Steering control device

Abstract

To provide a steering control device capable of improving steering response to the operation of a steering wheel while ensuring good steering feeling.SOLUTION: A control device calculates a target pinion angle of a pinion shaft rotating interlockingly with the turning operation of a turning wheel on the basis of a steering angle θs of a steering wheel obtained from a rotational angle of a reaction force motor. The control device calculates a steering reaction command value using an angular axial force which is an axial force of a steering shaft calculated on the basis of a steering angle torque Th obtained from a helix angle of a torsion bar and the target pinion angle. The control device includes a compensation value calculation section 81 for compensating for a helix angle δ by adding the helix angle δ to the steering angle θs as a compensation value. The compensation value calculation section 81 switches whether or not the helix angle of the torsion bar should be added to the steering angle on the basis of an inclination which is a proportion of a change of the angular axial force to the target pinion angle.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a steering control device. [Background technology]

[0002] Conventionally, there has been known a so-called steer-by-wire type steering device in which power transmission between the steering wheel and the steered wheels is separated. This steering device has a reaction motor, a turning motor, and a control device. The reaction motor generates a steering reaction force applied to a steering shaft. The turning motor generates a turning force that steers the steered wheels. When the vehicle is traveling, the control device generates a steering reaction force through control of the reaction motor, and steers the steered wheels through control of the turning motor.

[0003] For example, the control device in Patent Document 1 calculates an ideal axial force and a road axial force. The ideal axial force is an ideal rack axial force based on a target steering angle. The road axial force is an estimated value of the rack axial force based on the current value of the steering motor. The control device adds up the ideal axial force and the road axial force at a predetermined distribution ratio, and uses this added axial force to control the reaction motor. Since the road surface condition is reflected in the road surface axial force, the road surface condition is also reflected in the steering reaction force generated by the reaction motor. Therefore, the driver can feel the road surface condition as a response via the steering wheel. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-165219 A Summary of the Invention [Problem to be solved by the invention]

[0005] The steering control device of Patent Document 1 controls the reaction motor using an ideal axial force based on a target steering angle. Therefore, the response of the steering reaction force to the steering operation is determined by the response of the target steering angle. Therefore, when the target steering angle is adjusted so that the steering response matches the target response, the setting of the target steering angle also affects the steering reaction force. However, there is a risk that the adjustment to obtain the target steering response may adversely affect the response of the steering reaction force.

[0006] For example, when the target steering angle is adjusted to enhance the steering response, there is a concern that the response of the steering reaction force will become too high. In addition, if the response of the steering reaction force is excessively enhanced, the ideal axial force calculated by the control device and therefore the steering reaction force applied to the steering wheel may change suddenly. As a result, the steering feel of the steering wheel may deteriorate, causing the driver to feel uncomfortable. [Means for solving the problem]

[0007] A steering control device that can achieve the above object controls a reaction motor that generates a steering reaction force applied to a steering wheel, the power transmission of which is separated from a steering shaft that steers the steered wheels, based on a command value calculated in response to a steering state. The steering control device also controls a steering motor that generates a steering force, which is a force for steering the steered wheels, in response to the steering state. The steering control device includes a first calculation unit that calculates a target rotation angle of a shaft that rotates in conjunction with the steering operation of the steered wheels, based on the steering angle of the steering wheel obtained from the rotation angle of the reaction motor, a second calculation unit that calculates the command value based on the steering torque obtained from the torsion angle of a torsion bar that twists in response to the operation of the steering wheel and the target rotation angle, and a second calculation unit that adds the torsion angle to the steering angle as a compensation value. The The third calculation unit changes the value of the torsion angle to be added to the steering angle in accordance with the degree of change in the state variable used to calculate the command value.

[0008] According to this configuration, the value of the torsion angle to be added to the steering angle is changed according to the degree of change in the state variable used in the calculation of the command value. This prevents the command value from changing suddenly due to the addition of the torsion angle to the steering angle. This makes it possible to improve the steering response to the operation of the steering wheel while ensuring a good steering feel.

[0009] In the above steering control device, the second calculation unit may calculate the command value using the axial force of the steered shaft calculated based on the state variable. In this case, the third calculation unit may change a value of a torsion angle to be added to the steering angle in accordance with a gradient that is a rate of change in the axial force relative to the state variable.

[0010] According to this configuration, the value of the torsion angle to be added to the steering angle is changed according to the inclination, which is the ratio of the change in the axial force to the state variable used in the calculation of the command value. This prevents the command value from changing suddenly due to the addition of the torsion angle to the steering angle. This makes it possible to improve the steering response to the operation of the steering wheel while ensuring a good steering feel.

[0011] In the above steering control device, the second calculation unit may calculate the command value using the axial force of the steered shaft calculated based on the state variable. In this case, the third calculation unit may switch whether or not to add a torsion angle of the torsion bar to the steering angle based on a gradient that is a rate of change in the axial force with respect to the state variable.

[0012] According to this configuration, whether or not to add the torsion angle of the torsion bar to the steering angle is switched based on the slope, which is the ratio of change in the axial force to the state variable used in the calculation of the command value. This prevents the command value from changing suddenly due to the addition of the torsion angle to the steering angle. This makes it possible to improve the steering response to the operation of the steering wheel while ensuring a good steering feel.

[0013] In the above steering control device, the axial force may be an angular axial force calculated based on the target rotation angle. According to this configuration, the value of the torsion angle to be added to the steering angle is changed depending on the inclination, which is the rate of change of the angular axial force, or whether or not to add the torsion angle of the torsion bar to the steering angle is switched based on the inclination, which is the rate of change of the angular axial force.

[0014] In the above steering control device, the axial force may be a distribution axial force obtained by adding together values ​​obtained by multiplying an angle axial force, which is the axial force of the steered shaft calculated based on the target rotation angle, and a current axial force, which is the axial force of the steered shaft calculated based on a value of a current of the steering motor, by a distribution ratio that is individually set based on the target rotation angle and a vehicle speed.

[0015] According to this configuration, the value of the torsion angle added to the steering angle is changed depending on the inclination, which is the rate of change of the distributed axial force, or whether or not to add the torsion angle of the torsion bar to the steering angle is switched based on the inclination, which is the rate of change of the distributed axial force.

[0016] In the above steering control device, the second calculation unit may calculate the command value using a distribution axial force obtained by adding together values ​​obtained by multiplying an angle axial force, which is the axial force of the steered shaft calculated based on the target rotation angle, and a current axial force, which is the axial force of the steered shaft calculated based on a current value of the steered motor, by a distribution ratio that is individually set based on the target rotation angle and vehicle speed. In this case, the third calculation unit may change a value of a torsion angle to be added to the steering angle in accordance with the distribution ratio that is individually set for the current axial force and a lateral acceleration that is the acceleration when the vehicle turns.

[0017] According to this configuration, the value of the torsion angle added to the steering angle is changed according to the distribution ratio that is set individually for the current axial force and the lateral acceleration that is the acceleration when the vehicle turns. Therefore, a sudden change in the command value due to the addition of the torsion angle to the steering angle is suppressed. Therefore, it is possible to improve the steering response to the operation of the steering wheel while ensuring a good steering feel.

[0018] In the above steering control device, the second calculation unit may calculate the command value using a distributed axial force obtained by adding together values ​​obtained by multiplying an angle axial force, which is the axial force of the steered shaft calculated based on the target rotation angle, and a current axial force, which is the axial force of the steered shaft calculated based on a current value of the steering motor, by a distribution ratio that is individually set based on the target rotation angle and a vehicle speed. In this case, the third calculation unit may switch whether or not to add a torsion angle of the torsion bar to the steering angle, based on the distribution ratio that is individually set for the current axial force and a lateral acceleration that is the acceleration when the vehicle turns.

[0019] According to this configuration, whether or not to add the torsion angle of the torsion bar to the steering angle is switched based on the distribution ratio set individually for the current axial force and the lateral acceleration, which is the acceleration when the vehicle turns. Therefore, a sudden change in the command value caused by adding the torsion angle to the steering angle is suppressed. Therefore, it is possible to improve the steering response to the operation of the steering wheel while ensuring a good steering feel.

[0020] In the above steering control device, the third calculation unit may change a value of a torsion angle to be added to the steering angle in accordance with an inclination that is a rate of change of the target rotation angle with respect to the steering angle.

[0021] According to this configuration, the value of the torsion angle added to the steering angle is changed according to the inclination, which is the ratio of change in the target rotation angle to the steering angle. This prevents the command value from changing suddenly when the torsion angle is added to the steering angle. This makes it possible to improve the steering response to the operation of the steering wheel while ensuring a good steering feel.

[0022] In the above steering control device, the third calculation unit may switch whether or not to add the torsion angle of the torsion bar to the steering angle based on a gradient that is a rate of change of the target rotation angle with respect to the steering angle.

[0023] According to this configuration, whether or not to add the torsion angle of the torsion bar to the steering angle is switched based on the inclination, which is the ratio of change of the target rotation angle to the steering angle. This prevents the command value from changing suddenly when the torsion angle is added to the steering angle. This makes it possible to improve the steering response to the operation of the steering wheel while ensuring a good steering feel.

[0024] In the above steering control device, the second calculation unit may calculate the command value using a distributed axial force obtained by adding together values ​​obtained by multiplying an angle axial force, which is the axial force of the steered shaft calculated based on the target rotation angle, and a current axial force, which is the axial force of the steered shaft calculated based on a current value of the steered motor, by a distribution ratio that is individually set based on the target rotation angle and vehicle speed. In this case, the third calculation unit may change a value of a torsion angle to be added to the steering angle in accordance with the distribution ratio that is individually set for the current axial force.

