JPH03217373A - Left and right forces differential steering restraint - Google Patents

Abstract

PURPOSE:To improve each of travel stability and speed adjustability in a vehicle by generating a yet larger left and right forces difference of left and right wheels than when it is larger in the case where vehicle's adjustable operating speed is small. CONSTITUTION:Any left and right forces differential steering being generated in a vehicle due to a difference in left and right forces consisting of driving force and braking force or the like of left and right wheels LW, RW is restrained from occurring. In this case, the left and right forces are made independent respectively and controlled by a means A. On the other hand, the magnitude of operating speed in a means B operating the vehicle for adjustable speed is judged by a means C. Then, the device A is controlled, and any generation of the left and right forces difference is checked by a means D. When the operating speed judged by the means C is small, restrain by the means D is allowed so as to generate a yet larger left and right forces difference than when it is large. With this constitution, the restraint of the left and right forces differential steering is optimally controlled at need, through which each extent of travel stability and speed adjustability in the vehicle is thus improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a device for suppressing left-right force differential steering in which the direction of a vehicle changes due to a difference in left-right forces such as driving force and braking force between left and right wheels.

BACKGROUND OF THE INVENTION Japanese Patent Application Laid-Open No. 60-56662 describes a device for suppressing slippage of left and right drive wheels of a vehicle by independently controlling the drive forces of the drive wheels. This device includes a rotation sensor that detects the rotational speed of left and right driven wheels and non-driven wheels, a slip detection means that detects slipping of the left and right driven wheels based on the output signals of these rotation sensors, and a brake for the driven wheel that has slipped. The brake control means supplies hydraulic pressure to reduce the rotational torque of each drive wheel, and the drive source control means reduces the output of a drive source such as an engine when slip occurs in the drive wheels. The drive source control means and the brake control means work together to independently control the driving force of the left and right drive wheels, thereby suppressing the slip of the drive wheels within an appropriate range.

In addition, Japanese Patent Application No. 1-164663 discloses an anti-skid control system that controls the slip of the left and right wheels within an appropriate range by independently controlling the hydraulic pressure of the brake fluid that suppresses the rotation of the left and right wheels during braking. The equipment is described.

If a vehicle is equipped with a left-right force control device that independently controls left-right forces such as left-right driving force and braking force, the slip of the left and right wheels can be controlled within appropriate ranges to effectively accelerate or decelerate the vehicle. be able to. However, if the friction coefficients of the road surfaces in contact with the left and right wheels are significantly different, controlling the slip of the left and right wheels within appropriate ranges will increase the difference between the left and right forces and cause the vehicle to experience a rotational moment about the vertical axis. This causes left-right differential steering, which causes the vehicle to change direction.

On the other hand, when slipping occurs on either the left or right wheels, the driving force and braking force are reduced for one of them, and the other is also reduced in the same way. Although the occurrence of force differential steering can be avoided, it is unavoidable that the acceleration and deceleration performance of the vehicle will suffer greatly.

Therefore, in Japanese Patent Application No. 1-134224, in order to suppress steering that occurs based on the difference in left and right braking force, the applicant has proposed that one of the pressures in the left brake cylinder and the pressure in the right brake cylinder be controlled by anti-skid control. It has been proposed to provide differential pressure limiting means to control the non-antiskid brake cylinder pressure to prevent the pressure difference between the two brake cylinders from increasing beyond a set value when reduced by the device. In this way, by allowing the difference between the left and right forces to occur while also preventing the difference from becoming excessive, it is possible to reduce the sacrifice of acceleration and deceleration of the vehicle while suppressing the occurrence of left-right force differential steer. be able to.

Problems to be Solved by the Invention However, the degree to which it is desirable to suppress left-right force differential steering varies depending on the case. There are cases in which it is desirable to suppress the occurrence of left-right force differential steer as much as possible even at the expense of acceleration and deceleration, and conversely, there are cases in which it is desirable to suppress the occurrence of left-right force differential steer as much as possible, even at the expense of acceleration and deceleration.In contrast, there are cases in which it is desirable to increase acceleration and deceleration performance even if the occurrence of left-right force differential steer is allowed to occur to some extent. There are cases where this is desirable.

