JP3433418B2 - Vehicle steering control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set preferable transmission ratio under the condition where antilock braking system(ABS) is operated by turning wheels according to steering, setting a transmission ratio between steering amount and turning amount in accordance with the running condition of the vehicle, and by prohibiting change of the transmission ratio while the wheels are controlled by ABS. SOLUTION: In this unit, an input shaft 20 and an output shaft 40 are connected via a transmission ratio variable mechanism 30. The input shaft 20 is connected to a steering wheel 10, and the output shaft 40 is connected to a rack shaft 51 via a rack and pinion-type gear unit 50. Wheels FW1, FW2 are connected to the both ends of the rack shaft 51. Driving of the transmission ratio variable mechanism 30 is controlled by a steering control unit 70. In addition to each of the detection signals, an input angle sensor 21, an output angle sensor 41, and a vehicle speed sensor 61, a signal indicating the operating condition of ABS is given to the steering control unit 70, from an ABS controller 62 for controlling braking fluid pressure so that the wheel will not lock while braking. Driving of the transmission ratio variable mechanism 30 is controlled with the transmission ratio as set with the above signals.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle steering control device capable of changing a transmission ratio between a steering amount of a steering wheel and a turning amount of wheels.

[0002]

2. Description of the Related Art Conventionally, there has been known a vehicle steering control device provided with a transmission ratio variable mechanism capable of changing a transmission ratio between a steering amount of a steering wheel and a steering amount of wheels. In general,
The higher the vehicle speed, the slower the transmission ratio (the steering amount with respect to the steering amount decreases). For example, in Japanese Patent Laid-Open No. 63-227470, when g (acceleration, deceleration) in the front-rear direction of the vehicle is detected, the basic transmission ratio set according to the vehicle speed is shifted to the slower side,
It improves running stability during sudden acceleration and prevents the occurrence of entrainment during sudden deceleration.

[0003]

However, when the transmission ratio is changed according to the acceleration / deceleration applied to the vehicle in this way, for example, an antilock brake system (hereinafter referred to as an antilock brake system) for controlling the brake pressure so that the wheels are not locked during braking. , AB
Even under a unique situation in which (S) operates, the transmission ratio is changed as in the normal deceleration, and there is a case where a suitable transmission ratio is not set according to the situation.

Therefore, the present invention has been made to solve such a problem, and an object of the present invention is to provide a vehicle steering control capable of setting a suitable transmission ratio under a situation where the ABS operates. To provide a device.

[0005]

Therefore, a vehicle steering control device according to a first aspect of the present invention is a vehicle steering control device that steers wheels according to a steering operation.
Transmission ratio setting means for setting a transmission ratio between the steering amount and the turning amount, an antilock control means for performing antilock control of wheels, and a change of the transmission ratio is prohibited during operation of the antilock control means. Prohibition means and anti-lock control hand
The transmission ratio during the operation of the gear is set to the operation opening of the antilock control means.
It is characterized in that it is fixed to the initial transmission ratio .

Since the change of the transmission ratio is prohibited by the prohibiting means during the operation of the anti-lock control means, the wheel is steered regardless of the driver's intention to steer with the change of the transmission ratio during deceleration. Is avoided, and it becomes easier to perform correction steering when the vehicle behavior changes during deceleration.

A vehicle steering control device according to a second aspect of the present invention is a vehicle steering control device that steers wheels according to steering, and the steering amount and the steering amount are changed according to a running state of the vehicle. a transmission ratio setting means for setting a transmission ratio between the anti-lock control means for performing an anti-lock control of the wheel, Anne
When the chill lock control means is operating
Antilock the transmission ratio set by the transmission ratio setting means
And a changing means for changing the value to a value higher than the transmission ratio when the control means is not operating . A vehicle according to claim 3
The steering control device for a vehicle is a vehicle that steers wheels according to steering.
Steering control device for a vehicle according to the running condition of the vehicle.
Ratio setting means for setting a transfer ratio between the steering amount and the steering amount
And an anti-lock system that implements anti-lock control for the wheels
When the control means and the anti-lock control means are operating,
If not, change the transfer ratio set by the transfer ratio setting means.
Lower than the transmission ratio when the anti-lock control means is not activated
And a changing means for changing. Further, claim 3
The vehicle steering control device according to the
A steering control device for a vehicle that steers the vehicle, the traveling state of the vehicle
Transmission that sets the transmission ratio between the steering amount and the steering amount according to
Ratio setting means and an anti-lock control for wheels.
When chill lock control means and anti lock control means are activated
In the case of the steering holding state, it is set by the transmission ratio setting means.
Equipped with changing means to change the transmission ratio to the previously set transmission ratio
Configure.