[0025] According to this configuration, the value of the torsion angle added to the steering angle is changed according to the distribution ratio that is set individually for the current axial force. Therefore, a sudden change in the command value caused by adding the torsion angle to the steering angle is suppressed. Therefore, it is possible to improve the steering response to the operation of the steering wheel while ensuring a good steering feel.

[0026] In the above steering control device, the second calculation unit may calculate the command value using a distributed axial force obtained by adding together values ​​obtained by multiplying an angle axial force, which is the axial force of the steered shaft calculated based on the target rotation angle, and a current axial force, which is the axial force of the steered shaft calculated based on a current value of the steered motor, by a distribution ratio that is individually set based on the target rotation angle and vehicle speed. In this case, the third calculation unit may switch whether or not to add a torsion angle of the torsion bar to the steering angle, based on the distribution ratio that is individually set for the current axial force.

[0027] According to this configuration, whether or not to add the torsion angle of the torsion bar to the steering angle is switched based on the distribution ratio that is individually set for the current axial force. This prevents the command value from suddenly changing due to the addition of the torsion angle to the steering angle. This makes it possible to improve the steering response to the operation of the steering wheel while ensuring a good steering feel.

[0028] In the above steering control device, the second calculation unit may calculate the command value using a distributed axial force obtained by adding together values ​​obtained by multiplying an angle axial force, which is the axial force of the steered shaft calculated based on the target rotation angle, and a current axial force, which is the axial force of the steered shaft calculated based on a current value of the steering motor, by distribution ratios that are individually set based on the target rotation angle and vehicle speed. In this case, the third calculation unit may change a value of a torsion angle to be added to the steering angle in accordance with a first inclination, which is a rate of change of the current axial force relative to the target rotation angle, and a second inclination, which is a rate of change of the distributed axial force relative to the target rotation angle.

[0029] According to this configuration, the value of the torsion angle added to the steering angle is changed according to the first inclination, which is the rate of change of the current axial force relative to the target rotation angle, and the second inclination, which is the rate of change of the distributed axial force relative to the target rotation angle. This prevents the command value from changing suddenly due to the addition of the torsion angle to the steering angle. This makes it possible to improve the steering response to the operation of the steering wheel while ensuring a good steering feel. Effect of the Invention

[0030] According to the steering control device of the present invention, it is possible to improve the steering response to the operation of the steering wheel while ensuring a good steering feel. [Brief description of the drawings]

[0031] [Figure 1] 1 is a configuration diagram of a steering device in which a first embodiment of a steering control device is mounted. [Diagram 2] FIG. 2 is a block diagram of a control device according to the first embodiment. [Diagram 3] 5 is a graph showing the relationship between the steering angle and the target pinion angle in the first embodiment. [Figure 4] FIG. 2 is a block diagram of a steering reaction force command value calculation unit according to the first embodiment. [Diagram 5] 5 is a graph showing a relationship between a target pinion angle and an angular axial force in the first embodiment. [Figure 6] FIG. 2 is a block diagram of a compensation value calculation unit according to the first embodiment. [Figure 7] FIG. 11 is a block diagram of a compensation value calculation unit according to a second embodiment. [Figure 8] 10 is a graph showing a relationship between an inclination, which is a rate of change in angular axial force with respect to a target pinion angle, and a gain in the second embodiment. [Figure 9] FIG. 11 is a block diagram of an axial force calculation unit according to a third embodiment. [Figure 10] FIG. 13 is a block diagram of a compensation value calculation unit according to a third embodiment. [Figure 11] FIG. 13 is a block diagram of a compensation value calculation unit according to a fourth embodiment. [Figure 12]13 is a graph showing a relationship between lateral acceleration and gain in the fourth embodiment. [Figure 13] 13 is a graph showing the relationship between the distribution ratio of the current axial force and the gain in the fourth embodiment. [Figure 14] FIG. 13 is a block diagram of a compensation value calculation unit according to a fifth embodiment. [Figure 15] FIG. 13 is a block diagram of a compensation value calculation unit according to a sixth embodiment. [Figure 16] 13 is a graph showing a relationship between an inclination, which is a rate of change in a target pinion angle relative to a steering angle, and a gain in the sixth embodiment. [Figure 17] FIG. 23 is a block diagram of a compensation value calculation unit according to the seventh embodiment. [Figure 18] FIG. 23 is a block diagram of a compensation value calculation unit according to the eighth embodiment. [Figure 19] 13 is a graph showing a relationship between an axial force gradient and a gain in the eighth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] <First embodiment> A first embodiment in which the steering control device is embodied in a steer-by-wire type steering device will be described below.

[0033] As shown in Fig. 1, a vehicle steering device 10 has a steering shaft 12 connected to a steering wheel 11. The steering device 10 also has a steered shaft 14 extending in the vehicle width direction (left-right direction in Fig. 1). Left and right steered wheels 16, 16 are connected to both ends of the steered shaft 14 via tie rods 15, 15, respectively. The linear movement of the steered shaft 14 determines the steering angle θ of the steered wheels 16, 16. w The steering shaft 12 and the steered shaft 14 constitute a steering mechanism of the vehicle.

[0034] The steering device 10 also has a reaction force motor 31, a speed reduction mechanism 32, a rotation angle sensor 33, and a torque sensor 34 as components for generating a steering reaction force. Incidentally, the steering reaction force is a force acting in a direction opposite to the steering direction of the steering wheel 11 by the driver. By applying the steering reaction force to the steering wheel 11, it is possible to give the driver an appropriate sense of responsiveness.

[0035] The reaction motor 31 is a generating source of the steering reaction force. For example, a three-phase brushless motor is used as the reaction motor 31. The rotating shaft of the reaction motor 31 is connected to the steering shaft 12 via a reduction gear mechanism 32. The torque of the reaction motor 31 is applied to the steering shaft 12 as a steering reaction force.

[0036] The rotation angle sensor 33 is provided on the reaction motor 31. The rotation angle sensor 33 detects the rotation angle θ of the reaction motor 31. a The rotation angle θ of the reaction motor 31 is detected. a is the steering angle θ s The reaction motor 31 and the steering shaft 12 are linked via a reduction gear mechanism 32. Therefore, the rotation angle θ a and the steering angle θ which is the rotation angle of the steering shaft 12 and thus the rotation angle of the steering wheel 11. s Therefore, the rotation angle θ of the reaction force motor 31 is a Based on the steering angle θ s can be sought.

[0037] The torque sensor 34 detects the steering torque T h The torque sensor 34 detects the steering torque T applied to the steering shaft 12 based on the amount of twist of a torsion bar 34A provided midway on the steering shaft 12. h The torque sensor 34 is provided on the steering shaft 12 at a portion closer to the steering wheel 11 than the speed reduction mechanism 32 is.

[0038] Furthermore, the steering device 10 has a steering motor 41, a reduction gear mechanism 42, and a rotation angle sensor 43 as components for generating a steering force that is the power for steering the steered wheels 16, 16.

[0039] The steering motor 41 is a source of steering force. For example, a three-phase brushless motor is used as the steering motor 41. The rotating shaft of the steering motor 41 is connected to a pinion shaft 44 via a reduction mechanism 42. Pinion teeth 44a of the pinion shaft 44 mesh with rack teeth 14b of the steering shaft 14. The torque of the steering motor 41 is applied to the steering shaft 14 via the pinion shaft 44 as a steering force. In response to the rotation of the steering motor 41, the steering shaft 14 moves along the vehicle width direction, which is the left-right direction in FIG. 1.

[0040] The rotation angle sensor 43 is provided on the steering motor 41. The rotation angle sensor 43 detects a rotation angle θ b Detect. Incidentally, the steering device 10 has a pinion shaft 13. The pinion shaft 13 is provided so as to intersect with the steered shaft 14. The pinion teeth 13a of the pinion shaft 13 mesh with the rack teeth 14a of the steered shaft 14. The reason for providing the pinion shaft 13 is to support the steered shaft 14 together with the pinion shaft 44 inside a housing (not shown). That is, the steered shaft 14 is supported movably along its axial direction by a support mechanism (not shown) provided in the steering device 10, and is pressed toward the pinion shafts 13 and 44. In this way, the steered shaft 14 is supported inside the housing. However, another support mechanism for supporting the steered shaft 14 in the housing may be provided without using the pinion shaft 13.

[0041] Steering device 10 also has control device 50. Control device 50 controls reaction motor 31 and steering motor 41 based on the detection results of various sensors mounted on the vehicle. The sensors include rotation angle sensor 33, torque sensor 34 and rotation angle sensor 43 described above, as well as vehicle speed sensor 501. Vehicle speed sensor 501 detects vehicle speed V, which is the traveling speed of the vehicle.

[0042] The control device 50 controls the reaction motor 31 to generate a steering torque T h The control device 50 executes a reaction force control to generate a steering reaction force according to the steering torque T h and the vehicle speed V, and calculates a target steering reaction force based on the calculated target steering reaction force. The control device 50 supplies, to the reaction force motor 31, a current required to generate a steering reaction force according to the steering reaction force command value.

[0043] The control device 50 executes steering control for steering the steered wheels 16, 16 in accordance with the steering state through control of the steering motor 41. The control device 50 controls the rotation angle θ of the steering motor 41 detected through the rotation angle sensor 43. b Based on this, the actual rotation angle of the pinion shaft 44, that is, the pinion angle θ p This pinion angle θ p is the steering angle θ of the steered wheels 16, 16 w The control device 50 also detects the rotation angle θ of the reaction force motor 31 detected through the rotation angle sensor 33. a Based on the steering angle θ s The calculated steering angle θ s Based on the pinion angle θ p The control device 50 then calculates a target pinion angle, which is a target value of the target pinion angle θ p The deviation between the detected value and the actual value is calculated, and the power supply to the steering motor 41 is controlled so as to eliminate the deviation.

