JP3119126B2 - Vehicle turning assist device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turning assist device for assisting turning of a vehicle such as an automobile, and more particularly, to a turning assist device for assisting turning of a vehicle by applying a braking force difference between left and right wheels. According to.

[0002]

2. Description of the Related Art As one of the turning assisting devices for assisting turning of a vehicle such as an automobile, for example, Japanese Patent Application Laid-Open No. 63-279076.
As described in Japanese Patent Application Laid-Open Publication No. H10-260, a braking device that applies a braking force to the left and right rear wheels independently of each other, a means for detecting a steering angle of a front wheel, and a rear side in a steering direction as the front wheel steering angle increases. BACKGROUND ART A turning assist device having control means for increasing a braking force of a wheel has been conventionally known.

According to such a turning assist device, when the vehicle turns, the braking force of the rear wheel in the turning direction is increased, whereby a yaw moment in the turning direction is given to the vehicle. The turning performance of the vehicle can be improved as compared with the case where the vehicle is not provided, and the steering burden on the driver can be reduced.

[0004]

However, when the vehicle is running, a steering force due to disturbance from the road surface may act on the left and right front wheels, and when the left and right front wheels are steered by the disturbance, the steering displacement of the wheels is changed by the steering mechanism. And transmitted to the steering shaft and the steering wheel as rotational displacement. Therefore, in the conventional turning assist device described in the above publication, the rotation of the steering shaft or the like caused by road surface disturbance is detected by the steering angle detecting means, and the braking force of the wheels is increased based on the detection result. Therefore, there is a problem that wobbling of the vehicle due to road surface disturbance is rather promoted.

The present invention has been made in view of the above-described problems in the conventional turning assist device, and a main problem of the present invention is that the left and right front wheels are steered by a driver or a road surface disturbance. In the former case, the vehicle assists turning, but in the latter case, turning assist is prohibited or the yaw moment in the opposite direction to that of the turning assist is applied to the vehicle. Is to prevent the vehicle from wandering due to road surface disturbance and reduce the vehicle's wander.

[0006]

SUMMARY OF THE INVENTION According to the present invention, there are provided a first rotation direction detecting means for detecting a rotation direction of a steering wheel, and a first rotation direction detecting means. Second rotation direction detection means for detecting the rotation direction of the steering wheel on the wheel side, and a braking force difference corresponding to the rotation direction detected by the first or second rotation direction detection means is applied to the left and right wheels. Braking force control means, and when the detection of the rotation direction by the second rotation direction detection means is earlier than the detection of the rotation direction by the first rotation direction detection means, the provision of the braking force difference by the braking force control means. A turning assist device for a vehicle having a turning assist prohibiting means for prohibiting the vehicle, a first rotational direction detecting means for detecting a rotational direction of a steering wheel; Second rotation direction detection means for detecting the rotation direction of the steering wheel on the wheel side relative to the rotation direction detection means, and braking force corresponding to the rotation direction detected by the first or second rotation direction detection means Braking force control means for giving a difference to the left and right wheels, wherein the braking force control means detects a rotation direction by the second rotation direction detection means rather than a rotation direction detection by the first rotation direction detection means. The vehicle turning assist device is configured to apply a braking force difference corresponding to a direction opposite to the rotation direction detected by the first rotation direction detection means to the left and right wheels when the vehicle speed is early. Item 2).

[0007]

The first rotation direction detection means for detecting the rotation direction of the steering wheel, and the second rotation direction detection means for detecting the rotation direction of the steering wheel on the wheel side of the first rotation direction detection means are provided. In the vehicle provided, when the vehicle is steered by a driver, the rotational displacement of the steering wheel is finally transmitted as a steering displacement to the wheels via a steering mechanism, but is caused by road surface disturbance. When the steering wheel or the like is rotated, first, the wheel is steered, and the steering displacement is finally transmitted as a rotational displacement to the steering wheel via the steering mechanism. Depending on which of the means detects the rotation direction of the steering wheel first, the steering wheel or the like may be driven by the driver or by the road surface disturbance. It is possible to distinguish between when it is rolling.