In view of the above circumstances, the present invention has been made with the object of providing a left-right power differential steering suppression device that automatically changes the degree of suppression of left-right differential power steering as required.

Means for Solving the Problem In order to solve this problem, the left-right force difference steer suppression device according to the present invention includes (a) a left-right force control device that can independently control left-right force, as shown in FIG. (b) an operation speed determination means for determining the magnitude of the operation speed of the acceleration/deceleration operation means of the vehicle; and (C) controlling the left-right force control device to suppress the occurrence of left-right force differential steering, and to control the operation speed. It is configured to include a left-right force difference steering suppressing means that allows a larger left-right force difference to occur when the determining means determines that the operation speed is low than when determining that the operation speed is high.

Of course, the accelerator pedal that is depressed for acceleration or the brake pedal that is depressed for deceleration is an acceleration/deceleration operating means, but for example, if the accelerator pedal that has been depressed is released, , the engine brake acts and a braking force acts on the drive wheels, and in that sense the accelerator pedal also serves as a deceleration operating means. That is, the depression speed of the accelerator pedal is the operating speed of the acceleration operating means, and the release speed is the operating speed of the deceleration operating means.

Furthermore, the acceleration/deceleration operation means does not necessarily have to be capable of both acceleration and deceleration operations, but may be one that is capable of at least one of them.

Function In the left-right force difference steer suppression device according to the present invention, for example, the left-right force is the driving force of the left and right drive wheels, the left-right force control device is a brake device that suppresses rotation of the left and right drive wheels, and the acceleration/deceleration operating means is a brake device that suppresses rotation of the left and right drive wheels. In the case of an accelerator pedal, the left-right force difference steering suppressing means is configured to prevent the left and right drive wheels from having the same driving force or only a relatively small difference in driving force when the accelerator pedal is suddenly depressed. Since the brake devices for the left and right drive wheels are controlled, driving stability is guaranteed during acceleration. On the other hand, when the accelerator pedal is depressed gently, it is possible to allow a relatively large difference in the driving force between the left and right sides, so the drive wheel on the side with a larger friction coefficient with the road surface is driven on the side with a smaller friction coefficient. The vehicle can be driven with considerably greater driving force than the wheels, increasing the acceleration of the vehicle.

Normally, when the friction coefficients of the left and right road surfaces are significantly different, the driver depresses the accelerator pedal gently in anticipation of the occurrence of steering based on the difference in driving force between the left and right surfaces. This can be considered to mean that the driver is predicting the occurrence of left-right drive force differential steering. In such a case, even if steering occurs, it is relatively easy to perform a steering operation to cancel the steering, so there is no problem in allowing a certain degree of left-right drive force differential steering to occur. .

Furthermore, even if the driver did not press the accelerator pedal gently in anticipation of the occurrence of left-right drive force differential steer, if the accelerator pedal depression operation is gradual, left-right drive force differential steer will occur. However, since it is not so sudden, it should be relatively easy to cancel out the left-right drive force difference steer by steering operation.

The same can be said when the vehicle is decelerated by releasing the accelerator pedal or depressing the brake pedal.

Effects of the Invention As described above, in the left-right force difference steering suppression device according to the present invention, it is determined whether or not it is acceptable to cause a large difference in left-right force based on the magnitude of the operation speed of the acceleration/deceleration operating means. If there is no problem, a large left-right force difference may be allowed to occur. Therefore, although the occurrence of left-right force differential steering is usually sufficiently suppressed, if there is no problem, a relatively large difference in left-right force is allowed to occur, which has the effect of improving the acceleration or deceleration of the vehicle. is obtained.

Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

In Figure 2, 10.12 is the front wheel, 14, 16
is the rear wheel. The front wheels 10.12 are steered wheels whose direction can be changed by a steering device (not shown), and the rear wheels 14.16
The transmission 18. is driven by an engine (not shown).
These are drive wheels driven via a differential device 20. The output of the engine is controlled by a main throttle 24 that is opened and closed by operating an accelerator pedal 22, and a subthrottle 24 that is opened and closed by a subthrottle actuator 26. The opening degrees of the main throttle 24 and the sub-throttle 28 are detected by a main throttle sensor 30 and a sub-throttle sensor 32, respectively.

The front wheels 10.12 and the rear wheels 14.16 are provided with brakes 34.36.38 and 40, respectively,
Each brake is operated by brake fluid pressure generated in a mask cylinder 44 in response to operation of a brake pedal 42 as a brake operation member. The mask cylinder 44 has two independent pressurizing chambers, and the brake fluid pressure generated in one pressurizing chamber is transferred to the fluid passages 46 and 48.
The brake fluid pressure generated in the other pressure chamber is transmitted to the front wheel cylinders 50, 52 through fluid passages 54, 57 and 57 to actuate the brakes 34, 36, respectively, and is transmitted to the rear wheel cylinders 58, 60 through fluid passages 54, 56 and 57. The signal is transmitted to actuate the brakes 38 and 40. Each wheel 10, 12, 14 and 16 is provided with a rotation sensor 62, 64, 66 and 68, respectively, to detect the respective rotation speed.

An anti-skin brake system (hereinafter abbreviated as ABS) is installed between the liquid passage 46.54 and the liquid passage 48.56.
An actuator 70 is provided, which is controlled by an ABS computer 72 so that the slip of the wheels 10, 12, 14, and 16 during braking is controlled to an appropriate amount. Since these ABS actuator 70 and ABS computer 72 are well known, detailed description thereof will be omitted.

The main throttle sensor 30 and the sub-throttle sensor 32 are connected to an engine control computer 74.
4 controls the output of an engine (not shown) based on the detection results of these two sensors 3032, but since it is well known, a detailed explanation will be omitted.

A traction control (hereinafter abbreviated as TRC) brake actuator 80 is provided between the fluid passages 56 and 57 that transmit brake fluid pressure to the rear wheel cylinders 58 and 60.
As a result, the brakes 38, 40 are operated, and the slip of the rear wheels 14, 16, which are the drive wheels, is controlled to an appropriate value. A TRC cut switch 83 is connected to the TRC computer 82 and can be operated by the driver to put the TRC computer 82 into a non-operating state.

The TRC brake actuator 80 is normally connected to the liquid passage 5.
6 communicates with the liquid passage 57, but shuts off the liquid passage 56 when the TRC brake actuator 80 is activated, a unique hydraulic pressure source including a pump and an accumulator, and a hydraulic pressure supply from the hydraulic pressure source. In response, the rear wheel cylinder 58 is activated based on the command from the TRC computer 82.
．． This includes two electromagnetic hydraulic pressure control valves that independently control the hydraulic pressure of 60. Each electromagnetic hydraulic pressure control valve has a pressure increasing position that communicates the rear wheel cylinder 58, 60 with a hydraulic pressure source;
It has a depressurizing position that communicates with the reservoir tank and a holding position that does not communicate with either, and by switching to each position with the duty ratio shown in Table 1, the simple pressure increasing FFU,
Rapid pressure increase FIJ, slow pressure increase SU, holding H. It operates in seven modes: slow deflation SD, rapid deflation FD, and simple deflation FFD.

Table 1 The TRC computer 82 has a CPU as shown in FIG.
84, ROM 86, RAM 88, an input port 90 and an output port 92. The ROM 86 stores a TRC program shown in the flowchart of FIG. 4 for controlling the sub-throttle actuator 26 and the TRC brake actuator 8o.
The computer 82 executes this TRC program based on information from the ABS computer 72 and engine control computer 74.