While the antilock control means is in operation, by shifting the transmission ratio set by the transmission ratio setting means to, for example, the slow side, changes in the vehicle behavior due to steering are suppressed, and vehicle stability is improved. To do. Conversely, shifting to the quick side improves steering response.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows the configuration of the steering system 100 according to the embodiment.

The input shaft 20 and the output shaft 40 are connected via a transmission ratio variable mechanism 30, and the steering handle 10 is connected to the input shaft 20. The output shaft 40 is connected to a rack shaft 51 via a rack and pinion type gear device 50, and wheels FW1 and FW1 are provided on both sides of the rack shaft 51.
FW2 is connected.

The input shaft 20 is provided with an input angle sensor 21 for detecting the steering position of the steering wheel 10, and the output shaft 4
0 is an output angle sensor 4 that detects the rotational position of the output shaft 40.
1 is provided. The rotation angle of the output shaft 40 is the rack shaft 5
1 and the stroke position of the rack shaft 51 corresponds to the turning angle of the wheels FW1 and FW2. Therefore, by detecting the rotation angle of the output shaft 40 by the output angle sensor 41, the wheels FW1 and FW2 are detected. The steering angle of is detected.

The variable transmission ratio mechanism 30 includes a steering handle 10.
Has a function of changing the transmission ratio G (G = steering angle / steering angle) between the steering angle of the vehicle and the turning angles of the wheels FW1 and FW2, and is an actuator 3 serving as a drive source for changing the transmission ratio.
1 is provided.

Driving control of the variable transmission ratio mechanism 30 is carried out by the steering control device 70. The steering control device 70 includes an ABS controller 6 that controls the brake fluid pressure so that the wheels are not locked during braking, in addition to the detection signals of the input angle sensor 21, the output angle sensor 41, and the vehicle speed sensor 61.
2 provides a signal indicating the operating state of the ABS. Then, the transmission ratio is set based on these signals, and the drive control of the transmission ratio variable mechanism 30 is performed according to the set transmission ratio.

Here, each processing of the steering control device 70 having such a configuration will be described with reference to the flowchart of FIG.

This flowchart is started by turning on the ignition switch. First, the process proceeds to step (hereinafter referred to as “S”) 102, where the input angle θh detected by the input angle sensor 21 and the output angle sensor 41 are detected.
The value of the output angle θp detected in step 1 and the value of the vehicle speed V detected by the vehicle speed sensor 61 are read.

In the next step 104, a map search is performed from the map showing the relationship between the vehicle speed V and the transmission ratio G shown in FIG. 3 based on the vehicle speed V read in S102, and the transmission ratio G corresponding to the vehicle speed V is obtained.
To set.

In the subsequent S106, the ABS controller 6
2 is in operation, it is determined whether the ABS controller 62
Is not operating, it is determined to be “No” during normal operation,
Proceed to S110.

In S110, θ is calculated based on the transmission ratio G set in S104 and the input angle θh read in S102.
pm = G · θh is calculated, and the output angle target value θpm is set.

In subsequent S112, the deviation e between the output angle target value θpm set in S110 and the output angle θp detected by the output angle sensor 41 is calculated as e = θpm−θp.

In subsequent S114, the actuator 31 is set so that the deviation e is set to 0 without overshooting.
The control signal Is for controlling is determined. As an example of this processing, the PID is calculated based on the arithmetic expression of Is = C (s) e.
The control signal Is can be determined by appropriately setting the control parameters. In addition, "s" in a formula is a Laplace operator.

In subsequent S116, the control signal Is determined in S114 is output to the actuator 31, and the actuator 31 is driven according to the control signal Is.

Then, in S118, the value of the transmission ratio G set in this routine is stored as Gold.