According to the first aspect of the present invention, when the detection of the rotation direction by the second rotation direction detection means is earlier than the detection of the rotation direction by the first rotation direction detection means, the turning assist prohibition means controls the rotation. Since the application of the braking force difference by the power control means is prohibited, and the turning assist is not performed, the wandering of the vehicle due to road surface disturbance is reliably prevented from being promoted by the turning assist.

According to the second aspect of the present invention, when the detection of the rotation direction by the second rotation direction detection means is earlier than the detection of the rotation direction by the first rotation direction detection means, the braking force control means performs the first operation. Since the braking force difference corresponding to the direction opposite to the rotation direction detected by the one rotation direction detecting means is applied to the left and right wheels, the yaw caused by the steering of the wheel due to the road surface disturbance is generated. A yaw moment in a direction opposite to the moment is applied to the vehicle, whereby wobbling of the vehicle due to road surface disturbance is reliably reduced.

[0010]

In a preferred embodiment, when the wheels are steered by road surface disturbance, the rotation directions detected by the first and second rotation direction detection means are the same as each other, but the vehicle travels on a wheeled road surface. In such a case, when the steering wheel is steered by the driver in a direction opposite to the direction of the disturbance steering in order to travel straight ahead against the steering due to the road surface disturbance, the first and second rotation direction detecting means The detected rotation directions are opposite to each other.

According to one preferred embodiment of the present invention, in the above-described configuration of claim 2, the braking force control means is configured to detect the rotation direction in the second rotation direction more than the detection of the rotation direction by the first rotation direction detection means. If the detection of the rotation direction by the detection means is fast and the rotation directions detected by the first and second detection means are the same, the rotation direction is opposite to the rotation direction detected by the first rotation direction detection means. When a braking force difference corresponding to the direction is given to the left and right wheels, and the rotation directions detected by the first and second rotation direction detection means are opposite to each other,
The braking force difference corresponding to the rotation direction detected by the first rotation direction detection means is applied to the left and right wheels.

According to this configuration, when the wheel is steered due to the road surface disturbance, a yaw moment in a direction opposite to the yaw moment due to the disturbance is generated, and the driver opposes the steering due to the road surface disturbance. When the vehicle is steered, a yaw moment that assists the driver in steering is given to the vehicle, whereby wobbling of the vehicle due to road surface disturbance is reliably reduced, and the driver's steering load is reduced.

According to a preferred embodiment of the present invention,
At least one of the first and second rotation direction detection means is configured to detect the rotation degree together with the rotation direction, and the braking force control means applies a braking force difference corresponding to the rotation direction to the left and right wheels according to the rotation degree. It is configured as follows. In this case, the “degree of rotation” refers to a rotation angle, a rotation torque, and the like.

In the present specification, the "braking force difference corresponding to the detected rotation direction" means that a yaw moment is applied to the vehicle to assist the vehicle in turning in the turning direction corresponding to the rotation direction of the steering wheel. The difference in braking force between the left and right wheels means the difference in braking force in the direction opposite to the detected direction of rotation.The yaw moment in the direction opposite to the turning direction corresponding to the direction of rotation of the steering wheel is applied to the vehicle. It means the difference between the braking forces applied to the left and right wheels.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 1 is a schematic structural view showing a vehicle braking device to which the turning assist device according to the present invention is applied and an electric control device thereof.

In FIG. 1, a braking device 10 has a master cylinder 14 for pumping brake oil from first and second ports in response to a driver's depressing operation of a brake pedal 12, and a first port. Is connected to brake hydraulic control devices 18 and 20 for the front left and right wheels by a brake hydraulic control conduit 16 for the front wheels, and the second port is connected to the rear left and right wheels by a brake hydraulic control conduit 24 for the rear wheels having a proportional valve 22 in the middle. Brake hydraulic control devices 26 and 28. Further, the braking device 10 pumps up the brake oil stored in the reservoir 30 and supplies it to the high-pressure conduit 32 as high-pressure oil.
Four. The high-pressure conduit 32 is connected to each of the brake hydraulic control devices 18, 20, 26, 28, and an accumulator 36 is connected in the middle thereof.

