JP5304223B2 - Vehicle steering device, vehicle with vehicle steering device, and vehicle steering method - Google Patents

Description

  The present invention includes a steering unit that is steered by a driver, a steering unit that is mechanically separated from the steering unit and steers steered wheels according to a steering angle of the steering unit, and an operational reaction force applied to the steering unit. The present invention belongs to the technical field of a vehicle steering apparatus, a vehicle with a vehicle steering apparatus, and a vehicle steering method.

As this type of technology, the technology described in Patent Document 1 is disclosed. In this publication, a steering handle (steering unit) that can be operated by a driver, a steered shaft motor that is mechanically separated from the steering handle and steers steered wheels according to the steering angle of the steering handle, Vehicle steering equipped with a steering shaft motor (reaction force actuator) that applies a reaction force to the steering handle via the steering shaft by rotationally driving a steering shaft connected to the handle (applying a reaction force torque) In the device, the target turning amount is calculated based on the steering angle of the operation shaft connected to the steering handle, and the steering shaft motor is controlled based on the deviation between the calculated target turning amount and the turning displacement amount. The wheel is steered and the steering shaft motor is controlled based on the deviation between the steering force and the turning reaction force and the deviation between the target turning amount and the turning displacement amount to apply a reaction force to the steering wheel. Are disclosed.
JP-A-10-217998

  However, in the above prior art, when the change speed of the target turning amount increases, for example, when the driver steers the steering wheel suddenly, the deviation between the target turning amount and the turning displacement amount increases. The driver may feel uncomfortable.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to provide an appropriate steering reaction force to the steering wheel, thereby suppressing a sense of discomfort to the driver during steering. A vehicle steering device, a vehicle with a vehicle steering device, and a vehicle steering method are provided.

In order to achieve the above-described object, in the present invention, the sign of the turning angle deviation, which is the deviation between the estimated turning angle and the actual turning angle as an estimated value of the turning angle, and the change in the turning angle deviation. When the positive and negative signs of the speed coincide with each other, it is determined that the turning angle deviation is increased, and when the turning angle deviation is increased , the turning angle deviation is not increased. By adding an additional reaction force that increases as the change speed of the steering angle deviation increases, a larger steering reaction force is applied to the steering unit than when the steering angle deviation does not increase. I did it.

  Therefore, when the turning angle deviation is increased, a larger steering reaction force is applied than when the turning angle deviation is not increased, so that the steering speed of the operation unit by the driver can be suppressed. Become. As a result, the steered wheel steered angle by the steered actuator catches up with the estimated steered angle, and consequently the deviation between the target steered angle corresponding to the steered angle and the steered wheel steered angle is reduced. In addition, the uncomfortable feeling given to the driver can be suppressed.

  Hereinafter, the best mode for realizing the vehicle steering device, the vehicle with the vehicle steering device, and the vehicle steering method of the present invention will be described based on the first embodiment.

[Example 1]
First, the configuration will be described.
〔overall structure〕
FIG. 1 is an overall configuration diagram of a vehicle 1 to which a vehicle steering apparatus according to a first embodiment is applied. The vehicle 1 is a steered wheel in which the front wheel 2 of the front wheels 2FL and 2FR and the rear wheels 3RL and 3RR are steered. The vehicle steering apparatus according to the first embodiment is a so-called steer-by-wire system in which the steering mechanism 16 and the steering mechanism 17 are mechanically separated.

  In the vehicle steering apparatus according to the first embodiment, a steering mechanism 16 is used as a steering mechanism 16. A steering angle sensor for detecting a rotation angle (steering angle) of the steering shaft 18, a steering shaft 18 connected to the steering wheel 13, 19, a steering torque sensor 20 that detects torque (steering torque) input to the steering shaft 18, a steering shaft motor (reaction force actuator) 8 that applies rotational torque (steering reaction force) to the steering shaft 18, and steering And a steering shaft motor rotation angle sensor 12 for detecting the angle of the shaft motor 8.

  In addition, the vehicle steering apparatus according to the first embodiment includes a first turning motor 9a (steering actuator) and a second turning motor 9b (steering actuator) that steer the front wheels 2FL and 2FR as the turning mechanism 17; Steering motor rotation angle sensors 10a and 10b that detect the angles of the first steering motor 9a and the second steering motor 9b, pinions 11a and 11b that transmit the rotation of the steering motor 9 to the rack 5, and the rack 5 The connected tie rods 21a and 21b, the knuckle arms 4a and 4b connected to the tie rod 21, the front wheels (steering wheels) 2FR and 2FL connected to the knuckle arm 4, and the front wheels 2FR and 2FL as a lateral force from the front wheels 2FR and 2FL. Tire lateral force sensors 15a and 15b for detecting a force (tire lateral force) input in the axial direction of the rack 5 are provided.

  Further, the vehicle steering apparatus according to the first embodiment is configured such that the steering shaft 16 and the pinion 11b are mechanically connected to each other when the steering motor 9 cannot be accurately driven due to a failure of the vehicle steering apparatus or the like. And the steering mechanism 17 are mechanically connected to each other, and the driver has a backup clutch 7 as the backup mechanism 6 that enables the steering wheel 13 to steer the front wheels 2FR and 2FL.

  The vehicle steering apparatus according to the first embodiment includes a first electronic control unit 14a, a second electronic control unit 14b, and a third electronic control unit 14c as the control mechanism 23 of each apparatus.

