JP7026885B2 - Vehicle control device - Google Patents

Description

The present invention relates to a vehicle control device, and more particularly to a vehicle control device provided with a brake device capable of applying different braking forces to the left and right wheels.

Conventionally, there is known a device (sideslip prevention device or the like) that controls the behavior of a vehicle in a safe direction when the behavior of the vehicle becomes unstable due to slipping or the like. Specifically, it is known that when the vehicle is cornering or the like, it is detected that the vehicle has understeer or oversteer behavior, and an appropriate deceleration is applied to the wheels so as to suppress them. ing.

In addition, unlike the control for improving safety in a driving state where the behavior of the vehicle becomes unstable as described above, acceleration / deceleration linked to the steering wheel operation operated from the daily driving area is automatically performed, and the limit is reached. A vehicle motion control device that reduces skidding in the driving region is known (see, for example, Patent Document 1). In particular, Patent Document 1 discloses a vehicle motion control device including a first mode for controlling acceleration / deceleration in the front-rear direction of the vehicle and a second mode for controlling the yaw moment of the vehicle. There is. On the other hand, Patent Document 2 discloses a technique for ensuring the execution of the yaw moment control even when the driver depresses the brake pedal in the vehicle turning control device that controls the turning of the vehicle through the yaw moment control. ing.

Japanese Patent No. 5143103 Japanese Unexamined Patent Publication No. 2014-151785

As described above, in the technique disclosed in Patent Document 1, the yaw moment is added to the vehicle in the second mode. The control to add this yaw moment to the vehicle is typically performed when the steering wheel (hereinafter also simply referred to as "steering") is turned back. That is, when the steering is turned back, a yaw moment opposite to the yaw rate generated in the vehicle is added in order to suppress the turning of the vehicle, in other words, to promote the return of the vehicle in the straight direction. As described above, the braking force is applied to the turning outer ring by the braking device. Hereinafter, the control for adding such a yaw moment to the vehicle is appropriately referred to as "vehicle yaw control".

By the way, if the vehicle yaw control (yaw moment control) is executed even when the driver depresses the brake pedal as in the technique described in Patent Document 2, the following problems may occur. That is, if a braking force is applied to all the wheels by the braking device and a further braking force is applied to the turning outer ring by the vehicle yaw control, the turning outer ring may be locked. Further, when the wheels are locked in this way, wheel lock prevention control (in other words, ABS (Antilock Brake System) control) for controlling the braking force by the braking device is executed so as to prevent the wheels from being locked. It may give the driver a sense of discomfort.

The present invention has been made to solve the above-mentioned problems of the prior art, and in a vehicle control device that controls vehicle yaw to apply a yaw moment to a vehicle, a braking force is applied to all wheels by a braking device. The purpose is to appropriately prevent the wheels from locking due to the vehicle yaw control being executed while the vehicle is being controlled.

In order to achieve the above object, the present invention is a vehicle control device including a steering device, a brake device capable of applying different braking forces to the left and right wheels, and a controller, wherein the controller is a control device. Based on the return operation of the steering device, vehicle yaw control is executed to control the brake device so that the yaw moment opposite to the yaw rate generated in the vehicle is applied to the vehicle, and the brake device is used when the steering device is returned. When braking force is applied to all wheels, it is configured to suppress vehicle yaw control more than when it is not, and the controller is set when the value corresponding to the return operation of the steering device exceeds a predetermined threshold value. It is characterized in that the vehicle yaw control is executed and the threshold value is increased as the braking force applied to all the wheels by the braking device is larger .
According to the present invention configured as described above, the vehicle yaw control is suppressed when the braking force is applied to all the wheels by the braking device during the return operation of the steering device, and therefore the vehicle yaw control is executed at this time. As a result, it is possible to appropriately suppress the driver from feeling uncomfortable. Specifically, it is possible to suppress that the wheel is locked by applying a further braking force to the turning outer wheel by the vehicle yaw control, and it is possible to suppress that the wheel lock prevention control is executed by the lock of the wheel. Further, according to the present invention, the larger the braking force applied to all the wheels, the larger the threshold value for determining whether or not to execute the vehicle yaw control, so that the braking force applied to all the wheels is compared. Vehicle yaw control can be effectively suppressed when the target is large.

In the present invention, preferably, the controller is configured so that the larger the braking force applied to all the wheels by the braking device, the smaller the yaw moment applied by the vehicle yaw control.
According to the present invention configured as described above, the larger the braking force applied to all the wheels, the smaller the yaw moment of the vehicle yaw control. Therefore, when the braking force applied to all the wheels is relatively large, the vehicle yaw is reduced. Control can be effectively suppressed.

In the present invention, preferably, the controller is further configured to perform wheel lock prevention control to control the braking force by the braking device so as to prevent the wheels from being locked.
More preferably, the controller is configured to suppress wheel lock prevention control when performing vehicle yaw control than otherwise.
According to the present invention configured as described above, it is possible to effectively suppress the driver from feeling uncomfortable due to the wheel lock prevention control being executed during the vehicle yaw control.

