JP2005289291A - Steering control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering control device preventing a steering load from becoming lighter than required even when the steering direction and the yaw angle of the vehicle laterally invert, such as in high speed repeated inverting steering. <P>SOLUTION: The steering control device comprises: a yaw rate estimating means for estimating and detecting the yaw rate generated in a vehicle; and a yaw rate suppression control means for controlling the actuator in the direction for suppressing the yaw rate estimated by the yaw rate estimating means. The steering control device comprises: a steering direction detecting means for detecting the steering direction of a driver; a comparing means for comparing the yaw rate direction estimated by the yaw rate estimating means with the steering direction detected by the steering direction detecting means; and a yaw rate suppression control prohibiting means for prohibiting the yaw rate suppression control by the yaw rate suppression control means when the comparing means determines that the yaw rate direction is different from the steering direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vehicle steering control device that generates an auxiliary steering torque by an electric motor.

Conventionally, in a vehicle steering device, the vehicle yaw rate is measured, and the steering device is controlled in accordance with the yaw rate, thereby stabilizing the behavior of the vehicle and reducing the burden of the driver's steering operation. (For example, refer to Patent Document 1).
JP-A-11-147483 (see FIG. 7).

  However, the above-described vehicle steering control has the following problems. When the driver intentionally performs high-speed repeated turning, the steering feeling may be deteriorated by the traveling stability control. In particular, when the steering direction and the yaw rate of the vehicle are reversed left and right, the traveling stability control tries to generate a steering assist force in the direction opposite to the yaw rate, but the direction of the steering assist force is determined by the driver. Since it coincides with the steering direction, there is a problem that the steering load becomes lighter than necessary.

  The present invention has been made paying attention to the above problem, and even when the steering direction and the yaw rate of the vehicle are reversed left and right, such as during high-speed repetitive turning, the steering load becomes lighter than necessary. An object of the present invention is to provide a steering control device that can prevent the above-described problem.

  To achieve the above object, according to the present invention, a steering input means, an actuator for turning a steered wheel based on a steering amount inputted by the steering input means, and a yaw rate estimating means for estimating or detecting a yaw rate generated in a vehicle. And a yaw rate suppression control means for controlling the actuator in a direction to suppress the yaw rate estimated by the yaw rate estimation means. A steering direction detection means for detecting the steering direction of the driver, and a yaw rate estimation means The comparison means for comparing the yaw rate direction estimated by the steering direction and the steering direction detected by the steering direction detection means, and when the comparison means determines that the yaw rate direction and the steering direction are different, the yaw rate by the yaw rate suppression control means Yaw rate suppression control prohibiting means for prohibiting suppression control; It was decided to have.

  Therefore, in a situation where the steering assist direction of the yaw rate suppression control coincides with the steering operation direction of the driver, prohibiting the yaw rate suppression control can prevent the steering load from becoming lighter than necessary. .

  Hereinafter, the best mode for realizing the steering control device of the present invention will be described based on Examples 1 to 3 shown in the drawings.

[Configuration of steering control device]
FIG. 1 is a system configuration diagram of the steering control device according to the first embodiment. A vehicle equipped with a steering control device includes a steering wheel 101 (steering input means), a torque sensor 102, a camera 103 (yaw rate estimating means), an image processing control unit 104 (hereinafter referred to as an image processing ECU 104), and Steering angular velocity detector 105 (steering direction detector), electric power steering control unit 106 (hereinafter referred to as electric power steering ECU 106), drive control circuit 107, actuator 108, rack unit 109, and vehicle speed sensor 110 And a relative yaw rate control unit 200 (hereinafter referred to as a relative yaw rate ECU 200).

  Torque sensor 102 detects the steering torque by the driver, and outputs the detected torque value to relative yaw rate ECU 200. The camera 103 captures an image outside the vehicle, and outputs the captured image to the relative yaw rate ECU 200 via the image processing ECU 104. Further, the steering angular velocity detection unit 105 outputs the steering angular velocity ω to the relative yaw rate ECU 200 via the electric power steering ECU 106.

