JP2818902B2 - Vehicle travel control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a vehicle which performs slip control such as traction control or anti-skid control, and in which the content of the slip control is corrected in case of a rough road. It relates to a control device.

(Prior Art) Conventionally, wheel slip control such as traction control and anti-skid control has been known.

Traction control detects the slip ratio of the drive wheels and controls the engine output and control force to prevent the drive wheels from slipping due to excessive drive torque and deteriorating the acceleration during acceleration or the like. The slip ratio of the drive wheels is controlled to be a predetermined target slip ratio by decreasing or increasing the braking force.

Further, the anti-skid control detects a wheel slip ratio and brakes (reduces) the braking force in order to prevent the wheels from being locked due to excessive braking force during braking and reducing braking performance. The slip ratio of the wheel is controlled to be a predetermined target slip ratio.

By the way, in the traction control, when the traveling road surface is a rough road, that is, a road surface with a lot of unevenness, it is conceivable to increase the target slip ratio as compared with a case of a good road in order to prevent a decrease in acceleration.

That is, when the road is rough, the wheel speed changes greatly due to unevenness of the road surface, and the slip ratio detected based on the wheel speed also changes greatly. As a result, in actuality, the traction control is not particularly required. Regardless, the traction control is often performed when the slip ratio exceeds the target slip ratio, and a situation occurs in which the driving torque is reduced and the acceleration is reduced. Therefore, in the case of a rough road, it is conceivable to set a high target slip ratio and make it difficult to perform traction control, thereby preventing a reduction in driving torque and, consequently, a reduction in acceleration.

Also in anti-skid control, it is conceivable to increase the target slip ratio as compared to a good road in order to enhance braking performance on a bad road.

In other words, in the case of a rough road, the driving performance is improved by locking the wheels and hooking the wheels on unevenness of the road surface. Therefore, in the case of a rough road, it is conceivable that the target slip ratio is set to a high value and the anti-skid control is hardly performed, so that the wheels tend to lock and the braking performance is improved.

In order to perform the above-described rough road correction, that is, to correct the content of the slip control such as increasing the target slip ratio in the case of a rough road, it is necessary to determine whether or not the traveling road surface is a rough road. However, as an apparatus for performing such a rough road determination, for example, an apparatus described in Japanese Patent Application Laid-Open No. 64-29636 is known.

By the way, as a rough road determination, a determination based on a method different from that described in the above publication may be considered.

For example, a bad road determination is performed on each of the left and right wheels based on a change in the speed of the left and right wheels, and a final rough road determination is performed based on those results. It is conceivable that the road may be determined to be a rough road, or if one of the wheels is determined to be a rough road, the road is finally determined to be a rough road.

(Problems to be Solved by the Invention) However, in the rough road correction of the slip control, when any one of the wheels is determined to be a rough road, that is, when it is better to perform the rough road correction on a one-wheel rough road. In some cases, it may be better to perform rough road correction only when both wheels are determined to be a rough road, that is, only when both wheels are on a rough road. In other words, it should be different depending on various situations whether it is better to perform the rough road correction, and if the rough road correction is always performed in one of the situations, the appropriate rough road correction can be performed in a certain situation. In other situations, a situation may occur in which proper rough road correction cannot be performed.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a vehicle capable of always performing appropriate rough road correction in accordance with various situations when performing rough road correction based on the results of rough road determination performed on the left and right wheels. It is to provide a travel control device.

(Means for Solving the Problems) To achieve the above object, a traveling control device for a vehicle according to the present invention includes a slip control means for controlling a slip of a wheel, A left-wheel rough road determining means for determining whether or not a rough road is based on the change state; a right-wheel rough road determining means for determining whether or not the rough road is based on a changing state of the right wheel speed; First bad road determination means for determining a bad road when both the left wheel and right wheel rough road determination means determine a bad road, and at least one of the left wheel and right wheel rough road determination means for determining a bad road. And selecting one of the first and second rough road determination means in accordance with the traveling state or the type of slip control in the slip control means. The determined rough road determining means has determined that the road is rough. Characterized in that it comprises an, a rough road correction means for correcting the contents of the slip control of the slip control means.

As the slip control of the wheels, for example, traction control or anti-skid control can be considered.

The above-described left-wheel rough road determination means and right-wheel rough road determination means may be of any type as long as they perform rough road determination based on the respective wheel speed changes.