Each of the brake hydraulic pressure control devices 18, 20, 2
6, 28 are wheel cylinders 38FL, 38FR, 38RL, 38RR for controlling the braking force on the corresponding wheels, respectively.
And a 3-port 2-position switching type electromagnetic control valve 40FL,
The normally open electromagnetic on-off valves 44FL, 44FR, 44RL, 44RR provided between the 40FR, 40RL, 40RR and the low pressure conduit 42 and the high pressure conduit 32 connected to the reservoir 30 and the normally closed electromagnetic valve On-off valves 46FL, 46FR, 46RL, 46
RR. On-off valves 44FL, 44FR, 4 respectively
4RL, 44RR and open / close valve 46FL, 46FR, 46RL, 46RR
High-pressure conduit 32 between the connection conduits 48FL, 48FR, 48
Control valve 40FL, 40FR, 40RL, 40 by RL, 48RR
Connected to RR.

The control valves 40FL and 40FR are respectively connected to the brake hydraulic control conduit 16 for the front wheels and the wheel cylinder 38FL.
And 38FR and wheel cylinder 38FL
, 38FR and the connection conduits 48FL and 48FR, the first position shown in the figure, the brake hydraulic control conduit 16 and the wheel cylinders 38FL and 38FR, and the wheel cylinders 38FL and 38FR and the connection conduit 48FL.
, And a second position for communicating and connecting with the 48FR. Similarly, 40RL and 40RR are respectively a brake hydraulic control conduit 24 for the rear wheel and a wheel cylinder 3
8RL and 38RR, and wheel cylinder 3
8RL and 38RR and the first position shown to cut off the communication between the connecting conduits 48RL and 48RR, and the brake hydraulic control conduit 2
4 to cut off the communication between the wheel cylinders 38RL and 38RR and connect the wheel cylinders 38RL and 38RR to the connecting conduit 4.
The position is switched to a second position for communicating and connecting 8RL and 48RR.

When the control valves 40FL, 40FR, 40RL, 40RR are in the second position, the on-off valves 44FL, 44FR,
44RL, 44RR and on-off valves 46FL, 46FR, 46RL, 4
When 6RR is controlled to the state shown in FIG.
8FL, 38FR, 38RL, 38RR are control valves 40FL, 40F
R, 40RL, 40RR and connecting conduit 48FL, 48FR, 48R
L and 48RR are connected to the high-pressure conduit 32 to increase the pressure in the wheel cylinder. Conversely, when the control valve is in the second position, the on-off valve 44FL,
4FR, 44RL, 44RR are closed and on-off valves 46FL, 46F
When R, 46RL, 46RR is opened, the wheel cylinder is connected in communication with the low pressure conduit 42 via the control valve and the connecting conduit, thereby reducing the pressure in the wheel cylinder. Further, when the control valve is in the second position, the on-off valves 44FL, 44FR, 44RL, 44RR and the on-off valves 46FL,
When the valves 6FR, 46RL, and 46RR are closed, the wheel cylinder is disconnected from both the high-pressure conduit 32 and the low-pressure conduit 42, so that the pressure in the wheel cylinder is maintained.

Thus, the braking device 10 includes the control valve 40FL,
When the 40FR, 40RL, 40RR is in the first position, the wheel cylinders 38FL, 38FR, 38RL, 38RR generate a braking force according to the amount of depression of the brake pedal 12 by the driver, and the control valves 40FL, 40FR, 40RL, 40RR.
When any of RR is in the second position, the on-off valves 44FL, 44FR, 44RL, 44RR and on-off valves 46FL,
By controlling the opening and closing of the wheels 46FR, 46RL and 46RR, the braking force of the wheel can be controlled irrespective of the amount of depression of the brake pedal 12 and the braking force of the other wheels.

Control valves 40FL, 40FR, 40RL, 40RR,
On-off valves 44FL, 44FR, 44RL, 44RR and on-off valves 46
FL, 46FR, 46RL, 46RR are controlled by an electric control device 50 as described in detail later. The electric control device 50 includes a microcomputer 52 and a drive circuit 54. The microcomputer 52 is not shown in detail in FIG. 1, but is, for example, a central processing unit (CPU).
, A read only memory (ROM), a random access memory (RAM), and an input / output port device, which may be of a general configuration connected to each other by a bidirectional common bus.