  The relative yaw rate ECU 200 calculates a relative yaw rate from the above-described torque value, imaging, steering angular velocity ω, and vehicle speed Vx detected by the vehicle speed sensor 110, and based on this relative yaw rate, drive control is performed so that the stable steering amount is obtained. A command is issued to the circuit 107. Based on this command, the drive control circuit 107 drives the actuator 108. The relative yaw rate is a relative yaw rate of the vehicle with respect to the detected target. Hereinafter, with respect to what is described as a yaw rate, this relative yaw rate is indicated unless otherwise specified.

[Control block diagram of steering control device]
FIG. 2 is a diagram illustrating a control block in the steering control device. The relative yaw rate ECU 200 includes a yaw rate calculation unit 201, a direction comparison unit 202 (comparison unit), a yaw rate suppression prohibition determination unit 203 (yaw rate suppression control prohibition unit), and a yaw rate suppression unit 204 (yaw rate suppression control unit).

  The yaw rate calculation unit 201 receives the steering torque, the vehicle speed Vx, and the imaging from the torque sensor 102, the vehicle speed sensor 110, and the camera 103, calculates the relative yaw rate φ ′, and inputs the relative yaw rate φ ′ to the direction comparison unit 202 and the yaw rate suppression unit 204.

  The direction comparison unit 202 receives the steering angular velocity ω and the relative yaw rate φ ′ from the steering angular velocity detection unit 105 and the yaw rate calculation unit 201, and determines whether the detected steering direction or the relative yaw rate φ ′ is the left or right rotation direction. The detection result, the steering angular velocity ω, and the relative yaw rate φ ′ are output to the yaw rate suppression prohibition determination unit 203.

  The yaw rate suppression prohibition determination unit 203 determines whether to prohibit yaw rate suppression control according to outputs from the steering angular velocity detection unit 105, the torque sensor 102, and the direction comparison unit 202, and inputs the determination result to the yaw rate suppression unit 204. To do. The yaw rate suppression prohibition determination unit 203 includes a counter 203a, and the absolute value of the steering angular velocity ω is smaller than the predetermined value ω_en for determining the yaw rate suppression prohibition, and the absolute value of the yaw rate φ ′ is the predetermined value for determining the yaw rate suppression prohibition. Measure the time after becoming smaller than Y_en.

  The yaw rate suppression unit 204 outputs a command S to the drive control circuit 107 so that the yaw rate becomes a desired value in accordance with outputs from the yaw rate suppression prohibition determination unit 203, the electric power steering ECU 106, and the yaw rate calculation unit 201. In response to this command, the drive control circuit 107 drives the actuator 108.

[Control block diagram in yaw rate calculation unit]
FIG. 3 is a block diagram showing a configuration in the yaw rate calculation unit 201. The yaw rate calculation unit 201 includes a lateral displacement amount detection unit 201a, a differentiator 201b, a pseudo-differential filter 201c, and a control gain unit 201d, and estimates and estimates the relative yaw rate by filtering based on the detected lateral displacement amount. Based on the relative yaw rate signal, a relative yaw rate φ ′ that is a stable direction steering amount in which the vehicle is in a stable direction is output.

  The lateral displacement amount detection unit 201a detects the lateral displacement amount Y between the estimated position of the host vehicle at a predetermined forward distance L and a target object (for example, a white line) based on imaging information from the image processing ECU 104. Output to the differentiator 201b. The differentiator 201b differentiates the detected lateral displacement amount Y and outputs it to the pseudo-differential filter 201c. The pseudo differential filter 201c extracts the relative yaw rate from the predetermined forward distance L and the vehicle speed, and outputs the relative yaw rate to the control gain unit 201d. The control gain unit 201d gives a control gain in a direction to cancel the relative yaw rate extracted by the pseudo differential filter 201c, and outputs a relative yaw rate φ ′ that is a stable direction steering amount.

