JPH106949A - Motion characteristic controller for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly execute motion characteristic control such as anti-skid control for each wheel even if a speed difference exists among four wheels during turning so as to deal with the loading of different diameter tires. SOLUTION: In order to optimize the slipping condition of each wheel, based on a wheel car body speed VBW** (S150) set as a wheel speed VW** (S120) and a reference speed for each wheel to be controlled, a slip rate SW** is calculated for each of four wheels and then a brake liquid pressure is adjusted. That is, although in the conventional example, a car body speed VB common to the four wheels is used as a reference speed and a slip rate VBW** is calculated based on this, in the present invention, since a wheel car body speed VBW** of a reference speed itself is intrinsic to a wheel to be controlled, more proper motion characteristic control is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a kinetic characteristic control device for a vehicle that controls the kinetic characteristics of the vehicle by executing anti-skid control during braking of the vehicle or traction control during acceleration of the vehicle.

[0002]

2. Description of the Related Art Conventionally, anti-skid control (ABS) for preventing wheel lock during braking on a slippery road surface and shortening a braking distance while securing braking stability, and traction control (TRC) for accelerating slip. And so on,
2. Description of the Related Art A vehicle motion characteristic control device for improving the vehicle motion characteristics has been known.

When executing such anti-skid control or traction control, it is necessary to know the slip ratio of the wheel to be controlled. This slip ratio is obtained by estimating the vehicle speed VB common to all four wheels. This estimated vehicle speed V
The slip ratio has been calculated based on B and the wheel speed.

A method of estimating (calculating) the vehicle speed VB is generally based on, for example, the maximum one of the four wheel speeds. However, at the time of turning, it is not preferable to use the one at the maximum speed. Therefore, it is conceivable to use the one at the second highest speed or to make a correction according to the difference between the inner and outer wheel speeds.

[0005]

However, when turning, there is, of course, a difference in speed between the front and rear wheels depending on the turning state, of course, in addition to the difference in speed between the inner and outer wheels between the left and right wheels. In other words, since the turning radius is different between the front wheel and the rear wheel on the same inner wheel side, the wheel speeds are different, so that no matter how much correction is made by the difference between the inner and outer wheel speeds, the slip ratio obtained based on the common vehicle speed is an error. Therefore, more appropriate control is desired.

Further, for example, during anti-skid control, the wheel speed drops, so that the above-described correction based on the inner and outer wheel speed difference cannot be performed. Therefore, since the correction has to be performed before the control, if the turning radius changes during the anti-skid, the change cannot be dealt with. In this regard, more appropriate control is desired. Of course, it is conceivable to separately provide a device for determining the turning state and to estimate the inner and outer wheel speed difference and the like from the turning radius and the like, but for that purpose, a lateral acceleration (lateral G) sensor or the like is separately required. Therefore, in order to determine the turning state without using such a lateral G sensor, it is not possible to perform the anti-skid operation.

Further, when a tire having a different diameter or an extremely worn tire is mounted, a speed difference from other wheels is constantly generated, and it becomes impossible to appropriately determine a slip ratio and the like. For this reason, for example, even if the maximum wheel speed is reached, it is not used for estimating the vehicle body speed, and the control for that wheel is controlled based on the result of estimation based on the state of the other wheels. However, since the control is performed by estimation, there is a limit in the accuracy of the control. Therefore, even when such a different-diameter tire is mounted, more appropriate control is desired.

The present invention has been made in view of such a problem, and it is possible to appropriately execute motion characteristic control such as anti-skid control for each wheel even when there is a speed difference between the four wheels during turning. It is another object of the present invention to provide a vehicle motion characteristic control device that can cope with a case where different diameter tires or the like are mounted.

[0009]

According to a first aspect of the present invention, there is provided a vehicle motion characteristic control device for a vehicle braking force applying means and a wheel speed detecting means corresponding to a plurality of wheels. Means and reference speed setting means are provided. Therefore, the braking force adjusting means adjusts the wheel braking force applied by the wheel braking force applying means to the control target wheel based on the wheel speed and the reference speed for the control target wheel in order to optimize the slip state of each wheel. However, in this case, the reference speed itself is unique to the controlled wheel. That is, in the past, the vehicle speed common to all four wheels was adopted as the reference speed. However, in the present invention, the reference speed for each wheel to be controlled is, in a conventional manner, the vehicle speed for each wheel to be controlled. It will be based on.

Therefore, more appropriate motion characteristic control can be realized in the following points. At the time of turning, in addition to the speed difference between the inner and outer wheels between the left and right wheels, the speed difference between the front and rear wheels, that is, the turning radius differs between the front wheel and the rear wheel on the same inner wheel side, often causes a wheel speed difference. In this case, no matter how much the correction based on the inner and outer wheel speed difference is performed as in the conventional method, there is an error in the slip ratio of each wheel obtained based on the common vehicle speed.

On the other hand, in the case of the present invention, as described above, the control can be performed based on the reference speed for each control target wheel (the vehicle speed for each control target wheel), so that more appropriate control can be executed. . That is, the correction based on the inner and outer wheel speed difference is unnecessary. Further, for example, the wheel speed drops during the anti-skid control, so that the above-described correction based on the inner / outer wheel speed difference cannot be performed in the conventional method. Therefore, since the correction has to be executed before the control, if the turning radius changes during the anti-skid, the change cannot be dealt with.

On the other hand, in the present invention, since the vehicle speed is calculated for each of the control target wheels by always using the wheel speed of the control target wheel, regardless of whether or not the anti-skid control is being performed, the vehicle speed is calculated at each wheel position by turning. Is not affected by the difference in vehicle speed. Therefore, even during anti-skid control,
In particular, it is not necessary to perform the correction based on the inner and outer wheel speed difference, and appropriate control can be performed for each wheel. As a conventional method, it is conceivable to provide a separate device for determining a turning state and to estimate a difference in inner and outer wheel speeds from a turning radius and the like. However, a lateral acceleration (lateral G) sensor or the like is separately required for this purpose. .
In the present invention, it is not necessary to use such a lateral G sensor, and it is advantageous because it can be handled by control.

Further, when a tire having a different diameter or an extremely worn tire or the like is mounted, a speed difference from other wheels constantly occurs, and it becomes impossible to appropriately determine a slip ratio and the like. For this reason, in the conventional method, for example, even if the maximum wheel speed is reached, it is not used for estimating the vehicle body speed, and control for that wheel is controlled based on the result of estimation based on the state of other wheels. . However, since the control is performed by estimation, the accuracy of the control is inevitably limited.