TRCl7 View-48 2 (7) ROM8 6 also contains the map represented in Table 2 for controlling the TRC brake actuator 8o, and Table 2? Sub-throttle closing speed θS6 s=A expressed by the formula
・{ a-max(ΔV*) + b-min(Δ
■． ))/(a+b) 10B・{a′・max(VR*)
+b ′・min(V*-)) /(a '10b')
C ・min(P., l, PIL) H ” ” ”
'(1) However, ΔV. :Δ■． or Δ■2 νRll: VRI or V++■ may (ΔVyu): The larger of the left and right wheel speed differences mjn (Δ■yu): The smaller of the left and right wheel speed differences min (P Bu, PML): Lower left and right rear wheel brake fluid pressure A. B, C: Coefficient determined by experiment? The values of weights a, a', b, b'' for calculation are stored. The sub-throttle closing speed θ, is the speed at which the sub-throttle actuator 26 closes the sub-throttle 28, which is normally in a fully open state. , left and right wheel speed difference Δ
■2. The weighted average of Δ■, and the acceleration of the left and right rear wheels M, l■,
■It is determined based on the weighted average of , and by adding corrections for the braking effect of the rear wheels 14.16 by TRC. (
1) The weights a, a', b, b' in the formula are the accelerator pedal 2
The weights a, a' and b, b' are each set to two values, large and small. Here, the larger value of a, a' is 0.4, the smaller value is 0.2, b, b
The larger value of ' is 0. 8. The smaller value is 0.6. The fact that weights a and a' are large and weights b and b' are small means that
This means that the sub-throttle closing speed θ is determined by being strongly influenced by the larger of the left and right wheel speed difference and the rear wheel acceleration, and wheel slip is sufficiently suppressed. In addition, since the correction for the braking effect is made based on the lower of the brake fluid pressures of the left and right rear wheels 16.14, the correction will be smaller than the actual braking effect of each of the left and right rear wheels 16.14. Then, the subthrottle closing speed θ,
is determined to be larger than truly necessary, that is, on the safe side.

As shown in FIG. 5, the RAM 8B stores a previous accelerator opening degree memory 94, a current accelerator opening degree memory 96, a sub-throttle opening degree memory 98, a TRC flag 100, and a timer 102.
, accelerator opening speed memory 104, weight flag 106, wheel speed memory 108, wheel acceleration memory 110, wheel speed difference memory 112, and subthrottle closing speed memory 1
14 is provided along with working memory.

The TRC program in FIG. 4 is from step S15 to S1.
In step S9, it is determined whether TRC is necessary or not, and if it is necessary, in step S20, control of the TRC brake actuator 80 and sub-throttle control based on the above-mentioned formula (1) is performed based on the map in Table 2 above. The actuator 26 is controlled by the weight a of equation (1),
Processing for determining a', b, and b' is performed in steps S1 to S14. When the accelerator pedal 22 depression speed is high, the sub-throttle closing speed 6s becomes large and the engine output reduction speed becomes large, and when the accelerator pedal 22 depression speed is small, the sub-throttle closing speed θ becomes small. The weights a, a', b,
b' is determined.

Hereinafter, the operation of the TRC will be explained in detail based on the flowchart of FIG.

When the ignition switch is turned on with the TRC cut switch 83 being operated to a position that allows the TRC computer 82, or after the ignition switch is turned on, the TRC cut switch 83 allows the TRC computer 82 to operate. When the state is switched to the state where RA is
Each memory, flag, timer, etc. including the previous accelerator opening degree memory 94 of M88 is cleared or reset. Thereafter, the TRC program shown in FIG. 4 is executed once every fixed period of time (for example, 10 msec).

First, step Sl (hereinafter simply referred to as 31).

The same applies to other steps), after the contents of the current accelerator opening memory 96 are transferred to the previous accelerator opening memory 94, in S2, the accelerator opening θ at that time,
and sub-throttle opening degree θ, are read from the engine control computer 74, and the current accelerator opening degree memory 96 and sub-throttle opening degree memory 98, respectively.
is stored in

Next, the accelerator opening degree θN read in S3 is O
It is determined whether or not it is 0, and if it is 0, the weight flag 106 is turned OFF in S4.

"The weight flag OFFJ sets the weights a and a' to be large and weights b and b' to be small to increase the subthrottle closing speed θ, to reduce the engine output and sufficiently suppress the driving force difference between the rear wheels 14.16. means something to do.