A signal indicating the steering angle θ is input to an input / output port device of the microcomputer 52 from a steering angle sensor 56 as first rotation direction detecting means, and a torque sensor 58 as second rotation direction detecting means. Thus, a signal indicating the steering torque T is input. The steering angle sensor 56 is provided on the upper steering shaft 62 connected to the steering wheel 60 at the upper end, and the torque sensor 58 is provided on the elastic joint 6 at the upper end.
The lower steering shaft 70 is connected to the upper steering shaft 62 through the lower gear 4 and connected to the steering device 68 at the lower end. The steering angle sensor 56 and the torque sensor 58 detect the steering angle θ and the steering torque T with the direction when the vehicle is turned rightward by the driver's steering being positive.

The ROM of the microcomputer 52 stores a control flow to be described later. The CPU determines whether the driver is performing steering or the steering due to road disturbance is performed based on the parameters detected by the two sensors. When the steering is being performed by the driver, a braking force is applied to the turning inner wheel front and rear wheels to perform turning assist, and when the steering is performed by road surface disturbance, the turning outer wheel front and rear wheels are turned to the turning front wheel. A braking force is applied to cancel steering due to road surface disturbance, and when steering against steering due to road surface disturbance is performed by a driver, a braking force is applied to the front and rear wheels on the turning inner wheel side to cancel steering due to road surface disturbance. Has become.

Next, the turning assist control of the vehicle according to the first embodiment will be described with reference to the flowcharts shown in FIGS. The control according to the flowcharts shown in FIGS. 2 and 3 is started by closing an ignition switch (not shown) and is repeatedly executed at predetermined time intervals.

First, in step 10, a signal indicating the steering angle θ detected by the steering angle sensor 56 and a signal indicating the steering torque T detected by the torque sensor 58 are read. In step 20, It is determined whether or not the absolute value of the steering angle θ exceeds the reference value θo (small positive constant), that is, whether or not the steering wheel 60 is in a steered state. When it is determined in step 30 that the absolute value of the steering torque T has exceeded a reference value To (small positive constant), that is, whether or not a substantial torque is generated in the steering shaft. Is performed.

If an affirmative determination is made in step 30, a determination is made in step 40 as to whether the steering angle θ is positive, that is, whether or not the vehicle is turning right, and a negative determination is made. Is performed, the routine proceeds to step 190, and if a positive determination is made, the routine proceeds to step 50. If a negative determination is made in steps 20 and 30, the process proceeds to step 180.

In step 50, it is determined whether or not the time when the absolute value of the steering torque T becomes equal to or more than the reference value To is earlier than the time when the absolute value of the steering angle θ becomes equal to or more than the reference value θo. When a positive determination is made, that is, a determination is made that steering due to road surface disturbance is being performed, step 100 is executed.
When the determination is negative, that is, when it is determined that the change in the steering angle θ is earlier or simultaneous and the driver is performing steering, the process proceeds to step 60.

In step 60, it is determined whether or not the steering torque T is positive. If a negative determination is made, the process proceeds to step 90, and if an affirmative determination is made, the steering is performed in step 70. The differential value Δθ of the angle θ is calculated, and it is determined whether or not the absolute value of the differential value Δθ is equal to or smaller than a reference value θe (a small positive constant), that is, the degree of change of the steering angle θ is substantially zero. A determination is made as to whether there is. If an affirmative determination is made in this step, step 1
Go to step 70, and if a negative determination is made, step 80
It is determined whether or not the differential value Δθ is positive, that is, whether or not the turning of the steering wheel is being performed in the right-turning state. If an affirmative determination is made, the process proceeds to step 130. The process proceeds to step 140 when a negative determination is made.

In step 90, the differential value .DELTA..theta. Of the steering angle .theta. Is calculated and it is determined whether the differential value .DELTA..theta. Is negative, that is, whether the steering wheel is turned back in the right turning state. It is determined whether or not the determination is affirmative. When the determination is affirmative, the process proceeds to step 140, and when the determination is negative, the process proceeds to step 180.