On the other hand, in the present invention, even when such different diameter tires or the like are mounted, a reference speed corresponding to each different diameter tire is set. In other words, even when the diameter is small and the speed is steadily higher than that of the other wheels, the reference speed itself is still steadily set to a larger value than the reference speed of the other wheels. There is no particular problem even if the slip ratio and the like are individually estimated. Thus, appropriate control can be performed even when different diameter tires are worn.

The above-mentioned wheel braking force applying means may be based on a brake fluid pressure as described in claim 2. That is, in this case, the wheel braking force is applied by increasing the pressure by the hydraulic pressure from the master cylinder, decreasing the brake fluid pressure, or maintaining the brake fluid pressure. However, the braking force is adjusted by controlling the increased, reduced, and maintained states of the brake fluid.

Of course, the present invention is not limited to the application of the braking force by the brake fluid, but can be realized in the same manner by applying a braking force to the wheels by another configuration. It is known that the reference speed is set using a predetermined guard value. For example, when a four-wheel common vehicle speed is calculated as in the related art, an acceleration guard value or a deceleration guard value is used as a limit value. Therefore, it is conceivable to use the same guard value in the present invention, but since the reference value is set for each wheel, the guard value for limiting the change in the wheel speed is set for each wheel. The calculated reference value is used to set the reference speed.

In the case where such a guard value is used, for example, a wheel braking force applying means for applying a wheel braking force to a wheel, a wheel speed detecting means for detecting a wheel speed, and the like. Detecting means and reference speed setting means for setting a reference speed for the wheel based on the wheel speed detected by the wheel speed detecting means, corresponding to each of the plurality of wheels; Braking force adjusting means for adjusting a wheel braking force applied by the wheel braking force applying means to the control target wheel based on the wheel speed for the control target wheel and the reference speed for optimizing the slip state; Means for estimating the vehicle body speed of the vehicle based on the wheel speeds of the wheels detected by the means, and for the vehicle body speed estimated by the vehicle speed estimation means. It calculates a vehicle deceleration is a change,
Deceleration-side guard value setting means for setting a deceleration-side guard value based on the vehicle body deceleration, and the reference speed setting means includes:
It is conceivable to set a reference speed for each wheel based on the deceleration side guard value calculated by the deceleration side guard value degree calculation means and the wheel speed of each wheel detected by the wheel speed detection means.

Here, the deceleration side guard value setting means may set the calculated vehicle deceleration itself as a deceleration side guard value, or may add a predetermined value and perform a correction operation to obtain a deceleration side guard value. You may set as. The predetermined value is used to correct the change in consideration of, for example, a change in the vehicle speed at each wheel position that occurs when the turning radius of the vehicle changes.

Further, there is provided an acceleration side guard value setting means for setting a predetermined value as an acceleration side guard value, and the reference value setting means comprises a deceleration side guard value set by the deceleration side guard value setting means, and an acceleration side guard value. The reference speed may be set based on the acceleration side guard value set by the setting means and the wheel speed of each wheel.

As described above, when the reference speed is set, not only the wheel speed but also the deceleration side guard value calculated based on the vehicle body deceleration or the acceleration side guard value is used, so that a more appropriate value can be obtained. The reference speed can be set, and more precise control of the braking force can be performed for each wheel.

In the above-described control of the motion characteristics, the wheel braking force applied by the wheel braking force generating means such as the brake fluid pressure is adjusted. For example, in the traction control, the throttle opening and the like are controlled. In some cases, the driving force is adjusted by controlling the driving force. Therefore, as set forth in claim 6, there is provided a wheel driving force applying means for applying a driving force to the wheels, and the driving force applied by the wheel driving force applying means is provided based on the wheel speed and the reference speed for the wheel to be controlled. A kinematics control device for a vehicle that makes adjustments is conceivable.

In this case, as in the case of the braking force control described above, the vehicle speed is always calculated for each control target wheel using the wheel speed of the control target wheel. It is not affected by the difference in vehicle speed at each wheel position due to running. Therefore, even during the traction control, there is no need to particularly perform the correction based on the inner and outer wheel speed difference, and appropriate control can be performed for each wheel.

Further, when a tire having a different diameter is mounted, a reference speed corresponding to the tire having the different diameter is set individually. This is similar to the case of the above-described braking force control. Then, in the case of such a driving force control, similarly to the case of the above-described braking force control, the reference speed can be set by using a predetermined guard value.

As a configuration in the case of using such a guard value, for example, a wheel speed detecting means for detecting a wheel speed and a wheel speed detected by the wheel speed detecting means are provided. And a setting means for setting a reference speed for the corresponding wheel based on each of the plurality of wheels, and a wheel driving force applying means for applying a driving force to the wheels, and a slip state of each wheel. Driving force adjusting means for adjusting the driving force applied by the wheel driving force applying means based on the wheel speed and the reference speed for the control target wheel, and the wheel of each wheel detected by the wheel speed detecting means A vehicle speed estimating means for estimating the vehicle body speed of the vehicle based on the speed; and a vehicle acceleration which is a temporal change of the vehicle speed estimated by the vehicle speed estimating means, is calculated. Acceleration-side guard value setting means for setting an acceleration-side guard value based on the acceleration, wherein the reference speed setting means detects the acceleration-side guard value calculated by the acceleration-side guard value degree calculation means and the wheel speed detection means. It is conceivable to set a reference speed for each wheel based on the determined wheel speed of each wheel.

The acceleration-side guard value setting means may set the calculated vehicle body acceleration itself as an acceleration-side guard value, or may add a predetermined value and perform a correction operation as an acceleration-side guard value. May be set. further,
A deceleration-side guard value setting unit that sets a predetermined value as a deceleration-side guard value, wherein the reference value setting unit is set by the acceleration-side guard value set by the acceleration-side guard value setting unit and the deceleration-side guard value setting unit. Reduced side guard value,
The reference speed may be set based on the wheel speed of each wheel.

As described above, when the reference speed is set, not only the wheel speed but also the deceleration guard value calculated based on the vehicle deceleration or the acceleration guard value is used, so that a more appropriate value can be obtained. The reference speed can be set, and more precise control of the driving force can be performed for each wheel.

The function of realizing each means of such a vehicle motion characteristic control device with a computer system is as follows.
For example, it is provided as a program started on the computer system side. In the case of such a program, for example, a floppy disk, a magneto-optical disk, a CD-RO
It can be used by storing it in a machine-readable storage medium such as a hard disk or a hard disk, loading it into a computer system as needed, and starting up. In addition, RO
The program may be stored as a machine-readable storage medium such as M or a backup RAM, and the ROM or the backup RAM may be incorporated in a computer system and used.

