JP2002264784A - Vehicle running state control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem that sufficient effect cannot be obtained if the tendency for increase of sliding down speed is large when performing braking force control for reducing sliding down of a vehicle body in accordance with sliding down speed without relying on a degree of sliding. down. SOLUTION: When sliding down reduction control is performed by controlling a liquid pressure of a brake actuator, a vehicle body acceleration α is estimated (S220), and a control target pressure P is increased and compensated (S224) if the vehicle body acceleration α is larger than a predetermined value ('YES' at S222) to generate a larger braking force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle traveling state control device which functions when a vehicle slips down (falls) down a hill, such as when changing over from a brake pedal to an accelerator pedal.

[0002]

2. Description of the Related Art There is known a technique for automatically applying a braking force when a vehicle slips down on a slope (e.g., slips down) on an uphill road, for example, when changing from a brake pedal to an accelerator pedal. I have. For example, Japanese Patent Application Laid-Open No. H10-16745 discloses a technique in which, when a backward movement of a vehicle is detected despite a driver performing a forward operation, a braking force is applied to reduce the backward speed of the vehicle. Have been.

[0003]

Problems to be Solved by the Invention JP-A-10-1
According to No. 6745, the magnitude of the braking force applied to the wheels is set so that the retreat speed of the vehicle does not exceed a predetermined upper limit value, whereby the control is performed such that the vehicle retreats slowly at a speed within a certain range. Done.

However, when such control is performed, the increasing tendency of the reversing speed at which the vehicle slips down the slope is relatively small or relatively steep. , A braking force corresponding to the reverse speed is set. If the braking force is always set according to the reversing speed of the vehicle regardless of the degree of the vehicle slipping down the slope (acceleration situation) in this way, the tendency of the reversing speed at the time of downhill to increase is large. In such a case, there may be a case where the effect of the relaxation control of the sliding speed is not sufficiently exhibited.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to alleviate the speed of a vehicle going downhill on a slope in accordance with the state of the vehicle going down more effectively. It is an object of the present invention to provide a vehicle traveling state control device capable of performing the above-mentioned operations.

[0006]

SUMMARY OF THE INVENTION Therefore, a vehicle running state control device according to the present invention is characterized in that when a vehicle travels in a direction opposite to the traveling direction of the vehicle based on a forward operation or a reverse operation, the braking force is reduced. A vehicle traveling state control device for performing control, comprising: operation state detection means for detecting forward and backward operations; actual traveling direction detection means for detecting an actual traveling direction in which the vehicle actually travels; and detection of the operation state detection means. When the desired traveling direction of the driver and the actual traveling direction obtained from the result are opposite to each other, a predetermined braking force is applied to the wheel rotating along the actual traveling direction separately from the braking operation of the driver. And braking control means for controlling the magnitude of the braking force to be applied in accordance with the acceleration state of the vehicle traveling in the actual traveling direction.

[0007] When the vehicle slips down the slope, the braking control means determines the actual traveling direction (downhill direction).
The braking force to be applied is controlled according to the acceleration state of the vehicle traveling to. Accordingly, the braking force to be applied is corrected according to the acceleration condition in the downhill direction, and a suitable braking force according to the degree of downhilling is applied.

According to a second aspect of the present invention, there is provided a vehicle traveling state control device according to the first aspect.
The braking control means relates to the distribution ratio of the braking force applied to the wheels on the upper slope and the lower wheels on the slope, when the slope is large, as compared with the case where the slope is small. Increase the distribution ratio of the braking force to the wheels.

The load acting on the wheels on the upper slope and the lower wheels on the slope changes in accordance with the degree of the gradient of the slope, and the steeper the gradient, the greater the distribution of the load acting on the wheels on the lower slope. In consideration of such a change in load distribution, the braking control means increases the distribution ratio of the braking force to the wheels on the lower side of the sloping road when the slope is large compared to when the slope is small. Let it.

According to a third aspect of the present invention, there is provided a vehicle traveling state control device for controlling a braking force when the vehicle travels in a direction opposite to the traveling direction of the vehicle based on a forward operation or a backward operation. An operation state detection means for detecting forward and backward operations, a rotation direction detection means for detecting a rotation direction of each wheel, and detection of the operation state detection means based on a detection result of the rotation direction detection means. If there are wheels that rotate in the desired direction of travel of the driver and wheels that rotate in the opposite direction to the desired direction of travel, the wheels that rotate in the desired direction of travel and A brake control unit that applies a braking force separately from a driver's brake operation is separately provided for wheels that rotate in a direction opposite to a desired direction, and the brake control unit includes:
First braking control means for applying a braking force in accordance with the traveling state of the vehicle to a wheel rotating in a direction opposite to the desired traveling direction, and rotating state of the wheel to a wheel rotating in the desired traveling direction And a second braking control means for applying a braking force according to the above.

For example, assuming that the vehicle is started on an upward slope, the driver depresses an accelerator pedal to move the vehicle forward. At this time, on a low μ road where a part of the road surface is frozen or the like. In the meantime, a case may occur in which some wheels cause wheel spin while the vehicle body slides down the slope. In view of such a situation, focusing on the rotation direction of each wheel, if there is even one wheel that rotates in the direction opposite to the driver's desired traveling direction, that is, if the rotation directions of the four wheels do not match, It is also possible to immediately determine that the vehicle is in a downhill state, and thus, it is possible to immediately start the control for alleviating the downhill.

According to a third aspect of the present invention, there is provided a vehicle traveling state control device, comprising: a wheel that rotates along a desired traveling direction of a driver based on a detection result of a rotation direction detection unit that detects a rotation direction of the wheel; It is determined whether wheels that rotate in the opposite direction to the desired traveling direction are mixed. When the wheels having different rotation directions coexist as described above, the control for alleviating the state of the vehicle slipping down is immediately started by the braking control means. In this case, the wheel rotating in the opposite direction to the desired traveling direction, that is, the wheel rotating in the downhill direction, has a large frictional force with the road surface, and corresponds to the traveling state of the vehicle as the downhill state of the vehicle. By applying the braking force by the first braking control means, the skid state of the vehicle is effectively reduced. Further, a wheel rotating in the desired direction of travel, that is, a wheel that is causing wheel spin, has a small frictional force with the road surface, and applies a braking force according to the wheel rotation state as the wheel spin state to the second braking. By giving it by the control means, wheel spin is suppressed and directional stability of the vehicle is secured.