In step 100, it is determined whether or not the steering torque T is negative, that is, whether or not steering in the right turning direction is being performed due to road surface disturbance, and a negative determination is made. Proceeds to step 70, and when an affirmative determination is made, in step 110, it is determined whether or not the steering angle differential value Δθ is equal to or smaller than the reference value θe, that is, the degree of change in the steering angle θ is substantially 0. Is determined. If an affirmative determination is made in this step, the process proceeds to step 170, and if a negative determination is made, it is determined in step 120 whether or not the differential value Δθ is positive, that is, the right turning direction due to road disturbance. It is determined whether or not the steering angle has increased. When the determination is affirmative, the process proceeds to step 150, and when the negative determination is performed, the process proceeds to step 160.

In step 130, the braking pressure of the right front and rear wheels is increased, and in step 140, the braking pressure of the right front and rear wheels is reduced. In step 150, the braking pressure of the front left and right wheels is increased, and in step 160, the braking pressure of the front left and right wheels is reduced. In step 170, the braking pressure of the wheel whose braking pressure has been increased or decreased is maintained, and in step 180, the control of the braking pressure is stopped.

Although the increase or decrease of the braking pressure may be controlled with a constant gain, in the illustrated embodiment, step 13 is executed.
The increase and decrease of the braking pressure at 0 and 140 are controlled by the gain proportional to the magnitude of the steering angle θ and the differential value Δθ thereof. It is controlled by a gain proportional to the magnitude and the magnitude of its differential value ΔT.

When a negative determination is made in step 40, that is, a determination is made that the vehicle is turning left, steps 190 to 310 shown in FIG. 3 are executed. Step 2
Steps 190-31 except that the inequality sign of the discrimination in 00, 220, 230, 240, 260 is reversed, and the left and right wheels in steps 270-300 are reversed.
The execution content of 0 is the same as the execution content of steps 50 to 160.

Next, the turning assist control according to the first embodiment will be described for various types of right turn steering in which the generation states of the steering angle θ and the steering torque T are different, that is, when θ> 0.

(1) When neither steering by the driver nor steering due to road surface disturbance is performed In this case, the magnitude of the steering angle θ or the magnitude of the steering torque T is equal to or smaller than the reference value. A negative determination is made at step 20 or a negative determination is made at step 30 after a positive determination is made at step 20;
Thereafter, the routine proceeds to step 180. Accordingly, the turning assist is not performed, and the control valve of each wheel is reset to the first position, whereby the braking force of each wheel is controlled by the master cylinder pressure according to the amount of depression of the brake pedal 12.

(2) When Steering is Performed by the Driver In this case, since the change in the steering angle θ occurs before the change in the steering torque T, the magnitude of the steering angle θ and the steering torque T
Are determined in steps 20 to 40 at the stage when the magnitude of each exceeds the corresponding reference value.
At 0, a negative determination is made.

A) In the case where the steering wheel is turned further When the steering wheel 60 is turned further, the steering torque T becomes positive, so that an affirmative determination is made in step 60. Then, a negative determination is made in step 70, and an affirmative determination is made in step 80, whereby the braking pressure of the right front and rear wheels is increased in step 130. Therefore, as shown in FIG. 4, in addition to the yaw moment Ms in the right turning direction generated around the center of gravity O of the vehicle when the left and right front wheels 72FL and 72FR are steered,
An auxiliary yaw moment Ma in the right turning direction is generated by the braking force F by the right front and rear wheels, and this yaw moment is increased in accordance with the steering angle θ and the increase rate Δθ of the steering angle.

B) In the case of steering hold state When the steering wheel is held, the steering angle θ is substantially constant and the rate of change Δθ is substantially zero. Is performed, and in step 170, the braking pressures of the right front and rear wheels are held, whereby a constant auxiliary yaw moment Ma in the right turning direction is generated.

C) When the steering wheel is turned back When the steering wheel is turned back, the steering torque T becomes negative, so a negative determination is made in step 60. Since the change rate Δθ of the steering angle is negative, an affirmative determination is made in step 90, and
At this time, the braking pressure of the right front and rear wheels is reduced, whereby the auxiliary yaw moment Ma is reduced according to the steering angle θ and the reduction rate Δθ.