[0028]

Embodiments of the present invention will be described below with reference to the drawings. First, FIG. 1 is a schematic configuration diagram showing a configuration of an entire anti-skid control device as one embodiment of a motion characteristic control device of the present invention. In this embodiment,
This is an example applied to a front engine / front drive type four-wheeled vehicle.

As shown in FIG. 1, the right front wheel (FR) of the vehicle
1, a left rear wheel (RL) 2, a right rear wheel (RR) 3 and a left front wheel (FL) 4 each generate a pulse signal (rotation speed signal) corresponding to the rotation of each of the wheels 1 to 4. Rotation speed sensors 5, 6, 7, and 8 of an electromagnetic type, a magnetoresistive type or the like are provided. Each of the wheels 1 to 4 has a master cylinder 16
The brake devices 11, 12, 13, and 14 that receive the hydraulic pressure from the brakes to apply braking to the wheels 1 to 4 are disposed, and the hydraulic pressure from the master cylinder 16 is applied to the brake devices 11 to 14 by the actuators 21 and 22, 23, 24 and hydraulic lines. Furthermore, the master cylinder 1
The brake pedal 25 that generates the hydraulic pressure from 6 is provided with a stop switch 26 that detects the depressed state and outputs an ON signal during braking and an OFF signal during non-braking. In the present embodiment, the master cylinder 16
From the actuators 21 to 24 of the wheels 1 to 4
Is a so-called X pipe, which is divided into two lines, a hydraulic line for the right front wheel 1 and the left rear wheel 2 and a hydraulic line for the right rear wheel 3 and the left front wheel 4. .

Next, each of the actuators 21 to 24 is constituted by an electromagnetic three-position valve. Then, at the time of non-energization, it becomes the position A illustrated in the actuator 21,
Brake device 1 for each wheel 1-4 from master cylinder 16
The hydraulic lines from 1 to 14 communicate with each other to
To 14 brake hydraulic pressures (so-called wheel cylinder pressures, hereinafter simply referred to as W / C pressures).
The pressure is increased by the hydraulic pressure from 6.

At the time of energization, the actuator 21 is switched to the position B or C shown in the figure according to the current level. When the position B is reached by energization, the hydraulic pipeline is cut off to maintain the current state of the W / C pressure of the brake devices 11 to 14. When the position C is reached by energization, the brake devices 11 to 14 are stopped. The oil in the wheel cylinder is released to the reservoirs 28a and 28b provided for each of the two hydraulic lines, and the brake devices 11 to 1
The W / C pressure of No. 4 is reduced.

The actuators 21 to 24
Is temporarily switched to the C position (decompression position) during the anti-skid control by the operation of the electronic control device 40 to release the oil in the wheel cylinders of the brake devices 11 to 14 to the reservoirs 28a and 28b. , 28b
When is full, the pressure cannot be reduced.
The reservoirs 2 are provided between the hydraulic lines on the sides a and 28b and the hydraulic lines on the master cylinder 16 by driving the electric motor.
Motor pumps 27a and 27b for pumping oil on the 8a and 28b side to the master cylinder 16 side are provided.

Next, the electronic control unit 40 for controlling each of the actuators 21 to 24 to any one of the pressure increasing position, the pressure reducing position, and the holding position is constituted by a microcomputer including a CPU, a ROM, a RAM, an input / output interface and the like. It operates by receiving power supply when an ignition switch (not shown) is turned on. That is, the electronic control unit 4
Numeral 0 receives signals from the rotation speed sensors 5 to 8 of the respective wheels and the stop switch 26, performs arithmetic processing for anti-skid control based on these signals, and switches the valve positions of the actuators 21 to 24. .

The arithmetic processing executed by the electronic control unit 40 for anti-skid control will be described below with reference to FIG.
5 will be described with reference to the flowchart shown in FIG. As shown in FIG. 2, when the electronic control unit 40 is started, first, S1
At 00 (S: represents a step), initialization processing such as memory clear, flag reset, etc. is performed, and at S110, the subsequent arithmetic processing is performed for a predetermined time Ta (for example, 5 msec.).
In order to execute each time, it is determined whether or not the predetermined time Ta has elapsed, and the process waits until the predetermined time Ta has elapsed.

When it is determined in S110 that the predetermined time Ta has elapsed, the flow shifts to S120, where each wheel 1 is detected based on the rotation speed signals from the rotation speed sensors 5-8.
To 4 rotation speeds (hereinafter referred to as wheel speeds) VW ** (V
WFR, VWRL, VWRR, VWFL), and then proceeds to S13.
At 0, the rotational acceleration of each of the wheels 1 to 4, which is a differential value of the calculated wheel speed VW ** (hereinafter referred to as wheel acceleration).
dVW ** (dVWFR, dVWRL, dVWRR, dVWFL)
Is calculated. Note that the wheel speed VW ** and the wheel acceleration dV
The subscripts (** = FR, RL, RR, FL) added to W ** have values of right front wheel 1, left rear wheel 2, right rear wheel 3, left front wheel 4, respectively.
Represents the value of

Next, in S140, the vehicle speed VB common to the four wheels is calculated (estimated) based on the wheel speed VW ** of each of the wheels 1-4 obtained in S120. This processing will be described with reference to the flowchart of FIG. First step S2 in FIG.
In 10, the reference wheel speed VSW adopts the maximum one of the wheel speeds VW ** (VWFR, VWRL, VWRR, VWFL) of the wheels 1-4. And the following S220
Then, it is determined whether or not the anti-skid control is currently being performed. If the control is not being performed (S220: NO), the process proceeds to S230 and the upper limit acceleration KU is set to a predetermined value K1 (for example, 0.5).
Set to G). On the other hand, if the control is being performed (S220: Y
ES), and proceeds to S240 to set the upper limit acceleration KU to a predetermined value K2 (for example, 1.0 G). This upper limit acceleration K
U is set in order to suppress a change at or below the upper limit acceleration KU during acceleration.