In the present invention, preferably, when the braking force is applied to all the wheels by the braking device, it is when the brake pedal is depressed by the driver.
According to the present invention configured as described above, the vehicle yaw control can be appropriately suppressed when the driver is depressing the brake pedal, and the vehicle yaw control is executed at this time to give the driver a sense of discomfort. It is possible to effectively suppress the accident.

Further, in the present invention, preferably, the controller sets the yaw moment based on the target lateral jerk according to the steering speed and the vehicle speed when the steering speed of the steering device becomes equal to or higher than a predetermined threshold value, and this yaw is set. It is configured to perform vehicle yaw control to add moments to the vehicle.
According to the present invention configured as described above, a yaw moment having a magnitude corresponding to the speed of the steering operation of the driver can be applied in the direction of suppressing the turning of the vehicle, and the vehicle can be quickly operated according to the steering operation of the driver. The behavior can be stabilized.

Further, in the present invention, preferably, when the change speed of the difference between the target yaw rate according to the steering angle of the steering device and the vehicle speed and the actual yaw rate actually generated in the vehicle becomes equal to or higher than a predetermined threshold value. It is configured to set a yaw moment based on this rate of change and execute vehicle yaw control so as to add this yaw moment to the vehicle.
According to the present invention configured as described above, when the steering wheel is operated on a low μ road such as a snow-packed road, the steering wheel is immediately changed in response to a sudden change in the yaw rate difference due to the response delay of the actual yaw rate. It is possible to apply a yaw moment in the direction of suppressing turning to the vehicle, and it is possible to quickly stabilize the vehicle behavior according to the steering operation of the driver in the situation before the vehicle behavior becomes unstable.

According to the present invention, in a vehicle control device that performs vehicle yaw control in which a yaw moment is applied to a vehicle, the wheels are set by executing the vehicle yaw control when braking force is applied to all the wheels by the braking device. Locking can be appropriately suppressed.

It is a block diagram which shows the whole structure of the vehicle which mounts the control device of the vehicle by embodiment of this invention. It is a block diagram which shows the electric structure of the control device of a vehicle by embodiment of this invention. It is a flowchart of the attitude control processing by embodiment of this invention. It is a flowchart of the addition deceleration setting process by embodiment of this invention. It is a map which showed the relationship between the additional deceleration and the steering speed by embodiment of this invention. It is a flowchart of the target yaw moment setting process by embodiment of this invention. It is a map which showed the threshold value used in the target yaw moment setting process by embodiment of this invention. It is a map which showed the gain used in the target yaw moment setting process by embodiment of this invention. It is a map which showed the threshold value used in the target yaw moment setting process by the modification of embodiment of this invention. It is a map which showed the gain used in the target yaw moment setting process by the modification of embodiment of this invention.

Hereinafter, a vehicle control device according to an embodiment of the present invention will be described with reference to the accompanying drawings.

<System configuration>
First, with reference to FIG. 1, a system configuration of a vehicle equipped with a vehicle control device according to an embodiment of the present invention will be described. FIG. 1 is a block diagram showing an overall configuration of a vehicle equipped with a vehicle control device according to an embodiment of the present invention.

In FIG. 1, reference numeral 1 indicates a vehicle equipped with a vehicle control device according to the present embodiment. An engine 4 is mounted on the front portion of the vehicle body of the vehicle 1 as a drive source for driving the drive wheels (the left and right front wheels 2 in the example of FIG. 1). The engine 4 is an internal combustion engine such as a gasoline engine or a diesel engine, and in the present embodiment, it is a gasoline engine having a spark plug.

Further, the vehicle 1 mainly serves as a rotation angle of a steering device (steering wheel 6 or the like) for steering the vehicle 1 and a steering column (not shown) connected to the steering wheel 6 in this steering device. A steering angle sensor 8 that detects the steering angle, a vehicle speed sensor 10 that detects the vehicle speed, a yaw rate sensor 12 that detects the yaw rate, and a brake switch 11 that turns on / off according to the operation / release of a brake pedal (not shown). It has a brake depression amount sensor 13 for detecting the depression amount of the brake pedal (brake depression amount). Each of these sensors outputs the detected value to the PCM (Power-train Control Module) 14.

Further, the vehicle 1 is provided with a brake control system 18 that supplies brake fluid pressure to the wheel cylinders and brake calipers of the brake device 16 provided on each wheel. The brake control system 18 includes a hydraulic pump 20 that generates the brake fluid pressure required to generate braking force in the brake device 16 provided on each wheel. The hydraulic pump 20 is driven by, for example, the electric power supplied from the battery, and generates the brake hydraulic pressure required to generate the braking force in each brake device 16 even when the brake pedal is not depressed. It is possible. Further, the brake control system 18 is a valve unit 22 for controlling the hydraulic pressure supplied from the hydraulic pump 20 to the brake device 16 of each wheel, which is provided in the hydraulic pressure supply line to the brake device 16 of each wheel. (Specifically, it is equipped with a solenoid valve). For example, the opening degree of the valve unit 22 is changed by adjusting the amount of electric power supplied from the battery to the valve unit 22. Further, the brake control system 18 includes a hydraulic pressure sensor 24 that detects the hydraulic pressure supplied from the hydraulic pressure pump 20 to the brake device 16 of each wheel. The hydraulic pressure sensor 24 is arranged, for example, at the connection portion between each valve unit 22 and the hydraulic pressure supply line on the downstream side thereof, detects the hydraulic pressure on the downstream side of each valve unit 22, and determines the detected value by PCM (Power-train). Output to Control Module) 14.