[0044] <Control device> Next, the control device 50 will be described in detail. As shown in FIG. 2, the control device 50 has a reaction force control section 50a that executes reaction force control, and a steering control section 50b that executes steering control.

[0045] The reaction force control unit 50 a has a steering angle calculation unit 51 , a steering reaction force command value calculation unit 52 , and an electricity control unit 53 . The steering angle calculation unit 51 calculates the rotation angle θ of the reaction force motor 31 detected through the rotation angle sensor 33. a Based on this, the steering angle θ of the steering wheel 11 is s Calculate the following.

[0046] The steering reaction force command value calculation unit 52 calculates the steering torque T h and the steering reaction force command value T based on the vehicle speed V * Calculate the steering reaction force command value T * is a value corresponding to a target value of the torque to be generated by the reaction force motor 31. The torque to be generated by the reaction force motor 31 is a torque in the opposite direction to the steering direction of the steering wheel 11. The steering reaction force command value calculation unit 52 calculates the steering torque T h The larger the absolute value of and the slower the vehicle speed V, the larger the absolute value of the steering reaction force command value T * Calculate the following.

[0047] The power supply control unit 53 controls the steering reaction force command value T * The power supply control unit 53 supplies the reaction force motor 31 with electric power according to the steering reaction force command value T * The current control unit 53 calculates a current command value for the reaction motor 31 based on the current I a Detect the value of this current I a The value of I is the value of the actual current supplied to the reaction motor 31. The current control unit 53 calculates the current command value and the actual current I a The deviation from the steering reaction force command value T is calculated and the power supply to the reaction force motor 31 is controlled so as to eliminate the deviation. * It is possible to give the driver a sense of appropriate response according to the road reaction force.

[0048] The steering control unit 50b has a pinion angle calculation unit 61, a target pinion angle calculation unit 62, a pinion angle feedback control unit 63, and an energization control unit 64. The pinion angle calculation unit 61 calculates the rotation angle θ of the steering motor 41 detected through the rotation angle sensor 43. b Based on this, the actual rotation angle of the pinion shaft 44, that is, the pinion angle θ p The steering motor 41 and the pinion shaft 44 are linked via a reduction mechanism 42. Therefore, the rotation angle θ of the steering motor 41 is b and pinion angle θ p There is a correlation between the rotation angle θ of the steering motor 41 and the rotation angle θ of the steering motor 41. b From pinion angle θ p In addition, the pinion shaft 44 is meshed with the steered shaft 14. Therefore, the pinion angle θ p There is also a correlation between the pinion angle θ and the amount of movement of the steering shaft 14. p is the steering angle θ of the steered wheels 16, 16 w This is a value that reflects the

[0049] The target pinion angle calculation unit 62 calculates the steering angle θ s Based on the target pinion angle θ p * Calculate the target pinion angle θ p * is the pinion angle θ p The target pinion angle calculation unit 62 calculates the steering angle ratio by the steering angle θ s The target pinion angle θ p * The steering angle ratio is calculated by the steering angle θ s The steering angle θ w The target pinion angle calculation unit 62 calculates the ratio of the steering angle θ s The larger the absolute value of the target pinion angle θ p * Calculate the following.

[0050] The larger the steering angle ratio, the smaller the steering angle θ of the steered wheels 16 when the steering wheel 11 is operated. w When changing lanes while driving straight, the vehicle turning amount is suppressed to be smaller relative to the steering amount of the steering wheel 11, so that the vehicle steering stability is ensured. Also, the smaller the steering angle ratio, the smaller the steering angle θ of the steered wheels 16 when the steering wheel 11 is operated. w When parking the vehicle in a garage, the vehicle can turn more easily in response to the amount of steering of the steering wheel 11, ensuring ease of maneuverability.

[0051] The target pinion angle calculation unit 62 calculates the target pinion angle θ using, for example, a map M1 shown in the graph of FIG. p * The map M1 is stored in the storage device of the control device 50. The map M1 is expressed by a horizontal axis representing the steering angle θ s The absolute value of, the vertical axis is the target pinion angle θ p * The map has the following characteristics: s The larger the absolute value of the target pinion angle θ p * The absolute value of is set to a larger value. However, the steering angle θ s The greater the absolute value of the steering angle θ s Target pinion angle θ p * The slope, which is the rate of change of the steering angle θ s Absolute value of and target pinion angle θ p * The characteristic line in Fig. 3, which shows the relationship between the absolute value of the steering angle ratio and the steering angle θ, is a curve with a positive decreasing slope. The slope of the characteristic line in the graph of Fig. 3 shows the steering angle ratio.

[0052] Incidentally, the target pinion angle calculation unit 62 calculates the target pinion angle θ based on the viewpoint of changing the steering angle ratio in accordance with the vehicle speed V detected by the vehicle speed sensor 501. p *The target pinion angle calculation unit 62 may calculate the steering angle θ s The steering angle θ w The target pinion angle θ p * When parking at a low speed, a larger vehicle turning amount can be obtained relative to the steering amount of the steering wheel, ensuring the maneuverability of the vehicle. s The steering angle θ w The target pinion angle θ p * When changing lanes while driving at high speed, the amount of vehicle turning is suppressed to be smaller than the amount of steering of the steering wheel, ensuring the driving stability of the vehicle.

[0053] As shown in FIG. 2, the pinion angle feedback control unit 63 controls the target pinion angle θ p * , and the actual pinion angle θ calculated by the pinion angle calculation unit 61. p The pinion angle feedback control unit 63 receives the actual pinion angle θ p The target pinion angle θ p * The pinion angle θ p Through feedback control, the pinion angle command value T p * Calculate the following.

[0054] The current supply control unit 64 determines the pinion angle command value T p * The power supply control unit 64 supplies the steering motor 41 with electric power according to the pinion angle command value T p * The current control unit 64 calculates a current command value for the steering motor 41 based on the current I b Detect the value of this current I bThe value of is the value of the actual current supplied to the steering motor 41. The current control unit 64 calculates the current command value and the actual current I b The deviation from the value of I is calculated, and the power supply to the steering motor 41 is controlled so as to eliminate the deviation (current I b As a result, the steering motor 41 is controlled based on the pinion angle command value T p * It rotates by an angle according to

[0055] <Steering reaction force command value calculation unit> Next, the steering reaction force command value calculation unit 52 will be described in detail. As shown in FIG. 4, the steering reaction force command value calculation unit 52 has a steering force calculation unit 71, an axial force calculation unit 72, and a subtractor 73.

[0056] The steering force calculation unit 71 calculates the steering torque T h and vehicle speed V. The steering force T1 is a torque in the same direction as the steering direction of the steering wheel 11. The steering force T1 corresponds to an assist torque when the steering device 10 is an electric power steering device. The assist torque is a force for assisting the steering of the steering wheel 11. The steering force calculation unit 71 calculates the steering torque T h The larger the absolute value of T1 is and the slower the vehicle speed V is, the larger the absolute value of the steering force T1 is calculated.

[0057] The axial force calculation unit 72 calculates the target pinion angle θ p * The axial force calculation unit 72 receives the target pinion angle θ p * The axial force acting on the steering shaft 14 is calculated based on the target pinion angle θ p * The axial force calculated based on the above is converted into a torque for the steering wheel 11 or the steering shaft 12 to calculate the axial force torque T2.

[0058] Axial force calculation unit 72 calculates angular axial force F1 using, for example, map M2 shown in Fig. 5. Map M2 is stored in a storage device of control device 50. Angle axial force F1 is an ideal value of the axial force acting on steered shaft 14. Moreover, angle axial force F1 is an axial force that does not reflect the road surface condition or the force acting on steered shaft 14 from the road surface.

[0059] As shown in the graph of FIG. 5, the map M2 has a horizontal axis representing the target pinion angle θ p * The map has the following characteristics: p * As the absolute value of the target pinion angle θ increases, the absolute value of the angular axial force F1 is set to a larger value. p * The larger the absolute value of the target pinion angle θ p * The slope, which is the rate of change of the angular axial force F1 relative to the target pinion angle θ p * The characteristic line in FIG. 5 showing the relationship between the absolute value of the target pinion angle θ and the absolute value of the angular axial force F1 is a curve having a positive decreasing slope. p * The sign of is set to the same as the sign of

[0060] The axial force calculation unit 72 calculates the axial force torque T2 by converting the angular axial force F1 calculated using the map M2 into a torque. The subtractor 73 subtracts the axial force torque T2 calculated by the axial force calculation unit 72 from the steering force T1 calculated by the steering force calculation unit 71 to obtain a steering reaction force command value T * Calculate the following.

[0061] <Ensuring steering response and steering feel> According to the control device 50 configured in this manner, the steering force T1 and the axial torque T2 are calculated based on the steering reaction force command value T *By reflecting the steering reaction force to the steering wheel 11, it is possible to apply a steering reaction force to the steering wheel 11 according to the steering state of the steering wheel 11 or the steering state of the steered wheels 16. Therefore, the driver can grasp the vehicle behavior by feeling the steering reaction force via the steering wheel 11 as a response.