At S250, the four-wheel common vehicle speed VB is calculated as shown in the following equation (1). [Equation 1] → VB = MED (VB (n−1) −KD · Ta, VSW (n), VB (n
-1) + KU · Ta) In this equation 1, VB (n-1) is the vehicle speed obtained last time,
KD is a lower limit acceleration set to suppress a change below this value KD during deceleration, and is set to, for example, 1.2G. Ta is the predetermined time used in S110 of FIG. 2, VSW (n) is the reference wheel speed obtained this time in S210,
KU is the upper limit acceleration obtained this time in S220 or S230. Further, the meaning of Expression 1 for calculating VB is [V
B (n-1) -KD · Ta], [VSW (n)] and [VB (n-1) +
KU · Ta] means that the intermediate value is calculated as the four-wheel common vehicle speed VB.

When the four-wheel common vehicle speed VB is calculated in S250, the flow chart of FIG. 3 is terminated and S150 of FIG. 2 is ended.
Move to. In S140, the vehicle speed VB common to the four wheels is used.
In step 150, the vehicle speed VBW ** corresponding to every four wheels, that is, each of the wheels 1 to 4 is calculated. This processing will be described with reference to the flowchart of FIG.

In the first step S310 in FIG. 4, the vehicle deceleration dVB common to the four wheels is calculated as shown in the following equation 2. [Equation 2] → dVB = (VB (n−1) −VB (n)) / Ta Here, although the term “vehicle deceleration” refers to the temporal change rate of the vehicle body speed VB, the previous vehicle speed The value obtained by subtracting the current vehicle speed VB (n) from VB (n-1) is a predetermined time T
This is because the physical meaning indicates the degree of deceleration.

In S320, the vehicle deceleration d
It is determined whether or not VB is negative, that is, whether or not the vehicle body is accelerating. When the vehicle body is accelerating (S320:
In YES, the value of the vehicle body deceleration dVB is cleared in S330 (dVB = 0), and the routine goes to S340. On the other hand, when the vehicle body is in the deceleration state (S320: NO), the process directly proceeds to S340.

In S340, the vehicle speed reduction side guard value KDW
Is set as shown in the following Expression 3. [Equation 3] → KDW = dVB + KG1 This vehicle body deceleration side guard value KDW is the value KD during deceleration.
It is set to suppress the change to W or less. Further, for example, 0.1 G is set as the correction value KG1. This is because the correction is made in consideration of the change in the vehicle speed at each wheel position which occurs when the turning radius of the vehicle changes.

Then, in S350, it is determined whether the anti-skid control is currently being performed. If the anti-skid control is not being performed (S350: NO), the process proceeds to S360, and the vehicle body acceleration side guard value KUW is set to a predetermined value K3 (for example, 0.5G). On the other hand, if control is being performed (S
350: YES), proceeds to S370 and sets the vehicle body acceleration side guard value KUW to a predetermined value K4 (for example, 1.0G). The vehicle body acceleration side guard value KUW is set in order to suppress a change to be equal to or smaller than the vehicle body acceleration side guard value KUW during acceleration.

Then, in S380, the wheel body speed VBW ** for each of the four wheels is calculated as shown in the following equation (4). [Equation 4] → VBW ** = MED (VBW ** (n-1) -KDW · Ta, VW **
(n), VBW ** (n-1) + KUW · Ta) In this equation 4, VBW ** (n-1) is the wheel body speed obtained last time, and Ta is the value used in S110 of FIG. Predetermined time, V
W ** (n) is the wheel speed obtained this time, and KUW is the body acceleration side guard value obtained this time in S360 or S370. Equation 4 for calculating the wheel body speed VBW ** for each of the four wheels means [VBW ** (n-1) −KDW · T
a], [VW ** (n)] and [VBW ** (n-1) + KUW · T
a] means that the intermediate value is calculated as the wheel body speed VBW **.

In S380, the vehicle speed VBW corresponding to each wheel
When ** is calculated, the flowchart of FIG.
To S160. In S160, the slip ratio SW ** of each of the wheels 1 to 4 (SWFR, SWRL, SWRR, SWFL)
Is calculated. This slip ratio calculation processing will be described with reference to the flowchart of FIG.

First, at S410, the slip ratio SWFR of the right front wheel 1 is calculated as shown in the following equation 5. [Equation 5] → SWFR = (VBWFR−VWFR) / VBWFR That is, the deviation (VBWFR−VWFR) between the wheel speed VBWFR for the right front wheel 1 and the wheel speed VWFR is obtained by dividing the difference by the wheel speed VBWFR.

Similarly, in the processing of S420 to S440, the slip ratio SWFL of the left front wheel 4 and the right rear wheel 3
And the slip ratio SWRL of the left rear wheel 2 are calculated as shown in the following equations 6 to 8. [Equation 6] → SWFL = (VBWFL−VWFL) / VBWFL [Equation 7] → SWRR = (VBWRR−VWRR) / VBWRR [Equation 8] → SWRL = (VBWRL−VWRL) / VBWRL After calculating the slip rates SW ** of the wheels 1-4, the slip rates SWFR-SWFL and the wheel acceleration d of the wheels 1-4 are calculated in S170-S200 of FIG.
Based on VWFR to dVWFL, the control mode of each actuator 21 to 24 is set for each wheel 1 to 4,
An arithmetic process of a control mode for setting whether to control the pressure reduction mode, the holding mode, or the pulse increase mode is executed. That is, in S170, the control mode of the right front wheel (FR) 1 is set, in S180, the control mode of the left rear wheel (RL) 2 is set,
In S190, the control mode of the right rear wheel (RR) 3 is changed to S20.
At 0, the control mode of the left front wheel (FL) 4 is set respectively. And the processing of S170 to S200 is respectively
It is executed according to the procedure shown in FIG.

As shown in FIG. 6, in the control mode calculation process executed in S170 to S200, first, in S510, the controlled mode is set for the target wheel 1, 2, 3 or 4. It is determined whether anti-skid control (hydraulic control) has already been performed. Then, if the control-in-progress mode is not set, in S520, S1
It is determined whether or not the slip rate SW ** of the wheel determined at 60 exceeds a preset target slip rate KS (for example, 15%), and the slip rate SW ** is set to the target slip rate KS.
If it does not exceed, it is not necessary to execute the hydraulic control for the wheel, so the control mode is reset in S530, and in S540, the actuator is held at the position A (pressure increase position) shown in FIG. Then, the process is terminated.

On the other hand, if it is determined in S520 that the slip ratio SW ** has exceeded the determination slip ratio KS0, it is determined that the wheels are slipping and hydraulic pressure control needs to be executed, and the flow shifts to S550, where control is performed. Set the middle mode. Then, in this S550, the control mode is set, or
Alternatively, if it is determined in S510 that the current control mode is set, the process proceeds to S560, and the slip ratio S
It is determined whether or not W ** exceeds the target slip ratio KS.