[Explanation of relative yaw rate]
Here, the relative yaw rate φ ′ will be described. The relative yaw rate is a relative yaw rate of the vehicle with respect to the detected target, and is a yaw rate that cancels the yaw rate change caused by the curvature of the curve. FIG. 4 is a diagram showing the principle of relative yaw rate estimation. As described above, the reference to the yaw rate refers to this relative yaw rate unless otherwise specified.

  In the first embodiment, the host vehicle travels along the white line on the road, and calculates the amount of lateral displacement from the white line.

The white line on the road which is the target object is recognized from the captured image of the camera 103. Next, each parameter at a certain point is as follows.
Yaw rate: ψ '
Initial yaw angle: ψ
Vehicle speed: Vx
Estimated lateral displacement from the white line at a predetermined distance L as seen from the camera image: Y
Lateral displacement at a predetermined forward distance L when the yaw rate is 0: Y0
Amount of deviation at a predetermined forward distance L due to the occurrence of yaw rate: Y1

At this time, the following relational expression is established.
(Formula 1)
Y = Lψ + ∫Vx ・ ψ ・ dt

When the above (Formula 1) is Laplace transformed, the following (Formula 2) is obtained.
(Formula 2)
YS = (LS + Vx) ψ

Since the yaw rate ψ ′ is the rate of change of the yaw angle, the relative yaw rate with respect to the white line is expressed by the following (formula 3).
ψ '= ψS = {S / (LS + Vx)} · YS
From Equation 3, YS corresponds to the differentiator 201b that differentiates the input estimated lateral displacement, and {S / (LS + Vx)} corresponds to the pseudo-differential filter 201c.

  For the estimated relative yaw rate ψS, the control gain unit 201d gives a control gain in a direction to cancel the relative yaw rate ψS, and determines a stable direction steering amount.

In general, the detection capability of a yaw rate sensor installed in an existing vehicle is
Resolution> several deg / S (at least greater than 1 deg / S)
Temperature drift at zero point> several deg / S (at least greater than 1 deg / S)
It is said that.

In contrast, the detection capability in the relative yaw rate estimation of the present invention is:
Resolution> 0.06deg / S
Temperature drift at zero point It is basically possible to achieve no drift. That is, since the calculation is performed based on the captured image of the camera 103, the resolution can be determined by the level of the number of pixels of the camera 103. In particular, since detection is based on position information based on an image, there is no influence of temperature, and stable detection accuracy is ensured.

[Yaw rate suppression control processing when the steering direction and the yaw rate direction are different]
FIG. 5 is a flowchart showing the flow of yaw rate suppression control processing when the steering direction and the yaw rate direction are different. Hereinafter, each step will be described.

  In step S101, the direction comparison unit 202 reads the steering angular velocity ω and the yaw rate φ ′, and proceeds to step S102.

  In step S102, the direction comparison unit 202 determines whether or not the directions of the steering angular velocity ω and the yaw rate φ ′ are inconsistent. If YES, the process proceeds to step S103, and if NO, the process proceeds to step S106.

  In step S103, the yaw rate suppression prohibition determination unit 203 determines whether the absolute value of the steering angular velocity ω exceeds the predetermined value ω_Inh for yaw rate suppression prohibition determination. If YES, the process proceeds to step S104. The process proceeds to S106.

  In step S104, it is determined in the yaw rate suppression prohibition determination unit 203 whether or not the absolute value of the yaw rate φ 'exceeds the predetermined value Y_Inh for yaw rate suppression prohibition determination. If YES, the process proceeds to step S105. The process proceeds to S106.

  In step S105, the yaw rate suppression prohibition determination unit 203 sets the yaw rate suppression prohibition flag Fen to 1, sets the counter value of the counter 203a to 0, and proceeds to step S111.

  In step S106, it is determined whether the absolute value of the steering angular velocity ω is less than the predetermined value ω_en for yaw rate suppression prohibition release determination. If YES, the process proceeds to step S107, and if NO, the process proceeds to step S111.