[0062] However, the following concerns exist regarding the control device 50. That is, the control device 50 may be required to further improve the responsiveness of the steered wheels 16 to the steering of the steering wheel 11 depending on the product specifications, etc. For this reason, it is conceivable to provide the control device 50 with a compensation function for the torsion of the torsion bar 34A. Specifically, the steering angle θ s The torsion angle of the torsion bar 34A is added to the above. This is based on the following viewpoint.

[0063] That is, the control device 50 controls the rotation angle θ of the reaction force motor 31. a Based on the steering angle θ s The calculated steering angle θ s Based on the target pinion angle θ p * Therefore, when the steering wheel 11 is turned, the target pinion angle θ p * A phase lag occurs in the target pinion angle θ p * is the pinion angle θ p Since this is the control target value, a phase lag also occurs in the steering of the steered wheels 16.

[0064] Therefore, the steering angle θ calculated by the steering angle calculation unit 51 s By adding the torsion angle of the torsion bar 34A to the pinion angle θ p The target pinion angle θ p * Therefore, the phase of the target pinion angle θ caused by the torsion of the torsion bar 34A can be advanced.p * This in turn makes it possible to suppress the phase delay of the steered wheels 16. Therefore, the steering response to the steering of the steering wheel 11 can be improved.

[0065] However, the control device 50 does not detect the target pinion angle θ p * The reaction motor 31 is controlled using the angular axial force F1 based on the target pinion angle θ p * Therefore, the target pinion angle θ is set so that the steering response matches the target response. p * When adjusting the target pinion angle θ p * However, there is a risk that adjustments made to obtain a target steering response may adversely affect the response of the steering reaction force.

[0066] For example, as described above, in order to improve the steering response, the steering angle θ s By adding the torsion angle of the torsion bar 34A to the target pinion angle θ p * In the case of adjusting the target pinion angle θ, there is a concern that the responsiveness of the steering reaction force may become too high. p * The greater the gradient of the characteristic line of the map M2 shown in the graph of FIG. 5, the greater the absolute value of the angular axial force F1, and therefore the steering reaction force command value T * Therefore, the steering feel of the steering wheel 11 may deteriorate, which may cause the driver to feel uncomfortable.

[0067] Therefore, in this embodiment, the control device 50 has the following configuration. <Compensation value calculation unit for torsion angle> 6, the control device 50 has a compensation value calculation unit 81. The compensation value calculation unit 81 is provided in, for example, the steering control unit 50b. The compensation value calculation unit 81 calculates a compensation value for compensating for the torsion angle of the torsion bar 34A.

[0068] The compensation value calculation section 81 has a torsion angle calculation section 81A, a determination section 81B, a switch 81C, and an adder 81D. The torsion angle calculation unit 81A calculates the steering torque T h The torsion angle calculation unit 81A calculates the torsion angle δ of the torsion bar 34A based on, for example, the steering torque T h The torsion angle δ is calculated by multiplying this by the inverse of the torsional rigidity of the torsion bar 34A.

[0069] The determination unit 81B determines whether or not the torsion angle δ of the torsion bar 34A should be compensated for, that is, whether or not the steering angle θ s The determination unit 81B determines whether the target pinion angle θ p * The gradient α, which is the rate of change in the angular axial force F1 relative to the target pinion angle θ per unit time, is taken in from the axial force calculation unit 72. The axial force calculation unit 72 calculates, for example, the amount of change in the angular axial force F1 per unit time relative to the target pinion angle θ p * The slope α is calculated by dividing the amount of change in

[0070] The determination unit 81B determines the value of the slope α and the slope threshold value α th Through comparison with the steering angle θ s It is judged whether the torsion angle δ of the torsion bar 34A should be added to the steering angle θ s The situation in which the torsion angle δ of the torsion bar 34A should be added to the steering angle θ is, for example, a situation in which the responsiveness of the steering reaction force is not excessively increased but is maintained at an allowable level. s Add the torsion angle δ of the torsion bar 34A to the target pinion angle θ p * In the case of adjusting the target pinion angle θ p* With the change in the absolute value of the angular axial force F1, and therefore the steering reaction force command value T * In this situation, the probability that the steering angle θ s By adding the torsion angle δ of the torsion bar 34A to the target pinion angle θ p * It is preferable to adjust the slope threshold α th is set, for example, through simulation. th is, for example, the target pinion angle θ p * is set to a value close to "0°" corresponding to the neutral steering position.

[0071] The determination unit 81B determines whether the value of the inclination α input from the axial force calculation unit 72 is equal to or smaller than the inclination threshold value α th If the value of the inclination α taken from the axial force calculation unit 72 is equal to or less than the inclination threshold value α, the value of the flag FG is set to "1." th If the value is greater than 0, the value of flag FG is set to "0".

[0072] The switch 81C receives, as data inputs, the torsion angle δ calculated by the torsion angle calculation unit 81A and the fixed value "0" stored in the storage device of the control device 50. The switch 81C also receives, as a control input, the value of a flag FG set by the determination unit 81B. Based on the value of the flag FG, the switch 81C switches either the torsion angle δ calculated by the torsion angle calculation unit 81A or the fixed value "0" to the steering angle θ s When the value of flag FG is "1", switch 81C selects the torsion angle δ calculated by torsion angle calculation unit 81A as the final torsion angle δ1. When the value of flag FG is "0", switch 81C selects the fixed value "0" as the final torsion angle δ1. Incidentally, the final torsion angle δ1 is a compensation value for compensating for the torsion angle δ of torsion bar 34A.

[0073] The adder 81D calculates the steering angle θ s The target pinion angle θ is calculated by adding the final torsion angle δ1 selected by the switch 81C. p * The final steering angle θ used in the calculation s1 The value of the slope α is calculated as the slope threshold value α th When the value is the following, that is, when the value of the flag FG is "1", the torsion angle δ calculated by the torsion angle calculation unit 81A is the final torsion angle δ1, and the steering angle θ s The value of the slope α is added to the slope threshold α th When the steering angle θ is greater than the torsion angle δ1, that is, when the value of the flag FG is "0", the fixed value "0" is set as the final torsion angle δ1. s is added to.

[0074] <Operation of the First Embodiment> Next, the operation of the first embodiment will be described. As mentioned above, the value of the slope α is the slope threshold α th When the steering angle θ is the following value, the steering angle θ calculated by the steering angle calculation unit 51 is s The torsion angle δ of the torsion bar 34A is added to the target pinion angle θ p * is adjusted. As a result, the pinion angle θ p The target pinion angle θ p * Therefore, the phase of the target pinion angle θ caused by the twist of the torsion bar 34A is advanced. p * This in turn suppresses the phase delay of the steered wheels 16. Therefore, the steering response to the steering of the steering wheel 11 is improved.

[0075] The value of the slope α is the slope threshold α th When the steering angle θ s Add the torsion angle δ of the torsion bar 34A to the target pinion angle θ p *Even if the target pinion angle θ is adjusted, the possibility of excessively increasing the responsiveness of the steering reaction force is low. p * With the change in the absolute value of the angular axial force F1, and therefore the steering reaction force command value T * Therefore, a good steering feel can be obtained via the steering wheel 11. The driver does not feel uncomfortable.

[0076] In contrast, the value of the slope α is the slope threshold α th When the steering angle θ s Add the torsion angle δ of the torsion bar 34A to the target pinion angle θ p * Therefore, it is highly likely that the response of the steering reaction force will be excessively increased by adjusting the slope α. th When the steering angle θ calculated by the steering angle calculation unit 51 is greater than s The torsion angle δ of the torsion bar 34A is not added to the steering angle θ s This is the final steering angle θ s1 The target pinion angle θ p * This prevents the steering reaction force from becoming excessively responsive. p * With the change in the absolute value of the angular axial force F1, and therefore the steering reaction force command value T * Therefore, a good steering feel can be obtained via the steering wheel 11. The driver does not feel uncomfortable.

[0077] <Advantages of the First Embodiment> Therefore, according to the first embodiment, the following effects can be obtained. (1) Target pinion angle θ p * The steering angle θ depends on the inclination α, which is the ratio of change in the angle axial force F1 to the sThis allows the steering response to the steering of the steering wheel 11 to be improved while still ensuring a good steering feel.

[0078] <Second embodiment> Next, a second embodiment in which the steering control device is embodied in a steer-by-wire type steering device will be described. This embodiment basically has the same configuration as the first embodiment shown in Figs. 1 to 5. This embodiment differs from the first embodiment in the configuration of the compensation value calculation unit 81. Therefore, the same members and configurations as those in the first embodiment are given the same reference numerals, and detailed description thereof will be omitted.

[0079] As shown in FIG. 7, the compensation value calculation section 81 has a torsion angle calculation section 81A, a gain calculation section 81E, a multiplier 81F, and an adder 81D. The torsion angle calculation unit 81A calculates the steering torque T h The torsion angle δ of the torsion bar 34A is calculated based on this.

[0080] The gain calculation unit 81E calculates the target pinion angle θ p * The gradient α, which is the rate of change in the angular axial force F1 relative to the gradient α, is taken in from the axial force calculation unit 72. The gain calculation unit 81E calculates the gain G according to the gradient α. The gain calculation unit 81E calculates the gain G using a map M3 stored in the storage device of the control device 50. The map M3 is a two-dimensional map that defines the relationship between the gradient α and the gain G, and has the following characteristics.

[0081] That is, as shown in the graph of FIG. 8, the slope α is smaller than the slope threshold α th If the value of the slope α is less than the slope threshold α, the value of the gain G is maintained at "1". thIf the slope α is a value larger than , the value of gain G gradually decreases toward "0" as the value of slope α increases, and eventually reaches "0". After the value of gain G reaches "0", the value of gain G is maintained at "0" regardless of the increase in the value of slope α. Incidentally, the gain G can be set in the range from "0" to "1", for example, in increments of "0.1".