If it is determined in S560 that the slip ratio SW ** exceeds the target slip ratio KS, the flow shifts to S570, where the wheel acceleration d of the relevant wheel calculated in S130.
VW ** indicates whether the deceleration of the wheel is suppressed by the hydraulic control and the change direction of the wheel speed VW ** is reversed from the deceleration direction to the acceleration direction, that is, whether or not the acceleration becomes zero (0G) or more. to decide. Then, in S570, when it is determined that the wheel acceleration dVW ** is smaller than 0G and the wheel speed VW ** is changing in the deceleration direction, the process proceeds to S580, and the actuator is moved to C shown in FIG. Position (decompression position)
To set the pressure reduction mode for reducing the W / C pressure of the brake device, and terminate the process.

On the other hand, in S570, wheel acceleration dVW **
Becomes 0 G or more, and if it is determined that the changing direction of the wheel speed VW ** is from the deceleration direction to the acceleration direction, S59
The process proceeds to 0, the actuator is controlled to the position B (holding position) shown in FIG. 1, a holding mode for holding the W / C pressure of the brake device is set, and the process is terminated.

Next, at S560, the slip ratio SW
If it is determined that ** is less than or equal to the target slip ratio KS, the flow shifts to S600, and the actuator is moved to FIG.
The position A (pressure increasing position) and the position B (holding position) shown in FIG.
It is determined whether or not the control in the pulse increasing mode for gradually increasing the C pressure in a pressure increasing pattern corresponding to the change cycle has been executed a predetermined number of times (a predetermined pattern).

If it is determined in S600 that the control of the pulse increasing mode has been executed for a predetermined pattern, the slip of the wheel is completely suppressed, and the wheel no longer slips even after the hydraulic control is completed. S
The flow shifts to 530, in which the controlling mode is reset in S530, and the pressure increasing mode is set in S540, followed by terminating the process.

On the other hand, if it is determined in S600 that the control of the pulse increasing mode has not been performed for a predetermined pattern, the process proceeds to S600.
At 610, a pulse increasing mode is set as a control mode for the wheel, and the process is temporarily terminated. FIG. 8 shows the drive output to the solenoid of the actuator in the pressure increasing mode, the pressure decreasing mode, the holding mode, and the pulse increasing mode. That is, as shown in FIG. 8, in the present embodiment, when the pressure increasing mode is set as the control mode, energization of the solenoid is prohibited, the actuator is fixed at the pressure increasing position, and the pressure reducing mode is set. If so, the solenoid is continuously supplied with a predetermined current for pressure reduction to fix the actuator at the pressure reduction position.If the holding mode is set, the predetermined current for holding is continuously supplied to the solenoid. Then, when the actuator is fixed at the holding position and the pulse increase mode is set, a predetermined current for holding is supplied to the solenoid for a predetermined time, and then the energization to the solenoid is stopped for a predetermined time. Then, the actuator is alternately switched between the holding position and the pressure increasing position.

Therefore, in the pulse increasing mode, the W / C pressure of the brake devices 11 to 14 gradually increases,
In the present embodiment, the switching between the holding and the pressure increase is performed a predetermined number of times N.
If (for example, 10 patterns) continue, it is determined that the pulse increasing mode has ended in S600, and the process proceeds to S530 to reset the controlling mode, and then the control mode is switched to the pressure increasing mode in S540.

As described above, S170 to S2 in FIG.
When the control mode of each of the wheels 1 to 4 is set at 00, the process proceeds to S110 again, and thereafter, S110 to S210
Is repeatedly executed. The control mode of each of the wheels 1 to 4 is set in this manner, and the set control mode is set by the timer interrupt processing shown in FIG.
-4 are used to drive the actuators 21-24, respectively.

The timer interrupt processing shown in FIG.
In order to control the W / C pressures of the brake devices 11 to 14 respectively, this is a process executed by a timer interrupt for each predetermined time (for example, 1 msec.) Tb. First, in S710, the right front wheel (FR) 1 is read, and the solenoid of the actuator 21 is driven by the drive output shown in FIG. 8 according to this control mode, thereby controlling the actuator 21 to the valve position corresponding to the control mode. If the control mode is the pressure reduction mode or the pulse increase mode, the valve position is changed in a change pattern corresponding to the mode.

Then, the following S720, S730, S74
0, the left front wheel (FL) 4
Output of the right rear wheel (R
The drive output of the R) 3 to the actuator 23 and the drive output of the left rear wheel (RL) 2 to the actuator 22 are sequentially executed, and this interrupt processing is terminated.

As a result, the actuators 21 to 24 of the wheels 1 to 4 are controlled to any of the pressure increasing position, the pressure reducing position, and the holding position, and the brake devices 11 to 14 of the wheels 1 to 4 are controlled.
Is reduced, maintained, and increased in accordance with the set control mode. Here, an operation result by the above-described processing will be described with reference to FIGS.

FIG. 9 shows a state in which a vehicle equipped with a general Ackerman-Jean-To type steering device turns left at a relatively low speed and travels at each wheel (FF, FR, RR, RL) position. It is explanatory drawing which shows a locus | trajectory and a turning radius. In this case, since the speed is low and the lateral acceleration is small, the turning center is on the rear wheel axle, and each wheel follows a turning locus as shown. Therefore, the turning radii of the respective wheels are all different, and the magnitudes of the vehicle body speeds VBW ** at the respective wheel positions are all different.
That is, the relationship shown in the following equation 9 is obtained. [Equation 9] → VBWFR>VBWRR>VBWFL> VBWRL. Here, in order to simplify the explanation, the turning outer wheel 2
Only the wheels, that is, only the FR wheels and the RR wheels will be considered.

FIG. 10 shows two wheels (FR, RR) in this case.
5 is a time chart showing the relationship between the vehicle speed and the vehicle speed, in which braking is started at a time t2 during turning and then the anti-skid control is performed. Time t0 to t2
Is not braked during the period, the wheel speed VWF
R and VWRR are constant speeds, and a speed difference ΔVW according to the difference in turning radius occurs.