  The first electronic control unit 14a inputs rotation angle information of the first turning motor 9a from the turning motor rotation angle sensor 10a, and controls the first turning motor 9a. The second electronic control unit 14b inputs rotation angle information of the second turning motor 9b from the turning motor rotation angle sensor 10b, and controls the second turning motor 9b. The third electronic control unit 14c includes steering angle information from the steering angle sensor 19, steering torque information from the steering torque sensor 20, rotation angle information of the steering shaft motor 8 from the steering shaft motor rotation angle sensor 12, and tire lateral force sensors 15a and 15b. The tire lateral force information from the yaw rate sensor 26, the vehicle yaw rate from the yaw rate sensor 26, and the vehicle lateral acceleration from the acceleration sensor 25 are input, and the steering shaft motor 8 and the backup clutch 7 are controlled. Note that the actual turning angle, which is the actual turning angle of the front wheel 2, can be calculated from the rotation angle information of the turning motor 9a.

  The first electronic control unit 14a, the second electronic control unit 14b, and the third electronic control unit 14c are connected by a controller area network (CAN) 22. The first electronic control unit 14a, the second electronic control unit 14b, and the third electronic control unit 14c share information by transmitting and receiving data to and from each other via the CAN 22, and one of the electronic control units 14 fails. Even so, the remaining electronic control unit 14 can input information from each sensor and control each device. The first electronic control unit 14a, the second electronic control unit 14b, and the third electronic control unit 14c are connected to the battery 24, and power is supplied from the battery 24.

[Steering motor control processing]
The steering motor 9 is controlled by the following process.
The steering angle sensor 19 detects the steering angle of the steering wheel 13, and calculates the target turning angle θt based on the steering angle detected by the steering angle sensor 19 in the first electronic control unit 14a. The target turning angle θt is calculated by referring to a map in which the target turning angle θt with respect to the steering angle is predetermined. The map of the target turning angle θt with respect to the steering angle is such that, for example, the higher the vehicle speed, the smaller the target turning angle θt with respect to the steering angle, and the lower the vehicle speed, the larger the target turning angle θt with respect to the steering angle. It may be changed based on the state or the like.

  In the first and second electronic control units 14a and 14b, the drive command value of the steered motor 9 is calculated so that the actual steered angle θa matches the target steered angle θt, and the steered motor 9 is driven. A steering operation is performed.

The drive command values calculated by the first and second electronic control units 14a and 14b are calculated by an angle servo system that controls the actual turning angle θa to follow the target turning angle θt with a predetermined response characteristic. .
The angle servo system of the first and second electronic control units 14a and 14b is configured by a method using a robust model matching method. In this method, a drive command value for realizing a predetermined normative response characteristic with respect to the target turning angle θt is calculated by a model matching compensator for matching with a desired characteristic given in advance, and a robust compensator Thus, a compensation current corresponding to the disturbance component is calculated. As a result, it is possible to realize a control system with excellent disturbance resistance in which the actual turning angle θa can follow the normal response characteristics even when a disturbance occurs.

[Steering shaft motor control processing]
FIG. 2 is a flowchart showing a flow of control processing of the steering shaft motor 8 performed in the third electronic control unit 14c.

In step S1, the tire lateral force F1 detected by the tire lateral force sensors 15a and 15b as the vehicle state, the steering motor torque F2, the vehicle yaw rate F3 detected by the yaw rate sensor 26, and the vehicle lateral detected by the acceleration sensor 25 are detected. The acceleration F4, the steering angle θs, and the actual turning angle θa are input, and the process proceeds to step S2. The steered motor torque F can be obtained from the drive command value of the steered motor 9 by the first and second electronic control units 14a and 14b.
In step S2, the actual turning angular velocity dθa / dt obtained by differentiating the actual turning angle θa is calculated, and the process proceeds to step S3.

In step S3, the estimated turning angle θe is calculated, and the process proceeds to step S4. For the estimated turning angle θe, the target turning angle θt corresponding to the steering angle θs input in step S1 is calculated, and the calculated turning angle θt is multiplied by a filter Lp equivalent to the response delay of the turning motor 9. Then, an estimated turning angle θe, which is an estimated value of the turning angle, is calculated. That is, the actual turning angle with respect to the target turning angle θt mainly causes a delay due to a response delay of the turning motor 9. The response delay is obtained in advance by experiments, simulations, and the like, and the estimated turning angle θe, which is an estimated value of the turning angle, is calculated by multiplying the obtained target turning angle θt by a filter Lp that simulates the response delay.
θe = Lp ・ θt
In step S4, an estimated turning angular velocity dθe / dt, which is a differential value of the estimated turning angle θe, is calculated, and the process proceeds to step S5.

In step S5, the first steering reaction force TH1 is calculated, and the process proceeds to step S6. The first steering reaction force TH1 includes the tire lateral force F1, the steering motor torque F2, the vehicle yaw rate F3, and the vehicle lateral acceleration F4, which are input in step S1, and the steering angle θs (step Based on the steering angle θs) input in S1, the steering angular velocity that is a one-time differential value of the steering angle θs, and the steering state of the steering angular acceleration that is the second-order differential value of the steering angle θs, the following equation is used. That is, the first steering reaction force TH1 is a steering reaction force based on the vehicle state and the driver's steering state.
TH1 = G1 ・ F1 + G2 ・ F2 + G3 ・ F3 + G4 ・ F4 + G5 ・ S1 + G6 ・ S2 + G7 ・ S3
G1 to G7 are gains set in advance by experiments or the like.

In step S6, the second steering reaction force TH2 is calculated, and the process proceeds to step S8. The second steering reaction force TH2 is obtained by multiplying the difference (the turning angle deviation) between the estimated turning angle θe calculated in step S5 and the actual turning angle θa input in step S1 by a predetermined weighting factor K.
TH2 = K ・ (θe−θa)

In step S7, the third steering reaction force TH3 is calculated, and the process proceeds to step S9. The third steering reaction force TH3 is obtained by adding a predetermined weighting factor (a gain previously determined through experiments or the like) to the difference between the estimated turning angular velocity dθe / dt calculated in step S2 and the actual turning angular velocity dθa / dt input in step S4. ) Multiply by C.
TH3 = C ・ (dθe / dt−dθa / dt)
The above formula is
TH3 ＝ C ・ d / dt （θe-θa）
It may be.