According to a fourth aspect of the present invention, in the vehicle traveling state control device, the first braking control means is the braking control means according to the first or second aspect. (2) The braking control means controls the magnitude of the braking force to be applied so that the rotation of the wheel along the desired traveling direction is sufficiently suppressed.

As described above, the first braking control means further considers the acceleration state of the wheel rotating in the downhill direction, which is the opposite direction to the desired traveling direction, and further considers whether the vehicle is on the upper or lower side of the slope. A suitable braking force is provided. In the second braking control means, the magnitude of the braking force to be applied is controlled so as to sufficiently suppress the rotation (wheel spin) of the wheel along the desired traveling direction, thereby ensuring the directional stability of the vehicle.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described.
This will be described with reference to the accompanying drawings.

FIG. 1 schematically shows a drive system of a four-wheel drive vehicle according to the embodiment. A transmission 2 for shifting the rotational output of the engine 1 is provided at a rear stage of the engine 1, and a driving force transmitted from the transmission 2 is provided at a rear stage of the transmission 2 with a drive shaft 4 </ b> F on a front wheel side and a rear wheel. (Sub-transmission) 3 for distributing to the drive shaft 4R on the side. Transfer 3
The transmission 3 is provided with two types of gear trains: a high-speed high gear train that transmits the rotational output of the transmission 2 without deceleration, and a low-speed low gear train that further reduces the rotational output of the transmission 2. By operating the shift lever for
The high gear train and the low gear train can be switched and selectively used. The transfer 3 has a differential device (center differential) inside to absorb a difference in rotation between the front and rear wheels generated at the time of turning.

The front drive shaft 4F is connected to left and right drive shafts 6FL, 6FR via a front differential 5F, and the drive shafts 6FL, 6FR are connected to left and right front wheels FL, FR. Also, the drive shaft 4 on the rear wheel side
R is the left and right drive shaft 6 via the rear differential 5R.
RL, 6RR, and the drive shafts 6RL, 6RR
The left and right rear wheels RL and RR are connected. The driving torque of the engine 1 is transmitted to the wheels FL, FR, RL, RR via such a mechanism.

Each of the wheels FL, FR, RL, RR is provided with a braking device 20. The hydraulic system for hydraulic fluid that connects the wheel cylinder 21 and the master cylinder 30 that constitute the braking device 20 includes A brake actuator 200 that controls increase and decrease of the fluid pressure in the wheel cylinder 21 is provided separately from the brake operation of the user.

FIG. 2 schematically shows the structure of the brake actuator 200. The brake actuator 2
00 is a braking device 20 for each of the wheels FL, FR, RL, RR.
Each time, it is a mechanism that can control the hydraulic pressure independently.
Has a brake actuator 200 for one wheel
Is representatively shown, but the other wheels have the same configuration.

Master cylinder 30 and wheel cylinder 2
1 is provided with a shut-off valve (opened when not energized: valve opened) 210, which is closed when the hydraulic pressure control of the hydraulic fluid is executed, and the master cylinder 30 and the wheel cylinder 21 are closed. Is cut off. Further, the shutoff valve 21
A holding valve (when not energized: open) 220 is provided in the pipe 201 closer to the wheel cylinder 21 than the holding valve 2.
By closing the valve 20, the hydraulic system from the holding valve 220 to the wheel cylinder 21 can be closed.

A line 201 between the holding valve 220 and the wheel cylinder 21 is connected to the reservoir 40 by a line 202. The line 202 is provided with a pressure reducing valve (when not energized: closed) 230. In addition, the communication state of the pipeline 202 can be changed by duty-driving the pressure reducing valve 230 according to the drive control signal in the binary state of the energized state / non-energized state.

The hydraulic pump 51 rotated and driven by the motor 50 functions as a hydraulic pressure source for controlling the braking force, and the discharge port of the hydraulic pump 51 is
It is connected to a pipeline 201 between the shutoff valve 210 and the holding valve 220. A check valve 253 for preventing the flow of the hydraulic fluid in the direction opposite to the discharge direction is provided on the discharge port side of the hydraulic pump 51.
Is provided.

On the other hand, the suction port side of the hydraulic pump 51 is connected to the reservoir 40 through a conduit 204,
4 is provided with check valves 251 and 252 for preventing the flow of the hydraulic fluid in the direction opposite to the suction direction.

The pipeline 20 between the check valves 251 and 252
4 is connected to the reservoir tank 31 via the line 205, and the hydraulic fluid in the reservoir tank 31
4, it is sucked into the hydraulic pump 51. Further, a suction valve (when not energized: closed) 240 that opens and closes the pipeline 205 is provided in the middle of the pipeline 205.

As described above, the brake actuator 20 constituted by the hydraulic pump 51 and various valve devices, etc.
In the case of 0, the operation control is performed by the control device 100.

As shown in FIG. 3, the control device 100 includes:
Wheel speed sensor 110 for detecting the rotational speed of each wheel FL, FR, RL, RR, shift position sensor 120 for detecting the shift position of the shift lever, brake pedal sensor 130 for detecting the amount of depression of brake pedal 10, accelerator pedal Detection results of an accelerator pedal sensor 140 for detecting the amount of depression of the vehicle, a selected gear train detection sensor 150 for detecting a gear train selected by a shift lever for the transfer 3, a longitudinal acceleration sensor 160 for detecting the longitudinal acceleration of the vehicle, and the like. Is given. In addition, the wheel speed sensor 110 in this embodiment is:
It is constituted by a sensor capable of detecting not only the rotation speed of the wheel but also the rotation direction of the wheel.

Next, in the control processing of the actuator 200 performed by the control device 100, when the vehicle is going downhill on an uphill road or the like, the control processing for alleviating the downhill state is described below. 4 will be described along with the flowchart of FIG. Since this control is performed individually for each wheel, the flowchart of FIG. 4 shows a control flowchart for a specific wheel.

This flowchart is started by turning on the ignition switch. First, the process proceeds to step (hereinafter, “step” is described as “S”) 101, and FIG.
Each sensor 110, 120, 130, 140, 1 indicated by
60 and the detection result of the switch 150 are read, and
At 102, a desired traveling direction of the driver is determined based on the detection result of the shift position sensor 120. This is because when the shift lever is operated to the forward shift position, the driver's desired traveling direction is the forward direction, and when the shift lever is operated to the reverse shift position, It is determined that the desired traveling direction is the backward direction.