  In step S107, it is determined whether or not the absolute value of yaw rate φ ′ is less than the predetermined value Y_en for determining yaw rate suppression prohibition release. If YES, the process proceeds to step S108, and if NO, the process proceeds to step S111.

  In step S108, it is determined whether the measurement time by the counter 203a is less than the predetermined value T_en for yaw rate suppression prohibition release determination. If YES, the process proceeds to step S109, and if NO, the process proceeds to step S110.

  In step S109, the value of the counter 203a is incremented, and the process proceeds to step S111.

  In step S110, the yaw rate suppression prohibition determination unit 203 sets the yaw rate suppression prohibition flag Fen to 0, and the process proceeds to step S111.

  In step S111, the yaw rate suppression unit 204 reads the value of yaw rate φ ′, and the process proceeds to step S112.

  In step S112, the yaw rate suppression unit 204 determines whether the value of the yaw rate prohibition flag Fen is 1. If YES, the process proceeds to step S113, and if NO, the process proceeds to step S114.

  In step S113, the yaw rate suppression unit 204 determines that the yaw rate suppression control prohibition mode is set, and the yaw rate suppression control amount S is set to 0, and the process ends.

  In step S114, the yaw rate suppression unit 204 determines that the yaw rate suppression control prohibit mode is not in effect, and multiplies the yaw rate φ ′ by a predetermined value K and a value obtained by multiplying the yaw rate φ ′ by the minus value to make the yaw rate φ ′ in the opposite direction. Exit as S.

[Yaw rate suppression control action when the steering direction and the yaw rate direction are different]
(1) The direction of the steering angular velocity ω and the yaw rate φ ′ are inconsistent, the absolute value of the steering angular velocity ω exceeds the predetermined value ω_Inh for yaw rate suppression prohibition determination, and the absolute value of the yaw rate φ ′ is the predetermined value for determination of yaw rate suppression prohibition When all the conditions of exceeding Y_Inh are satisfied, the yaw rate suppression control prohibit mode is set.

  (2) Any one of the conditions in (1) is not satisfied, the absolute value of the steering angular velocity ω is less than the predetermined value ω_en for determining the yaw rate suppression prohibition cancellation, and the absolute value of the yaw rate φ ′ is for determining the yaw rate suppression prohibition cancellation If all the conditions that the value of the counter 203a is less than the predetermined value Y_en and the value of the counter 203a is less than the predetermined value T_en for determining the yaw rate suppression prohibition release are satisfied, the yaw rate suppression prohibition and the prohibition release are not performed, and the previous state is maintained.

  (3) When neither of (1) and (2) is met, the yaw rate suppression prohibition is canceled and the normal yaw rate suppression mode is set.

[Time-dependent change in yaw rate suppression control action]
FIG. 6 is a diagram illustrating a time chart when the yaw rate suppression control is performed when the steering direction and the yaw rate direction are different. First, at time t ₀ , since the steering angular velocity ω and the yaw rate φ ′ exceed the prohibition determination values and the directions do not match, the yaw rate suppression prohibition flag Fen is set to 1 in step S105.

Near the times t ₁ , t ₂ , and t ₃ , the steering angular velocity ω and the yaw rate φ ′ are within the yaw rate suppression control prohibition release determination values ω_en and Y_en, respectively. However, since the steering angular velocity ω and the yaw rate φ ′ exceed the prohibition determination values ω_Inh and Y_Inh before the measurement time reaches the release determination value T_en, the release determination is not performed. At times t _{4 to} t ₅ , since there are regions where the steering angular velocity ω and the yaw rate φ ′ exceed the yaw rate suppression control prohibition release determination values ω_en and Y_en, the yaw rate suppression control prohibition state continues.

After time t ₅ in the steering angular velocity ω and the yaw rate phi 'values each yaw rate suppression control cancellation determination value Omega_en, becomes a value within Y_en, the value of the counter 203a is led to cancellation determination value, the release determination flag Fen in step S110 0 The yaw rate suppression control is canceled.