In any case, a value obtained by multiplying the differential value of the deviation between the estimated turning angle θe and the actual turning angle θa (the turning angle deviation) by a predetermined coefficient C corresponds to the third steering reaction force TH3.
Hereinafter, in order to distinguish the third steering reaction force TH3 from the first steering reaction force and the second steering reaction force, the third steering reaction force TH3 is referred to as an additional reaction force TH3. In addition, the deviation between the estimated turning angle θe and the actual turning angle θa is hereinafter also referred to as a turning angle deviation.

  In step S8, the sign of the deviation (θe-θa) between the estimated turning angle θe and the actual turning angle θa, and the sign of the deviation (θt-θa) between the target turning angle θt and the actual turning angle θa are determined. The process proceeds to step S9 if they are the same, and the process proceeds to step S14 if they are not the same.

  In step S9, the sign of the deviation (θe−θa) between the estimated turning angle θe and the actual turning angle θa is the same as the sign of the differential value of the deviation (dθe / dt−dθa / dt). If it is determined whether or not there is the same code, the process proceeds to step S10. If the code is not the same, the process proceeds to step S14.

  In step S10, it is determined whether or not the additional reaction force TH3 is larger than a limiter TL that is a predetermined upper limit value. If the additional reaction force TH3 is larger than the limiter TL, the process proceeds to step S12, where When TH3 is equal to or less than the limiter TL, the process proceeds to step S11. Note that the limiter TL is a value obtained by experimentally determining in advance a value that can cause the steering reaction force to become too large due to the additional reaction force TH3 being too large, which may cause the driver to feel uncomfortable.

In step S11, it is determined whether or not the changing speed of the additional reaction force TH3 is higher than a predetermined speed SL. If the changing speed of the additional reaction force TH3 is higher than the predetermined speed SL, the process proceeds to step S13. When the change speed of the additional reaction force TH3 is equal to or lower than the predetermined change speed SL, the process proceeds to step S15.
In addition, the predetermined change speed SL is a value set in advance by experimentally determining a value that may cause a sudden change in the steering reaction force due to the change speed of the additional reaction force TH3 being too large and causing the driver to feel uncomfortable. It is.

In step S12, the additional reaction force TH3 is set to the limiter TL, and the process proceeds to step S15.
In step S13, the product obtained by multiplying the additional reaction force TH3 by the filter S is set as a new additional reaction force TH3, and the process proceeds to step S15. This filter S suppresses the rate of change of the additional reaction force TH3 and suppresses a sudden rise in the additional reaction force TH3.
In step S14, the additional reaction force TH3 is set to 0 (zero), and the process proceeds to step S15.
In step S15, the drive command value for the steering shaft motor 8 is calculated from the sum of the first steering reaction force TH1, the second steering reaction force TH2, and the additional reaction force TH3, and the process ends.

[Steering shaft motor control processing operation]
The sign of the deviation (θe-θa) between the estimated turning angle θe and the actual turning angle θa and the sign of the deviation (θt-θa) between the target turning angle θt and the actual turning angle θa are: If they are the same, the process proceeds from step S1, step S2, step S3, step S4, step S5, step S6, step S7, step S8, and step S9, and the deviation between the estimated turning angle θe and the actual turning angle θa. If the sign of (θe−θa) and the sign of the deviation (θt−θa) between the target turning angle θt and the actual turning angle θa are not the same, step S1 → step S2 → step S3 → step The process proceeds from S4 → step S5 → step S6 → step S7 → step S8 → step S14.

In step S9, the sign of the deviation (θe−θa) between the estimated turning angle θe and the actual turning angle θa is the same as the sign of the differential value of the deviation (dθe / dt−dθa / dt). If not, the process proceeds from step S14 to step S15 to RETURN.
In step S9, when the sign of the deviation (θe−θa) between the estimated turning angle θe and the actual turning angle θa is the same as the sign of the differential value of the deviation (dθe / dt-dθa / dt), The process proceeds to S10.

In step S10, when the additional reaction force TH3 is larger than the limiter TL, the process proceeds from step S12 to step S15 to RETURN.
On the other hand, when the additional reaction force TH3 is less than the limiter TL in step S10, the process proceeds to step S11.

  In step S11, when the increasing speed of the additional reaction force TH3 is higher than the predetermined speed SL, the process proceeds from step S13 to step S15 to RETURN.

  On the other hand, when the increase speed of the additional reaction force TH3 is equal to or lower than the predetermined speed SL in step S11, the process proceeds from step S15 to RETURN.

(About steering reaction force)
In step S5, the first steering reaction force TH1 is calculated, and in step S7, the second steering reaction force TH2 is calculated. The first steering reaction force TH1 and the second steering reaction force TH2 are a vehicle steering apparatus in which the steering mechanism 16 and the steering mechanism 17 are mechanically coupled (that is, not a steer-by-wire system). The steering reaction force acting on the steering shaft 18 is simulated.

  The steered motor torque F used for the calculation of the first steering reaction force TH1 is generated by the reaction force of the rack 5 axial force (rack axial force). FIG. 3 is a graph showing the rise of the rack axial force. As for this rack axial force, the front wheel 2 is steered by the steering motor 9 in accordance with the steering angle θs of the steering 13, and as a result, the rack axial force is generated. Therefore, as shown in FIG. 3, the rack axial force is not generated at the initial stage of steering, and the rack axial force is generated after a while after the steering is started. Therefore, the first steering reaction force TH1 is small at the initial stage of steering, and the first steering reaction force TH1 also increases after a while from the start of steering.