In the following S104, the actual traveling direction of the vehicle body, which is the direction in which the vehicle body is actually traveling, between forward and backward, is determined. For example, in a situation in which the vehicle starts on a slope, when the brake pedal is changed from the brake pedal to the accelerator pedal, a state in which both the brake pedal 10 and the accelerator pedal are not depressed temporarily occurs, so that the vehicle body slips down the slope. There are cases. In such a case, each of the wheels FL, FR, RL, and RR normally rotates in the same direction as the body leans down, so that the rotation direction of the wheels (specific wheels or all the wheels) is determined. The actual traveling direction of the vehicle body can be determined.

After the actual traveling direction of the vehicle body is determined in S104, the process proceeds to S106, in which it is determined whether the value of the flag F indicating whether or not the skid mitigation control is being executed is set to F = 1, which indicates that the execution is being executed. to decide. Initially, the value of the flag F is F =
Since it is set to 0, it is determined as “No” and S10
Proceed to 8.

In S108, it is determined whether or not the actual traveling direction of the vehicle body matches the desired traveling direction of the driver based on the determination results in S102 and S104, and the actual traveling direction of the vehicle body and the desired traveling direction of the driver are determined. If the directions match, S10
At 8, “Yes” is determined, and this routine ends as it is.

On the other hand, if the actual traveling direction of the vehicle body is opposite to the desired traveling direction of the driver ("No" in S108), the process proceeds to S110, and the value of the flag F is set to F = 1. This indicates that the slippage mitigation control is being executed, and
At 112, the count of the timer for measuring the execution time of the sliding mitigation control is started.

As described above, in a state where the vehicle is slipping down a sloping road with neither the brake pedal 10 nor the accelerator pedal depressed, each wheel F
L, FR, RL, and RR are rotating in the same direction as the body leans down. Therefore, in the subsequent S200, the hydraulic pressure of the brake device 20 which is the target in this flowchart is controlled to increase the hydraulic pressure of the hydraulic fluid supplied to the wheel cylinder 21 so as to become the control target pressure P described later. .

Referring to FIG. 2, during the pressure increase control of the brake actuator 200, the shutoff valve 210 is energized to close the valve, and the suction valve 240 is energized to open the valve. The hydraulic fluid is pumped from the pressure pump 51. Thereby, the working fluid is supplied into the wheel cylinder 21 via the pipeline 203 and the pipeline 201. Then, after the time corresponding to the predetermined control target pressure P has elapsed, the holding valve 220 is energized to close the valve, so that the internal pressure of the wheel cylinder 21 increases to the predetermined control target pressure P. Become. The specific setting process of the control target pressure P will be described later.

Such control processing is performed for each of the wheels FL, FR,
This control process is performed for the RL and RR braking devices 20. By this control process, a braking force is applied to each wheel rotating in the vehicle body downhill direction, thereby suppressing the vehicle body downhill speed. become.

In the next routine, S102 and S104
In the same manner, after the desired traveling direction of the driver and the actual traveling direction of the vehicle body are determined, the process proceeds to S106, and if the skid mitigation control is started, the value of the flag F is set to F = 1.
Is set to “Yes”, the determination is “Yes” in S106, and the process proceeds to S114.

In the control process of this flowchart, it is assumed that the driver steps on the accelerator pedal from the brake pedal. When the accelerator pedal is depressed, the actual traveling direction of the vehicle body is reversed, and the desired traveling direction of the driver is obtained. When it is determined that the vehicle speed is lower than the vehicle speed, it is desirable to immediately end the vehicle body slippage mitigation control. Therefore, in S114, it is determined again whether the actual traveling direction of the vehicle body matches the desired traveling direction of the driver based on the determination results of S102 and S104, and the actual traveling direction of the vehicle body and the desired traveling direction of the driver are determined. If the directions coincide with each other, “Yes” is determined in S114, and the process shifts to control end processing in and after S130. The control end processing after S130 will be described later.

Also, paying attention to the movement of each wheel, the engine 1
As a result of the transmission of the driving force, if there is a wheel that has started to rotate in the direction in which the driver wants to travel, it is desirable to terminate the vehicle body slipping mitigation control for this wheel. Therefore, if the braking force was applied in the previous routine, but the actual traveling direction of the vehicle body is still opposite to the desired traveling direction of the driver, “No” is determined in S114, and the process proceeds to S116. Further, it is determined whether or not the rotation direction of the wheel to be controlled matches the driver's desired traveling direction. As a result, if the rotation direction of the wheel to be controlled in this flowchart coincides with the desired traveling direction of the vehicle body, it is determined “Yes” in S116 and S
The processing shifts to control end processing after 130. Therefore, when the accelerator pedal is depressed, the rolling mitigation control is sequentially terminated from the wheel whose rotation direction matches the desired traveling direction.

On the other hand, while the wheels are rotating in the direction in which the vehicle body slides down, "No" is determined in S116, and the process proceeds to S118.

In S118, it is determined whether or not the count value T of the timer started in S112 is equal to or smaller than a predetermined threshold value Ta. The threshold value Ta is used to prevent the driver from determining that the vehicle can travel downhill at the current speed, and to activate the valve devices such as the shut-off valve 210 constituting the brake actuator 200 by continuous energization. This is a predetermined time to protect against heat generation.
The Ta time serving as the threshold can be appropriately set according to the design concept, the durability of the brake actuator 200, and the like, and is not particularly limited, but is, for example, about 3 seconds.

If the count value T of the timer is equal to or smaller than the threshold value Ta, it is determined as "Yes" in S118, and the process proceeds to S12.
Go to 0.

When the skid mitigation control is functioning properly, the wheels gradually rotate downward on the slope, but when the frictional force between the wheels and the road surface is small, for example, on a low μ road, The wheels may be locked due to the braking force set in S114 in the previous routine. Therefore, in S120, it is determined whether the wheel to be controlled is in the locked state in which the rotation of the wheel is stopped.

As a result, if the wheels are not in the locked state, "No" is determined in S120, and the process proceeds to S200.
The wheel cylinder pressure is controlled so as to reach a predetermined control target pressure P.

On the other hand, if the wheel to be controlled is in the locked state, "Yes" is determined in S120 and S
Proceeding to 124, pressure reduction control for reducing the currently set wheel cylinder pressure by ΔP is performed.