[Steering control in the conventional example]
FIG. 7 is a time chart showing the yaw rate control in the conventional example. When the driver performs repeated continuous steering, the steering angular velocity when the yaw rate suppression control is performed is indicated by a broken line, and the steering angular velocity when the yaw rate suppression control is not performed is indicated by a solid line.

When the driver performs an iterative continuous steering, the yaw rate is generated at time t _0. Since the yaw rate is generated with a time delay with respect to the steering angular speed, depending on the operation pattern is when the direction of the direction and yaw rate of the steering angular velocity is thus totally a reverse direction as indicated by t ₀ ~t _1.

  At this time, when the yaw rate suppression control in the conventional example is executed, in order to cancel the yaw rate, a command is issued to the steering actuator to output in the direction opposite to the yaw rate. However, since the steering angular velocity and the yaw rate direction are opposite to each other at this time, the output direction of the steering actuator and the steering angular velocity direction coincide with each other, and the steering angular velocity is increased by the output of the steering actuator as shown by the broken line. Become.

  As described above, if the yaw rate suppression control is executed when the steering angular velocity and the yaw rate direction are different, the steering angular velocity increases, the load on the steering wheel operation becomes lighter than necessary, and the steering feeling deteriorates. There was a problem.

  On the other hand, in the steering control device of the embodiment of the present application, the direction comparison unit 202 that compares the direction of the yaw rate φ ′ and the steering angular velocity ω determines that the direction of the yaw rate φ ′ and the steering angular velocity ω are different, and the yaw rate When the suppression prohibition determining unit 203 determines that the absolute value of the steering angular velocity ω is greater than the predetermined value ω_Inh for yaw rate suppression prohibition determination and the absolute value of the yaw rate φ ′ is greater than the predetermined value Y_Inh for yaw rate suppression prohibition determination, the yaw rate By prohibiting the suppression control, it is possible to prevent the steering load from becoming lighter than necessary, and to prevent deterioration of the steering feeling (corresponding to claim 1).

  Next, a second embodiment will be described with reference to FIGS. Since the basic configuration of the steering control device is the same as that of the first embodiment, only different points will be described. In the first embodiment, the yaw rate suppression is prohibited or canceled by the mismatch between the steering angular velocity ω and the yaw rate φ ′, or the values of the steering angular velocity ω and the yaw rate φ ′. In the second embodiment, the yaw rate suppression is performed by the steering torque Td. Prohibit and release. Further, the counter 203a measures the time after the absolute value of the steering torque Td becomes within the predetermined value Td_en for yaw rate suppression prohibition determination.

[Yaw rate suppression control processing based on steering torque value]
FIG. 8 is a flowchart showing the flow of yaw rate suppression control processing based on the steering torque value. Hereinafter, each step will be described.

  In step S201, the value of the steering torque Td is read from the torque sensor 102, and the process proceeds to step S202.

  In step S202, the yaw rate suppression prohibition determination unit 203 determines whether or not the absolute value of the steering torque Td exceeds the predetermined value Td_Inh for yaw rate suppression prohibition determination. If YES, the process proceeds to step S203. The process proceeds to S204.

  In step S203, the yaw rate suppression prohibition determination unit 203 sets the yaw rate suppression prohibition flag Fen to 1, sets the counter value of the counter 203a to 0, and proceeds to step S111.

  In step S204, it is determined whether or not the absolute value of the steering torque Td is less than the predetermined value Td_en for yaw rate suppression prohibition release determination. If YES, the process proceeds to step S205, and if NO, the process proceeds to step S111.

  In step S205, it is determined whether the value of the counter 203a is less than the predetermined value T_en for yaw rate suppression prohibition release determination. If YES, the process proceeds to step S206, and if NO, the process proceeds to step S207.

  In step S206, the value of the counter 203a is incremented, and the process proceeds to step S111.

  In step S207, the yaw rate suppression prohibition determination unit 203 sets the yaw rate suppression prohibition flag Fen to 0, and the process proceeds to step S111.

  In step S111, the yaw rate suppression unit 204 reads the value of yaw rate φ ′, and the process proceeds to step S112.