  The second steering reaction force TH2 is calculated based on the deviation between the estimated turning angle θe and the actual turning angle θa. FIG. 4 is a graph showing the rise of the deviation between the estimated turning angle θe and the actual turning angle θa. If it corresponds to the increase in the steering angle θs at the initial stage of steering but is delayed, as shown in FIG. 4, the deviation between the estimated turning angle θe and the actual turning angle θa increases rapidly. Therefore, the second steering reaction force TH2 rises greatly from the initial stage of steering. As a result, the steering reaction force can be generated from the initial stage of steering when the first steering reaction force TH1 is small.

  The additional reaction force TH3 is calculated based on the differential value of the deviation between the estimated turning angle θe and the actual turning angle θa. This additional reaction force TH3 can provide a steering reaction force (additional reaction force) at an early stage before the magnitude of the deviation between the estimated turning angle θe and the actual turning angle θa becomes large.

In step S8, the sign of the deviation (steering angle deviation) between the estimated turning angle θe and the actual turning angle θa and the sign of the difference between the target turning angle θt and the actual turning angle θa are obtained. If they are not the same, the additional reaction force TH3 is set to 0 (zero).
When the steering speed of the steering wheel 13 is decelerated, such as when the front wheel 2 is turned (increase) or when the steering wheel is switched back to turning, the actual rotation is performed with respect to the estimated turning angle θe set according to the steering angle θs. The steering angle θa may overshoot. In that case, the additional reaction force TH3 calculated based on the differential value of the deviation (steering angle deviation) between the estimated turning angle θe and the actual turning angle θa is the steering reaction force in the direction of continuing cutting and turning back. The value is calculated so as to occur. As a result, the steering reaction force acting on the steering 13 becomes unstable, giving the driver a feeling of strangeness.

  Therefore, the sign of the deviation (θe-θa) between the estimated turning angle θe and the actual turning angle θa and the sign of the deviation (θt-θa) between the target turning angle θt and the actual turning angle θa Are not the same, the additional reaction force TH3 is set to 0 (zero), and the steering reaction force is generated in the steering 13 based only on the first steering reaction force TH1 and the second steering reaction force.

  In step S9, the sign of the deviation (θe−θa) between the estimated turning angle θe and the actual turning angle θa and the sign of the differential value of the deviation (dθe / dt-dθa / dt) are obtained. If they are the same, in step S15, the additional reaction force TH3 is added to the first steering reaction force TH1 and the second steering reaction force.

  When the sign of the deviation (θe-θa) between the estimated turning angle θe and the actual turning angle θa is the same as the sign of the differential value of the deviation (dθe / dt-dθa / dt), that is, When a deviation between the estimated turning angle θe and the actual turning angle θa occurs and the change speed of the estimated turning angle θe is larger than the turning angle speed of the actual turning angle θa, the estimated turning angle θe The deviation from the actual turning angle θa (the turning angle deviation) is increasing.

  Therefore, when the sign of the deviation (θe-θa) between the estimated turning angle θe and the actual turning angle θa is the same as the sign of the differential value of the deviation (dθe / dt-dθa / dt) In this case, by adding the additional reaction force TH3 to the first steering reaction force TH1 and the second steering reaction force, an increase in the steering speed of the driver is suppressed, and the estimated turning angle θe and the actual turning angle θa Before the deviation increases, the change speed of the target turning angle θt set according to the steering angle of the steering can be reduced, and the increase in deviation between the estimated turning angle θe and the actual turning angle θa is suppressed. be able to.

(Additional resistance)
In step S7, step S12, and step S13, an additional reaction force TH3 is calculated. Whereas the first steering reaction force TH1 and the second steering reaction force TH2 simulate the steering reaction force, the additional reaction force TH3 is a displacement of the target turning angle θt calculated according to the steering angle of the steering wheel 13. When the speed is high and the change speed of the estimated turning angle θe exceeds the maximum turning speed of the front wheels 2 by the turning motor 9, an additional is given to suppress the steering speed of the steering wheel 13 by the driver. Resistance force (additional reaction force). Details of the additional reaction force TH3 will be described later.

(About gain)
Here, the weighting coefficients K and C used for the calculation of the second steering reaction force TH2 and the additional reaction force TH3 are set according to the vehicle speed. FIG. 5 is a map of the weighting factors K and C. As shown in FIG. 5, the weighting factors K and C are set low at low vehicle speeds and high at high vehicle speeds. By setting in this way, the steering reaction force can be reduced at low vehicle speeds, and the driver can steer the steering wheel 13 with a small steering force at low vehicle speeds. For this reason, the driver can easily steer even when the turning angle of the front wheels 2 is increased, such as in a garage. On the other hand, the steering reaction force can be increased at high vehicle speeds, and the driver needs a large steering force to steer the steering wheel 13 at high vehicle speeds. Therefore, it is possible to ensure straight running stability when traveling at a high vehicle speed.

[Operation of Example 1]
When the change speed of the estimated turning angle θe set according to the steering angle of the steering wheel 13 exceeds the speed of the turning angle of the front wheel 2 by the turning motor 9, the estimated turning angle θe and the actual turning angle θa Differences accumulate. When the difference between the estimated turning angle θe and the actual turning angle θa is accumulated, the second steering reaction force TH2 calculated according to the deviation between the estimated turning angle θe and the actual turning angle θa increases. An excessive steering reaction force is applied to the driver, and the steering amount does not increase despite the increase in the steering amount and the steering reaction force, which may cause the driver to feel uncomfortable.