Referring to FIG. 2, the operation control of the brake actuator 200 at the time of pressure reduction is performed at a predetermined dut.
A drive control signal based on the y ratio is supplied to the pressure reducing valve 230, and the pressure reducing valve 230 is duty-driven. Thereby, the holding valve 22
The working fluid stored between 0 and the wheel cylinder 21 flows into the reservoir 40 via the pressure reducing valve 230. Then, after the time corresponding to the pressure reduction amount of ΔP2 has elapsed, the power supply to the pressure reduction valve 230 is stopped to close the valve, and the internal pressure of the wheel cylinder 21 becomes ΔP2.
The state is lowered by two.

In the next and subsequent routines as well, if the wheel to be controlled is in the locked state, the process proceeds to S124, where the same pressure reduction control is performed, and S1 is performed until the wheel leaves the locked state.
24 are performed. By performing such a process, the rotation speed of the wheel rotating in the downhill direction can be reduced while preventing the wheel from being locked.

When such a sliding mitigation control continues for more than the threshold value Ta time, "N" is determined in S118.
"o" is determined, the process proceeds to S126, and it is further determined whether the count value T is equal to or smaller than another threshold value Tb (Ta <Tb). The Tb time serving as this threshold is S128
This is a time for continuing the gentle pressure reduction control implemented in the above, and gives the driver sufficient time to depress the brake pedal 10 and the accelerator pedal, and prevents a sudden pressure drop to prevent a predetermined gentle pressure reduction gradient. Is a predetermined time, as is drawn. Although not particularly limited, for example, it is about 8 seconds.

When the count value T of the timer exceeds Ta,
In the situation of a <T ≦ Tb, “Yes” is determined in S126, and the process proceeds to S128, in which the gentle pressure reduction control for gradually terminating the downslope mitigation control is performed.

Normally, when ending the control of the brake actuator 200, the motor 50 is stopped and the valve devices (the shutoff valve 210, the holding valve 220,
A process of stopping energization of the pressure reducing valve 230 and the suction valve 240) is performed. In the normal termination processing, each valve device is de-energized, so that the shut-off valve 210 is open, the holding valve 220 is open, the pressure reducing valve 230 is closed, and the suction valve 2 is closed.
40 is closed.

As shown in FIG. 5, from the start of the control at T = 0 to the time T = Ta, the wheel cylinder pressure is maintained at a predetermined pressure. Assuming a case where a proper end process is performed, the wheel cylinder pressure changes so as to sharply decrease as shown by a chain line in FIG.

Therefore, in the gradual pressure reduction control performed in S128, the pressure reduction of the wheel cylinder pressure is performed so that the gradual decrease gradient is smaller than the decrease gradient indicated by the one-dot chain line a in FIG. That is, in this slow pressure reduction control, the shutoff valve 21
0 and holding valve 220 to close the valve,
The drive control signal having the ty ratio of, for example, about 10% is supplied to the pressure reducing valve 23.
0, and the pressure reducing valve 230 is duty-driven. In addition,
The pressure reducing valve 230 is fully opened when a drive control signal having a duty ratio of 100% is supplied.

As a result, the working fluid stored between the holding valve 220 and the wheel cylinder 21 is removed from the pressure reducing valve 23.
While the flow rate is controlled by 0 and flows out to the reservoir 40 via the pipe line 202, the wheel cylinder pressure gradually decreases as shown by the solid line b in FIG.

If "No" in S126, that is, if the count value T of the timer has exceeded the threshold value Tb during the execution of the slow pressure reduction control, the process proceeds to S130.
The normal control end processing as described above is performed. That is, the motor 50 is stopped, and each valve device is turned off. As a result of this processing, the shutoff valve 210 is opened, the holding valve 220 is opened, the pressure reducing valve 230 is closed, and the suction valve 240 is closed, and the wheel cylinder pressure is greatly reduced as compared with the slow pressure reduction control. It becomes a gradient,
Since the threshold value Tb is set in advance so that the termination control process is started in a state where the pressure is sufficiently reduced, the braking force does not change significantly.

Thereafter, the flow advances to S132 to reset the count value of the timer, and in S134, the value of the flag F is set to F
= 0 to be ready for the next and subsequent routines.

While the count value T of the timer satisfies T ≦ Tb, the driver operates the accelerator to perform the operation.
When the actual traveling direction of the vehicle body coincides with the desired traveling direction of the driver ("Yes" in S114), or when the rotation direction of the wheels coincides with the desired traveling direction of the driver ("Ye" in S116).
s "), the process proceeds to S130 to S134 in order to end the vehicle body slipping mitigation control.

Here, the hydraulic control process shown as S200 in FIG. 4 will be described with reference to the flowchart in FIG. This control is also performed individually for each wheel, as in the flowchart of FIG. 4. Therefore, the flowchart of FIG. 6 shows a control flowchart for a specific wheel.

Since the distribution of the load acting on each wheel changes according to the grade of the slope, it is desirable that the hydraulic pressure applied to the wheel cylinder 21 is also adjusted according to the grade of the slope. Therefore, in S202, a process of estimating the slope gradient θ is performed, and the degree of the slope of the slope is determined. As a process for estimating the slope gradient θ, for example, even if the vehicle is stopped on a slope, the longitudinal acceleration sensor 16
Since the acceleration in the front-rear direction according to the slope gradient is detected by 0, the slope gradient θ can be grasped directly from the detection result of the longitudinal acceleration sensor 160. Also,
In addition to the estimation processing of the slope gradient θ, the detection result of the inclinometer for detecting the inclination angle of the road surface, the change state of the rotation speed of the wheels rotating downward on the slope, or the geographical information obtained from the navigation system It is also possible to estimate based on information and the like.

At S204, it is determined whether or not the slope gradient θ estimated at S202 is greater than a predetermined threshold value θth. If the slope gradient θ is relatively gentle below the threshold value θth, the process proceeds to S204. ("No" in S204), it is considered that there is no significant change in the load distribution, and the process proceeds to S206.
Control target pressure (wheel cylinder pressure as control target) P
Is set to P0 defined in advance. This “P0” is a predetermined pressure increase target value such that the braking force acts to such an extent that the wheels do not lock on the slope gradient equal to or smaller than the threshold value θth.

On the other hand, if the estimated slope gradient θ is greater than the predetermined threshold value θth (“Yes” in S204), the process proceeds to S208, where the change in load distribution caused by the slope of the slope is determined. Make adjustments to accommodate this. Therefore, first, it is determined whether the target wheel in the flowchart is a wheel located on the upper side or a wheel located on the lower side along the slope. This is because the loads acting on the wheels located on the upper side along the slope and the wheels located on the lower side differ. For example, in a situation where the vehicle is uphill,
The front wheel is a wheel on the upper side of the slope, and the rear wheel is a wheel on the lower side of the slope. Further, when the vehicle is on a down slope, the front wheels are wheels on the lower side of the sloping road, and the rear wheels are wheels on the upper side of the sloping road.