The brake control system 18 calculates the hydraulic pressure independently supplied to the wheel cylinders and brake calipers of each wheel based on the braking force command value input from the PCM 14 and the detection value of the hydraulic pressure sensor 24, and calculates the hydraulic pressure thereof. The rotation speed of the hydraulic pump 20 and the opening degree of the valve unit 22 are controlled according to the hydraulic pressure.

Further, the brake control system 18 executes wheel lock prevention control (ABS control) for controlling the braking force by the brake device 16 so as to prevent the wheels from being locked. Specifically, the brake control system 18 forcibly lowers the brake fluid pressure in order to release the lock of the wheel when the wheel is locked (in other words, when the wheel slips). After that, the hydraulic pump 20 and the valve unit 22 are controlled so as to repeat the operation of raising the brake fluid pressure again in a short time. In this case, the brake control system 18 calculates the slip ratio of each wheel based on the wheel speed, and determines that the wheel is in the locked state when the calculated slip ratio exceeds a predetermined threshold value. Perform wheel lock prevention control.

Next, with reference to FIG. 2, the electrical configuration of the vehicle control device according to the embodiment of the present invention will be described. FIG. 2 is a block diagram showing an electrical configuration of a vehicle control device according to an embodiment of the present invention.

In the PCM 14 according to the present embodiment, in addition to the detection signals of the sensors 8, 10, 11, 12, 13, and 24 described above, each part of the engine 4 is based on the detection signals output by various sensors for detecting the operating state of the engine 4. (Typically, the spark plug 26. In addition, the throttle valve, the turbo supercharger, the variable valve mechanism, the fuel injection valve, the EGR device, etc.) and the brake control system 18 are controlled to be controlled. Output a signal.

The PCM 14 and the brake control system 18 each include one or more processors and various programs (basic control programs such as an OS) that are interpreted and executed on the processors, and application programs that are started on the OS and realize specific functions. ), And a computer equipped with an internal memory such as a ROM or RAM for storing programs and various data. Although the details will be described later, the PCM 14 and the brake control system 18 correspond to the "controller" in the present invention.

<Vehicle attitude control>
Next, the specific control contents executed by the vehicle control device will be described. First, with reference to FIG. 3, the overall flow of the attitude control process performed by the vehicle control device in the embodiment of the present invention will be described. FIG. 3 is a flowchart of the attitude control process according to the embodiment of the present invention.

The attitude control process of FIG. 3 is activated when the ignition of the vehicle 1 is turned on and the power is turned on to the PCM 14 or the like, and is repeatedly executed at a predetermined cycle (for example, 50 ms).
When the attitude control process is started, as shown in FIG. 3, in step S1, the PCM 14 acquires various information of the vehicle 1. Specifically, the PCM 14 includes a steering angle detected by the steering angle sensor 8, a vehicle speed detected by the vehicle speed sensor 10, a yaw rate detected by the yaw rate sensor 12, a brake depression amount detected by the brake depression amount sensor 13, and the like. The detection signals output by the various sensors of 1 are acquired.

Next, in step S2, the PCM 14 executes the additional deceleration setting process and sets the additional deceleration to be added to the vehicle 1.
Subsequently, in step S3, the PCM 14 executes the target yaw moment setting process and sets the target yaw moment to be applied to the vehicle 1.

Next, in step S4, the PCM 14 controls the engine 2 so as to add the additional deceleration set in step S2 to the vehicle 1. In this case, the PCM 14 reduces the output torque of the engine 2 so as to add the set additional deceleration to the vehicle 1. Typically, the PCM 14 controls the spark plug 26 to retard the ignition timing in the engine 4 to reduce the output torque of the engine 2.

Further, in step S4, the brake control system 18 controls the brake device 16 so as to apply the target yaw moment set in step S3 to the vehicle 1. The brake control system 18 stores in advance a map that defines the relationship between the yaw moment command value and the rotation speed of the hydraulic pump 20, and by referring to this map, it is set in the target yaw moment setting process in step S3. The hydraulic pump 20 is operated at the rotation speed corresponding to the yaw moment command value (for example, by increasing the power supply to the hydraulic pressure pump 20, the hydraulic pressure pump 20 reaches the rotation speed corresponding to the braking force command value. Increase the number of revolutions).

Further, the brake control system 18 stores, for example, a map that defines the relationship between the yaw moment command value and the opening degree of the valve unit 22 in advance, and by referring to this map, it corresponds to the yaw moment command value. The valve unit 22 is individually controlled so as to have an opening degree (for example, by increasing the power supplied to the solenoid valve, the opening degree of the solenoid valve is increased to the opening degree corresponding to the braking force command value). Adjust the braking force of the wheels. If the target yaw moment is not set in step S3, the brake control system 18 does not control step S4.

After step S4 described above, the PCM 14 ends the attitude control process.