[0041] As shown in FIG. 6, for example, time t ₁
At right, steering in the right turning direction is started by the driver,
In time t ₂ exceeds the magnitude reference value θo of the steering angle theta, when the magnitude of the steering torque T at the time t ₃ As a result exceeds the reference value To, the substantially time t ₃ Then, the increase of the braking pressure of the right front and rear wheels is started. When the rate of increase of the steering angle θ becomes equal to or less than the reference value θe at the time point t ₄ , the braking pressure of the right front and rear wheels is kept constant substantially from that time point. Switching back of the steering wheel is started at a between times t ₄ and t _5, the reduction rate of the steering angle θ at the point ₅ is less than or equal to a criterion value -Shitai, right substantially at its point The pressure reduction of the front and rear wheels is started, and the braking pressure of the right front and rear wheels is gradually reduced.

(3) When Steering Due to Road Surface Disturbance is Performed Also in this case, step 2 is performed when the magnitude of the steering angle θ and the magnitude of the steering torque T exceed the corresponding reference values.
An affirmative determination is made at 0 to 40, but the steering torque T
Is made before the change in the steering angle θ, an affirmative determination is made in step 50.

D) The case where the steering wheel is steered in the direction of turning more due to disturbance In this case, since the steering torque is negative, step 100
In step 110, a negative determination is made in step 110 if the disturbance is large. When the steering angle is increased by the steering due to the disturbance, an affirmative determination is made in step 120, and in step 150, the braking pressure of the left front and rear wheels is increased. Accordingly, as shown in FIG. 5, a left turning yaw moment Mc for canceling the yaw moment Md due to the disturbance is generated by the braking force F of the left and right front wheels, and this yaw moment is the steering torque T.
And its rate of change ΔT.

On the other hand, if the disturbance decreases and the steering angle decreases accordingly, a negative determination is made in step 120, and in step 160, the braking pressures of the left and right front wheels are reduced. The yaw moment Md due to disturbance
Is reduced in accordance with the magnitude of the steering torque T and the magnitude of its change rate ΔT.

[0045] As shown in FIG. 7, for example, time t ₁
The steering torque T due to disturbance starts to increase at time t
₂ exceeds the magnitude reference value To of the torque T at the reference value is the magnitude of the steering angle θ at the time t ₃ Accordingly θo
When exceeding a pressure increase of the brake pressure of the left front and rear wheels is started at substantially time t _3. When the rate of increase of the steering angle θ becomes equal to or smaller than the reference value θe at the time point t ₄ , the braking pressure of the left front and rear wheels is kept constant substantially from that time point. Time point t ₄
And at beginning steering torque T by the steering angle θ and the disturbance is reduced between t _5, when the reduction rate of the steering angle θ at the point ₅ is less than or equal to a criterion value -Shitai, substantially at its point Then, the pressure reduction of the braking pressure of the left front wheel is started, and the braking pressure of the left front wheel is gradually reduced.

E) When the driver performs steering against steering due to road surface disturbance In this case, for example, a disturbance due to wheel running or the like acts in the left turning direction, and the driver turns right in response to this. Since the steering wheel is steered in the direction, the steering torque T is positive, and a negative determination is made in step 100.

If the rate of change in the counter-steering by the driver is large, a negative determination is made in step 70, and an affirmative determination is made in step 80. The yaw moment Mc is generated in the right turning direction to cancel the yaw moment Md due to disturbance, and this yaw moment is increased according to the magnitude of the steering angle θ and the rate of change Δθ. You. If the rate of change in counter-steering by the driver is small, such as when the driver is holding the steering wheel, an affirmative determination is made in step 70, and in step 170, the braking pressure of the right front and rear wheels is determined. Is maintained, whereby a constant yaw moment Mc in the right-turning direction against the yaw moment Md due to disturbance is generated.