The running state corresponds to various things such as an accelerator opening, a yaw rate, and a traction control mode.

The type of the slip control refers to, for example, traction control, anti-skid control, and the like.

To correct the content of the slip control means to change the direction in which less control is applied. As the correction in the direction in which no control is applied, for example, a method of increasing a target slip ratio or a method of setting a control start threshold value may be used. There are those that make it larger and those that make the control amount smaller.

The following can be considered as a specific example as to which of the two-wheel rough road and the one-wheel rough road is used to perform the rough road correction.

(1) In the case of the anti-skid control as described in claim 2, a rough road correction is performed on a rough road with two wheels.

(2) As described in claim 3, in traction control, when the accelerator opening is small, a rough road correction is performed on a rough road with both wheels.

(3) As described in claim 4, in traction control, when the accelerator opening is large, rough road correction is performed on a single-wheel rough road.

(Operation) Whether it is better to perform the rough road correction on a two-wheel rough road or the bad road correction on a one-wheel rough road depends on the type of slip control and the traveling state, among various situations. It depends on how.

Therefore, by selecting whether to perform the rough road correction on the two-wheel rough road or the one-wheel rough road depending on the type of slip control and the running state as described in claim 1, it is possible to solve various situations. Optimal rough road correction can always be performed.

Further, in the case of the anti-skid control as described above, if the rough road correction is performed, the wheels tend to lock. However, in this case, if a rough road correction is performed immediately on a rough road with one wheel, both wheels are subjected to the rough road correction and tend to lock, so that the other wheel that is not on a rough road also tends to lock, and as a result, The braking performance of the wheels is deteriorated, and the braking performance of the entire wheels is reduced.

Therefore, in the case of the anti-skid control as described in the second aspect, by performing the rough road correction when the two wheels are on a rough road, it is possible to prevent a decrease in the braking performance of the vehicle due to the rough road correction.

In addition, as described above, the rough road correction in the traction control improves the acceleration. However, when the accelerator opening is small, it can be said that the driver does not demand much acceleration. Therefore, it is not necessary to immediately perform a rough road correction on a one-wheel rough road, and it is sufficient to perform a rough road correction after a two-wheel rough road.

Therefore, when the accelerator opening is small in the traction control as described in the third aspect, by performing the rough road correction on the two-wheel rough road, it is possible to more appropriately match the driver's intention with the rough road. Road correction becomes possible.

Furthermore, when the accelerator opening is large, the driver seeks acceleration. Therefore, when the accelerator opening is large in the traction control as described in claim 4, the rough road correction is performed on a one-wheel rough road, so that an appropriate more suitable for the driver's intention can be obtained. Bad road correction becomes possible.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of a travel control device according to the present invention.

As shown in the drawing, the present embodiment includes a slip control unit 100 that controls wheel slip, a left wheel rough road determination unit 200 that determines whether or not a rough road is based on a change state of the left wheel speed,
The right wheel bad road determination means 300 that determines whether or not the road is bad based on the change state of the right wheel speed, and the bad road when both the left wheel and the right wheel bad road determination means determine a bad road. A first rough road determining means 400 for determining, a second rough road determining means 500 for determining a rough road when at least one of the left wheel and the right wheel rough road determining means determines a rough road, One of the first and second rough road determination means is selected according to the type of slip control in the slip control means, and when the selected rough road determination means determines that the road is rough, the slip control means And a rough road correcting means 600 for correcting the content of the slip control.

Next, of the above embodiments, an embodiment including a slip control means for performing traction control as slip control will be described more specifically.

FIG. 2 is a diagram specifically showing such an embodiment. In this embodiment, slip control as traction control is performed on drive wheels, and in this traction control, both engine control and brake control are performed. .