Next, the additional deceleration setting process according to the embodiment of the present invention will be described with reference to FIGS. 4 and 5. FIG. 4 is a flowchart of the additional deceleration setting process according to the embodiment of the present invention, and FIG. 5 is a map showing the relationship between the additional deceleration and the steering speed according to the embodiment of the present invention.

As shown in FIG. 4, when the additional deceleration setting process is started, in step S11, the PCM 14 calculates the steering speed based on the steering angle acquired in step S1 of the behavior control process of FIG.

Next, in step S12, the PCM 14 determines whether or not the steering wheel 6 is in the cutting operation (that is, the steering angle (absolute value) is increasing) and the steering speed is equal to or higher _than the predetermined threshold value S1.
As a result, if the cutting operation is in progress and the steering speed is equal to or higher than the threshold value S ₁ , the process proceeds to step S13, and the PCM 14 sets the additional deceleration based on the steering speed. This additional deceleration is a deceleration that should be added to the vehicle 1 according to the steering operation in order to accurately realize the vehicle behavior intended by the driver.

Specifically, the PCM 14 sets the additional deceleration corresponding to the steering speed calculated in step S11 based on the relationship between the steering speed and the additional deceleration shown in the map of FIG.
In FIG. 5, the horizontal axis indicates the steering speed, and the vertical axis indicates the additional deceleration. As shown in FIG. 5, when the steering speed is less than the threshold value S ₁ , the corresponding additional deceleration is 0. That is, when the steering speed is less than the threshold value S ₁ , the PCM 14 does not perform control for adding deceleration to the vehicle 1 based on the steering operation (specifically, reduction of the output torque of the engine 4).
On the other hand, when the steering speed is equal to or higher than the threshold value S ₁ , the additional deceleration corresponding to the steering speed gradually approaches a predetermined upper limit value D _max as the steering speed increases. That is, as the steering speed increases, the additional deceleration increases, and the rate of increase in the amount of increase decreases. This upper limit value D _max is set to such a deceleration that the driver does not feel that there is control intervention even if the deceleration is added to the vehicle 1 according to the steering operation (for example, 0.5 m / s ² ≈ 0). .05G).
Further, when the steering speed is equal to or higher than the threshold value S ₂ larger than the threshold value S ₁ , the additional deceleration is maintained at the upper limit value D _max .
After step S13, the PCM 14 ends the additional deceleration setting process and returns to the main routine.

If the steering wheel 6 is not being cut (that is, the steering angle is constant or decreasing) or the steering speed is _less than the threshold value S1 in step S12, the PCM 14 ends the additional deceleration setting process and the main routine. Return to.

The PCM 14 reduces the output torque of the engine 4 in step S4 of the attitude control process of FIG. 3 so as to realize the additional deceleration set based on the increasing speed of the steering angle in the above-mentioned additional deceleration setting process. In this way, when the steering wheel 6 is cut, the vertical load of the front wheels 2 is increased by reducing the output torque of the engine 4 based on the steering speed, which is good for the cutting operation by the driver. The behavior of the vehicle 1 can be controlled by the responsiveness.

Next, the target yaw moment setting process in the embodiment of the present invention will be described with reference to FIGS. 6 to 8.

FIG. 6 is a flowchart of the target yaw moment setting process according to the embodiment of the present invention, FIG. 7 is a map showing a threshold value used in the target yaw moment setting process according to the embodiment of the present invention, and FIG. 8 is a map showing the present invention. It is a map which showed the gain used in the target yaw moment setting process by embodiment of an invention.

As shown in FIG. 6, when the target yaw moment setting process is started, in step S31, the PCM 14 sets the target yaw rate and the target lateral jerk based on the steering angle and the vehicle speed acquired in step S1 of the attitude control process of FIG. calculate. Specifically, the PCM 14 calculates the target yaw rate by multiplying the steering angle by a coefficient corresponding to the vehicle speed. Further, the PCM 14 calculates the target lateral jerk based on the steering speed and the vehicle speed.

Next, in step S32, the PCM 14 determines the difference (yaw rate difference) Δγ between the yaw rate (actual yaw rate) detected by the yaw rate sensor 12 acquired in step S1 of the attitude control process of FIG. 3 and the target yaw rate calculated in step S31. calculate.

Next, in step S33, the PCM 14 sets the threshold values Y ₁ and S ₃ used in the determination in the following processing according to the brake depression amount acquired in step S1, and sets the target yaw moment in the following processing. Set the gain used to do this.

First, the setting of the threshold values Y ₁ and S ₃ will be specifically described with reference to FIG. 7. These thresholds Y ₁ and S ₃ are used in different determinations in step S34 (including S36) and step S37, which will be described later, but are basically predetermined according to the turning back operation of the steering wheel 6. It is used to set the target yaw moment to be applied to the vehicle when the parameters are greater than or equal to the thresholds Y ₁ and S ₃ (ie, the target yaw when the given parameters are less than or equal to the thresholds Y ₁ and S ₃ ). No moment is set). In the description of FIG. 7, "threshold value Y ₁ " and "threshold value S ₃ " may be simply referred to as "threshold value".