Thereafter, the process proceeds to S120, it is determined whether the ignition switch (IG) is turned off, and "No" is determined.
In the case of, the process returns to S102, and the above-described processing of S102 and subsequent steps is repeatedly executed until “Yes” is determined in S120.

If it is determined in S106 that the ABS is operating, the process proceeds to S108, where the Gold value, which is the transmission ratio set in the previous routine, is set to the transmission ratio set in this routine. Replace as G. In the following S110, the output angle target value θpm is set using the value of the transmission ratio G set by such replacement processing.
Is calculated.

As described above, during the ABS operation, the value of the transmission ratio Gold set in the previous routine in S108 is set as the transmission ratio G set in the present routine, and as a result, during the ABS operation. The transmission ratio G becomes a constant value, and the change of the transmission ratio G is prohibited.

Therefore, under the condition that the ABS operates, the situation that the wheels are steered due to the change of the transmission ratio due to the change of the vehicle speed is avoided and the transmission is performed regardless of the steering holding state. By fixing the value of the ratio G, it becomes easier to perform the correction steering when the vehicle behavior changes. Furthermore, as a result of maintaining the transmission ratio at the time when the vehicle speed is high, the transmission ratio is set slower (the steering amount is smaller than the steering amount) compared to the normal transmission ratio that is set according to the vehicle speed. It is possible to suppress the change in the behavior of the vehicle due to the change and improve the stability of the vehicle.

Next, the second embodiment will be described with reference to the flowchart of FIG.

This flowchart is started by turning on the ignition switch. First, in S202, the input angle θh detected by the input angle sensor 21, the output angle θp detected by the output angle sensor 41, and the vehicle speed sensor 61.
The value of the vehicle speed V detected in step S6 is read.

At S204, it is determined whether the ABS controller 62 is operating. In the normal state where the ABS controller 62 is not operating in S204, it is determined to be "No", the process proceeds to S206, and the map A for the normal traveling in FIG. 5 is selected.

Further, in S204, the ABS controller 62
When it is determined that is in operation, the process proceeds to S208, and it is determined whether or not the steering state is maintained based on the change amount of the input angle θh read in S202. Then, when it is determined that the steering is not maintained, the process proceeds to S210, and FIG.
Map B in is selected. The map B is a map in which the transmission ratio G (G = steering angle / steering angle) is shifted to a higher value than the map A.

In the following S212, S206 or S21
Based on the map selected with 0, the transmission ratio G according to the vehicle speed V
To set.

On the other hand, if it is determined in S208 that the steering is maintained, the process proceeds to S214, where the value of Gold which is the transmission ratio set in the previous routine is set to the transmission ratio G set in this routine. Set as.

The processing of S216 to S226 executed after passing through S212 or S214 is S11 in FIG.
Since the processing is the same as that of 0 to S120, the description thereof is omitted.

As described above, when the steering is performed during the ABS operation, the transmission ratio G is set based on the map B, so that the transmission ratio G becomes slower than that in the map A during normal traveling. The change in vehicle behavior due to steering is suppressed and the stability of the vehicle is improved. Also, AB
When the S operation is in progress and the steering is maintained, the transmission ratio G is maintained at a constant value in S214.
Even when the steering is held under the condition that 2 operates, the change of the transmission ratio G due to deceleration is prohibited. This allows ABS
It is possible to avoid a situation in which the wheels FW1 and FW2 are steered due to a change in the transmission ratio G when the vehicle is in operation and in the steering holding state.

In the second embodiment described above, S21
An example of selecting the map B at 0 is shown in FIG.
It is also possible to select the map C in which the transmission ratio G is shifted to a lower value than the map A as shown in FIG. In this case, when the steering is performed during the ABS operation, the transmission ratio is set to be quicker (the steering amount is larger than the steering amount) as compared with the map A during the normal traveling, and thus the ABS is set.
It is possible to improve steering responsiveness during operation.

Further, the case where the map is changed in this way is illustrated, but the present invention is not limited to this example.
It is also possible to adopt a method of setting the transmission ratio during ABS operation by multiplying or adding / subtracting a predetermined correction term to correct the transmission ratio set during normal traveling during ABS operation.