Therefore, in the case of the wheel on the upper side of the slope (S2
08, “Yes”), the process proceeds to S210, and the control target pressure P is set to a predetermined P1. In the case of the wheel on the lower side of the sloping road (“No” in S208), the process proceeds to S212 to increase the control target pressure P. It is set to P2 (P2> P1) defined in advance.

Here, an example of a change in the distribution of the control target pressures for the front wheels and the rear wheels according to the slope gradient will be schematically described, taking the case of an uphill gradient as an example. The slope gradient θ is the threshold value θt
h, the control target pressure set for the front wheels is Pf1, and the control target pressure set for the rear wheels is Pr1.
And When the slope gradient θ is greater than the threshold value θth, the control target pressure set for the front wheels is Pf
2. Let Pr2 be the control target pressure set for the rear wheels. In the case of an ascending slope, as the slope increases, the load acting on the rear wheels increases and the load acting on the front wheels decreases. For this reason, the control target pressure for the rear wheels is set so that Pr2> Pr1. At this time, the control target pressure Pr2 for the rear wheels may be increased as the slope of the slope is increased. For the front wheels, the control target pressure Pf2 for the rear wheels is set so that Pf2 <(Pf1 / Pr1) * Pr2.

In order to satisfy such a relationship, S210
P1 and P2 of S212 are defined in advance. In the flowchart of FIG. 6, for convenience of explanation, control processing relating to a specific wheel is shown. Therefore, in the flowchart for the front wheels and the flowchart for the rear wheels,
The values of P1 and P2 are individually defined.

After setting the control target pressure P according to the slope gradient θ, the process proceeds to S214. In S214, the gear train selected by the transfer 3 is read based on the detection result of the selected gear train detection switch 150 that detects the operation position of the transfer shift lever.

At S216, it is determined whether the gear train selected by the transfer is a high-speed gear train. When the high gear train for high speed is selected, since the gear ratio is lower than that when the low gear train is selected, the vehicle body is more likely to slip downhill. Therefore, when the high gear train for high speed is selected (“Yes” in S216), the process proceeds to S218 and S20.
6. A value obtained by adding a predetermined correction value P3 to the control target pressure P set in S210 or S212 is updated as a new control target pressure P, and the process proceeds to S220. By this processing, the control target pressure P is corrected to a pressure increasing side, so that a larger braking force acts on the wheels to be controlled to brake the rotation of the wheels, and the vehicle body slips down. Is suppressed. On the other hand, when the low gear train for low speed is selected in the transfer 3 (“No” in S216), the process proceeds to S220 without updating the control target pressure P. Therefore, a suitable braking force can be applied to the wheels in accordance with a change in the state of the body leaning down due to the selected gear train of the transfer.

In the following S220, the vehicle acceleration α that falls down the slope is estimated. As an example of this estimation process, based on the rotation speed of the wheel rotating downward on the slope, the average value of the rotation speed of each wheel is calculated to obtain an estimated vehicle speed,
From the state of change of the estimated vehicle speed per unit time, it can be estimated as vehicle acceleration α.

At S222, it is determined whether the vehicle acceleration α estimated at S220 is larger than a predetermined threshold value αth. When the vehicle body acceleration α is equal to or smaller than the predetermined threshold αth (“No” in S222), the process proceeds to S226 without updating the control target pressure P.

On the other hand, when the vehicle body acceleration α is larger than the predetermined threshold value αth (“Ye
s "), and proceeds to S224, in which a predetermined correction value P4 is set for the control target pressure P set before this step.
Is updated as a new control target pressure P. By this processing, the control target pressure P is corrected to the pressure increasing side, so that a larger braking force acts on the wheel to be controlled. In this way, when setting the control target pressure P, by reflecting the magnitude of the actual vehicle body acceleration α, a control form such as a simple feedback control is performed, so that a more appropriate control amount is set. I can do it. Further, when the vehicle body starts to slide down, a large braking force can be applied, and the increase in the sliding down speed can be effectively reduced by this action.

After the control target pressure P is finally set in this way, the routine proceeds to S226, where the set control target pressure P
Based on the above, the operation control of the brake actuator 200 is performed, and this flowchart ends.

In the flowchart of FIG. 6 described above,
In S222 and S224, the case where the control target pressure P is corrected when the vehicle body acceleration α is larger than the threshold value αth has been described as an example. However, the present invention is not limited to the case where the threshold value is provided as described above. The value of the correction value P4 may be set according to the magnitude of the vehicle body acceleration α so that the value of the correction value P4 increases as the value of the vehicle body acceleration α increases.

In the embodiment described above, although omitted from the flowchart, when the brake pedal 10 is depressed in a situation where the anti-slipping control is being executed (flag F = 1), the brake pedal 10 is depressed. S130 to S134 are executed at the time when the depression of the vehicle is detected, and the skid mitigation control is immediately terminated.

In the above-described embodiment, the pressure reducing valve 230 is operated while the count value T of the timer is Ta <T ≦ Tb.
Has been described as an example in which the switching operation is performed by a drive control signal having a duty ratio of about 10%, but the operation is not necessarily limited to the case where the duty ratio is kept constant. For example, by changing the duty ratio of the drive control signal stepwise so that the wheel cylinder pressure decreases stepwise, the wheel cylinder pressure may be reduced more gradually than the decrease gradient indicated by the one-dot chain line a in FIG. It suffices if the pressure can be gradually reduced.

As a method of determining the actual traveling direction of the vehicle body performed in S104, in addition to the above-described determination method, for example, when the rotation directions of the three wheels are aligned, the rotation direction is determined by the actual traveling direction of the vehicle body. The direction is not particularly limited. In the case of a two-wheel drive vehicle, the rotation direction of a driven wheel that is a non-drive wheel may be determined as the actual traveling direction of the vehicle body.

Furthermore, the actual traveling direction of the vehicle body can be directly detected by using a ground speed sensor. For example, an ultrasonic wave of a predetermined frequency is transmitted from a vehicle-mounted ground speed sensor toward a road surface behind the vehicle, and a reflected wave thereof is received. At this time, for example, when the frequency of the received wave is higher than the frequency of the transmitted wave, it can be determined that the vehicle body is moving backward, and when the frequency of the received wave is lower than the frequency of the transmitted wave, the vehicle body moves forward. Can be determined.