FIG. 7 is a map defining a threshold value used to set a target yaw moment in an embodiment of the present invention. This map is created in advance and stored in a memory or the like. In FIG. 7, the horizontal axis shows the brake depression amount, and the vertical axis shows the threshold value. As shown in FIG. 7, when the brake depression amount is larger than 0, that is, when the brake pedal is depressed, the threshold value is uniformly set to "Th1", and when the brake depression amount is 0, that is, The map is defined so that when the brake pedal is not depressed, the threshold is set to "Th2", which is smaller than "Th1". For the threshold value Th1, a considerably large value is applied, which cannot actually be taken by a predetermined parameter (parameter to be determined using the above-mentioned threshold values Y ₁ and S ₃ ) according to the turning back operation of the steering wheel 6. The wheel. On the other hand, a value relatively smaller than the value that such a predetermined parameter can actually take is applied to the threshold value Th2.

According to such a map, when the brake depression amount is larger than 0, a considerably large threshold value Th1 is applied, so that a condition that a predetermined parameter corresponding to the turning back operation of the steering wheel 6 is equal to or more than the threshold value is satisfied. There is nothing to do. As a result, the target yaw moment is not set in the following processing. That is, when the braking force is applied to all the wheels by the brake device 16, the control (vehicle yaw control) of applying the yaw moment in the direction opposite to the actual yaw rate to the vehicle 1 by the brake device 16 is not executed, in other words. Vehicle yaw control will be prohibited. As a result, it becomes possible to appropriately suppress the driver from feeling uncomfortable by executing the vehicle yaw control when the braking force is applied to all the wheels.

On the other hand, when the brake depression amount is 0, a relatively small threshold value Th2 is applied, so that there is an appropriate opportunity to satisfy the condition that the predetermined parameter corresponding to the turning back operation of the steering wheel 6 is equal to or higher than the threshold value. Secured. Therefore, when the braking force is not applied to all the wheels by the brake device 16, the vehicle yaw control is appropriately executed. Therefore, when the braking force is not applied to all the wheels, it is possible to appropriately secure the responsiveness improving function of the vehicle 1 by the vehicle yaw control, that is, the function of quickly stabilizing the vehicle behavior according to the steering operation.

Note that FIG. 7 schematically shows the tendency of both the threshold values Y ₁ and S ₃ according to the brake depression amount, and actually, according to such a tendency, the threshold value Y according to the brake depression amount. Each of ₁ and S ₃ is set separately. That is, for each of the threshold value Y ₁ and the threshold value S ₃ used in the different determinations of step S34 (including S36) and step S37, a map corresponding to the brake depression amount is defined, and in principle, the threshold value Y ₁ and the threshold value S are defined. It is set to a value different from ₃ . Further, these threshold values Y ₁ and S ₃ are set by matching the values according to the characteristics of the vehicle 1 to which the vehicle yaw control is applied by performing simulations and experiments in advance (the same applies to the gain described later). be).

Next, with reference to FIG. 8, the gain used for setting the target yaw moment in the embodiment of the present invention will be specifically described. FIG. 8 is a map defining the gain according to the embodiment of the present invention. This map is created in advance and stored in a memory or the like. In FIG. 8, the horizontal axis shows the amount of brake depression, and the vertical axis shows the gain. This gain is set to a value from 0 to 1 according to the brake depression amount (0 ≦ gain ≦ 1), and is used to multiply the target yaw moment calculated by the method described later. That is, the value obtained by multiplying the gain, which is a value from 0 to 1, is used as the target yaw moment to be finally applied.

As shown in FIG. 8, when the brake depression amount is larger than 0, that is, when the brake pedal is depressed, the gain is set to 0, and when the brake depression amount is 0, that is, the brake pedal is depressed. When not, the map is specified so that the gain is set to "G1". For example, "1" is applied to the gain G1. According to such a map, when the brake depression amount is larger than 0, the gain becomes 0, so that the set target yaw moment becomes 0. As a result, when the braking force is not applied to all the wheels by the braking device 16, the vehicle yaw control is substantially prohibited. This also makes it possible to appropriately suppress the driver from feeling uncomfortable by executing the vehicle yaw control when braking force is applied to all the wheels.

On the other hand, when the brake depression amount is 0, a gain G1 having an appropriate value (for example, "1") is applied. As a result, when braking force is not applied to all wheels by the braking device 16, an appropriate target yaw moment is applied and vehicle yaw control is executed, so that the vehicle behavior is quickly stabilized according to the steering operation of the driver. It is possible to properly secure the conversion function.

Returning to FIG. 6, the description of the processes after step S34 will be resumed. In step S34, the PCM14 is in the turning back operation of the steering wheel 6 (that is, the steering angle is decreasing), and the change speed Δγ ′ of the yaw rate difference obtained by time-differentiating the yaw rate difference Δγ is the threshold value Y ₁ . It is determined whether or not it is the above. The PCM 14 uses the value set in step S33 as the threshold value Y ₁ .