Here, considering the vehicle speed VB common to the four wheels at time t2, the larger one of the wheel speeds, that is, VWFR, becomes the reference wheel speed VSW, which is guarded by the upper limit acceleration KU and the lower limit acceleration KD. An intermediate value between the three speeds VU and VD, that is, the reference wheel speed VSW is selected, and is represented by the following equation (10). [Equation 10] → VB (t2) = VSW (t2) = VWFR (t2) The vehicle speed corresponding to each of the FR wheel and the RR wheel at the time t2 is a change amount of the vehicle speed VB common to the four wheels. = 0G
Becomes Therefore, each vehicle body speed is subjected to a change guard of the vehicle body deceleration side guard value KDW = KGI and the vehicle body acceleration side guard value KUP = K1.
Since it is 0 and the change guard is not applied, the wheel speed is eventually selected, as shown in the following equations 11 and 12, respectively. [Equation 11] → VBWFR (t2) = VWFR (t2) [Equation 12] → VBWRR (t2) = VWRR (t2) Then, braking is started, and at time t3, the vehicle body starts to decelerate, but still has two wheels. Since no slip occurs and the amount of change in each wheel is smaller than the lower limit acceleration KD and the vehicle body deceleration side guard value KDW, the wheel speed is also selected at this time. Therefore, the vehicle speed VB (t3) at time t3, F
The wheel speeds VBWFR (t3) and VBWRR (t3) corresponding to the R wheel and the RR wheel are represented by the following equations 13 to 15, respectively. [Equation 13] → VB (t3) = VSW (t3) = VWFR (t3) [Equation 14] → VBWFR (t3) = VWFR (t3) [Equation 15] → VBWRR (t3) = VWRR (t3) At time t4 Then, the FR wheel is not slipping,
Since the R-wheel starts slipping and the slip ratio of the RR-wheel becomes equal to or higher than the braking start reference KS, control for the RR-wheel is started at this time. Also in this case, VWFR> VWRR, so that VSW = VWFR, the change amount of the reference wheel speed VSW is within the lower limit acceleration KD, the reference wheel speed VSW is selected, and the vehicle speed VB (t4) at time t4 is expressed by the following equation. As shown in FIG. [Equation 16] → VB (t4) = VSW (t4) = VWFR (t4) Similarly, the amount of change of VWFR is also the vehicle deceleration side guard value KD.
Since it is within W, VWFR is selected, and the vehicle speed VBWFR (t4) corresponding to the FR wheel at time t4 is expressed by the following equation 17. [Equation 17] → VBWFR (t4) = VWFR (t4) Further, the vehicle speed VBWRR for the RR wheel is represented by the wheel speed VWRR.
Exceeds the deceleration-side guard value of dVB '+ KG1, the deceleration-side guard value is selected, and VBWRR (t4) at time t4 is selected.
Is as shown in the following Expression 18. [Equation 18] → VBWRR (t4) = VBWFR (t3) − (dVB ′ (t4) +
KG1) × ΔT The same applies until time t6, and the vehicle speed VB
(T), the vehicle speed VBWFR corresponding to the FR wheel and the RR wheel
(T) and VBWRR (t) are given by the following equations 19 to 21, respectively.
It becomes as shown in. [Equation 19] → VB (t) = VWFR (t) [Equation 20] → VBWFR (t) = VWFR (t) [Equation 21] → VBWRR (t) = VBW (t−1) − (dVB ′ (t) ) + K
G1) × ΔT At time t7, the change in the wheel speed of the FR wheel also becomes larger than the deceleration guard value, so that the vehicle body speed VB (t7) is expressed by the following equation (22). [Equation 22] → VB (t7) = VB (t6) − (KD × ΔT) Further, the vehicle speeds VBWFR (t7) and VBWRR (t7) corresponding to the FR and RR wheels at this time are given by the following equations, respectively. 2
2 and 23. [Equation 23] → VBWFR (t7) = VBWFR (t6) − (dVB ′ (t7) +
KG1) × ΔT [Equation 24] → VBWRR (t7) = VBWRR (t6) − (dVB ′ (t7) +
KG1) × ΔT.

Further, until the time t10, to select the deceleration guard value while the wheel is still slipping, the time t
7, the vehicle speed VB (t) and the vehicle speed VBW ** (t) corresponding to the FR and RR wheels are given by the following equation (2).
5 and 26. [Equation 25] → VB (t) = VB (t−1) − (KD × ΔT) [Equation 26] → VBW ** (t) = VBW ** (t−1) − (dVB ′ (t7)
+ KG1) × ΔT At time t8, the wheel slip of the FR wheel becomes larger than the control start reference KS, and the anti-skid control is started.

At time t11, the FR wheels return, the common vehicle speed becomes the FR wheel selection, and the vehicle speed VB (t11)
Is as shown in the following Expression 27. [Equation 27] → VB (t11) = VWFR (t11) At the same time, the change of the vehicle body speed VB turns to the + (plus) side, and therefore dVB = 0, and the deceleration side guard value of the vehicle body speed of each wheel is Only KG1.

At this time, the vehicle speed VBWFR of the FR wheel is
The wheels are selected in the same manner as the common vehicle speed VB, and the following equation 28
It becomes as shown in. [Equation 28] → VBWFR (t11) = VWFR (t11) On the other hand, since the RR wheel has a large slip, the vehicle speed of the RR wheel is selected by selecting the deceleration side guard value, and becomes as shown in the following equation 29. [Equation 29] → VBWRR (t11) = VBWRR (t10) − (KG1 × ΔT) Further, the vehicle body speed VB (t) is similarly obtained until time t12.
, FR and RR wheels corresponding to the vehicle speed VBWFR (t)
And VBWRR (t) are as shown in the following equations 30 to 32, respectively. [Equation 30] → VB (t) = VWFR (t) [Equation 31] → VBWFR (t) = VWFR (t) [Equation 32] → VBWRR (t) = VBWRR (t−1) − (KG1 × ΔT After time t13, since the RR wheels also return and start selecting the wheel speeds, the vehicle speed VB (t), the vehicle speeds VBWFR (t) and VBWRR (t) corresponding to the FR wheels and the RR wheels.
Are as shown in the following equations 33 to 35, respectively. [Equation 33] → VB (t) = VWFR (t) [Equation 34] → VBWFR (t) = VWFR (t) [Equation 35] → VBWRR (t) = VWRR (t) In FIG. In the correction of the speed difference between the inner and outer wheels at the time, the speed difference ΔVW between the front and rear wheels is not corrected, and the FR wheel and the RR wheel, which are the same turning outer wheels, are determined and controlled by the common vehicle speed VB to determine the slip. For this reason, the VB is larger than the true vehicle speed for the RR wheel even though it is appropriate for the FR wheel, so that the slip of the RR wheel is determined to be large.