In FIG. 2, A is an automobile provided with a travel control device according to the present embodiment. Car A has left and right front wheels 1FL and 1FR
Are the driven wheels, and the left and right rear wheels 1RL and 1RR are the drive wheels. That is, the engine 2 mounted on the front of the vehicle body
Is transmitted to the left rear wheel 1RL via the left drive shaft 6L after passing through the automatic transmission 3, the propeller shaft 4, and the differential gear 5, while being transmitted to the right rear wheel 1RR via the right drive shaft 6R.
Is transmitted to

Configuration of Automatic Transmission The automatic transmission 3 includes a torque converter 11 and a multi-stage transmission gear mechanism 12. The shift is performed by changing the combination of the excitation and the demagnetization of the plurality of solenoids 13a incorporated in the hydraulic circuit of the transmission gear mechanism 12. Further, the torque converter 11 has a hydraulically operated lock-up clutch 11A. By switching between excitation and demagnetization of a solenoid 13b incorporated in a hydraulic circuit of the clutch, engagement and engagement of the lock-up clutch 11A are performed. Release is performed.

The solenoids 13a and 13b are controlled by a control unit UAT for an automatic transmission. This control unit UAT
As is known, the shift characteristic and the lock-up characteristic are stored in advance, and the shift control and the lock-up control are performed based on these characteristics. For this control, the control unit UA
T is a main throttle opening signal from a main throttle opening sensor 61 that detects the opening of the main throttle valve 43 described below, and a sub throttle opening sensor 62 that detects the opening of the sub throttle valve 45. , And a vehicle speed signal (in the embodiment, a rotation speed signal of the propeller shaft 4) from a vehicle speed sensor 63 for detecting the vehicle speed.

Configuration of Brake Fluid Pressure Adjusting Mechanism Each wheel 1FR-1RR is provided with a brake 21FR-21RR. Brake fluid pressure is supplied to calipers (brake cylinders) 22FR to 22RR of the brakes 21FR to 21RR via pipes 23FR to 23RR.

The structure for supplying the brake fluid pressure to each of the brakes 21FR to 21RR is as follows. First, the depressing force of the brake pedal 25 is boosted by a booster 26 using a hydraulic booster and transmitted to a tandem-type master cylinder 27. The hydraulic pressure transmitted to the master cylinder 27 is applied to the left front wheel brake 21FL via a brake pipe 23FL connected to the first discharge port 27a of the master cylinder 27.
Is transmitted to the right front wheel brake 21FR via the brake pipe 23FR connected to the second discharge port 27b of the master cylinder 27.

Hydraulic fluid pressure from a pump 29 is supplied to the booster 26 via a pipe 28, and excess hydraulic fluid is returned to a reservoir tank 31 via a return pipe 30. A branch pipe 28a branches from the pipe 28, and an electromagnetic on-off valve 32 is connected to the branch pipe 28a.
Is connected. A pipe 33 is branched from the booster 26, and the pipe 33 is connected to an electromagnetic on-off valve 34 and a one-way valve 35 arranged in parallel with the on-off valve 34.

The branch pipe 28a and the pipe 33 are joined at a junction a, and the brake pipes 23RL and 23R for the left and right rear wheels are connected to the junction a.
R is connected. Electromagnetic on-off valves 36A, 37A are connected to the pipes 23RL, 23RR, respectively, and electromagnetic on-off valves 36B, 37B are connected to relief passages 38L, 38R connected downstream of the valves 36A, 37A, respectively. I have.

Each of the valves 32, 34, 36A, 37A, 36B, and 37B described above is controlled by a traction control control unit UTR. That is, when the slip control as the brake control is not performed, the valve 32 is closed, the valve is opened, and the valve
B and 37B are closed, and valves 36A and 37A are opened. Thus, when the brake pedal 25 is depressed, the front wheel brakes 21FR, 21F
The brake fluid pressure is supplied to L via the master cylinder 27. Alternatively, the working hydraulic pressure of the booster 26 is supplied to the rear wheel brakes 21RR and 21RL via the pipe 33 as brake hydraulic pressure.

As will be described later, when the slip ratio of the rear wheels 1RR and 1RL as drive wheels to the road surface is increased and slip control as brake control is performed, the valve 34 is closed and the valve 32 is opened. Then, by the duty control of the valves 36A, 36B, 37A, 37B, the holding of the brake fluid pressure, the pressure increase and the pressure decrease are performed. More specifically, assuming that the valve 32 is closed, when the valves 36A, 36B, 37A, 37B are closed, the brake fluid pressure is maintained, the valves 36A, 37A are opened, and the valves 36B, 37B are opened. When is closed, the pressure rises, valves 36A and 37A close, and valves 36B and 3
When 7B is open, the voltage drops. The brake fluid pressure passing through the branch pipe 28a is prevented from acting as a reaction force on the brake pedal 25 by the action of the one-way valve 35.