[0048] As shown in FIG. 8, for example, time t ₁
The steering torque T due to disturbance starts to increase at time t
₂ exceeds the magnitude reference value To of the torque T at the reference value is the magnitude of the steering angle θ at the time t ₃ Accordingly θo
When exceeding a pressure increase of the right front and rear wheels of the braking pressure is started at substantially time t _3. When the rate of increase of the steering angle θ becomes equal to or less than the reference value θe at the time point t ₄ , the braking pressure of the right wheel is substantially kept constant from that time point onward, and thereafter the control is performed according to Δθ. The steering angle θ and the magnitude of the steering torque T due to disturbance are reduced, and the rate of decrease of the steering angle θ is equal to the reference value −θe.
At this point, the braking pressure of the right front and rear wheels is substantially reduced at that time, and the braking pressure of the right front and rear wheels is gradually reduced.

In the case of a left turn, the same control as in the above cases is performed except that the left and right wheels are controlled in reverse.

Thus, the first embodiment corresponds to the configuration of the second aspect described above. According to this embodiment, when steering is performed by the driver, the auxiliary yaw moment Ma in the turning direction is reduced. This assists the vehicle to turn, thereby improving the turning performance of the vehicle and reducing the driver's steering burden.The steering is performed when the steering wheel is steered by disturbance and when the steering is counteracted by the road surface disturbance. When performed by a driver, a yaw moment Mc that cancels out the yaw moment Md due to the disturbance is generated, whereby the running stability of the vehicle can be improved and the steering load on the driver can be reduced.

FIGS. 9 and 10 are flowcharts showing a turning assist control routine according to a second embodiment of the turning assist device according to the present invention. In these figures, steps corresponding to the steps shown in FIGS. 2 and 3 in FIGS. 2 and 3 have the same step numbers as those in FIGS. 2 and 3. Have been. 9 and FIG.
The control according to the flowchart shown in FIG. 0 is also started by closing an ignition switch (not shown), and is repeatedly executed at predetermined time intervals.

In the second embodiment, step 5
If the determination at 0 or 190 is affirmative, that is, if the change in the steering torque is first and it is determined that the steering is being performed due to the road surface disturbance, the process proceeds to step 180, where the turning assist yaw moment is generated. Is forbidden. Thus, the second embodiment corresponds to the configuration of claim 1 described above. According to this embodiment, when steering is performed by the driver, the auxiliary yaw moment Ma in the turning direction is generated. Turn assist is provided, which can improve the turning performance of the vehicle and reduce the driver's steering burden,
When the steering wheel is steered by disturbance and when the driver performs steering against steering due to road surface disturbance, the generation of the auxiliary yaw moment Ma is prohibited, and the running stability of the vehicle is degraded by turning assist. Can be prevented.

In the above-mentioned two embodiments, the first and second rotational direction detecting means are provided with the steering angle sensor 56, respectively.
And the torque sensor 58, the second rotational direction detecting means may be a steering angle sensor, and the second rotational direction detecting means is a sensor for detecting a moving direction or an axial force of a steering member such as a rack bar. It may be. However, when the second rotation direction detecting means is a steering angle sensor for detecting the steering angle θ2, the determination in steps 60 and 240 of the first embodiment depends on whether the steering angle θ2 is negative. Done,
The determination in steps 100 and 200 is made based on whether or not the steering angle θ2 is positive.

In the above two embodiments, the braking pressure of the wheels is increased or decreased for both the front wheels and the rear wheels, but the braking pressure is increased or decreased for either the front wheels or the rear wheels. It may be configured to perform only this.

Although the present invention has been described in detail with reference to specific embodiments, the present invention is not limited to the above-described embodiments, and various other embodiments may be included within the scope of the present invention. It will be clear to those skilled in the art that is possible.

For example, in the first embodiment described above, the gain of the control for increasing or decreasing the braking pressure in steps 150 and 160 is a gain proportional to the magnitude of the steering torque T and the magnitude of its differential value ΔT. However, these gains may be gains proportional to the steering angle θ or gains proportional to the steering angle θ and its derivative Δθ. Conversely, step 100
Alternatively, when steps 130, 140, 270, and 280 are performed by performing a negative determination in 240, in other words, when the driver performs steering against steering due to road surface disturbance, braking is performed. The gain of the pressure increase / decrease control may be a gain that is proportional to the magnitude of the steering torque T and the magnitude of its derivative ΔT.