As a result, when the switchback operation is performed and the yaw rate difference change rate Δγ ′ is equal to or higher than the threshold value Y ₁ , the process proceeds to step S35, and the PCM 14 sets the yaw rate difference change rate Δγ ′ and the gain set in step S33. Based on this, the yaw moment in the direction opposite to the actual yaw rate of the vehicle 1 is set as the target yaw moment. Specifically, the PCM 14 calculates the magnitude of the reference target yaw moment by multiplying a predetermined coefficient by the change rate Δγ'of the yaw rate difference, and further increases the gain with respect to the reference target yaw moment. By riding, the magnitude of the target yaw moment to be applied to the vehicle 1 is calculated.

On the other hand, in step S34, when the steering wheel 6 is not being turned back (that is, the steering angle is constant or increasing), the process proceeds to step S36, and the PCM14 targets the actual yaw rate at the change speed Δγ ′ of the yaw rate difference. It is determined whether or not the direction is larger than the yaw rate (that is, the direction in which the behavior of the vehicle 1 becomes oversteer) and the change speed Δγ ′ of the yaw rate difference is equal to or more than the threshold value Y ₁ . Specifically, the PCM14 is used when the yaw rate difference is decreasing when the target yaw rate is equal to or higher than the actual yaw rate, or when the yaw rate difference is increasing when the target yaw rate is less than the actual yaw rate. It is determined that the change rate Δγ ′ of the yaw rate difference is the direction in which the actual yaw rate becomes larger than the target yaw rate.

As a result, when the change rate Δγ ′ of the yaw rate difference is in the direction in which the actual yaw rate is larger than the target yaw rate and the change rate Δγ ′ of the yaw rate difference is the threshold value Y ₁ or more, the process proceeds to step S35, and the PCM 14 is the same as described above. Then, based on the change rate Δγ ′ of the yaw rate difference and the gain set in step S33, the yaw moment opposite to the actual yaw rate of the vehicle 1 is set as the target yaw moment.

After step S35 or in step S36, if the change rate Δγ ′ of the yaw rate difference is in the direction in which the actual yaw rate is larger than the target yaw rate or the change rate Δγ ′ of the yaw rate difference is less than the threshold value Y ₁ , the process proceeds to step S37. , _PCM14 determines whether or not the steering wheel 6 is being turned back (that is, the steering angle is decreasing) and the steering speed is equal to or higher than a predetermined threshold value S3. The PCM 14 uses the value set in step S33 as the threshold value S ₃ .

As a result, when turning back and the steering speed is the threshold value S3 or more _, the process proceeds to step S38, and the PCM14 of the vehicle 1 is based on the target lateral jerk calculated in step S31 and the gain set in step S33. The yaw moment opposite to the actual yaw rate is set as the second target yaw moment. Specifically, the PCM14 calculates the magnitude of the reference second target yaw moment by multiplying the target lateral jerk by a predetermined coefficient, and gains with respect to the reference second target yaw moment. Is further multiplied to calculate the magnitude of the second target yaw moment to be applied to the vehicle 1.

After step S38, or when the steering wheel 6 is not being turned back (that is, the steering angle is constant or increasing) or the steering speed is less than the threshold value S3 in step S37 _, the process proceeds to step S39 and PCM14. Sets the larger of the target yaw moment set in step S35 and the second target yaw moment set in step S38 as the yaw moment command value. If the target yaw moment is not set in both steps S35 and S38 (that is, if the processes of steps S35 and S38 are not executed), the PCM 14 does not set the yaw moment command value in step S39. .. After step S39, the PCM 14 ends the target yaw moment setting process and returns to the main routine.

<Action effect>
Next, the operation and effect of the vehicle control device according to the embodiment of the present invention will be described.

According to the present embodiment, when the braking force is applied to all the wheels by the braking device 16 at the time of turning back operation of the steering wheel 6, the PCM 14 has the actual yaw rate generated in the vehicle 1 as compared with the case where the braking force is not applied. Suppresses the vehicle yaw control for applying the reverse yaw moment to the vehicle 1. As a result, it is possible to appropriately suppress the driver from feeling uncomfortable by executing the vehicle yaw control when the braking force is applied to all the wheels. Specifically, it is possible to suppress that the wheel is locked by applying a further braking force to the turning outer wheel by the vehicle yaw control, and it is possible to suppress that the wheel lock prevention control is executed by the lock of the wheel. In addition, the vehicle yaw control applies a braking force that is greater than the depressing operation of the brake pedal. It can be suppressed from being lost.

In particular, according to the present embodiment, the PCM 14 prohibits vehicle yaw control when braking force is applied to all wheels by the brake device 16, so that the driver feels uncomfortable by executing vehicle yaw control at this time. Can be reliably suppressed.

Further, according to the present embodiment, in the PCM 14, the value (change speed Δγ ′ or steering speed of yaw rate difference) corresponding to the turning back operation of the steering wheel 6 becomes a predetermined threshold value (threshold Y ₁ or S ₃ ) or more. At that time, vehicle yaw control is executed, and when braking force is applied to all wheels by the braking device 16, a considerably large value is applied to the threshold value, so that vehicle yaw control can be reliably prohibited.

Further, according to the present embodiment, the PCM 14 can reliably prohibit the vehicle yaw control by setting the gain applied to the yaw moment to 0 when the braking force is applied to all the wheels by the braking device 16. become.