When the brake pedal 25 is depressed during such slip control by the brake control, the hydraulic fluid pressure of the booster 26 corresponding to the depression is applied as brake fluid pressure via the one-way valve 35 to the rear wheel. Brakes 21RR and 21RL are supplied.

Configuration of the engine generated torque adjustment mechanism The control unit UTR for traction control is the drive wheel 1R
In order to perform the slip control by reducing the applied torque to L, 1RR, the brake control by applying the brake to the drive wheels 1RL, 1RR is performed, and the engine control by reducing the generated torque of the engine 2 is also performed. Therefore, a main throttle valve 43 connected to an accelerator pedal 42 and an actuator for adjusting the throttle opening are provided in the intake passage 41 of the engine.
A sub-throttle valve 45 connected to 44 is provided, and the sub-throttle valve 45 is controlled by the control unit UTR for traction control via the actuator 44.

Configuration of Control Unit The traction control control unit UTR performs brake control and engine control by controlling the throttle opening adjustment actuator 44 during slip control. The control unit UTR receives signals from wheel speed sensors 64 to 67 for detecting each wheel speed, a main throttle opening signal from a main throttle opening sensor 61, and a sub-throttle signal from a sub-throttle opening sensor 62. Throttle opening signal, vehicle speed signal from vehicle speed sensor 63, accelerator opening signal from accelerator opening sensor 68, yaw rate sensor 69
, A shift position signal from the shift position sensor 70, a steering angle signal from the steering angle sensor 71, and a traction control mode signal from a manually operated traction control mode selection switch 72.

Further, the control unit UTR has an input interface for receiving each signal from each of the above sensors, a CPU, a ROM, and an RA.
M, a microcomputer, an output interface, and a drive circuit for driving the valves 32, 34, 36A, 37A, 36B, 37B and the actuator 44.The ROM stores control programs and various control programs required for traction control. A map and the like are stored, and various memories necessary for executing control are provided in the RAM.

Next, the contents of the slip control by the control unit UTR will be described with reference to FIG.

In FIG. 3, the target slip ratio for engine control of the drive wheel is indicated by SET, and the target slip ratio for brake control of the drive wheel is indicated by SBT. Note that SBT is set to a value larger than SET.

Now, until time point t ₁ before, a large slip on the drive wheels has not occurred, the engine control is not performed, thus the sub-throttle valve 47 is fully opened, the throttle opening degree (both the throttle valve 43, Tn corresponds to the main throttle opening TH · M, and it is the accelerator opening (the opening of the accelerator pedal, which corresponds to the opening of the throttle valve having the smaller opening). , Fully open when the accelerator pedal is fully depressed).

t ₁ time, the slip ratio of the driving wheels, is started slip control by the engine control when a target slip ratio SET for the engine control, the throttle opening Tn by closing the sub-throttle valve 45 by controlling the actuator 44 Is reduced all at once to the lower limit control value SM. Then, after the throttle opening Tn is temporarily set to SM, the opening TH · S of the sub-throttle valve 45 is feedback-controlled so that the slip wheels of the drive wheels have the engine control target slip ratio SET. When the engine control is started in this way, the sub-throttle valve opening TH · S becomes smaller than the main throttle valve opening TH · M, and thus the throttle opening Tn becomes the sub-throttle valve opening TH · S. .

If a sufficient slip rate lowering effect cannot be obtained by the above engine control alone, the slip rate continues to increase,
equal to or greater than the target slip ratio SBT for the brake control in t ₂ time.

When the slip ratio of the driving wheels t ₂ time becomes equal to or higher than the target slip ratio SBT for controlling brake, drive wheel brake 21RR, 21RL
Is supplied to the vehicle, and slip control by both the engine control and the brake control is started. The brake fluid pressure is feedback-controlled such that the slip ratio of the drive wheels becomes the brake control target slip ratio SBT.

t ₃ time, the slip ratio of the driving wheels is less than the target slip ratio SBT for controlling brake, the brake fluid pressure is the pressure reduction, the slip control is terminated by the brake control eventually become the brake fluid pressure is zero. However, the slip control by the engine control is still continued.