  Therefore, in the third electronic control unit 14c of the first embodiment, when the displacement speed of the target turning angle θt exceeds the turning speed of the front wheels 2 by the turning motor 9, it is added in addition to the steering reaction forces TH1 and TH2. The steering shaft motor 8 is controlled so that the reaction force TH3 is applied to the steering wheel 13.

  With this configuration, when the displacement speed of the target turning angle θt exceeds the turning speed of the front wheels 2 by the turning motor 9, the additional reaction force TH3 acts on the steering shaft 18 in addition to the steering reaction forces TH1 and TH2, It becomes possible to suppress the steering speed of the steering wheel 13 by the driver. Therefore, before the deviation between the estimated turning angle θe and the actual turning angle θa increases, the change speed of the estimated turning angle θe set according to the steering angle of the steering wheel 13 can be reduced, and the turning motor can be reduced. Since the turning angle of the front wheel 2 by 9 catches up with the estimated turning angle θe, an increase in deviation between the estimated turning angle θe and the actual turning angle θa can be suppressed. Therefore, an increase in the second steering reaction force TH2 calculated according to the deviation between the estimated turning angle θe and the actual turning angle θa can be suppressed, and as a result, the steering reaction applied to the driver is suppressed. Since the force is decreased and the turning amount increases according to the increase of the steering amount and the steering reaction force, it is possible to suppress the uncomfortable feeling given to the driver.

  Further, in the third electronic control unit 14c of the first embodiment, when the deviation between the estimated turning angle θe and the actual turning angle θa coincides with the sign of the differential value of this deviation, it is added based on the differential value of the deviation. The reaction force TH3 was calculated.

  FIG. 6 is a time chart of the estimated turning angle θe, the actual turning angle θa, the deviation between the estimated turning angle θe and the actual turning angle θa, and the differential value of this deviation. From FIG. 6, when the sign of the difference between the estimated turning angle θe and the actual turning angle θa matches the sign of the differential value of the deviation, the change speed of the estimated turning angle θe is actual. It can be seen that the turning angle θa is larger than the turning angular velocity. At this time, by generating the additional reaction force TH3 (shaded portion in FIG. 6), the steering speed of the driver's steering wheel 13 can be suppressed. Therefore, an increase in the second steering reaction force TH2 calculated according to the deviation between the estimated turning angle θe and the actual turning angle θa can be suppressed, and as a result, the steering reaction applied to the driver is suppressed. Since the force is decreased and the turning amount increases according to the increase of the steering amount and the steering reaction force, it is possible to suppress the uncomfortable feeling given to the driver. On the other hand, when the change speed of the estimated turning angle θe is equal to or lower than the turning angular speed of the actual turning angle θa, the steering speed of the driver's steering wheel 13 is decreased. At this time, by not generating the additional reaction force TH3, it is possible to prevent the driver from being given an extra operation burden.

  In the third electronic control unit 14c of the first embodiment, the sign of the difference between the estimated turning angle θe and the actual turning angle θa and the deviation between the target turning angle θt and the actual turning angle θa are as follows. When the positive and negative signs are not the same, the additional reaction force TH3 is set to 0 (zero).

  FIG. 7 is a time chart of the target turning angle θt, the estimated turning angle θe, the actual turning angle θa, the deviation between the estimated turning angle θe and the actual turning angle θa, and the differential value of this deviation. As shown in FIG. 7, the actual turning angle θa may overshoot the estimated turning angle θe due to the inertial force of the turning motor 9. In that case, the additional reaction force TH3 calculated based on the deviation between the estimated turning angle θe and the actual turning angle θa is calculated so that a force is generated in the same direction as the driver's steering direction. End up. When the absolute value of the actual turning angle θa is larger than the absolute value of the estimated turning angle θe, the steering reaction force acting on the steering 13 is stabilized by calculating the additional reaction force TH3 as 0 (zero), and the driver Can suppress a sense of incongruity.

In the third electronic control unit 14c of the first embodiment, the additional reaction force TH3 is calculated using the filter S that suppresses the increase in the additional reaction force TH3.
With this configuration, it is possible to suppress a sudden increase in the additional reaction force TH3, and it is possible to suppress a sense of discomfort given to the driver.

In the third electronic control unit 14c of the first embodiment, the calculation is performed using the limiter TL that limits the magnitude of the additional reaction force TH3.
With this configuration, it is possible to prevent the resistance force (reaction force) acting on the steering shaft 18 from being too viscous due to the additional reaction force TH3, and it is possible to prevent the driver from being burdened with an extra operation.

[Effect of Example 1]
Next, effects of Example 1 are listed below.

  (1) A steering motor 9 that steers the front wheel 2 that is a steering wheel mechanically separated from the steering wheel 13 that the driver steers, and an actual steering angle θa that is the actual steering angle of the front wheel 2 The target turning angle θt of the front wheels 2 is calculated according to the detected steering motor rotation angle sensor 10 and the steering angle θs of the steering 13, and the turning is performed so that the turning angle of the front wheels 2 becomes the target turning angle θt. The first and second electronic control units 14a and 14b for controlling the motor 9, the third electronic control unit 14c for calculating the steering reaction force applied to the steering 13, and the steering reaction force calculated by the third electronic control unit 14c. And a steering shaft motor 8 that applies a steering reaction force to the steering wheel 13 based on the steering wheel motor 8, and the third electronic control unit 14c determines the turning angle of the front wheels 2 based on the response delay of the turning angle with respect to the target turning angle θt. Guess The estimated turning angle θe, which is a value, is calculated, and the turning angle deviation, which is the deviation between the calculated estimated turning angle θe and the actual turning angle θa detected by the turning motor rotation angle sensor 10, is increasing. In this case, a larger steering reaction force is calculated than when the turning angle deviation is not increased.