Further, in the embodiment described above, the flowchart of FIG. 4 is described as being started by turning on the ignition switch. However, the present invention is not limited to this example. For example, the shift position of the shift lever is set to the forward position. Alternatively, the flowchart may be activated in a state where both the brake pedal 10 and the accelerator pedal are not depressed at the retreat position.

Further, in the embodiment described above, the case where the braking force is controlled by the hydraulic pressure of the working fluid has been described.
In addition, the present invention can be applied to operation control of an electronic motor brake which generates a braking force by a driving force generated by a motor. In this case as well, when the count value T of the timer is Ta <T ≦ Tb, the drive generated by the electronic motor brake is such that the braking force tends to decrease more slowly than in the normal control end processing. Slow decrease control is performed to gradually decrease the force.

Next, another embodiment will be described.

For example, assuming a situation in which the vehicle body is slipping downhill on an uphill slope, the driver steps on the accelerator pedal to move the vehicle body forward. At this time, for example, a part of the road surface is frozen. On low μ roads, some wheels may cause wheel spin. With reference to the flowchart of FIG. 7, a description will be given of a control process in consideration of a case where the vehicle body is slipping down a sloping road in a state where some of the wheels have caused wheel spin. Since this control is also performed individually for each wheel, as in the flowcharts of FIGS. 4 and 6, the flowchart of FIG. 7 shows a control flowchart for one specific wheel.

This flowchart is started by turning on the ignition switch. First, in S302,
Slip mitigation control in S312 described later, or S
It is determined whether the slip suppression control in 314 is in operation. If any of the controls is in operation, the routine is terminated without executing the subsequent processing steps.

If neither the slippage mitigation control (S312) nor the slip suppression control (S314) is being started, "No" is determined in S302, and the program proceeds to S304.
Each sensor 110, 120, 130, 14 shown in FIG.
0, 160 and the detection result of the switch 150 are read.

At S306, it is determined whether or not the vehicle body is going downhill on the basis of the read detection result. As described above, when the vehicle body slips down the slope on a low μ road with some wheels undergoing wheel spin, each of the wheels FL, FR, RL, RR.
Are not aligned. Therefore, each wheel F
Paying attention only to the rotation directions of L, FR, RL, RR, it is determined whether or not the rotation directions of the wheels FL, FR, RL, RR are all the same. It can be immediately determined that the vehicle is in the downhill state. By determining the state of the body slipping based on the difference in the rotation direction of each of the wheels FL, FR, RL, and RR in this manner, compared with the case where the determination is made based on the difference between the wheel speeds and the magnitude of the wheel speed, The sliding state can be determined at an earlier timing.

Further, other examples of the determination of the vehicle body slipping state include the aforementioned S102 and S104 in FIG.
When the desired traveling direction of the driver does not match the actual traveling direction of the vehicle body as performed in S114 and S114, the vehicle body may be determined to be in a downhill state. Further, when there is at least one wheel rotating in the direction opposite to the driver's desired traveling direction, it may be determined that the vehicle body is in a downhill state.

After the vehicle body is determined to be in the downhill state in S306 in this manner, the process proceeds to S308 and proceeds to S306.
It is determined whether the vehicle body is determined to be in a downhill state in. When it is determined in S306 that the vehicle body is not in the downhill state (“No” in S308), this routine ends as it is, but when it is determined that the vehicle is in the downhill state (“Yes in S308”). )), S310
Proceed to.

At S310, it is determined whether or not the wheel to be controlled in this flowchart is a wheel rotating in the downhill direction of the vehicle body. As a result, if the wheel is rotating in the downhill direction, "Ye" is determined in S310.
s "is determined, and the flow proceeds to S312 to activate the sliding mitigation control. On the other hand, if the wheel is rotating in the direction opposite to the downhill direction, the wheel is spinning due to a low frictional force with the road surface. In this case, “No” is determined in S310 and S314 is performed. To activate the slip suppression control.

When the corresponding control is started in S312 or S314 in this way, in the next and subsequent routines, “Yes” is determined in S302 as described above, and
This routine ends without executing the processing steps after S304. Then, when the control started in S312 or S314 started ends, “N
o "is determined, and the processing steps after S304 are performed again.

FIG. 8 is a flow chart showing the slip mitigation control started in S312 of FIG. Note that the flowchart of FIG. 8 is a control process substantially similar to the sliding mitigation control described with reference to FIG. 4, and the same processing steps as those in the flowchart of FIG. 4 are denoted by the same step numbers.

In the flowchart of FIG. 8, S10 of FIG.
8 is deleted, and as another difference, after the start, the process first proceeds to S106, and the value of the flag F1 indicating whether or not the sliding mitigation control is being executed is determined. Immediately after startup, the value of the flag F1 is set to F1 = 0.
It is determined as “No” in 06, the process proceeds to S110, and the flag F
The value of 1 is set to F1 = 1, indicating that the skid mitigation control has been executed. Then, the process proceeds to S112, in which the timer for counting the execution time of the sliding mitigation control is started. After that, the process proceeds to S200, and the hydraulic pressure control shown in detail in FIG. 6 is performed.

In the next routine, the value of the flag F1 is set to F
Since 1 = 1 has been set, “Yes” is determined in S106, the process proceeds to S101, and the processes in and after S101 similar to FIG. 4 are repeatedly performed.

Then, while the routine of FIG. 8 is repeatedly performed, the actual traveling direction of the vehicle body coincides with the desired traveling direction of the driver (“Ye” in S114).
s "), when the direction of rotation of the wheels matches the desired direction of travel of the driver (" Yes "in S116), and when the count value T of the timer exceeds the threshold value Tb (" N "in S126).
o)), the control end processing in S130 to S134 is performed as in FIG. 4, and the control routine ends.

Next, the slip suppression control started in S314 of FIG. 7 is shown in the flowchart of FIG.

After startup, the process first proceeds to S502, where the value of a flag F2 indicating whether or not the slip suppression control is being executed is determined. Immediately after the startup, the value of the flag F2 is set to F2 = 0, so it is determined as “No” in S502 and S504
Then, the value of the flag F2 is set to F2 = 1, indicating that the slip suppression control has been executed. And S506
To P5, which is defined in advance to suppress slip,
Control target pressure (wheel cylinder pressure as control target) P
Set as Then, the process proceeds to S508, and based on the set control target pressure P, the brake actuator 200
Operation control is performed.