The target slip ratios SBT and SET may be determined as appropriate. For example, the target slip ratios SBT and SET are determined by the control unit UTR based on a road surface μ, a vehicle speed, an accelerator opening, a steering angle, a selection mode of sports or hardware, and the like. Also, the SM is appropriately determined by the control unit UTR based on, for example, the road surface μ.

The brake control is performed independently on the left and right sides based on, for example, the slip ratios S _L and S _R of the left and right drive wheels. In addition, the engine control is performed by, for example, determining a slip ratio of the left and right drive wheels.
This is performed based on the larger slip ratio S _E of S _L and S _R. Incidentally, the slip ratio S _L, S _R, in the control unit UTR, based on the wheel speed signals from the wheel speed sensors 63 to 66, is calculated according to the following equation.

Where, VK _L : rotation speed of left driving wheel VK _R : rotation speed of right driving wheel JV: average value of rotation speed of left and right driven wheels Note that the slip ratio is always calculated based on the above formula. It is not necessary, and any value may be used as long as the value substantially indicates the slip state of the wheel. For example, a value obtained by simply subtracting the driven wheel speed from the driving wheel speed may be used.

By the way, as described above, in addition to the slip control means 100 (configured by the control unit UTR) for controlling the slip of the drive wheels by traction control, the travel control device further includes the wheel speed sensors 64 to 67 and From the control unit UTR, the left wheel rough road determination means 200 and the right wheel rough road determination means 300, the first rough road determination means 400 and the second rough road determination means 500 comprising the control unit UTR, and from the control unit UTR And a rough road correcting means 600.

Then, in the traveling control device, the slip control is performed by the slip control means 100 so that the slip ratio of the wheel becomes the traction control target slip ratio which is set separately as described above, and the left wheel and the right wheel Rough road determination is performed for each of the left and right wheels by the road determination means 200 and 300. In the first rough road determination means 400, both wheels are determined to be a rough road when both roads are rough. However, in the case of a rough road, it is determined that the road is a rough road, and the rough road correction means 600 appropriately determines whether the type of slip control is traction control and whether the accelerator opening degree, which is one of the running conditions, is large or small. Either one of the first rough road determining means 400 and the second rough road determining means 500 is selected, and when the selected rough road determining means determines that the road is rough, the vehicle slips. Rough road correction is performed for control (traction control).

Bad Road Correction in Traction Control Next, a specific example of bad road correction in the traction control will be described in detail with reference to FIG.

In the traction control, first, it is determined in R1 whether the accelerator opening is equal to or less than a predetermined value.

If the accelerator opening is equal to or greater than a predetermined value (for example, 50%), R2
To determine whether at least one of the left and right wheels is on a rough road, that is, the left wheel and right wheel rough road determination means 20
It is determined whether or not at least one of 0 and 300 is determined as a bad road. This determination is made by the second rough road determination means 500
Done by The rough road determination by the left and right wheel rough road determination means 200 and 300 will be described later.

If none of the roads is determined to be bad in R2, that is, if the road is not determined to be bad by the second
Proceed to 3,34 and perform normal traction control, that is,
The target slip ratio STA (SET, SBT in the above embodiment) is set to a normal target slip ratio, and slip control is performed based on the normal target slip ratio. Alternatively, the control start threshold value VSPA is set when performing the slip control, and the slip ratio is set to the VSPA (this is the target slip ratio STA).
When the slip control is started and the slip rate is controlled to reach the target slip rate STA, the control start threshold value VSPA is set to the normal control start threshold value. To perform slip control based on the VSPA.

On the other hand, if any one of the above R2 is determined as a rough road, that is, if the second rough road determination unit 500 determines that the road is a rough road, the process proceeds to R5 and R6, and after performing a rough road correction, Perform traction control. That is, the target slip ratio STA of the traction control is set to a slip ratio STA ₁ larger than the normal target slip ratio, or the control start threshold VSPA is set to a threshold VSPA larger than the normal control start threshold. Set to ₁ and perform slip control based on them.

In the above rough road correction, both the STA and the VSPA may be increased, or one of them may be increased. If there are STAs and VSPAs for engine control and brake control, both engine control and brake control may be increased, or either of them may be increased. FIG. 3 shows a mode in which the brake control target slip ratio is increased by the rough road correction (SBT → SBT ₁ ).

On the other hand, if the accelerator opening is smaller than the predetermined value in R1, the process proceeds to R7, where it is determined whether both left and right wheels have been determined to be bad roads. This determination is made by the first rough road determination means.
Done by 400.