  Therefore, when the turning angle deviation is increased, a larger steering reaction force is applied than when the turning angle deviation is not increased, so that the steering speed of the operation unit by the driver can be suppressed. Become. As a result, the steered angle of the front wheel 2 by the steered motor 9 catches up with the estimated steered angle θe, and as a result, the deviation between the target steered angle θt corresponding to the steered angle and the steered angle of the front wheel 2 is increased. This can reduce the uncomfortable feeling given to the driver.

  (2) The third electronic control unit 14c calculates the change speed of the turning angle deviation. When the turning angle deviation increases, the third electronic control unit 14c determines the steering reaction force when the turning angle deviation does not increase. On the other hand, by adding an additional reaction force TH3 that increases as the change speed of the turning angle deviation increases, a larger steering reaction force is calculated than when the turning angle deviation does not increase.

  Therefore, when the turning angle deviation is increasing, the additional reaction force TH3, which increases as the change speed of the turning angle deviation increases, is added to the steering reaction force. It becomes possible. As a result, the steered angle of the front wheel 2 by the steered motor 9 catches up with the estimated steered angle θe, and as a result, the deviation between the target steered angle θt corresponding to the steered angle and the steered angle of the front wheel 2 is increased. This can reduce the uncomfortable feeling given to the driver.

  (3) The third electronic control unit 14c differentiates the turning angle deviation to calculate the changing speed of the turning angle deviation.

  Therefore, when the turning angle deviation is increasing, the additional reaction force TH3, which increases as the change speed of the turning angle deviation increases, is added to the steering reaction force. It becomes possible. As a result, the steered angle of the front wheel 2 by the steered motor 9 catches up with the estimated steered angle θe, and as a result, the deviation between the target steered angle θt corresponding to the steered angle and the steered angle of the front wheel 2 is increased. This can reduce the uncomfortable feeling given to the driver.

  (4) The third electronic control unit 14c determines that the turning angle deviation has increased when the sign of the turning angle deviation matches the sign of the change speed of the turning angle deviation. I did it.

  When the sign of the turning angle deviation matches the sign of the change speed of the turning angle deviation, the turning angle deviation is displaced in the increasing direction. At this time, the additional reaction force TH3 is added to the steering reaction force, and the increase in the second steering reaction force TH2 calculated according to the turning angle deviation can be suppressed. As a result, it is given to the driver. The steering reaction force to be reduced is decreased and the turning amount is increased in accordance with the increase of the steering amount and the steering reaction force, so that it is possible to suppress a sense of discomfort given to the driver.

(5) The third electronic control unit 14c calculates the estimated turning angle θe of the front wheels 2 based on the target turning angle θt and the response delay of the turning motor 9.
Therefore, the additional reaction force TH3 can be generated before the turning angle deviation actually starts to occur, and the increase of the turning angle deviation can be suppressed.

(6) The third electronic control unit 14c calculates the change rate of the additional reaction force TH3, and suppresses the change rate of the additional reaction force TH3 when the calculated change rate is greater than a predetermined change rate. I did it.
Therefore, it is possible to suppress a sudden increase in the additional reaction force TH3 and to suppress a sense of discomfort given to the driver.

(7) The third electronic control unit 14c limits the additional reaction force TH3 to a predetermined value or less.
Therefore, it is possible to suppress a significant increase in the additional reaction force TH3 and to suppress a sense of discomfort given to the driver.

(8) When the sign of the deviation between the target turning angle θt and the actual turning angle θa is not the same as the sign of the turning angle deviation, the third electronic control unit 14c sets the additional reaction force TH3 to zero. I tried to do it.
When the sign of the turning angle deviation does not coincide with the sign of the change speed of the turning angle deviation, it is when the turning angle deviation is displaced in a decreasing direction. At this time, by not generating the additional reaction force TH3, it is possible to prevent the driver from being given an extra operation burden.

(9) When the turning angle deviation does not increase, the third electronic control unit 14c calculates a steering reaction force based on the vehicle state, the driver's steering state, and the turning angle deviation, and turns the turning angle. When the deviation increases, the additional reaction force TH3 is added to the steering reaction force.
When the turning angle deviation does not increase, the steering feeling can be improved, and when the turning angle deviation increases, the steering speed of the operation unit by the driver can be suppressed. Therefore, the uncomfortable feeling given to the driver can be suppressed.

(10) The vehicle state is a tire lateral force F1, a steering motor torque F2, a vehicle yaw rate F3, and a vehicle lateral acceleration F4, and the driver's steering state is a steering angle θs, a steering angular velocity, and a steering angular acceleration.
Therefore, it is possible to obtain the steering reaction force by simulating the reaction force acting on the steering in a vehicle in which the steering and the front wheels are mechanically connected, so that the operational feeling can be improved.

  (11) Steering motor 9 that steers front wheel 2 that is a steered wheel mechanically separated from steering 13 that is steered by the driver in vehicle 1, and actual steering that is the actual steering angle of front wheel 2 The target turning angle θt of the front wheels 2 is calculated according to the steering motor rotation angle sensor 10 that detects the angle θa and the steering angle θs of the steering 13 so that the turning angle of the front wheels 2 becomes the target turning angle θt. Calculated by the first and second electronic control units 14a and 14b for controlling the steering motor 9, the third electronic control unit 14c for calculating the steering reaction force applied to the steering 13, and the third electronic control unit 14c. The third electronic control unit 14c includes a steering shaft motor 8 that applies a steering reaction force to the steering wheel 13 based on the steering reaction force, and the third electronic control unit 14c performs a front operation based on a response delay of the turning angle with respect to the target turning angle θt. An estimated turning angle θe that is an estimated value of the turning angle 2 is calculated, and the turning is a deviation between the calculated estimated turning angle θe and the actual turning angle θa detected by the turning motor rotation angle sensor 10. When the angle deviation increases, a larger steering reaction force is calculated than when the turning angle deviation does not increase.