On the other hand, according to the present invention, the FR wheel is
Wheel body speed VBWFR, RR wheels are RR wheel body speed VB
Each wheel slip is determined by WRR and controlled.
For this reason, more accurate control based on the appropriate vehicle speed can be performed for both the FR wheel and the RR wheel.

Even if the wheel slips greatly as shown in FIG. 10 and the anti-skid control is started, the vehicle speed of each wheel is calculated using the wheel speed of each wheel. Irrespective of the control, it is possible to always remove the influence of the speed difference due to the traveling locus during turning. That is, by applying to four wheels, it is possible to always remove the influence of the speed difference between the inner and outer wheels and the front and rear wheels even during the anti-skid control.

The predetermined correction value KG1 is added in consideration of, for example, a change in the speed of each wheel that occurs when the vehicle changes from going straight to turning. It is possible to more accurately estimate the wheel body speed. In other words, estimate higher than the true vehicle speed,
It is possible to prevent a situation where the slip amount is detected to be larger than the actual value and the pressure is reduced to reduce the deceleration.

As described above, in the present embodiment, in order to optimize the slip state of each wheel, the wheel speed VW ** for the wheel to be controlled and the wheel body speed VBW for each wheel set as the reference speed for each wheel. Based on **, the brake fluid pressure for the control target wheel is adjusted. That is, conventionally, the vehicle speed VB common to the four wheels is adopted as the reference speed,
Although the slip ratio SW ** etc. were calculated based on this,
In the present embodiment, the vehicle body speed VBW for the wheel, which is the reference speed, is used.
** They are unique to the wheel to be controlled.
Therefore, more appropriate motion characteristic control can be realized in the following points.

During turning, usually, in addition to the difference between the inner and outer wheel speeds between the left and right wheels (between FR and FL or between RR and RL), the difference between the front and rear wheels (between FR and RR or between FL and R).
Also, the turning radius is different and a wheel speed difference occurs in many cases. In this case, there is an error in the slip ratio of each wheel obtained based on the common vehicle speed VB, no matter how much the correction based on the inner and outer wheel speed difference is performed as in the conventional method.
In other words, in the calculation of the slip ratio for each of the four wheels, conventionally, the slip ratio SW ** is calculated based on the vehicle speed VB and the wheel speed VB.
Although the deviation (VB-VW **) from W is determined by dividing the vehicle speed by the vehicle speed VB, the vehicle speed VB is not an appropriate value for all the wheels.

On the other hand, in the case of this embodiment, FIG.
As described with reference to FIG.
Deviation between BW ** and wheel speed VW ** (VBW **-VW **
) Is divided by the vehicle body speed for wheels VBW **. That is, since it can be based on the wheel body speed VBW ** set for each control target wheel, more appropriate control can be executed.

Also, for example, during the anti-skid control, the wheel speed VW ** drops, so that the above-described correction based on the inner and outer wheel speed difference cannot be performed in the conventional method. Therefore, since the correction has to be executed before the control, if the turning radius changes during the anti-skid, the change cannot be dealt with.

On the other hand, in the present embodiment, the difference between the inner and outer wheel speeds is automatically corrected even during the anti-skid control. As a conventional method, it is conceivable to provide a separate device for determining a turning state and to estimate a difference in inner and outer wheel speeds from a turning radius and the like. However, a lateral acceleration (lateral G) sensor or the like is separately required for this purpose. . This point is also advantageous in this embodiment because such a lateral G sensor need not be used and can be dealt with only by the wheel speed sensor.

Further, when a tire having a different diameter, an extremely worn tire, or the like is mounted, a speed difference from other wheels constantly occurs, and it becomes impossible to appropriately determine the slip ratio SW ** and the like. Therefore, in the conventional method, for example, even if the maximum wheel speed VW ** is used, it is not used for estimating the vehicle body speed, and control for the wheel is controlled based on the result of estimation based on the state of the other wheels. Was. However, since the control is performed by estimation, the accuracy of the control is inevitably limited.

On the other hand, in the present embodiment, even if such different-diameter tires or the like are mounted, a reference speed corresponding to each of the different-diameter tires is set. In other words, even when the diameter is small and the speed is steadily higher than the other wheels, the wheel body speed VBW ** itself, which is the reference speed, is still higher than the wheel body speed VBW ** of the other wheels. Is constantly set to a large value.
There is no problem in estimating ** etc. individually. in this way,
Appropriate control can be performed even when different diameter tires are worn.

As described above, one embodiment of the present invention has been described, but the present invention is not limited to such an embodiment, and can take various aspects. For example, in the above-described embodiment, the anti-skid control device has been described as an example of the motion characteristic control device. However, the anti-skid control is an example of the motion characteristic control, and traction control or the like can be considered as another example of the motion characteristic control. Therefore, another embodiment in which the invention is applied to traction control will be described next. However, description of general control contents in the traction control is omitted here, and processing corresponding to the processing in FIGS. 3 and 4 in the case of the above-described anti-skid control will be described with reference to FIGS. 11 and 12. . That is, FIG. 11 shows the calculation (estimation) of the four-wheel common vehicle speed VB for traction control.
FIG. 12 shows a process for every four wheels for traction control.
That is, the vehicle speed VBW corresponding to each of the wheels 1 to 4
This is the arithmetic processing of **.

First, the calculation process (FIG. 11) of the four-wheel common vehicle speed VB for traction control will be described. FIG.
In the first step S1210, the reference wheel speed VS
As W, the wheel speeds VW ** (VWFR, VW
WRL, VWRR, VWFL). In the case of a so-called FF (front engine front drive) vehicle, the smaller one of the rear two wheel speeds (VWRL, VWRR) is adopted as this reference wheel speed VSW, and FR (front engine rear drive) is used. In the case of a vehicle, the smaller of the front two wheel speeds (VWFL, VWFR) may be adopted as the reference wheel speed VSW. That is, the smaller one of the two rolling wheels having the lower wheel speed is adopted.

Then, in subsequent S1220, it is determined whether or not the traction control is currently being performed. If the traction control is not being performed (S1220: NO), the flow shifts to S1230 to set the lower limit acceleration KD to a predetermined value K5 (for example, 1.0G). Set to.
On the other hand, if the control is being performed (S1220: YES), S12
The process proceeds to 40, where the lower limit acceleration KD is set to a predetermined value K6 (for example, 3.0 G). The lower limit acceleration KD is set to suppress the change to be equal to or less than the lower limit acceleration KD during deceleration during traction control.