Further, according to the present embodiment, the PCM 14 sets a target lateral jerk based on the steering speed and the vehicle speed when the steering speed acquired based on the detection value of the steering angle sensor 8 becomes the threshold value S ₃ or more. Set the yaw moment applied in vehicle yaw control based on the target lateral jerk. As a result, a yaw moment of a magnitude corresponding to the speed of the driver's steering operation can be applied in the direction of suppressing the turning of the vehicle 1, and the vehicle behavior can be quickly stabilized according to the driver's steering operation. ..

Further, according to the present embodiment, in the PCM 14, the change speed of the difference between the actual yaw rate actually generated in the vehicle 1 and the target yaw rate set based on the detection value of the steering angle sensor 8 is the threshold value Y ₁ or more. At that time, the yaw moment applied in the vehicle yaw control is set based on the change speed. As a result, when the steering wheel is operated on a low μ road such as a snow-packed road, the yaw moment in the direction of immediately suppressing the turn in response to a sudden change in the yaw rate difference due to the response delay of the actual yaw rate is applied to the vehicle. It can be given to 1, and in the situation before the behavior of the vehicle 1 becomes unstable, the behavior of the vehicle can be quickly stabilized according to the steering operation of the driver.

<Modification example>
Next, a modified example of this embodiment (synonymous with other embodiments) will be described. The plurality of modifications shown below can be implemented in combination with each other as appropriate.

(Modification 1)
In the above embodiment, when the braking force is applied to all the wheels by the braking device 16, by using a threshold value having a considerably large value, the vehicle yaw control is substantially prohibited and applied to the yaw moment. By setting the gain to 0, the vehicle yaw control was substantially prohibited. In the modified example, when braking force is applied to all wheels by the braking device 16, vehicle yaw control is uniformly prohibited without performing determination or processing using such a threshold value or gain. good.

Further, in the above-described embodiment, when the brake depression amount detected by the brake depression amount sensor 13 is larger than 0, it is determined that the braking force is applied to all the wheels by the brake device 16, and the vehicle yaw control is performed. However, in the modified example, instead of using such a brake depression amount, it is determined that the braking force is applied to all the wheels by the braking device 16 when the brake switch 11 is on. Then, the vehicle yaw control may be prohibited. In a further modification, based on the hydraulic pressure (brake hydraulic pressure) detected by the hydraulic pressure sensor 24, it is determined whether or not braking force is applied to all the wheels by the braking device 16, and vehicle yaw control is performed. It may be prohibited.

(Modification 2)
In the above-described embodiment, the threshold value is set to a constant value Th1 regardless of the magnitude of the brake depression amount (see FIG. 7), but the threshold value is not limited to be defined in this way. In the modified example, the size of the threshold value may be changed according to the size of the brake depression amount. FIG. 9 is a map showing a threshold value used in the target yaw moment setting process according to the modified example of the embodiment of the present invention. This map is created in advance and stored in a memory or the like. In FIG. 9, the horizontal axis shows the brake depression amount, and the vertical axis shows the threshold value. This threshold value is also applied to the above-mentioned threshold values Y ₁ and S ₃ , and is used in the determination of step S34 (including S36) and step S37 in FIG.

As shown in FIG. 9, when the brake depression amount is less than the predetermined value, the threshold value increases from "Th2" as the brake depression amount increases, and when the brake depression amount is equal to or more than the predetermined value, the threshold value is increased. The map is defined so that is uniformly set to "Th1" which is larger than "Th2". The same values as in FIG. 7 are applied to the threshold values Th1 and Th2. According to such a map, when the brake depression amount is less than a predetermined value, the vehicle yaw control is suppressed as the brake depression amount increases while ensuring the execution of the vehicle yaw control when the brake depression amount is small to some extent. The degree can be increased, and on the other hand, when the brake depression amount is equal to or more than a predetermined value, vehicle yaw control can be reliably prohibited.

Further, in the above-described embodiment, the gain is set to 0 regardless of the magnitude of the brake depression amount (see FIG. 8), but the gain is not limited to be specified in this way. In the modified example, the magnitude of the gain may be changed according to the magnitude of the brake depression amount. FIG. 10 is a map showing the gain used in the target yaw moment setting process according to the modified example of the embodiment of the present invention. This map is created in advance and stored in a memory or the like. In FIG. 10, the horizontal axis shows the amount of brake depression, and the vertical axis shows the gain. This gain is also set to a value from 0 to 1 according to the brake depression amount (0 ≦ gain ≦ 1), and is used to multiply the target yaw moment in steps S35 and S38 of FIG.

As shown in FIG. 10, when the brake depression amount is less than the predetermined value, the gain decreases from "G1" as the brake depression amount increases, and when the brake depression amount is more than the predetermined value, the gain The map is specified so that is set to a fairly small value (a constant value close to 0). A value similar to that in FIG. 8 is applied to the gain G1. According to such a map, when the brake depression amount is less than a predetermined value, the vehicle yaw control is suppressed as the brake depression amount increases while ensuring the execution of the vehicle yaw control when the brake depression amount is small to some extent. The degree can be increased, and on the other hand, when the brake depression amount is equal to or more than a predetermined value, the vehicle yaw control can be substantially prohibited.