  Therefore, if the variation speed of the target turning angle θt exceeds the turning speed of the front wheels 2 by the turning motor 9, the additional reaction force TH3 acts on the steering shaft 18 in addition to the steering reaction force, so that the steering 13 by the driver is performed. It is possible to reduce the steering speed. Thereby, before the deviation between the estimated turning angle θe and the actual turning angle θa increases, the change speed of the estimated turning angle θe set according to the steering angle of the steering wheel 13 can be reduced, and the turning can be performed. Since the turning angle of the front wheel 2 by the motor 9 catches up with the estimated turning angle θe, it is possible to suppress an increase in deviation between the estimated turning angle θe and the actual turning angle θa. Therefore, an increase in the second steering reaction force TH2 calculated according to the deviation between the estimated turning angle θe and the actual turning angle θa can be suppressed, and as a result, the steering reaction applied to the driver is suppressed. Since the force is decreased and the turning amount increases according to the increase of the steering amount and the steering reaction force, it is possible to suppress the uncomfortable feeling given to the driver.

  (12) A steering motor 9 that steers the front wheel 2 that is a steered wheel mechanically separated from the steering wheel 13 that is steered by the driver, and an actual steering angle θa that is an actual steering angle of the front wheel 2 The target turning angle θt of the front wheels 2 is calculated according to the detected steering motor rotation angle sensor 10 and the steering angle θs of the steering 13, and the turning is performed so that the turning angle of the front wheels 2 becomes the target turning angle θt. The first and second electronic control units 14a and 14b that control the motor 9 are provided, the target turning angle θt of the front wheels 2 is calculated according to the steering angle θs of the steering 13, and the turning angle of the front wheels 2 is set as the target. The steering motor 9 is controlled so that the turning angle θt is obtained, the steering reaction force applied to the steering 13 is calculated, and the turning angle of the front wheels 2 is determined based on the response delay of the turning angle with respect to the target turning angle θt. The estimated turning angle θe, which is an estimated value, is calculated, and the calculated estimated turning angle θe and the turning motor speed When the turning angle deviation, which is a deviation from the actual turning angle θa detected by the angle sensor 10, is increased, a larger steering reaction force is calculated than when the turning angle deviation is not increased. I made it.

  Therefore, if the displacement speed of the target turning angle θt exceeds the turning speed of the front wheels 2 by the turning motor 9, the additional reaction force TH3 acts on the steering shaft 18 in addition to the steering reaction force, so that the steering by the driver 13 It is possible to reduce the steering speed. Thereby, before the deviation between the estimated turning angle θe and the actual turning angle θa increases, the change speed of the estimated turning angle θe set according to the steering angle of the steering wheel 13 can be reduced, and the turning can be performed. Since the turning angle of the front wheel 2 by the motor 9 catches up with the estimated turning angle θe, it is possible to suppress an increase in deviation between the estimated turning angle θe and the actual turning angle θa. Therefore, an increase in the second steering reaction force TH2 calculated according to the deviation between the estimated turning angle θe and the actual turning angle θa can be suppressed, and as a result, the steering reaction applied to the driver is suppressed. Since the force is decreased and the turning amount increases according to the increase of the steering amount and the steering reaction force, it is possible to suppress the uncomfortable feeling given to the driver.

[Other examples]
The best mode for carrying out the present invention has been described based on the first embodiment. However, the specific configuration of the present invention is not limited to the first embodiment and does not depart from the gist of the present invention. Any change in the design of the range is included in the present invention.

  In Example 1, the additional reaction force TH3 is calculated based on the differential of the deviation between the estimated turning angle θe and the actual turning angle θa. However, when there is no response delay in the steering motor 9 or a response delay that can be ignored, the calculation of the additional reaction force TH3 is performed to differentiate the deviation between the target turning angle θt and the actual turning angle θa. You may make it calculate based on.

  The steering wheel 13 corresponds to the steering section of the present invention, the front wheel 2 corresponds to the steered wheel of the present invention, the steering motor 9 corresponds to the steering actuator of the present invention, and the steering shaft motor 8 corresponds to the steering wheel of the present invention. The turning motor rotation angle sensor 10 corresponds to a reaction angle actuator, the turning angle detection means of the present invention, and the first electronic control unit 14a and the second electronic control unit 14b are target turning angle calculation means of the invention. The third electronic control unit 14c corresponds to the steering reaction force calculation means of the present invention.

1 is an overall configuration diagram of a vehicle to which a vehicle steering apparatus according to a first embodiment is applied. 3 is a flowchart illustrating a flow of control processing of the steering shaft motor according to the first embodiment. 3 is a graph showing the rise of rack axial force in Example 1. It is a graph which shows the standup of the deviation of the presumed turning angle and the actual turning angle of Example 1. 3 is a map of weighting factors K and C according to the first embodiment. 3 is a time chart illustrating the operation of the first embodiment. 3 is a time chart illustrating the operation of the first embodiment.