And if none of them are bad roads,
If the rough road determination means 400 determines that the road is not a rough road, R8,
Proceeding to R9, normal traction control is performed in exactly the same manner as in the case of R3 and R4, and both wheels are determined to be a rough road, that is, when the first rough road determination means 400 determines that the road is rough. Goes to R10 and R11, and performs traction control after performing rough road correction in exactly the same manner as in the case of R5 and R6.

As described above, in the case of traction control, the first rough road determination means 400 and the second rough road determination means 500 are selectively used according to the magnitude of the accelerator opening, and when the accelerator opening is small, the first rough road determination means is used. Performs rough road correction based on the determination result of 300,
When the accelerator opening is large, the rough road correction is performed based on the determination result of the second rough road determination means 500, so that an appropriate rough road that matches the driver's will, Corrections can be made.

Wheel bad road determination Next, the left and right wheel bad road determination means 200, 300
The rough road determination for each wheel will be described.

This rough road determination focuses on the fact that in the case of a rough road, the wheels vibrate due to unevenness of the road surface, and the vibrations appear at the wheel speeds, thereby causing the time change rate (wheel acceleration) of the wheel speeds to vibrate. It is checked whether or not the number of times the amplitude of the wheel acceleration vibration (change over time of the wheel acceleration) within the time exceeds a predetermined threshold value α is larger than a predetermined threshold value β. Is determined.

The above-mentioned rough road determination may be performed on either the front or rear left and right wheels.

FIG. 5 is a flowchart showing a procedure for determining a bad road on the left front wheel. To explain according to this flowchart, first,
In S1, it is determined whether or not the timer is equal to or more than a predetermined value, that is, whether or not a predetermined time (for example, 0.7 seconds) has elapsed. If not, the acceleration DWFL of the left front wheel is calculated in S2. Calculation of DWFL is determined from the current left wheel speed WFL _n by subtracting the left front wheel speed WFL _n-1 of the last time.

DWFL = WFL _n -WFL _n-1 Then, an offset correction of the left front wheel acceleration based on the following equation in S3.

This offset correction is for obtaining the above-described true wheel acceleration. That is, the actual wheel acceleration obtained in S2 includes the acceleration of the vehicle body, and therefore, the offset correction for obtaining the true wheel acceleration is performed by subtracting the vehicle acceleration from the actual wheel acceleration. In the above equation, the vehicle body acceleration is represented by (WFL _n -WFL _n-4 ) / 4. This is because when considering the relationship between the wheels and the vehicle body, the wheels first start to rotate, whereby the vehicle body starts to move. That is, the vehicle body starts to move with a delay with respect to the wheels, and the delay corresponds to approximately four cycles of the rough road determination flow in the present embodiment (flow processing cycle: 14 msec;
msec). Therefore, the average of the actual wheel accelerations up to four cycles before the present is set as the vehicle body acceleration.

Subsequently, the number of times PCFL (left front wheel peak count) in which the true wheel acceleration DWFL obtained in S3 exceeds a predetermined threshold value α is counted. That is, when the vibration of the DWFL is as shown in FIG. 6, the number of times PCFL in which the peak of the vibration of the DWFL exceeds + α, −α is counted. In this counting, as shown in FIG. 6, the number of peaks PCFL exceeding + α, −α is counted, and the counting is performed when the peaks alternately exceed + α, −α. For example, if one peak exceeds + α and the next peak does not exceed -α and exceeds + α, the second peak exceeding + α is not counted. When the wheel acceleration vibrates due to a bad road, it should generally fluctuate in the (+) direction and the (-) direction in general. Therefore, only when + α and −α are alternately exceeded as described above. By performing the counting, it is possible to perform a rough road determination with higher accuracy.

Specifically, it is determined in S4 whether or not the DWFL in S3 is 0 or more. If the DWFL is 0 or more, it is determined in S5 whether or not the DWFL is greater than + α. Then S6
It is determined whether or not the left front wheel peak flag PFFL is 1. The last time PFFL was set to 1, that is,
Since the DWFL has exceeded -α, it means that the PCFL has been counted once. The fact that the PFFL has been reset, that is, has been reset, means that the PCW has been counted once since the last time the DWFL exceeded + α. If the PFFL is 1, the PCFL is counted once because it exceeded -α the previous time.
And increment the PCFL by one, and then reduce the PFFL to 0 in S8
Then, the flow ends. Further, if the PFFL is not 1 in S6, it means that it exceeds -α following the previous time, and from the viewpoint of preventing one peak from being counted twice, it is also the previous (−) side. In order to prevent counting on the (+) side once again when counting is not performed in S8, S8 without counting PCFL
To end the flow.