In the next routine, the value of the flag F2 becomes F
Since 2 = 1 is set, “Yes” is determined in S502, and the process proceeds to S510, where each sensor 11 shown in FIG.
0, 120, 130, 140, 160 and switch 15
The detection result of 0 is read.

In S512, it is determined whether or not the vehicle body is going downhill on the basis of the read detection result. This determination is also similar to S306 in FIG.
It is determined whether or not the rotation directions of the wheels FL, FR, RL, and RR all match, and if they do not match, it is determined that the vehicle body is leaning down. Alternatively, when the desired traveling direction of the driver does not match the actual traveling direction of the vehicle body, the vehicle body may be determined to be in a downhill state. Further, when there is at least one wheel rotating in the direction opposite to the driver's desired traveling direction, it may be determined that the vehicle body is in a downhill state.

In the following 514, it is checked whether or not the vehicle body is determined to be in a downhill state in S512. If it is determined that the vehicle body is in a downhill state ("Y" in S514).
es "), and proceeds to S515.

In S515, it is determined whether the rotation direction of the wheel targeted in this flowchart is the direction in which the driver wants to proceed. This takes into account the case where the frictional state of the road surface where the wheels are in contact with the ground changes as the vehicle body slides down. That is, for example, when the road surface is partially frozen, the wheels may move from a frozen road surface to a non-freezing road surface as the vehicle body slides down. The direction of rotation of the wheels may be reversed, and the wheels may start to rotate in the sliding direction. Therefore, when the wheel starts rotating in the sliding direction, "No" is determined in S515, the process proceeds to S526 and thereafter, and the slip suppression control is ended. In this case, returning to the flow chart of FIG. 7 described above, the sliding mitigation control in S312 is activated.

Similarly, a wheel that has been rotating in the downhill direction may cause a wheel spin due to a change in the frictional state of the road surface. In this case, the sliding mitigation control of FIG. 8 corresponds to the case where the rotation direction of the wheel matches the driver's desired traveling direction (“Yes” in S116), and also in this case, S130 and subsequent steps are started to reduce the sliding. The control ends, returning to the flowchart of FIG. 7, and the slip suppression control of S314 is started.

Returning to FIG. 9, if "Yes" in S515, that is, if the rotation direction of the wheel coincides with the desired traveling direction (in the case of a slip state), the flow proceeds to S516 and becomes a control target in this flowchart. The slip amount ΔV of the wheel that is present is set. As a control for suppressing wheel slip, there is traction control control for suppressing acceleration slip at the time of starting and accelerating. Usually, a reference rotation speed of a wheel obtained based on a target slip rate and an estimated vehicle speed, and Is set as the slip amount ΔV. However, the situation assumed in this flowchart is that the vehicle body slips down the slope,
In addition, this is a situation where the wheels are spinning wheels, which is different from the situation assumed in normal traction control. Therefore, here, for convenience, the detected rotational speed of the wheel is directly set as the wheel slip amount ΔV. That is, this corresponds to the case where the estimated vehicle speed is regarded as zero.

At S518, the wheel slip amount ΔV set at S516 is set to a sufficiently small threshold value ΔV.
If the wheel slip amount ΔV is smaller than the threshold value ΔV, for example, as in the case where the wheels are locked (“No” in S518), Proceeding to S524, the value of the control target pressure P set in the previous routine is set as the control target pressure P in the current routine, and the value of the control target pressure P is held.

Thereafter, the flow proceeds to S508, where the operation of the brake actuator 200 is controlled based on the control target pressure P set in S524.

On the other hand, if it is determined in step S518 that the wheel slip amount ΔV is equal to or larger than the threshold value ΔVth, (518)
Then, the process proceeds to S520, and the changing state of the wheel speed is determined for the wheel in charge in this flowchart. In this determination, for example, the wheel acceleration is obtained based on the deviation between the slip amount ΔV set in the previous step S516 and the slip amount ΔV set in the previous routine S516 and the time interval therebetween, and the wheel acceleration becomes “+ (Correct) ","-
(Negative) ”or“ 0 (no increase / decrease) ”. As an example of the determination in this case, if the absolute value of the wheel acceleration is a predetermined small value (the change in the wheel speed is within a predetermined minute range), it is determined that there is no increase or decrease, and the wheel speed increases / decreases beyond this range. If so, the wheel acceleration is determined as “+” / “−”.

In the following S522, based on the chart shown in FIG. 10, the wheel speed change state (+,
The control target pressure P is set according to 0,-). From FIG. 10, for example, when the change state of the wheel speed is “− (negative)”, the control target pressure P is held, and the value of the control target pressure P set in the previous routine is used as it is in the current control target pressure P. Set as When the change state of the wheel speed is "0 (no increase / decrease)", the control target pressure P is increased, and a predetermined pressure P6 (P6) is set with respect to the control target pressure P set in the previous routine.
> 0) is set as the control target pressure P (P ←
P + P6). Also, the change state of the wheel speed is "+ (correct)"
In the case of, the control target pressure P is rapidly increased to a predetermined pressure P7 (P7> P) with respect to the control target pressure P set in the previous routine.
6) is set as the control target pressure P (P ← P
+ P7).

After the control target pressure P is set in this way, the process proceeds to S508, and the operation control of the brake actuator 200 is performed based on the control target pressure P set in S522.

In the process of repeatedly executing the above-described processing, if the vehicle body has been lowered, the result of the determination in step S514 is "No", and the flow advances to step S526. A predetermined control end process for decreasing the target pressure P is performed, and in S528, the value of the flag F2 is reset to F2 = 0, and the slip suppression control is ended.

By performing such a control process, the braking device 20 is applied to the wheel that is causing the wheel spin.
Thus, a braking force can be applied to suppress idle running of the wheels. Therefore, it will function as a differential limit that limits the wheel's idling.When the differential limit function is not provided, the drive torque is prevented from being lost from the wheel that is causing the wheel spin, and the hole spin is caused. It is possible to prevent the drive torque to be transmitted from being reduced for a wheel that is not rotating (a wheel rotating in the downhill direction).

When the vehicle body starts to move in the desired direction of the driver and the wheels are spinning, the traction control control for suppressing the acceleration slip as described above is started. become.