[0057]

As is apparent from the above description, according to the configuration of the first aspect of the present invention, the rotation direction detected by the second rotation direction detecting means is more than the rotation direction detected by the first rotation direction detecting means. Is early, the turning assist prohibiting means prohibits the application of the braking force difference by the braking force control means, and the turning assist is not performed. Therefore, the wobble of the vehicle due to road surface disturbance is promoted by the turning assist. Thus, the running stability of the vehicle can be improved as compared with the related art without deteriorating the turning performance of the vehicle or increasing the steering burden on the driver.

According to the second aspect of the present invention, the braking force control means determines whether the second rotation direction detecting means detects the rotation direction earlier than the first rotation direction detection means detects the rotation direction. Since the braking force difference corresponding to the direction opposite to the rotation direction detected by the one rotation direction detecting means is applied to the left and right wheels, the yaw caused by the steering of the wheel due to the road surface disturbance is generated. A yaw moment in the direction opposite to the moment is applied to the vehicle, whereby the vehicle can be reliably prevented from wobbling due to road surface disturbance. Therefore, the running stability of the vehicle is further improved as compared with the case of the first embodiment. Performance can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a vehicle braking device to which a turning assist device according to the present invention is applied and an electric control device thereof.

FIG. 2 is a flowchart showing a part of a turning assist control routine according to a first embodiment of the turning assist device according to the present invention.

FIG. 3 is a flowchart showing the remaining part of the turning assist control routine according to the first embodiment of the turning assist device according to the present invention.

FIG. 4 is an explanatory diagram showing turning assistance according to the first embodiment when steering is performed by a driver.

FIG. 5 is an explanatory diagram showing turning assistance according to the first embodiment when steering is performed due to road surface disturbance.

FIG. 6 is a time chart showing turning assistance according to the first embodiment when steering is performed by a driver.

FIG. 7 is a time chart illustrating turning assistance according to the first embodiment when steering is performed due to road surface disturbance.

FIG. 8 is a time chart showing turning assist according to the first embodiment in a case where steering against steering due to road surface disturbance is performed by a driver.

FIG. 9 is a flowchart showing a part of a turning assist control routine according to a second embodiment of the turning assist device according to the present invention.

FIG. 10 is a flowchart showing the remaining part of a turning assist control routine according to a second embodiment of the turning assist device according to the present invention.

[Explanation of symbols]

 10: Braking device 14: Master cylinder 18, 20, 26, 28 ... Brake hydraulic pressure control device 34: Oil pump 38FL, 38FR, 38RL, 38RR: Wheel cylinder 40FL, 40FR, 40RL, 40RR: Control valve 44FL, 44FR, 44RL, 44RR: open / close valve 46FL, 46FR, 46RL, 46RR: open / close valve 50: electric control device 56: steering angle sensor 58: torque sensor 60: steering wheel

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B62D 11/00-11/24 B62D 6/00-6/06 B62D 5/04

Claims (2)

(57) [Claims] 1. A first rotation direction detecting means for detecting a rotation direction of a steering wheel, and a second rotation direction for detecting a rotation direction of the steering wheel on a wheel side relative to the first rotation direction detection means. Detection means, braking force control means for applying a braking force difference corresponding to the rotation direction detected by the first or second rotation direction detection means to the left and right wheels, and a rotation direction by the first rotation direction detection means A turning assist prohibiting means for prohibiting the application of a braking force difference by the braking force control means when the detection of the rotation direction by the second rotation direction detecting means is earlier than the detection of the rotation direction. 2. A first rotation direction detecting means for detecting a rotation direction of a steering wheel, and a second rotation direction for detecting a rotation direction of the steering wheel on a wheel side of the first rotation direction detection means. Detection means, and braking force control means for applying a braking force difference corresponding to the rotation direction detected by the first or second rotation direction detection means to the left and right wheels, wherein the braking force control means When the detection of the rotation direction by the second rotation direction detection means is earlier than the detection of the rotation direction by one rotation direction detection means, the rotation direction corresponds to the direction opposite to the rotation direction detected by the first rotation direction detection means. A turning assist device for a vehicle, which is configured to apply a braking force difference to left and right wheels.