[0082] The multiplier 81F multiplies the torsion angle δ of the torsion bar 34A calculated by the torsion angle calculation unit 81A by the gain G calculated by the gain calculation unit 81E to calculate the final torsion angle δ2. th If the value is less than or equal to the inclination threshold value α, the value of the gain G is set to "1". Therefore, the torsion angle δ calculated by the torsion angle calculation unit 81A becomes the final torsion angle δ2 as it is. th If the value of the inclination α is larger than 1, the value of the gain G is set to a value less than "1" or to "0" according to the value of the inclination α. ​​Therefore, the final value of the torsion angle δ2 becomes a value smaller than the torsion angle δ calculated by the torsion angle calculation unit 81A, or becomes "0."

[0083] The adder 81D calculates the steering angle θ s The target pinion angle θ is calculated by adding the final torsion angle δ2 calculated by the multiplier 81F to the target torsion angle θ p * The final steering angle θ used in the calculation s1 The slope α is calculated based on the slope threshold α th If the torsion angle δ is the following value, the torsion angle δ calculated by the torsion angle calculation unit 81A is set as the final torsion angle δ2 and the steering angle θ s The value of the slope α is added to the slope threshold α th When the steering angle θ is greater than the torsion angle δ calculated by the torsion angle calculation unit 81A, or when the steering angle θ is set to “0”, the final torsion angle δ2 is set to “0”. s is added to.

[0084] <Advantages of the second embodiment> Therefore, according to the second embodiment, the following effects can be obtained. (2) Target pinion angle θ p * The steering angle θ s The value of the torsion angle δ of the torsion bar 34A added to the steering angle θ s The degree to which the torsion angle δ of the torsion bar 34A is reflected with respect to the inclination α is changed according to the inclination α. ​​This makes it possible to improve the steering response to the steering of the steering wheel 11 while ensuring a good steering feel.

[0085] <Third embodiment> Next, a third embodiment in which the steering control device is embodied in a steer-by-wire type steering device will be described. This embodiment basically has the same configuration as the first embodiment shown in Figs. 1 to 5. This embodiment differs from the first embodiment in the configurations of the axial force calculation unit 72 and the compensation value calculation unit 81. Therefore, the same members and configurations as those in the first embodiment are given the same reference numerals, and detailed description thereof will be omitted.

[0086] As shown in FIG. 9, the axial force calculation section 72 has an angle axial force calculation section 72A, a current axial force calculation section 72B, a distribution ratio calculation section 72C, a distribution axial force calculation section 72D, and a converter 72E. The angle axial force calculation unit 72A calculates the target pinion angle θ p * The angular axial force F1 is calculated based on the above. The angular axial force calculation unit 72A calculates the angular axial force F1 using the map M2 shown in FIG.

[0087] The current axial force calculation unit 72B calculates the current I b The current axial force F2 is calculated based on the value of the current I b The current I of the steering motor 41 is an estimated value of the axial force based on the value of b The value of the target pinion angle θ p* and the actual pinion angle θ p That is, the current I b The value of the current I of the steering motor 41 reflects the actual road surface condition. b It is possible to calculate an axial force that reflects the influence of the road surface condition based on the value of b The current axial force F2 is an axial force that reflects the road surface condition or the force acting on the steered shaft 14 via the steered wheels 16.

[0088] The distribution ratio calculation unit 72C calculates the target pinion angle θ p * , and the vehicle speed V detected through the vehicle speed sensor 501, the allocation ratio calculation unit 72C calculates the allocation ratio DR1 of the angle axial force F1 and the allocation ratio DR2 of the current axial force F2. The allocation ratio calculation unit 72C can set the values ​​of the two allocation ratios DR1, DR2 in the range of "0" to "1" in increments of, for example, "0.1" based on the product specifications, etc. However, the allocation ratio calculation unit 72C sets the values ​​of the two allocation ratios DR1, DR2 so that the sum of the two allocation ratios DR1, DR2 is "1".

[0089] The distribution ratio calculation unit 72C calculates, for example, a target pinion angle θ p * As the absolute value of the target pinion angle θ increases, the distribution ratio DR1 of the angular axial force F1 is set to a smaller value, while the distribution ratio DR2 of the current axial force F2 is set to a larger value. p * As the absolute value of F1 decreases, the distribution ratio DR1 of the angular axial force F1 is set to a larger value, whereas the distribution ratio DR2 of the current axial force F2 is set to a smaller value.

[0090] Also, for example, the faster the vehicle speed V, the larger the allocation ratio DR1 of the angle axial force F1 is set to, while the smaller the allocation ratio DR2 of the current axial force F2 is set to. That is, the slower the vehicle speed V, the smaller the allocation ratio FR1 of the angle axial force F1 is set to, while the larger the allocation ratio DR2 of the current axial force F2 is set to.

[0091] The distribution axial force calculation unit 72D multiplies the angle axial force F1 by a distribution ratio DR1 that is set individually, and multiplies the current axial force F2 by a distribution ratio DR2 that is set individually, and calculates the distribution axial force F3 by adding up these multiplied values. The distribution axial force F3 is calculated based on the steering reaction force command value T * The distribution ratio DR1 is also a value indicating the degree to which the angle axial force F1 is reflected in the distributed axial force F3. The distribution ratio DR2 is also a value indicating the degree to which the current axial force F2 is reflected in the distributed axial force F3.

[0092] The converter 72E converts the distributed axial force F3 calculated by the distributed axial force calculation unit 72D into a torque for the steering wheel 11 or the steering shaft 12 to calculate the axial force torque T2.

[0093] According to the control device 50 configured in this manner, the axial force torque T2 obtained by converting the distributed axial force F3 calculated by the axial force calculation unit 72 into a torque is set to the steering reaction force command value T * By reflecting the steering reaction force in the steering wheel 11, it becomes possible to apply a steering reaction force corresponding to the vehicle behavior or road surface condition to the steering wheel 11. Therefore, the driver can grasp the vehicle behavior or road surface condition by feeling the steering reaction force via the steering wheel 11 as a response.

[0094] 10, the compensation value calculation unit 81 includes a torsion angle calculation unit 81A, a determination unit 81B, a switch 81C, and an adder 81D, similar to the first embodiment. However, the determination process executed by the determination unit 81B is different from that of the first embodiment.

[0095] The determination unit 81B determines the target pinion angle θ p * The value of the inclination α, which is the ratio of the change in the angular axial force F1 to the inclination threshold value α th Here, for example, if the following two conditions (A1) and (A2) are both satisfied, the value of the slope α is indirectly determined to be greater than the slope threshold value α th It is noted that the value is large enough to exceed

[0096] (A1) The axial force acting on the steering shaft 14 is close to “0”. (A2) The vehicle is stopped, i.e., the vehicle speed V is close to "0." The determination unit 81B determines whether the two conditions (A1) and (A2) are satisfied based on the distribution ratio DR2 of the lateral acceleration LA and the current axial force F2, and determines whether to compensate the torsion angle δ of the torsion bar 34A based on the determination result.

[0097] Lateral acceleration LA is the acceleration when the vehicle turns, and is detected by on-board lateral acceleration sensor 502. Lateral acceleration LA and the axial force acting on steered shaft 14 are correlated with each other. For example, as lateral acceleration LA increases, the axial force acting on steered shaft 14 increases. Conversely, as lateral acceleration LA decreases, the axial force acting on steered shaft 14 decreases. For this reason, it is possible to recognize the degree of the axial force acting on steered shaft 14 from the lateral acceleration LA.

[0098] The allocation ratio DR2 is set according to the vehicle speed V. For example, the slower the vehicle speed V, the larger the allocation ratio DR2 of the current axial force F2 is set to. Also, the faster the vehicle speed V, the smaller the allocation ratio DR2 of the current axial force F2 is set to. Therefore, it is possible to recognize the level of the vehicle speed V from the allocation ratio DR2.

[0099] Determination unit 81B receives lateral acceleration LA detected by lateral acceleration sensor 502 mounted on the vehicle, and allocation ratio DR2 calculated by allocation ratio calculation unit 72C. The determination unit 81B determines the lateral acceleration LA and the lateral acceleration threshold value LA th Through a comparison with the lateral acceleration threshold value LA, it is determined whether the above condition (A1) is satisfied. th is set, for example, through simulation. th is set, for example, based on the lateral acceleration LA when the value of the axial force acting on the steered shaft 14 becomes a value close to "0".

[0100] The determination unit 81B determines whether the value of the lateral acceleration LA is a lateral acceleration threshold value LA th When the value of the lateral acceleration LA is greater than the lateral acceleration threshold value LA, the axial force acting on the steered shaft 14 is not close to "0", that is, the previous condition (A1) is not satisfied. th When the value is below this value, it is determined that the axial force acting on the steered shaft 14 is a value close to "0", that is, the above condition (A1) is satisfied.

[0101] The determination unit 81B determines the distribution ratio DR2 of the current axial force F2 and the distribution ratio threshold value DR th Through a comparison with the above, it is determined whether the above condition (A2) is satisfied. th is set based on the distribution ratio DR2 when the value of the vehicle speed V is "0", for example. th is set to, for example, "1" or a value slightly less than "1".

[0102] The determination unit 81B determines whether the value of the distribution ratio DR2 of the current axial force F2 is equal to or smaller than the distribution ratio threshold value DR th , the vehicle is not stopped, that is, the previous condition (A2) is not satisfied. th If the value is larger than , it is determined that the vehicle is stopped, that is, the above condition (A2) is satisfied.