If DWFL is less than 0 in S4, then in S9
It is determined whether DWFL is smaller than -α. If not smaller, the flow is terminated. If smaller, the procedure proceeds based on the same concept as in S6 to S8. That is, first, in S10, P
Judge whether or not FFL is 0. If it is 0, count PCFL once in S11, then set PFFL to 1 in S12 and end the flow. If PFFL is not 0 in S10, count PCFL The process proceeds to S12 without performing and ends the flow.

The procedure of S1 to S12 is repeated as described above, and when the predetermined time has elapsed, the timer is determined to be equal to or more than the predetermined value in S1, so the process proceeds to S13, the timer is reset, and the PCFL is set in advance in S14. It is determined whether or not the threshold value is larger than a threshold value β (for example, β = 10). If not, the left front wheel rough road flag AKRFL is set to 0 in S15, the PCFL is set to 0 in S16, and the flow is terminated. . If PCFL is β in S14 above
If it is larger, the left front wheel rough road flag AKRFL is set to 1 in S17, and the process proceeds to S16 to end the flow.

The above is the rough road determination flow for the left front wheel, but the rough road determination is also performed for the right front wheel in exactly the same flow.

It should be noted that the thresholds α and β and whether to target the left and right front wheels or the right and left rear wheels can be appropriately set or changed according to various conditions.

Bad road correction in anti-skid control Next, bad road correction in anti-skid control will be described.

In the case of the slip control as the anti-skid control, the only difference is that the brake control of the slip control as the traction control is to appropriately increase the brake fluid pressure, whereas the brake control is to appropriately reduce the brake fluid pressure.
Therefore, the basic device configuration and control mode are the same as those in the case of the slip control as the traction control (however, the control unit UTA stores a control program and various maps for anti-skid control, and also controls the front wheels. It is necessary to control the brake fluid pressure in the same way as for the rear wheels). Therefore, the description of the specific device and the anti-skid control itself is omitted, and a specific example of the rough road correction in the anti-skid control will be described below with reference to FIG.

In the case of anti-skid control, the first rough road determination means
The rough road correction is performed based on 400. That is, it is determined whether or not both wheels are bad roads in Q1, and if none of them is a bad road, that is, if the first bad road determination means 400 does not determine that the road is bad, the process proceeds to Q2, Q3. , Normal anti-skid control is performed. That is, a normal target slip ratio is set as the target slip ratio S for anti-skid control, and the slip control is performed based on the normal target slip ratio.

If both wheels are on a rough road, that is, if the first rough road determination means 400 determines that the road is a rough road, the process proceeds to Q4 and Q5, and slip control is performed after correcting the rough road. That is, setting the target slip ratio S ₁ greater than the normal target slip ratio S, the slip control is performed based on the large target slip ratio S _1.

As described above, in the case of the anti-skid control, by performing the rough road determination based on the determination result of the first rough road determination means 400, it is possible to prevent the braking performance from being deteriorated due to the rough road correction as described in the section of the operation. it can.

Another Example of Using One-Wheeled Road and Two-Wheeled Bad Road Next, Another Example of Using One-Wheeled Road and Two-Wheeled Bad Road
That is, another embodiment of selectively using the two-wheel rough road and the one-wheel rough road according to the type of the slip control and the running state will be described with reference to FIG. This embodiment relates to a case in which both anti-skid control and traction control are performed as slip control. In the case of anti-skid control, it is clarified that rough road determination of the left and right front wheels is used. The use of rough road judgment on the rear wheels is clarified, and in the case of traction control, not only the accelerator opening but also the yaw rate and traction control mode (the sports mode that emphasizes acceleration and the normal mode that does not emphasize acceleration) This is different from the above-described embodiment in that they are properly used in consideration of the above.

First, in P1, it is determined whether or not the anti-skid control is being performed. If the anti-skid control is being performed, when both the left and right front wheels are determined to be a rough road, the road is determined to be a rough road, and a rough road correction in the anti-skid control is performed.

