control device according to claim 1, wherein when the magnitude of a time differential value of the one steering index value is larger than the reference value, the control device is configured such that the driving support device A steering reaction force control device for a vehicle, which calculates the target steering damping force so as to be larger when the driving support device is operating than when the driving support device is not operating. The vehicle steering reaction force control device according to claim 2, wherein the target steering damping force when the driving support device is operating and the target steering damping force when the driving support device is not operating. The difference is 0 when the magnitude of the time differential value of the one steering index value is the reference value, and the difference between the magnitude of the time differential value of the one steering index value and the reference value is Steering reaction force control device for a vehicle that gradually increases as it increases in a range of a predetermined value or less

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