  In step S112, the yaw rate suppression unit 204 determines whether the value of the yaw rate prohibition flag Fen is 1. If YES, the process proceeds to step S113, and if NO, the process proceeds to step S114.

  In step S113, the yaw rate suppression unit 204 determines that the yaw rate suppression control prohibition mode is set, and the yaw rate suppression control amount S is set to 0, and the process ends.

  In step S114, the yaw rate suppression unit 204 determines that the yaw rate suppression control prohibit mode is not in effect, and multiplies the yaw rate φ ′ by a predetermined value K and a value obtained by multiplying the yaw rate φ ′ by the minus value to make the yaw rate φ ′ in the opposite direction. Exit as S.

[Yaw rate suppression control action by steering torque value]
(1) When the absolute value of the steering torque Td exceeds the predetermined value Td_Inh for yaw rate suppression prohibition determination, the yaw rate suppression control prohibit mode is set.

  (2) The condition of (1) is not satisfied, the absolute value of the steering torque Td is less than the predetermined value Td_en for yaw rate suppression prohibition release determination, and the value of the counter 203a is less than the predetermined value T_en for determination of yaw rate suppression prohibition release If all the conditions are satisfied, the yaw rate suppression prohibition and prohibition release are not performed, and the previous state is maintained.

  (3) When neither of (1) and (2) is met, the yaw rate suppression prohibition is canceled and the normal yaw rate suppression mode is set.

[Time-dependent change in yaw rate suppression control by steering torque value]
FIG. 9 is a diagram illustrating a time chart when the yaw rate suppression control based on the steering torque value is performed. First, since the steering torque value Td exceeds the prohibition determination value at time t ₀ , the yaw rate suppression prohibition flag Fen is set to 1 in step S203.

Near the times t ₁ , t ₂ , and t ₃ , the steering torque value Td is within the yaw rate suppression control prohibition release determination value, and the time measurement after the time is within the prohibition release determination value is started by the counter 203a. Since the steering torque value Td exceeds the prohibition determination value Td_Inh before reaching the cancellation determination value T_en, the cancellation determination is not performed. Also since the region where the steering torque value Td exceeds the yaw rate suppression control prohibiting cancellation determination value Td_en exists, yaw rate suppression control prohibition state continues at time t ₄ ~t _5.

Steering torque Td is a value within the yaw rate suppression control cancellation determination value at after time t _5, the counter 203a reaches the the cancellation determination value, is cleared to release determination flag Fen is 0 at step S110, the yaw rate suppression control release Is done.

[Effect of yaw rate suppression control by steering torque value]
When the steering torque exceeds a predetermined value, the yaw rate suppression control prohibit mode is set. As a result, if the normal steering torque by the driver is set lower than a predetermined value, the yaw rate suppression control can be prohibited during the normal steering by the driver, the driving steering is not hindered, and deterioration of the steering feeling is avoided. can do.

  Next, a third embodiment will be described with reference to FIGS. Since the basic configuration of the steering control device is the same as that of the first embodiment, only different points will be described. In the third embodiment, the yaw rate suppression is prohibited and canceled by the change speed Tdv of the steering torque Td. The method for calculating the change speed is not particularly limited. It may be a differential value, or may be a difference between the previous value and the current value in digital sampling. Further, the counter 203a measures the time after the absolute value of the steering torque change speed Tdv becomes within the predetermined value Tdv_en for yaw rate suppression prohibition determination.

[Yaw rate suppression control process based on steering torque change speed]
FIG. 10 is a flowchart showing the flow of yaw rate suppression control processing based on the steering torque value. Hereinafter, each step will be described.

  In step S301, the value of the steering torque Td is read from the torque sensor 102, and the process proceeds to step S202.

  In step S302, the value of the steering torque change speed Tdv is calculated, and the process proceeds to step S303.

  In step S303, the yaw rate suppression prohibition determination unit 203 determines whether or not the absolute value of the steering torque change speed Tdv exceeds the predetermined value Tdv_Inh for yaw rate suppression prohibition determination. If YES, the process proceeds to step S304, and NO. If so, the process proceeds to step S305.