Further, the case where the vehicle speed V is detected as the traveling state of the vehicle and the transmission ratio G is set according to the vehicle speed V has been exemplified, but in addition to this, the vehicle speed V and the input angle θh are also represented as the traveling state of the vehicle. It is also possible to detect and set the transmission ratio G according to the vehicle speed V and the input angle θh.

[0039]

As described above, according to the vehicle steering control device of the first aspect, since the anti-lock control means is provided with the prohibiting means for prohibiting the change of the transmission ratio during the operation, the ABS operation is performed. It is possible to avoid the situation in which the wheels are steered regardless of the driver's intention to steer due to the change of the transmission ratio due to deceleration, and to facilitate the correction steering when the vehicle behavior changes during the ABS operation. Because you can
It becomes possible to set a suitable transmission ratio under the condition that S operates.

Further, according to the vehicle steering control device of the second aspect, since the changing means for changing the transmission ratio set by the transmission ratio setting means is provided according to the operating state of the antilock control means, for example, By shifting the transmission ratio to the slow side, it is possible to suppress the behavior change of the vehicle due to the steering during the ABS operation, thereby improving the stability of the vehicle. Further, by shifting to the quick side, it becomes possible to improve the responsiveness of steering during ABS operation.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of a steering control device.

FIG. 2 is a flowchart showing steering control processing according to the first embodiment.

FIG. 3 is a map defining a relationship between a vehicle speed V and a transmission ratio G.

FIG. 4 is a flowchart showing steering control processing according to a second embodiment.

FIG. 5 is a map defining the relationship between vehicle speed V and transmission ratio G.

[Explanation of symbols]

30 ... Transmission ratio variable mechanism, 31 ... Actuator, 62 ...
ABS controller, 70 ... Steering control device.

Continuation of front page (51) Int.Cl. ⁷ Identification symbol FI B62D 137: 00 B62D 137: 00 (72) Inventor Kawamuro Toko, Toyota City, Aichi Prefecture Toyota Town 1 Toyota Motor Corporation (56) Reference Documents JP-A 5-85386 (JP, A) JP-A 3-193560 (JP, A) JP-A 63-227473 (JP, A) JP-A 63-219480 (JP, A) JP-A 63- 227470 (JP, A) JP-A-62-238171 (JP, A) Actual development 1-62965 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B62D 6/00

Claims (4)

(57) [Claims] 1. A vehicle steering control device for steering wheels according to steering, comprising: a transmission ratio setting means for setting a transmission ratio between a steering amount and a steering amount according to a traveling state of the vehicle. the anti-lock control means for performing an anti-lock control of a wheel, during operation of the anti-lock control means, and a prohibiting means for prohibiting the change of the transmission ratio, the transmission ratio during operation of the anti-lock control means , The above
Fix the transmission ratio at the start of operation of the
And a steering control device for a vehicle. 2. A vehicle steering control device for steering wheels according to steering, comprising a transmission ratio setting means for setting a transmission ratio between a steering amount and a steering amount according to a traveling state of the vehicle. , Anti-lock control means for carrying out anti-lock control of the wheels, and when the anti-lock control means is in operation, it is not in the steering holding state
If the transmission ratio set by the transmission ratio setting means
A value higher than the transmission ratio when the anti-lock control means is not activated
A steering control device for a vehicle, comprising: 3. A vehicle steering system that steers wheels according to steering.
The steering control device is a transmission ratio between the steering amount and the steering amount according to the running state of the vehicle.
Ratio setting means for setting the wheel and anti-lock control hand for carrying out anti-lock control of the wheels.
And when the anti-lock control means is activated, it is not in the steering holding state.
If the transmission ratio set by the transmission ratio setting means
A value lower than the transmission ratio when the anti-lock control means is not activated
And a vehicle steering control device. 4. A vehicle steering system for steering wheels according to steering.
The steering control device is a transmission ratio between the steering amount and the steering amount according to the running state of the vehicle.
Ratio setting means for setting the wheel and anti-lock control hand for carrying out anti-lock control of the wheels.
And the steering holding state at the time of actuation of the anti-lock control means.
Is set to the previous transmission ratio set by the transmission ratio setting means.
Steering for a vehicle, comprising: changing means for changing to a fixed transmission ratio
Control device.