After execution of S4, TRC flag 100 is OFF in S5.
At the same time, the count value of the timer 102 is set to 0, and one program execution ends.

On the other hand, if the accelerator opening degree θ is not 0, S3
The determination result is No, and the TRC flag is set to 1 in S6.
It is determined whether or not 00 is ON. When this step is executed for the first time, the result of this determination is NO, and it is determined in S7 whether the accelerator opening degree θ is small, medium or constant. If the accelerator pedal 22 is being depressed, the result of this determination is No, and the count value T of the timer 102 is increased by 1 in S8, and the accelerator opening degree θ at that time and the count value T of the timer 102 are incremented in S9. From this, the accelerator opening speed θ is calculated and stored in the accelerator opening speed memory 104.

In addition, if step 36 is executed after the TRC flag 100 is turned ON in S21, the result of the determination is YES, and the SIO determines whether the subthrottle opening θ is greater than the constant value α than the accelerator opening θ9. is determined,
If the result of the determination is YES, TRC termination processing in S4 and S5 is performed. [The sub-throttle opening degree θ, is larger than the accelerator opening degree θa by a certain value α or more” is a condition for terminating the TRC, along with the above-mentioned “accelerator opening degree θ8 being O.”

After executing S7, S9 or SIO, it is determined in Sll whether the accelerator opening speed θe is greater than the reference accelerator opening speed eK, and if the result of the determination is NO, the accelerator pedal 22 has been gently depressed. Then, in S12, the weight flag 106 is turned ON. In this case, later in 320, the weights a and a' are set to a small value of 0.2,
The weights b and b' are set to a large value of 0.8, and the subthrottle closing speed θ3 is determined to be a small value.

If the depression speed of the accelerator pedal 22 is small, it is presumed that the accelerator pedal 22 was depressed carefully, and the sub-throttle closing speed θ is determined to be a small value, the amount of reduction in engine output is reduced, and the amount of reduction in engine output is reduced. A large driving force will be transmitted to 16. On the other hand, if the determination result of Sll is YES, that is, if the depression speed of the accelerator pedal 22 is high, 31
2 is skipped, and the weight flag 106 is not changed.

Next, in 313, it is determined whether the previous accelerator opening θ, is larger than the current accelerator opening θ9, that is, whether the accelerator pedal 22 has been returned, and the determination result is YE.
If S, the weight flag 106 is turned off in step 314, but if the result of the determination is NO, S14 is skipped. That is, at 312 the weight flag 106
Even after the accelerator pedal 22 is turned on,
When the weight flag 106 is returned, the weight flag 106 is turned OFF again. These 313 and 314 increase the engine output as the accelerator pedal 22 is depressed, and the rear wheel 14 increases.
．． When the driving force of the rear wheels 14.1'6 increased, the difference in the coefficient of friction of the road surface that the two rear wheels 14.1'6 were in contact with caused left and right driving force differential steering, which caused the driver to change the accelerator pedal 22. This step is designed to assume that the pedal pedal is loosened, and in such a case, the difference in driving force between the rear wheels 14 and 16 can be kept small as usual.

Subsequently, in S15, each wheel speed and acceleration are adjusted to ABS.
The wheel speed memory 1 is read from the computer 72.
08 and after being stored in the wheel acceleration memory 110, 3
At 16, the right wheel speed difference Δ■ and the left wheel speed difference Δ
(2) is calculated, and in S17 and S18, the absolute value of each wheel speed difference is the reference wheel speed difference V. It is determined whether the value is greater than or not. And S17 or Sl8
If the determination result is YES, it is determined that TRC is necessary, subthrottle control and brake control are performed in S20, and TRC flag 100 is turned ON in S21.