  In step S304, the yaw rate suppression prohibition determination unit 203 sets the yaw rate suppression prohibition flag Fen to 1, sets the counter value of the counter 203a to 0, and proceeds to step S111.

  In step S305, it is determined whether the absolute value of the steering torque change speed Tdv is less than a predetermined value Tdv_en for determining yaw rate suppression prohibition release. If YES, the process proceeds to step S306, and if NO, the process proceeds to step S111. .

  In step S306, it is determined whether or not the value of the counter 203a is less than the predetermined value T_en for yaw rate suppression prohibition release determination. If YES, the process proceeds to step S307, and if NO, the process proceeds to step S308.

  In step S307, the value of the counter 203a is incremented, and the process proceeds to step S111.

  In step S308, the yaw rate suppression prohibition determination unit 203 sets the yaw rate suppression prohibition flag Fen to 0, and the process proceeds to step S111.

  In step S111, the yaw rate suppression unit 204 reads the value of yaw rate φ ′, and the process proceeds to step S112.

  In step S112, the yaw rate suppression unit 204 determines whether the value of the yaw rate prohibition flag Fen is 1. If YES, the process proceeds to step S113, and if NO, the process proceeds to step S114.

  In step S113, the yaw rate suppression unit 204 determines that the yaw rate suppression control prohibition mode is set, and the yaw rate suppression control amount S is set to 0, and the process ends.

  In step S114, the yaw rate suppression unit 204 determines that the yaw rate suppression control prohibit mode is not in effect, and multiplies the yaw rate φ ′ by a predetermined value K and a value obtained by multiplying the yaw rate φ ′ by the minus value to make the yaw rate φ ′ in the opposite direction. Exit as S.

[Yaw Rate Suppression Control Action by Steering Torque Change Speed]
(1) When the absolute value of the steering torque change speed Tdv exceeds the predetermined value Tdv_Inh for yaw rate suppression prohibition determination, the yaw rate suppression control prohibit mode is set.

  (2) The condition of (1) is not satisfied, the absolute value of the steering torque change speed Tdv is less than the predetermined value Tdv_en for the yaw rate suppression prohibition release determination, and the value of the counter 203a is less than the predetermined value T_en for the yaw rate suppression prohibition release determination When all the conditions are satisfied, the yaw rate suppression prohibition and the prohibition release are not performed, and the previous state is maintained.

  (3) When neither of (1) and (2) is met, the yaw rate suppression prohibition is canceled and the normal yaw rate suppression mode is set.

[Time-dependent change in yaw rate suppression control based on steering torque change speed]
FIG. 11 is a diagram illustrating a time chart when the yaw rate suppression control based on the steering torque change speed is performed. First, since the steering torque change speed Tdv exceeds the prohibition determination value at time t ₀ , the yaw rate suppression prohibition flag Fen is set to 1 in step S203.

Near the times t ₁ , t ₂ , and t ₃ , the steering torque change speed Tdv is within the yaw rate suppression control prohibition release determination value, and the time measurement after the time is within the prohibition release determination value is started by the counter 203a. Since the steering torque value Tdv_Inh is exceeded before reaching the release determination value T_en, the release determination is not performed. Also since the region where the steering torque value Tdv is greater than the yaw rate suppression control prohibiting cancellation determination value Tdv_en exists, yaw rate suppression control prohibition state continues at time t ₄ ~t _5.

The value of the steering torque change rate Tdv becomes a value within the yaw rate suppression control cancellation determination value Tdv_en in after time t _5, the counter 203a reaches the the cancellation determination value, is cleared to release determination flag Fen is 0 at step S110, the yaw rate The suppression control is released.

[Effect of yaw rate suppression control by steering torque change speed]
When the steering torque change speed exceeds a predetermined value, the yaw rate suppression control prohibit mode is set. As a result, the normal steering torque change speed by the driver can be set lower than a predetermined value, and the yaw rate suppression control can be prohibited during normal steering by the driver. It can be avoided.