It should be noted that the brake depression amount may change during the turning back operation of the steering wheel 6, but it is preferable that the threshold value and the gain applied are not changed according to such a change in the brake depression amount. Is good. That is, after the predetermined parameter corresponding to the turning back operation of the steering wheel 6 becomes equal to or greater than the threshold value and the vehicle yaw control is started, the threshold value and the gain are not changed according to the change in the brake depression amount, and the threshold value and the gain are not changed. It is better to apply a fixed value as the gain. In particular, the threshold value and the gain are set based on the brake depression amount when the steering wheel 6 turning back operation is started, and the threshold value and the gain are set according to the change in the brake depression amount during the vehicle yaw control. It is advisable to consistently apply the thresholds and gains thus set without change.

Further, in the above-mentioned modification, both the threshold value and the gain are changed according to the brake depression amount, but in the further modification example, even if only one of these threshold value and the gain is changed according to the brake depression amount. good.

(Modification 3)
The suppression of vehicle yaw control in the present invention is not limited to being applied when the driver depresses the brake pedal. In general cruise control (auto cruise), braking force is automatically applied by the brake device 16 to decelerate the vehicle even if the driver does not depress the brake pedal so as to maintain the set vehicle speed. There is. INDUSTRIAL APPLICABILITY The present invention can apply the suppression of vehicle yaw control even in such a case, that is, when the braking force is automatically applied to all the wheels without the driver depressing the brake pedal.

(Modification example 4)
In the above-described embodiment, when the braking force is applied to all the wheels by the braking device 16, the vehicle yaw control is suppressed, and as a result, the wheel lock prevention control is suppressed, but in the modified example, the wheel lock prevention control is suppressed. , The wheel lock prevention control may be suppressed when the vehicle yaw control is executed. For example, when executing vehicle yaw control, a threshold value applied to the wheel slip ratio to determine whether to execute wheel lock prevention control (wheel lock prevention control when the slip ratio exceeds the threshold). (Used to execute) should be increased. According to such a modification, it is possible to effectively suppress the driver from feeling uncomfortable due to the wheel lock prevention control being executed during the vehicle yaw control.

(Modification 5)
In the above-described embodiment, both the setting of the target yaw moment based on the change rate Δγ'of the yaw rate difference (step S35 in FIG. 6) and the setting of the target yaw moment based on the target lateral jerk (step S38 in FIG. 6) are executed. However, in the modified example, only one of these two target yaw moments may be set.

(Modification 6)
In the above embodiment, an example is shown in which the rotation angle (angle detected by the steering angle sensor 8) of the steering column connected to the steering wheel 6 is used as the steering angle of the vehicle 1, but in the modified example, the steering column Even if various state quantities in the steering system (rotation angle of the motor that applies assist torque, rack displacement in rack and pinion, etc.) are used as the steering angle of the vehicle 1 instead of the rotation angle or together with the rotation angle of the steering column. good.

1 Vehicle 2 Front wheels 4 Engine 6 Steering wheel 8 Steering angle sensor 10 Vehicle speed sensor 11 Brake switch 12 Yaw rate sensor 13 Brake depression sensor 14 PCM
16 Brake device 18 Brake control system

Claims (7)

A vehicle control device having a steering device, a brake device capable of applying different braking forces to the left and right wheels, and a controller.
The controller
Based on the return operation of the steering device, vehicle yaw control for controlling the brake device is executed so as to apply a yaw moment in the direction opposite to the yaw rate generated in the vehicle to the vehicle.
When braking force is applied to all wheels by the braking device during the return operation of the steering device, the vehicle yaw control is suppressed more than when braking force is not applied.
The controller executes the vehicle yaw control when the value corresponding to the return operation of the steering device becomes a predetermined threshold value or more, and the larger the braking force applied to all the wheels by the braking device, the more the said. A vehicle control device characterized in that it is configured to increase the threshold . The vehicle control device according to claim 1, wherein the controller is configured to reduce the yaw moment applied by the vehicle yaw control as the braking force applied to all wheels by the brake device increases. The controller according to claim 1 or 2 , further comprising a wheel lock prevention control for controlling the braking force of the braking device so as to prevent the wheels from being locked. Vehicle control device. The vehicle control device according to claim 3 , wherein the controller is configured to suppress the wheel lock prevention control when the vehicle yaw control is executed as compared with the case where the control is not performed. The vehicle control device according to any one of claims 1 to 4 , wherein the braking force is applied to all the wheels by the brake device when the brake pedal is depressed by the driver. When the steering speed of the steering device becomes equal to or higher than a predetermined threshold value, the controller sets the yaw moment based on the target lateral jerk according to the steering speed and the vehicle speed, and transfers this yaw moment to the vehicle. The vehicle control device according to any one of claims 1 to 5 , which is configured to execute the vehicle yaw control so as to be added. The controller determines the change speed when the change speed of the difference between the target yaw rate according to the steering angle and the vehicle speed of the steering device and the actual yaw rate actually generated in the vehicle becomes equal to or more than a predetermined threshold value. The vehicle control device according to any one of claims 1 to 5 , which is configured to set the yaw moment based on the yaw moment and execute the vehicle yaw control so as to add the yaw moment to the vehicle. ..

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