The sub-throttle control calculates the sub-throttle closing speed θ, using equation (1) above, and operates the sub-throttle actuator 26 based on the calculation result. This is a control that allows The brake control is a control that operates the TRC brake actuator 80 based on the map shown in Table 2 above, and the front wheel speed ■F. is a coefficient β (in this example, 1
．． 2) Target speed and rear wheel speed found by multiplying ■. (hereinafter referred to as wheel speed difference) ΔV distortion and each reference speed V
XI. Whether or not the rear wheel acceleration VR is greater than VK2 and VKff is negative acceleration G, lI and positive acceleration G.
A control mode is determined based on whether or not the value is larger than Kz, and a command is given to the TRC brake actuator 80.

Reference wheel speed difference VKl+ VK2. VK3 is the 6th
As shown at the top of the figure, ■κ, >V, 2>V. The relationship is as follows, and the wheel speed difference ΔV. is each reference wheel speed difference ■. ，
VXZ. Whether or not the rear wheel speed is greater than VKI means whether the rear wheel speed ■R is greater than ■Fy/β+■■, V,*・β+VX2 and ■Fyy/β+VK3, respectively. Also, the reference rear wheel acceleration GK, . G. (2) are negative and positive accelerations, respectively, as shown in the lower part of FIG. 6, and the control mode is changed depending on whether or not the rear wheel acceleration Vie is larger than each reference acceleration Gx+, Gx (2). In addition,
The wheel speed difference (2) is used to determine whether TRC control is necessary. is a value smaller than the reference wheel speed difference VKI.

If the determination results in S17 and S18 are both NO, it is determined in 319 whether or not the TRC flag 100 is OFF, and if the determination result is YES, S20 and 321 are skipped and the program continues. One execution of S20 and S21 is completed, but S20 and S21
is executed, TRC flag 1 is turned ON in S21.
00 means S4 when the termination conditions of S3 or S10 are met.
Since it remains ON unless it is turned OFF in S17
Even if the determination result of 31B is NO, the determination result of S19 is NO, and S20 and S2l are executed.

As is clear from the above explanation, in this example,
Sub throttle 28, TRC brake actuator 8
0, the TRC computer 82 and the like constitute a lateral force control device, and the portion of the TRC computer 82 that executes S7, S8, S9 and Sll in the flowchart of FIG. 4 constitutes an operation speed determination means, and the other steps are The left and right force difference steering suppressing means is configured by the portion to be executed.

In this embodiment, the accelerator opening speed is 1. is greater than the reference opening speed θ8, that is, the accelerator pedal 2
The engine output reduction speed is changed depending on whether or not the pedal speed of accelerator pedal 2 is higher than the standard pedal speed.
If the depression speed of step 2 exceeds the standard depression speed, the rear wheel 14
．． While the slip of the rear wheels 14 and 16 is suppressed as usual and the running stability of the vehicle is obtained, when the depression speed of the accelerator pedal 22 is below the reference depression speed, more slip of the rear wheels 14 and 16 is allowed than usual. Large acceleration can be obtained. This means that if the r accelerator pedal 22 is depressed at a depression speed lower than the standard depression speed, it means that the driver is expecting the rear wheels to slip, and if this is the case, there will be some degree of left-right drive. This is done based on the idea that even if differential steering occurs, it should be possible to cancel it through steering, so it is better to emphasize acceleration rather than driving stability. In this sense, determining whether the depression speed of the accelerator pedal 22 is greater than the reference depression speed can be said to be an example of determining whether the driver anticipates the occurrence of left-right drive force differential steering.

Furthermore, when the r accelerator pedal 22 is depressed at a depression speed lower than the reference depression speed, the driving force of the rear wheels 14.16 also increases gradually, even if the coefficient of friction of the road surface they are in contact with is different. It can be considered that it is better to focus on acceleration because a sudden left-right drive force difference steer does not occur, and therefore it is relatively easy for the driver to cancel the left-right drive force difference steer by steering. In this sense, it can be said that determining whether or not the depression speed of the accelerator pedal 22 is greater than the reference depression speed is an example of determining whether or not sudden left-right drive force differential steering occurs.

Further, if the r accelerator pedal 22 is depressed at a depression speed lower than the reference depression speed, it means that the driver is driving carefully, and in that case, even if a certain degree of left-right drive force differential steering occurs, the driver can It can be considered that it is better to focus on the acceleration since this will be adequately dealt with.In that sense, determining whether or not the depression speed of the accelerator pedal 22 is greater than the standard depression speed is a matter of careful driving. It can also be said that this is an example of determining whether or not it is true.