If the anti-skid control is not being performed, it is determined whether the yaw rate is equal to or more than a predetermined value in P3, P4, and P5, whether the TRC mode is a normal mode, and whether the accelerator opening is 50% or more.
When the yaw rate is smaller than the predetermined value, the TRC mode is not the normal mode (the sport mode), and the accelerator opening is 50% or more, at least one of the left and right rear wheels is on a rough road. The road is determined to be a bad road, and a bad road correction is performed during traction control.

Also, when the yaw rate is equal to or greater than a predetermined value, the TRC mode is normal, or the accelerator opening is less than 50%,
When the left and right rear wheels are both determined as a rough road, it is determined as a rough road,
Rough road correction is performed during traction control.

(Effects of the Invention) As described in detail above, the traveling control device for a vehicle according to the present invention performs a rough road correction when both wheels are determined to be a rough road or a single wheel depending on the type of slip control and the traveling state. However, since it is appropriately selected whether to perform the rough road correction when it is determined that the rough road is determined, it is possible to always perform the optimum rough road correction in various situations.

Further, in the case of the anti-skid control, when both of the wheels are determined to be on a rough road, the rough road is corrected, so that it is possible to prevent a decrease in braking performance due to the rough road correction.

In the case of traction control, when the accelerator opening is large, rough road correction is performed when one of the wheels is determined to be a bad road, and when the accelerator opening is small, bad road correction is performed when both wheels are determined to be a bad road. Since the road correction is performed, it is possible to perform the rough road correction that more closely matches the driver's intention.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing an embodiment of the present invention, FIG. 2 is an overall system diagram specifically showing an embodiment of the present invention, FIG. 3 is a time chart showing an aspect of traction control, FIG. Fig. 5 is a flowchart showing a rough road correction control in the case of traction control, Fig. 5 is a flowchart showing a rough road determination, Fig. 6 is a diagram showing vibration of true wheel acceleration, and Fig. 7 is a case of an anti-skid control. FIG. 8 is a flowchart showing a rough road correction control, and FIG. 8 is a flowchart showing a rough road correction when performing both traction control and anti-skid control. 100 (UTR): slip control means 200 (UTR, 65, 67): left wheel rough road determination means 300 (UTR, 64, 66): right wheel rough road determination means 400 (UTR): first rough road Judging means 500 (UTR): Second rough road determining means 600 (UTR): Bad road determining means

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Toru Onaka 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (72) Haruki Okazaki 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Matsu (72) Inventor Fumio Kageyama 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Inside Mazda Corporation (72) Inventor Makoto Kawamura 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Inside Mazda Corporation (58) Field surveyed (Int.Cl. ⁶ , DB name) B60T 8/58

Claims (4)

(57) [Claims] 1. Slip control means for controlling wheel slip, left wheel bad road determination means for determining whether or not the vehicle is on a rough road based on a change in left wheel speed; Right wheel rough road determination means for determining whether or not the road is rough,
When both the left wheel and the right wheel rough road determination means determine a rough road, the first rough road determination means determines that the road is bad, and at least one of the left wheel and the right wheel rough road determination means determines that the rough road is rough road. And selecting one of the first and second rough road determination means in accordance with the traveling state or the type of slip control in the slip control means. A vehicle travel control device comprising: a rough road correction unit that corrects the content of the slip control of the slip control unit when the selected rough road determination unit determines that the road is a rough road. 2. The vehicle travel control device according to claim 1, wherein said rough road correction means includes a rough road by said first rough road determination means when a type of slip control of said slip control means is anti-skid control. A travel control device for a vehicle, wherein the control content of the anti-skid control is corrected based on the determination. 3. The traveling control device for a vehicle according to claim 1, wherein the bad road determination means is configured to determine whether the type of slip control of the slip control means is traction control and the accelerator opening is equal to or less than a predetermined value. A cruise control device for correcting the control content of the traction control based on the bad road determination by the first bad road determination means. 4. The travel control device for a vehicle according to claim 1, wherein the bad road correction means is configured to perform a traction control when the slip control means is of a traction control type and when the accelerator opening is larger than a predetermined value. Is a device for correcting the control content of the traction control based on the rough road determination by the second rough road determination means.