[0103] When at least one of the two conditions (A1) and (A2) is not satisfied, the judgment unit 81B sets the value of the flag FG to "1." When both the two conditions (A1) and (A2) are satisfied, the judgment unit 81B sets the value of the flag FG to "0."

[0104] When the value of flag FG is "1", switch 81C selects the torsion angle δ calculated by torsion angle calculation unit 81A as the final torsion angle δ1. When the value of flag FG is "0", switch 81C selects the fixed value "0" as the final torsion angle δ1.

[0105] The adder 81D calculates the steering angle θ s The final steering angle θ is calculated by adding the final torsion angle δ1 selected by the switch 81C. s1 When the value of the flag FG is "1", the torsion angle δ calculated by the torsion angle calculation unit 81A is set as the final torsion angle δ1 and the steering angle θ s When the value of the flag FG is "0", the fixed value "0" is added to the steering angle θ s is added to.

[0106] <Advantages of the Third Embodiment> Therefore, according to the third embodiment, the following effects can be obtained. (3) Based on the distribution ratio DR2 of the lateral acceleration LA and the current axial force F2, the slope α is set to the slope threshold value α th Based on the result of the determination, the torsion angle δ of the torsion bar 34A is adjusted to the steering angle θ s This makes it possible to improve the steering response to the steering of the steering wheel 11 while ensuring a good steering feel.

[0107] Depending on the product specifications, the determination unit 81B may be configured not to consider the lateral acceleration LA. In this case, the determination unit 81B determines the torsion angle δ of the torsion bar 34A in relation to the steering angle θ based only on the distribution ratio DR2 of the current axial force F2, which has a correlation with the axial force gradient. s Even in this way, the steering angle θ s The steering reaction force command value T * A sudden change in the

[0108] <Fourth embodiment> Next, a fourth embodiment in which the steering control device is embodied in a steer-by-wire type steering device will be described. This embodiment basically has the same configuration as the third embodiment shown in Fig. 9. This embodiment differs from the third embodiment in the configuration of the compensation value calculation unit 81. Therefore, the same members and configurations as those in the third embodiment are given the same reference numerals, and detailed description thereof will be omitted.

[0109] As shown in FIG. 11, the compensation value calculation section 81 has a torsion angle calculation section 81A, two gain calculation sections 81G and 81H, a multiplier 81I, and an adder 81D. The torsion angle calculation unit 81A calculates the steering torque T h The torsion angle δ of the torsion bar 34A is calculated based on this.

[0110] Gain calculation unit 81G takes in lateral acceleration LA detected through lateral acceleration sensor 502. Gain calculation unit 81G calculates gain G1 according to lateral acceleration LA. Gain calculation unit 81G calculates gain G1 using map M4 stored in the storage device of control device 50. Map M4 is a two-dimensional map that defines the relationship between the absolute value of lateral acceleration LA and gain G1, and has the following characteristics.

[0111] That is, as shown in the graph of FIG. 12, when the absolute value of the lateral acceleration LA is less than the lateral acceleration threshold value LA thIf the absolute value of the lateral acceleration LA is equal to or greater than the lateral acceleration threshold value LA, the value of the gain G1 is maintained at "0". th If the value is larger than , the value of gain G1 gradually increases toward "1" as the absolute value of lateral acceleration LA increases, and eventually reaches "1". After the value of gain G1 reaches "1", the value of gain G1 is maintained at "1" regardless of the increase in the absolute value of lateral acceleration LA. Incidentally, gain G1 can be set in the range of "0" to "1", for example, in increments of "0.1".

[0112] The gain calculation unit 81H takes in the allocation ratio DR2 of the current axial force F2 calculated by the allocation ratio calculation unit 72C. The gain calculation unit 81H calculates the gain G2 according to the allocation ratio DR2. The gain calculation unit 81H calculates the gain G2 using a map M5 stored in the storage device of the control device 50. The map M5 is a two-dimensional map that defines the relationship between the allocation ratio DR2 and the gain G2, and has the following characteristics.

[0113] That is, as shown in the graph of FIG. 13, when the value of the distribution ratio DR2 is greater than the distribution ratio threshold value DR th If the value is as follows, the value of the gain G2 is maintained at "1". th is set to a value slightly smaller than the maximum value of the distribution ratio DR2, which is "1." The value of the distribution ratio DR2 is set to the distribution ratio threshold value DR th If the value is greater than 0, the value of gain G2 gradually decreases toward "0" as the value of allocation ratio DR2 increases, and eventually reaches "0". After the value of gain G2 reaches "0", the value of gain G2 is maintained at "0" regardless of the increase in the value of allocation ratio DR2. Incidentally, gain G2 can be set in the range of "0" to "1", for example, in increments of "0.1".

[0114] As shown in FIG. 11, multiplier 81I calculates the final torsion angle δ3 by multiplying the torsion angle δ calculated by torsion angle calculation unit 81A by the gain G1 calculated by gain calculation unit 81G and the gain G2 calculated by gain calculation unit 81H.

[0115] When the values ​​of the two gains G1, G2 are both "1", the torsion angle δ calculated by the torsion angle calculation unit 81A becomes the final torsion angle δ3 as is. When the values ​​of the two gains G1, G2 are both greater than "0" and at least one of the two gains G1, G2 is less than "1", the value of the final torsion angle δ3 becomes smaller than the torsion angle δ calculated by the torsion angle calculation unit 81A. When the value of at least one of the two gains G1, G2 is "0", the value of the final torsion angle δ3 becomes "0".

[0116] The adder 81D calculates the steering angle θ s The target pinion angle θ is calculated by adding the final torsion angle δ3 calculated by the multiplier 81I to the target torsion angle θ p * The final steering angle θ used in the calculation s1 Calculate the following.

[0117] <Advantages of the Fourth Embodiment> Therefore, according to the fourth embodiment, the following effects can be obtained. (4) The steering angle θ is adjusted according to the distribution ratio DR2 of the lateral acceleration LA and the current axial force F2, which are correlated with the axial force gradient. s The value of the torsion angle δ of the torsion bar 34A added to the steering angle θ s The degree of reflection of the torsion angle δ of the torsion bar 34A with respect to the lateral acceleration LA is changed according to the distribution ratio DR2 of the current axial force F2. This makes it possible to improve the steering response to the steering of the steering wheel 11 while ensuring a good steering feel.

[0118] <Fifth embodiment> Next, a fifth embodiment in which the steering control device is embodied in a steer-by-wire type steering device will be described. This embodiment basically has the same configuration as the first embodiment shown in Figs. 1 to 5. This embodiment differs from the first embodiment in the configuration of the compensation value calculation unit 81. Therefore, the same members and configurations as those in the first embodiment are given the same reference numerals, and detailed description thereof will be omitted.

[0119] In this embodiment, the steering angle θ s The greater the gradient of the characteristic line of the map M1 shown in FIG. 3, the greater the target pinion angle θ p * The absolute value of the steering reaction force command value T * This is done in light of the risk that the

[0120] 14, the compensation value calculation unit 81 includes a torsion angle calculation unit 81A, a determination unit 81B, a switch 81C, and an adder 81D, similar to the first embodiment. However, the determination process executed by the determination unit 81B is different from that of the first embodiment.

[0121] The torsion angle calculation unit 81A calculates the steering torque T h The torsion angle δ of the torsion bar 34A is calculated based on this. The determination unit 81B determines whether or not the torsion angle δ of the torsion bar 34A should be compensated for, that is, whether or not the steering angle θ s The determination unit 81B determines whether or not the steering angle θ s Target pinion angle θ p * The inclination β, which is the rate of change of the target pinion angle θ p * The amount of change in the steering angle θ s The slope β is calculated by dividing the amount of change in

[0122] The determination unit 81B determines the value of the slope β and the slope threshold value β th Through comparison with the steering angle θ s It is judged whether or not the torsion angle δ of the torsion bar 34A should be added to the inclination threshold value β th is set, for example, through simulation. th For example, the steering angle θ s is set based on the inclination β when the inclination β is a value close to "0°" which corresponds to the neutral steering position.

[0123] The determination unit 81B determines whether the value of the inclination β received from the target pinion angle calculation unit 62 is equal to or smaller than the inclination threshold value β th If the value of the inclination β taken from the target pinion angle calculation unit 62 is equal to or less than the inclination threshold value β, the value of the flag FG is set to "1." th If the value is greater than 0, the value of flag FG is set to "0".

[0124] When the value of flag FG is "1", switch 81C selects the torsion angle δ calculated by torsion angle calculation unit 81A as the final torsion angle δ1. When the value of flag FG is "0", switch 81C selects the fixed value "0" as the final torsion angle δ1.

[0125] The adder 81D calculates the steering angle θ s The target pinion angle θ is calculated by adding the final torsion angle δ1 selected by the switch 81C. p * The final steering angle θ used in the calculation s1 Calculate the following.

[0126] <Advantages of the Fifth Embodiment> Therefore, according to the fifth embodiment, the following effects can be obtained. (5) Steering angle θ s Target pinion angle θ p * The steering angle θ sThis allows the steering response to the steering of the steering wheel 11 to be improved while still ensuring a good steering feel.

[0127] Sixth embodiment Next, a sixth embodiment in which the steering control device is embodied in a steer-by-wire type steering device will be described. This embodiment basically has the same configuration as the fifth embodiment. This embodiment differs from the first embodiment in the configuration of the compensation value calculation unit 81. Therefore, the same members and configurations as those in the fifth embodiment are given the same reference numerals, and detailed description thereof will be omitted.