Furthermore, if the r accelerator pedal 22 is depressed at a depression speed lower than the standard depression speed, it means that the driver depressed the accelerator pedal 22 knowing that left-right drive force differential steering may occur. In order to respond to the driver's strong intention to accelerate, it is better to place emphasis on acceleration.'' In this sense, it is up to the driver to determine whether the accelerator pedal 22 depression speed is greater than the standard depression speed. It can also be said that this is an example of determination of will.

Furthermore, in this embodiment, the brake control is performed so that each of the rear wheels 14, 16 slips by an appropriate amount, and the generation of the difference in driving force between the left and right wheels is suppressed by reducing the engine output. In this way, it is possible to suppress the difference in driving force between the left and right sides while avoiding wasted energy, but the generation of the difference in driving force can be suppressed only by controlling the brake fluid pressure. It is also possible.

Further, in this embodiment, it is determined whether or not the driver predicts the occurrence of left-right drive force differential steering based on the depression speed of the accelerator pedal 22. Although a determination is made as to whether or not the brake pedal 42 is depressed, a similar determination can also be made based on the depression speed of the brake pedal 42. The fact that the brake pedal depression speed is less than the reference pedal depression speed can be considered to mean that the driver is anticipating the occurrence of left-right drive force difference steering due to braking, and even if the left-right drive force difference is It can also be assumed that even if steering occurs, it should be possible to adequately deal with it through steering. Further, determining whether the brake pedal depression speed is equal to or lower than the reference depression speed can be considered to be an example of determining whether the driver is driving carefully or has a strong intention to brake.

Therefore, for example, the anti-skid control device is designed to be able to independently control the brake fluid pressure of the left and right wheels, and the magnitude of the brake operation speed is determined based on the operation speed of the brake operation member such as the brake pedal and the rising gradient of the brake fluid pressure. By providing an operation speed determination means for determining the operation speed and a left-right braking force difference steering suppressing means for allowing a larger brake fluid pressure difference to occur when the operation speed is small than when the operation speed is large, it is possible to achieve the same result as in the previous embodiment. effect can be obtained.

Further, the operation speed determination means determines the magnitude of the operation speed based on the release speed of the accelerator pedal, and the left-right force difference steering suppressing means changes the control state of the TRC brake actuator 80 by the TRC computer 82 based on the determination result. Even if it is provided, the effects of the present invention can be enjoyed.

It goes without saying that the present invention can be implemented in various other forms with various modifications and improvements based on the knowledge of those skilled in the art.

[Brief explanation of drawings]

FIG. 1 is a block diagram conceptually showing the configuration of the present invention. FIG. 2 is a system diagram of a left-right drive force differential steering suppressing device which is an embodiment of the present invention. Figure 3 shows T in the above arrangement.
FIG. 4 is a block diagram showing the configuration of the RC computer;
The figure is a flowchart showing only the parts deeply related to the present invention out of the control program stored in the ROM, and FIG. 5 is a diagram conceptually showing the configuration of the same RAM. FIG. 6 is a graph for explaining brake control in the above device. 14, 16: Rear wheel 22: Accelerator pedal 24: Main throttle actuator 28: Subthrottle actuator 34, 36, 38, 40: Brake

Claims (1)

[Scope of Claims] A device for suppressing left-right force differential steering that occurs in a vehicle due to a difference in left-right forces such as driving force and braking force between left and right wheels, comprising: a left-right force control device that can independently control the left-right forces; , an operation speed determination means for determining the magnitude of the operation speed of the acceleration/deceleration operation means of the vehicle; and an operation speed determination means that controls the left-right force control device to suppress the occurrence of the left-right force difference steer; A left-right force difference steering suppressing device comprising a left-right force difference steering suppressing means that allows a larger left-right force difference to occur when it is determined that the operation speed is low than when it is determined that the operation speed is high.