Further, technical ideas other than the claims that can be grasped from the respective embodiments will be described below together with the effects thereof.
(A) In the steering control device according to claim 1,
The steering control device further includes a steering torque detecting means for detecting a steering torque generated between the steering input means and the steering wheel,
The yaw rate suppression control means prohibits yaw rate suppression control when the steering torque detected by the steering torque detection means is greater than or equal to a predetermined value.

The yaw rate that occurs when the steering torque is greater than or equal to a predetermined value is likely due to the driver's steering operation. Therefore, the yaw rate suppression control does not hinder the steering operation by prohibiting the yaw rate suppression control. .
(B) In the steering control device according to claim 1,
The steering control device further includes a steering speed detecting means for detecting a steering speed by the steering input means,
The yaw rate suppression control prohibiting means is configured such that the steering speed detected by the steering speed detecting means is not less than a predetermined value, the yaw rate estimated by the yaw rate estimating means is not less than a predetermined value, and the yaw rate direction and the steering direction are compared by the comparing means. Is determined to be different, yaw rate suppression control is prohibited.

  In a situation where the steering speed and the yaw rate are low, matching and mismatching of the steering direction and the yaw rate direction are frequently repeated. When the execution and prohibition of the yaw rate suppression control are repeated in such a region, the control becomes complicated and the steering feeling may be deteriorated. Therefore, deterioration of the steering feeling can be prevented by switching execution / prohibition of the yaw rate suppression control only when the steering speed or the yaw rate is equal to or higher than a predetermined value.

1 is a system configuration diagram of a steering control device in Embodiment 1. FIG. It is a figure which shows the control block in the steering control apparatus of Example 1. FIG. FIG. 3 is a block diagram illustrating a configuration in a yaw rate calculation unit according to the first embodiment. It is a figure showing the relative yaw rate estimation principle in Example 1. FIG. 7 is a flowchart illustrating a flow of yaw rate suppression control processing when the steering direction and the yaw rate direction are different in the first embodiment. It is a figure which shows the time chart at the time of performing the yaw rate suppression control in case the steering direction in Example 1 differs from a yaw rate direction. It is a time chart which shows the yaw rate control in a prior art example. 12 is a flowchart illustrating a flow of yaw rate suppression control processing based on a steering torque value in the second embodiment. 6 is a time chart when performing yaw rate suppression control based on a steering torque value in the second embodiment. 12 is a flowchart illustrating a flow of yaw rate suppression control processing based on a steering torque value in the third embodiment. It is a figure which shows the time chart at the time of performing the yaw rate suppression control by the steering torque change speed in Example 3. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Steering wheel 102 Torque sensor 103 Camera 104 Image processing control unit 105 Steering angular velocity detection part 106 Electric power steering control unit 107 Drive control circuit 108 Actuator 109 Rack unit 110 Vehicle speed sensor 200 Relative yaw rate control control unit 201 Yaw rate calculating part 201a Lateral displacement amount Detection unit 201b Differentiator 201c Pseudo-differential filter 201d Control gain unit 202 Direction comparison unit 203 Yaw rate suppression prohibition determination unit 203a Counter 204 Yaw rate suppression unit

Claims (1)

Steering input means;
An actuator for turning the steered wheel based on the steering amount input by the steering input means;
Yaw rate estimating means for estimating or detecting the yaw rate generated in the vehicle;
Yaw rate suppression control means for controlling the actuator in a direction to suppress the yaw rate estimated by the yaw rate estimation means;
In a steering control device having
Steering direction detecting means for detecting the steering direction of the driver;
Comparing means for comparing the direction of the yaw rate estimated by the yaw rate estimating means and the steering direction detected by the steering direction detecting means;
When the comparison means determines that the yaw rate direction and the steering direction are different, the yaw rate suppression control prohibiting means for prohibiting the yaw rate suppression control by the yaw rate suppression control means;
A steering control device comprising:

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