[0128] As shown in FIG. 15, the compensation value calculation section 81 has a torsion angle calculation section 81A, a gain calculation section 81J, a multiplier 81K, and an adder 81D. The torsion angle calculation unit 81A calculates the steering torque T h The torsion angle δ of the torsion bar 34A is calculated based on this.

[0129] The gain calculation unit 81J calculates the steering angle θ s Target pinion angle θ p * The tilt β, which is the rate of change of the tilt β, is taken in from the target pinion angle calculation unit 62. The gain calculation unit 81J calculates the gain G3 according to the tilt β. The gain calculation unit 81J calculates the gain G3 by using a map M6 stored in the storage device of the control device 50. The map M6 is a two-dimensional map that defines the relationship between the tilt β and the gain G3, and has the following characteristics.

[0130] That is, as shown in the graph of FIG. 16, the slope β is smaller than the slope threshold β th If the value of the slope β is less than the slope threshold β, the value of the gain G is maintained at "1". thIf the value of the slope β is greater than 0, the value of the gain G3 gradually decreases toward "0" as the value of the slope β increases, and eventually reaches "0". After the value of the gain G3 reaches "0", the value of the gain G3 is maintained at "0" regardless of the increase in the value of the slope β. Incidentally, the gain G3 can be set in the range of "0" to "1", for example, in increments of "0.1".

[0131] The multiplier 81K multiplies the torsion angle δ of the torsion bar 34A calculated by the torsion angle calculation unit 81A by the gain G3 calculated by the gain calculation unit 81J to calculate a final torsion angle δ4. th If the value is below the threshold value β, the value of the gain G3 is set to "1". Therefore, the torsion angle δ calculated by the torsion angle calculation unit 81A becomes the final torsion angle δ4 as it is. th If the value is larger than β, the value of gain G3 is set to a value less than "1" or to "0" according to the value of gradient β. Therefore, the final value of torsion angle δ4 becomes a value smaller than the torsion angle δ calculated by torsion angle calculation unit 81A, or becomes "0."

[0132] The adder 81D calculates the steering angle θ s The target pinion angle θ is calculated by adding the final torsion angle δ4 calculated by the multiplier 81K to the target torsion angle θ p * The final steering angle θ used in the calculation s1 The slope β is calculated based on the slope threshold α th If the torsion angle δ is equal to or smaller than the steering angle θ s The value of the slope β is added to the slope threshold β th When the steering angle θ is greater than the torsion angle δ calculated by the torsion angle calculation unit 81A, or when the steering angle θ is set to “0”, the final torsion angle δ4 is set to “0”. s is added to.

[0133] <Advantages of the Sixth Embodiment> Therefore, according to the sixth embodiment, the following effects can be obtained. (6) Steering angle θ s Target pinion angle θ p * The steering angle θ s The value of the torsion angle δ of the torsion bar 34A added to the steering angle θ s The degree to which the torsion angle δ of the torsion bar 34A is reflected with respect to the inclination β is changed according to the inclination β. This makes it possible to improve the steering response to the steering of the steering wheel 11 while ensuring a good steering feel.

[0134] <Seventh embodiment> Next, a seventh embodiment in which the steering control device is embodied in a steer-by-wire type steering device will be described. This embodiment differs from the previous fourth embodiment in the configuration of the compensation value calculation unit 81. Therefore, the same members and configurations as those in the fourth embodiment are given the same reference numerals, and detailed description thereof will be omitted.

[0135] 17, the compensation value calculation section 81 has a torsion angle calculation section 81A, a gain calculation section 81H, a multiplier 81I, and an adder 81D. That is, the compensation value calculation section 81 of the present embodiment has a configuration in which the gain calculation section 81G in the compensation value calculation section 81 of the fourth embodiment shown in FIG.

[0136] The torsion angle calculation unit 81A calculates the steering torque T h The torsion angle δ of the torsion bar 34A is calculated based on this. The gain calculation unit 81H calculates the gain G2 according to the distribution ratio DR2 of the current axial force F2 calculated by the distribution ratio calculation unit 72C. The gain calculation unit 81H calculates the gain G2 using the map M5 shown in FIG.

[0137] Multiplier 81I calculates the final torsion angle δ5 by multiplying the torsion angle δ calculated by torsion angle calculation unit 81A by the gain G2 calculated by gain calculation unit 81H. When the value of gain G2 is "1", the torsion angle δ calculated by torsion angle calculation unit 81A becomes the final torsion angle δ5 as is. When the value of gain G2 is greater than "0" and less than "1", the value of the final torsion angle δ5 becomes smaller than the torsion angle δ calculated by torsion angle calculation unit 81A. When the value of gain G2 is "0", the value of the final torsion angle δ5 becomes "0".

[0138] The adder 81D calculates the steering angle θ s The target pinion angle θ is calculated by adding the final torsion angle δ5 calculated by the multiplier 81I to the target torsion angle θ p * The final steering angle θ used in the calculation s1 Calculate the following.

[0139] <Advantages of the Seventh Embodiment> Therefore, according to the seventh embodiment, the following effects can be obtained. (7) The steering angle θ is adjusted according to the distribution ratio DR2 of the current axial force F2, which is correlated with the axial force gradient. s The value of the torsion angle δ of the torsion bar 34A added to the steering angle θ s The degree of reflection of the torsion angle δ of the torsion bar 34A with respect to the current axial force F2 is changed according to the distribution ratio DR2 of the current axial force F2. This makes it possible to improve the steering response to the steering of the steering wheel 11 while ensuring a good steering feel.

[0140] <Eighth embodiment> Next, an eighth embodiment in which the steering control device is embodied in a steer-by-wire type steering device will be described. This embodiment basically has the same configuration as the third embodiment shown in Fig. 9. This embodiment differs from the third embodiment in the configuration of the compensation value calculation unit 81. Therefore, the same members and configurations as those in the third embodiment are given the same reference numerals, and detailed description thereof will be omitted.

[0141] As shown in FIG. 18, the compensation value calculation section 81 has a torsion angle calculation section 81A, an axial force gradient calculation section 81L, a gain calculation section 81M, a multiplier 81N, and an adder 81D. The torsion angle calculation unit 81A calculates the steering torque T h The torsion angle δ of the torsion bar 34A is calculated based on this.

[0142] The axial force gradient calculation unit 81L takes in the current axial force F2 calculated by the current axial force calculation unit 72B and the distribution axial force F3 calculated by the distribution axial force calculation unit 72D. The axial force gradient calculation unit 81L calculates a current axial force gradient γ based on the current axial force F2 and the distribution axial force F3. The axial force gradient γ is calculated based on the target pinion angle θ p * This refers to the slope, which is the ratio of the change in axial force to the change in axial force.

[0143] The axial force gradient calculation unit 81L calculates the target pinion angle θ p * The axial force gradient calculation unit 81L calculates a first gradient, which is a rate of change in the current axial force F2 relative to the target pinion angle θ p * The axial force gradient calculation unit 81L calculates a second gradient which is a rate of change of the distributed axial force F3 relative to the current axial force F2. The axial force gradient calculation unit 81L, for example, compares the value of the first gradient with the value of the second gradient, and sets the axial force gradient γ based on the comparison result. When the value of the first gradient is greater than the value of the second gradient, the axial force gradient calculation unit 81L sets the first gradient which is the gradient of the current axial force F2 as the axial force gradient γ. When the value of the second gradient is greater than the value of the first gradient, the axial force gradient calculation unit 81L sets the second gradient which is the gradient of the distributed axial force F3 as the axial force gradient γ.

[0144] The axial force gradient calculation unit 81L may set the average value of the first gradient and the second gradient as the axial force gradient γ. The gain calculation unit 81M takes in the axial force gradient γ calculated by the axial force gradient calculation unit 81L. The gain calculation unit 81M calculates a gain G4 according to the axial force gradient γ. The gain calculation unit 81M calculates the gain G4 by using a map M7 stored in the storage device of the control device 50. The map M7 is a two-dimensional map that defines the relationship between the axial force gradient γ and the gain G4, and has the following characteristics.

[0145] That is, as shown in the graph of FIG. 19, when the value of the axial force gradient γ is greater than the axial force gradient threshold value γ th If the value of the axial force gradient γ is equal to or less than the axial force gradient threshold value γ, the value of the gain G4 is maintained at "1". th If the axial force gradient γ exceeds 0, the value of the gain G4 gradually decreases toward "0" as the value of the axial force gradient γ increases, and eventually reaches "0". After the value of the gain G4 reaches "0", the value of the gain G4 is maintained at "0" regardless of the increase in the value of the axial force gradient γ. Incidentally, the gain G4 can be set in the range of "0" to "1", for example, in increments of "0.1".

[0146] As shown in FIG. 18, a multiplier 81N multiplies the torsion angle δ calculated by the torsion angle calculation section 81A by a gain G4 calculated by a gain calculation section 81M to calculate a final torsion angle δ6.

[0147] When the value of gain G4 is "1", the torsion angle δ calculated by torsion angle calculation unit 81A becomes the final torsion angle δ6 as is. When the value of gain G4 is greater than "0" and less than "1", the final torsion angle δ6 becomes smaller than the torsion angle δ calculated by torsion angle calculation unit 81A. When the value of gain G4 is "0", the final torsion angle δ6 becomes "0".

[0148] The adder 81D calculates the steering angle θ sThe target pinion angle θ is calculated by adding the final torsion angle δ6 calculated by the multiplier 81N to the target torsion angle θ p * The final steering angle θ used in the calculation s1 Calculate the following.