Explanation of symbols

2 Front wheels (steering wheels)
9a, 9b Steering motor (steering actuator)
8 Steering shaft motor (steering shaft actuator)
10a, 10b Steering motor rotation angle sensor (steering angle detection means)
13 Steering (operation part)
14a First electronic control unit (target turning angle calculation means, turning angle control means)
14b Second electronic control unit (target turning angle calculation means, turning angle control means)
14c Third electronic control unit (steering reaction force calculation means)
18 Steering shaft

Claims (9)

A steering unit that the driver steers,
A steering actuator for steering steered wheels mechanically separated from the steering unit;
A turning angle detection means for detecting an actual turning angle that is an actual turning angle of the steered wheel;
Target turning angle calculating means for calculating a target turning angle of the steered wheel according to a steering angle of the steering unit;
Turning angle control means for controlling the turning actuator so that the turning angle of the steered wheel becomes the target turning angle;
Steering reaction force calculating means for calculating a steering reaction force applied to the steering unit;
A reaction force actuator for applying a steering reaction force to the steering unit based on the steering reaction force calculated by the steering reaction force calculation means;
With
The steering reaction force calculating means includes:
Calculating an estimated turning angle that is an estimated value of the turning angle of the steered wheel based on a response delay of the turning angle with respect to the target turning angle;
Calculating a turning angle deviation which is a deviation between the calculated estimated turning angle and the actual turning angle detected by the turning angle detection means ;
Differentiating the steering angle deviation to calculate the change speed of the steering angle deviation,
When the sign of the turning angle deviation matches the sign of the change speed of the turning angle deviation, it is determined that the turning angle deviation is increased,
When the turning angle deviation increases, an additional reaction force that increases as the change speed of the turning angle deviation increases with respect to the steering reaction force when the turning angle deviation does not increase. A vehicle steering apparatus characterized by calculating a steering reaction force larger than that when the turning angle deviation is not increased by adding . In the vehicle steering device according to claim 1,
The vehicle steering apparatus, wherein the steering reaction force calculating means calculates the estimated turning angle of the steered wheel based on the target turning angle and a response delay of the turning actuator . The vehicle steering apparatus according to claim 1 or 2,
The steering reaction force calculating means calculates a change speed of the additional reaction force, and suppresses the change speed of the additional reaction force when the calculated change speed is larger than a predetermined change speed. A vehicle steering apparatus. An apparatus as claimed in any one of claims 1 to claim 3,
The vehicle steering apparatus according to claim 1, wherein the steering reaction force calculation means limits the additional reaction force to a predetermined value or less . The vehicle steering apparatus according to any one of claims 1 to 4, wherein:
The steering reaction force calculation means sets the additional reaction force to zero when the sign of the deviation between the target turning angle and the actual turning angle is not the same as the sign of the turning angle deviation. A vehicle steering apparatus characterized by the above. In the vehicle steering apparatus according to any one of claims 1 to 5,
The steering reaction force calculation means calculates a steering reaction force based on a vehicle state, a driver's steering state, and the turning angle deviation when the turning angle deviation does not increase, and the turning angle When the deviation increases , the vehicle steering apparatus is characterized in that the additional reaction force is added to the steering reaction force . The vehicular steering apparatus according to according to 請 Motomeko 6,
The vehicle state is a tire lateral force, a steering motor torque, a vehicle yaw rate, and a vehicle lateral acceleration, and a driver's steering state is a steering angle, a steering angular velocity, and a steering angular acceleration. . A steering unit that the driver steers,
A steering actuator for steering steered wheels mechanically separated from the steering unit;
A turning angle detection means for detecting an actual turning angle that is an actual turning angle of the steered wheel;
Target turning angle calculating means for calculating a target turning angle of the steered wheel according to a steering angle of the steering unit;
Turning angle control means for controlling the turning actuator so that the turning angle of the steered wheel becomes the target turning angle;
Steering reaction force calculating means for calculating a steering reaction force applied to the steering unit;
A reaction force actuator for applying a steering reaction force to the steering unit based on the steering reaction force calculated by the steering reaction force calculation means;
With
The steering reaction force calculating means includes:
Calculating an estimated turning angle that is an estimated value of the turning angle of the steered wheel based on a response delay of the turning angle with respect to the target turning angle;
Calculate the calculated estimated turning angle,
Differentiating the steering angle deviation to calculate the change speed of the steering angle deviation,
When the sign of the turning angle deviation matches the sign of the change speed of the turning angle deviation, it is determined that the turning angle deviation is increased,
When the turning angle deviation increases, an additional reaction force that increases as the change speed of the turning angle deviation increases with respect to the steering reaction force when the turning angle deviation does not increase. A vehicle with a steering device for a vehicle , wherein a steering reaction force larger than that when the turning angle deviation is not increased is calculated by addition . A steering actuator for steering steered wheels mechanically separated from a steering unit operated by a driver;
A turning angle detection means for detecting an actual turning angle that is an actual turning angle of the steered wheel;
A reaction force actuator for applying a steering reaction force to the steering unit based on the steering reaction force calculated by the steering reaction force calculation means;
Have
A target turning angle of the steered wheel is calculated according to a steering angle of the steering unit,
Controlling the steering actuator so that the steering angle of the steered wheel becomes the target steering angle;
A steering reaction force applied to the steering unit is calculated;
Calculating an estimated turning angle that is an estimated value of the turning angle of the steered wheel based on a response delay of the turning angle with respect to the target turning angle;
Calculating a turning angle deviation which is a deviation between the calculated estimated turning angle and the actual turning angle detected by the turning angle detection means;
Differentiating the steering angle deviation to calculate the change speed of the steering angle deviation,
When the sign of the turning angle deviation matches the sign of the change speed of the turning angle deviation, it is determined that the turning angle deviation is increased,
When the turning angle deviation increases, an additional reaction force that increases as the change speed of the turning angle deviation increases with respect to the steering reaction force when the turning angle deviation does not increase. A vehicle steering method characterized by calculating a steering reaction force larger than that when the turning angle deviation is not increased by adding .

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