In each of the embodiments described above, as shown in FIG. 2, an actuator in a vacuum booster type brake system is exemplified. However, in addition to the above, an actuator of a brake system having a hydro booster or a motor may be applied to a wheel. An actuator that applies a braking force may be used, and is not particularly limited as long as it is a brake actuator that can apply a braking force to wheels separately from a driver's braking operation.

Although the wheel speed sensor 110 has been described as a sensor capable of detecting both the rotational speed and the rotational direction of the wheel, the wheel speed sensor 110 is constituted as a sensor capable of detecting only the rotational speed of the wheel. It is also possible to adopt a configuration provided with a separate sensor for detecting the rotation direction of.

[0107]

According to a first aspect of the present invention, there is provided a vehicle traveling state control device for a wheel that rotates in the same direction as the actual traveling direction of a vehicle when the desired traveling direction of the driver and the actual traveling direction of the vehicle body are opposite to each other. A braking control means for applying a braking force to the vehicle is provided, and the magnitude of the braking force applied by the braking control means is controlled according to the acceleration state of the vehicle traveling in the actual traveling direction.

As a result, the braking force to be applied is corrected according to the condition of acceleration in the downhill direction, and a suitable braking force according to the degree of downhilling can be applied.

According to the vehicle running state control device according to the second aspect, the braking control means according to the first aspect relates to the slope ratio of the braking force applied to the wheels on the upper side of the slope and the wheels on the lower side of the slope. Is larger, the distribution ratio of the braking force to the wheels on the lower side of the hill is increased as compared with the case where the hill gradient is small. It is possible to apply a suitable braking force.

According to the vehicle traveling state control device of the third aspect, since the braking control means starts the braking control based on the detection result of the rotation direction detecting means, the rotation directions of the four wheels do not match. In such a case, it can be immediately determined that the vehicle is in the downhill state, whereby the downhill mitigation control can be started at an earlier timing. In addition, wheels that rotate in the downhill direction of the vehicle,
By the first braking control means, it is possible to apply a suitable braking force according to the state of the vehicle rolling down,
A suitable braking force according to the wheel spin state can be applied to the wheel that is causing the wheel spin by the second braking control means.

According to the vehicle running state control device of the fourth aspect, the first braking control means is constituted as the braking control means of the first or second aspect, so that the degree of downhill movement, and further, the upper side of the slope or the lower side of the slope. A more suitable braking force can be applied in consideration of the side. Also, in order to sufficiently suppress the rotation of the wheel along the desired direction of travel,
By controlling the magnitude of the braking force by the second braking control means, wheel spin can be sufficiently suppressed, and directional stability of the vehicle can be ensured.

[Brief description of the drawings]

FIG. 1 is a configuration diagram schematically showing a drive system and a hydraulic control system of a vehicle according to an embodiment.

FIG. 2 is a configuration diagram representatively showing a hydraulic control system relating to braking force control of one wheel in the configuration of a brake actuator.

FIG. 3 is a block diagram schematically showing a configuration of an overall control system of an electric system and a hydraulic system.

FIG. 4 is a flowchart showing a vehicle slippage mitigation control.

FIG. 5 is a graph showing an example of a change in wheel cylinder pressure with respect to the duration of the vehicle's downhill mitigation control.

FIG. 6 is a flowchart illustrating a hydraulic control process performed in S200 of FIG. 4;

FIG. 7 is a flowchart showing another embodiment.

FIG. 8 is a flowchart showing the downslope mitigation control started in S312 of FIG. 7;

FIG. 9 is a flowchart illustrating slip suppression control started in S314 of FIG. 7;

FIG. 10 is a chart showing a control target pressure P set according to a change state of a wheel speed.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine, 10 ... Brake pedal, 20 ... Braking device, 21 ... Wheel cylinder, 100 ... Control device, 20
0: brake actuator, 210: shut-off valve, 220
... Holding valve, 230 ... Reducing valve, 240 ... Suction valve

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Akira Nagae 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Toshinobu 2-1-1 Asahi Town, Kariya City, Aichi Prefecture Aisin Seiki Co., Ltd. (72) Inventor Yasuhito Ishida 2-1-1 Asahi-cho, Kariya-shi, Aichi F-term (reference) 3D037 FA24 FA25 3D046 AA01 BB02 BB29 HH02 HH07 HH25 HH36 JJ02 JJ19 JJ21 KK11

Claims (4)

[Claims] 1. A vehicle traveling state control device for controlling a braking force when a vehicle travels in a direction opposite to a traveling direction of a vehicle based on a forward operation or a reverse operation, wherein the forward / backward operation is performed. Operating state detecting means for detecting, an actual traveling direction detecting means for detecting an actual traveling direction in which the vehicle actually travels, a desired traveling direction of the driver grasped from a detection result of the operating state detecting means, When the direction is opposite to the direction, while applying a predetermined braking force to the wheel rotating along the actual traveling direction separately from the driver's braking operation, the magnitude of the applied braking force is: A vehicle traveling state control device comprising: a braking control unit configured to control the vehicle traveling in the actual traveling direction according to an acceleration state of the vehicle. 2. The braking control means according to claim 1, wherein a distribution ratio of a braking force applied to a wheel on an upper slope and a wheel on a lower slope is larger when the slope is larger than when the slope is smaller. The vehicle running state control device according to claim 1, wherein the distribution ratio of the braking force to the wheels on the lower side of the slope is increased. 3. A vehicle running state control device for controlling a braking force when a vehicle travels in a direction opposite to a traveling direction of the vehicle based on a forward operation or a reverse operation, comprising: Operating state detecting means for detecting, a rotating direction detecting means for detecting a rotating direction of each wheel, and a driver's desire to advance which is grasped from the detection result of the operating state detecting means based on the detection result of the rotating direction detecting means When the wheels that rotate along the direction and the wheels that rotate in the opposite direction to the desired traveling direction are mixed, the wheels that rotate along the desired traveling direction and the opposite direction to the desired traveling direction Individually for the rotating wheels,
Braking control means for applying a braking force separately from the driver's braking operation, wherein the braking control means responds to a wheel rotating in a direction opposite to the desired traveling direction according to the traveling state of the vehicle. Vehicle running state control comprising: first braking control means for applying a braking force; and second braking control means for applying a braking force to wheels rotating along the desired traveling direction in accordance with the rotation state of the wheels. apparatus. 4. The braking control means according to claim 1, wherein the first braking control means is configured to control the rotation of the wheels along the desired traveling direction to be sufficiently suppressed. The vehicle running state control device according to claim 3, wherein the magnitude of the braking force to be applied is controlled.