[0149] <Advantages of the Eighth Embodiment> Therefore, according to the eighth embodiment, the following effects can be obtained. (8) The steering angle θ is adjusted according to the axial force gradient γ based on the current axial force F2 and the distributed axial force F3. s The value of the torsion angle δ of the torsion bar 34A added to the steering angle θ s The degree to which the torsion angle δ of the torsion bar 34A is reflected with respect to the axial force gradient γ is changed according to the axial force gradient γ. This makes it possible to improve the steering response to the steering of the steering wheel 11 while ensuring a good steering feel.

[0150] (9) The current axial force F2 reflects the road surface condition and, in turn, the axial force acting on the steered shaft 14. For this reason, the steering angle θ s Whether the torsion angle δ of the torsion bar 34A should be added to the steering angle θ s It is possible to more appropriately determine whether or not a situation occurs in which the responsiveness of the steering reaction force increases excessively when the torsion angle δ is added to the steering reaction force.

[0151] <Other embodiments> The first to eighth embodiments may be modified as follows. In the first embodiment, the axial force calculation unit 72 may have an angle axial force calculation unit 72A, a current axial force calculation unit 72B, a distribution ratio calculation unit 72C, a distribution axial force calculation unit 72D, and a converter 72E, as in the third embodiment shown in FIG. 9. However, the "inclination α which is the rate of change in the angle axial force F1" is replaced with "inclination α which is the rate of change in the distribution axial force F3." Even in this case, the same effect as in the first embodiment can be obtained. That is, the torsion angle δ of the torsion bar 34A is calculated based on the inclination α which is the rate of change in the distribution axial force F3, and the steering angle θ is calculated based on the inclination α which is the rate of change in the distribution axial force F3.s This makes it possible to improve the steering response to the steering of the steering wheel 11 while ensuring a good steering feel.

[0152] In the second embodiment, the axial force calculation unit 72 may have an angle axial force calculation unit 72A, a current axial force calculation unit 72B, a distribution ratio calculation unit 72C, a distribution axial force calculation unit 72D, and a converter 72E, similar to the third embodiment shown in FIG. 9. However, the "inclination α which is the rate of change of the angle axial force F1" is to be read as "inclination α which is the rate of change of the distribution axial force F3." Even in this way, the same effect as in the second embodiment can be obtained. That is, the steering angle θ can be calculated according to the inclination α which is the rate of change of the distribution axial force F3. s The value of the torsion angle δ of the torsion bar 34A added to the steering wheel 11 is changed. This makes it possible to improve the steering response to the steering of the steering wheel 11 while ensuring a good steering feel.

[0153] In the first to eighth embodiments, the reaction force control section 50a and the steering control section 50b in the control device 50 may be configured as separate electronic control units (ECUs) independent of each other. In the first to eighth embodiments, a clutch may be provided in the steering device 10. In this case, as shown by a two-dot chain line in FIG. 1, the steering shaft 12 and the pinion shaft 13 are connected via a clutch 21. An electromagnetic clutch that switches between connecting and disconnecting power by turning on and off current to an exciting coil is used as the clutch 21. The control device 50 executes an on-off control that switches between connecting and disconnecting the clutch 21. When the clutch 21 is disconnected, the power transmission between the steering wheel 11 and the steered wheels 16 is mechanically disconnected. When the clutch 21 is connected, the power transmission between the steering wheel 11 and the steered wheels 16 is mechanically connected. [Explanation of symbols]

[0154] 11…Steering wheel 14…Steering shaft 16…Steering wheel 31...Reaction motor 34A…Torsion bar 41...Steering motor 44…Pinion shaft (shaft) 50...Control device (steering control device) 50a...Reaction force control section 50b...Steering control section 52...Steering reaction force command value calculation unit (second calculation unit) 62... target pinion angle calculation unit (first calculation unit) 81...Compensation value calculation unit (third calculation unit) F1…Angle axial force F2…Current axial force F3: Distributed axial force DR2: Current axial force distribution ratio I b …Current (state variable) LA…Lateral acceleration T h …Steering torque T * …Steering reaction force command value (command value) α…Angle axial force inclination β: Inclination of target rotation angle θ a …Reaction motor rotation angle θ s …Steering angle θ p * … Target pinion angle (target rotation angle, state variable) δ…Twist angle

Claims

1. A steering control device that controls a reaction force motor that generates a steering reaction force applied to a steering wheel, the power transmission of which is separated from a steering shaft that steers steered wheels, based on a command value calculated in accordance with a steering state, and controls a steering motor that generates a steering force that is a force for turning the steered wheels, in accordance with the steering state, a first calculation unit that calculates a target rotation angle of a shaft that rotates in conjunction with a steering operation of the steered wheels, based on a steering angle of the steering wheel obtained from a rotation angle of the reaction force motor; a second calculation unit that calculates the command value based on a steering torque obtained from a torsion angle of a torsion bar that is twisted in accordance with an operation of the steering wheel and the target rotation angle; a third calculation unit that adds the torsion angle as a compensation value to the steering angle, The third calculation unit changes a value of a torsion angle to be added to the steering angle in accordance with a degree of change in a state variable used in calculation of the command value.

2. the second calculation unit calculates the command value using an axial force of the steered shaft calculated based on the state variable, 2. The steering control device according to claim 1, wherein the third calculation unit changes a value of a torsion angle to be added to the steering angle in accordance with a gradient that is a rate of change in the axial force relative to the state variable.

3. the second calculation unit calculates the command value using an axial force of the steered shaft calculated based on the state variable, 2. The steering control device according to claim 1, wherein the third calculation unit switches whether or not to add the torsion angle of the torsion bar to the steering angle based on a slope that is a rate of change in the axial force with respect to the state variable.

4. 4. The steering control device according to claim 2, wherein the axial force is an angular axial force calculated based on the target rotation angle.

5. 4. The steering control device according to claim 2 or 3, wherein the axial force is a distribution axial force obtained by adding together values ​​obtained by multiplying an angle axial force, which is the axial force of the steered shaft calculated based on the target rotation angle, and a current axial force, which is the axial force of the steered shaft calculated based on a value of a current of the steering motor, by a distribution ratio that is individually set based on the target rotation angle and a vehicle speed.

6. the second calculation unit calculates the command value using a distribution axial force obtained by adding together values ​​obtained by multiplying an angle axial force, which is an axial force of the steered shaft calculated based on the target rotation angle, and a current axial force, which is an axial force of the steered shaft calculated based on a value of a current of the steered motor, by a distribution ratio that is individually set based on the target rotation angle and a vehicle speed; 2. The steering control device according to claim 1, wherein the third calculation unit changes a value of a torsion angle to be added to the steering angle in accordance with the distribution ratio that is individually set for the current axial force and a lateral acceleration that is an acceleration when the vehicle turns.

7. the second calculation unit calculates the command value using a distribution axial force obtained by adding together values ​​obtained by multiplying an angle axial force, which is an axial force of the steered shaft calculated based on the target rotation angle, and a current axial force, which is an axial force of the steered shaft calculated based on a value of a current of the steered motor, by a distribution ratio that is individually set based on the target rotation angle and a vehicle speed; 2. The steering control device according to claim 1, wherein the third calculation unit switches whether or not to add the torsion angle of the torsion bar to the steering angle based on the distribution ratio that is individually set for the current axial force and a lateral acceleration that is an acceleration when the vehicle turns.

8. 2. The steering control device according to claim 1, wherein the third calculation unit changes a value of a torsion angle to be added to the steering angle in accordance with an inclination that is a rate of change of the target rotation angle relative to the steering angle.

9. 2. The steering control device according to claim 1, wherein the third calculation unit switches whether or not to add the torsion angle of the torsion bar to the steering angle based on an inclination that is a rate of change of the target rotation angle with respect to the steering angle.

10. the second calculation unit calculates the command value using a distribution axial force obtained by adding together values ​​obtained by multiplying an angle axial force, which is an axial force of the steered shaft calculated based on the target rotation angle, and a current axial force, which is an axial force of the steered shaft calculated based on a value of a current of the steered motor, by a distribution ratio that is individually set based on the target rotation angle and a vehicle speed; 2. The steering control device according to claim 1, wherein the third calculation unit changes a value of a torsion angle to be added to the steering angle in accordance with the distribution ratio that is set individually for the current axial force.

11. the second calculation unit calculates the command value using a distribution axial force obtained by adding together values ​​obtained by multiplying an angle axial force, which is an axial force of the steered shaft calculated based on the target rotation angle, and a current axial force, which is an axial force of the steered shaft calculated based on a value of a current of the steered motor, by a distribution ratio that is individually set based on the target rotation angle and a vehicle speed; 2. The steering control device according to claim 1, wherein the third calculation unit switches whether or not to add the torsion angle of the torsion bar to the steering angle based on the distribution ratio that is set individually for the current axial force.

12. the second calculation unit calculates the command value using a distribution axial force obtained by adding together values ​​obtained by multiplying an angle axial force, which is an axial force of the steered shaft calculated based on the target rotation angle, and a current axial force, which is an axial force of the steered shaft calculated based on a value of a current of the steered motor, by a distribution ratio that is individually set based on the target rotation angle and a vehicle speed; 2. The steering control device according to claim 1, wherein the third calculation unit changes a value of a torsion angle to be added to the steering angle in accordance with a first gradient which is a ratio of a change in the current axial force to the target rotation angle, and a second gradient which is a ratio of a change in the distributed axial force to the target rotation angle.

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