Then, in S1250, the four-wheel common vehicle speed VB is calculated as shown in the following equation (36). [Equation 36] → VB = MED (VB (n−1) −KD · Ta, VSW (n), VB (n
-1) + KU · Ta) In the equation (36), VB (n-1) is the vehicle speed obtained last time, KD is the value set in S1230 or S1240, Ta is the execution interval of the main processing, and VSW ( n) is S1
The reference wheel speed and KU obtained this time at 210 is an upper limit acceleration (for example, 0.5 G) set to suppress a change below this value KU during acceleration. Further, the meaning of this expression 36 is [VB (n-1) −KD · Ta], [VSW (n)], and [V
B (n-1) + KU · Ta] means that the intermediate value is calculated as the four-wheel common vehicle speed VB.

Next, the traction control wheels 1-4
The calculation processing (FIG. 12) of the vehicle speed VBW ** corresponding to each of FIG. First step S1 in FIG.
At 310, the vehicle acceleration dVB2 common to the four wheels is expressed by the following equation 37.
It is calculated as shown in FIG. [Equation 37] → dVB2 = (VB (n) −VB (n−1)) / Ta Here, although the term “vehicle acceleration” refers to the temporal change rate of the vehicle speed VB, the current vehicle speed VB The value obtained by subtracting the previous vehicle speed VB (n-1) from (n) is a predetermined time T
This is because the physical meaning indicates the degree of acceleration.

At S1320, it is determined whether or not the vehicle body acceleration dVB2 is negative, that is, whether or not the vehicle body is in a deceleration state. When the vehicle body is in the deceleration state (S13
20: YES), in S1330, the vehicle body acceleration dVB2
Is cleared (dVB2 = 0), and the flow shifts to S1340. On the other hand, when the vehicle body is accelerating (S1320:
If NO, the process directly proceeds to S1340.

In S1340, the vehicle body acceleration side guard value KU is determined.
W is set as shown in the following Expression 38. [Equation 38] → KUW = dVB2 + KG2 This vehicle body acceleration side guard value KUW is obtained by
It is set to suppress the change to W or less. Further, for example, 0.05 G is set as the correction value KG2. This is because the correction is made in consideration of the change in the vehicle speed at each wheel position which occurs when the turning radius of the vehicle changes.

At S1350, it is determined whether or not traction control is currently being performed. If the traction control is not being performed (S1350: NO), the process proceeds to S1360, where the vehicle deceleration side guard value KDW is set to a predetermined value K7 (for example, 1.0G)
Set to. On the other hand, if the control is being performed (S1350: YE
S), the flow shifts to S1370, where a vehicle speed reduction side guard value KD is set.
W is set to a predetermined value K8 (for example, 3.0 G). The vehicle body deceleration side guard value KDW is set in order to suppress a change equal to or less than the vehicle body deceleration side guard value KDW during deceleration.

Then, in S1380, the wheel body speed VBW ** for each of the four wheels is calculated as shown in the following Expression 39. [Equation 39] → VBW ** = MED (VBW ** (n-1) -KDW · Ta, VW **
(n), VBW ** (n-1) + KUW · Ta) In equation (39), VBW ** (n-1) is the vehicle speed for the wheel previously obtained, and KDW is the current value obtained in S1360 or S1370. The body acceleration side guard value, VW ** (n), is the wheel speed obtained this time. The expression 39 for calculating the wheel body speed VBW ** for each of the four wheels means [VBW **
(n-1) −KDW · Ta], [VW ** (n)], and [VBW ** (n
-1) + KUW · Ta] means that the intermediate value is calculated as the wheel body speed VBW **.

Also in the case of executing the traction control in this manner, more appropriate control can be realized for the same reason as described in the above-mentioned anti-skid control. As means for applying the braking force to the wheels, a means based on the brake fluid pressure as described in the above-described embodiment is generally considered. However, a means for applying the braking force to the wheels by other configurations is similarly used. realizable.
In addition, for example, in traction control, there is also a traction control device that controls the throttle opening and the like to adjust the driving force. Therefore, a traction control device that controls the throttle opening and the like to adjust the applied driving force may be used. realizable.

Further, in the above-described embodiment, an example of a four-wheeled vehicle of the front engine / front drive system is shown, but the invention can be applied to a two-wheeled vehicle, a three-wheeled vehicle, and a vehicle having five or more wheels. Further, the present invention can be applied to a front engine / rear drive system or an all-wheel drive system.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating a configuration of an entire anti-skid control device as an embodiment of a motion characteristic control device.

FIG. 2 is a flowchart showing processing contents of a main routine repeatedly executed by an electronic control unit.

FIG. 3 is a flowchart showing a calculation process of a four-wheel common vehicle speed (VB) executed in S140 of FIG. 2;

FIG. 4 is a flowchart showing a calculation process of a vehicle speed (VBW **) for each four wheels executed in S150 of FIG.

FIG. 5 is a flowchart showing a calculation process of a slip ratio (SW **) for each of the four wheels, which is executed in S160 of FIG. 2;

FIG. 6 is a flowchart showing a control mode calculation process executed for each wheel in S170 to S200 of FIG. 2;

FIG. 7 is a flowchart showing a timer interrupt process executed by a timer interrupt at predetermined time intervals in the electronic control unit.

FIG. 8 is an explanatory diagram illustrating a relationship between a control mode and a drive output to a solenoid of an actuator for hydraulic control.

FIG. 9 shows a traveling trajectory and a turn at each wheel (FF, FR, RR, RL) position in a state where a vehicle equipped with a general Ackerman-Jean-To type steering device is turning left at a relatively low speed. It is explanatory drawing which shows a radius.

FIG. 10 is a time chart showing behavior of two outer wheels (a front left wheel FR and a rear right wheel RR) when anti-skid control is performed while the vehicle is turning left.

FIG. 11 is a flowchart illustrating a calculation process of a four-wheel common vehicle speed (VB) in traction control as another embodiment.

FIG. 12 is a flowchart illustrating a calculation process of a vehicle speed (VBW **) for every four wheels in traction control as another embodiment.

[Explanation of symbols]

1-4 wheels (1 right front wheel, 2 left rear wheel, 3 right rear wheel,
4 left front wheel) 5-8 rotational speed sensor 11-14 brake device 16 master cylinder 21-24 actuator (three-position valve) 25 brake pedal 27a, 27b motor pump 28a, 28b reservoir 40 electronic Control device

Claims (9)

[Claims] 1. A wheel braking force applying means for applying a wheel braking force to a wheel, a wheel speed detecting means for detecting a wheel speed, and a wheel braking force based on the wheel speed detected by the wheel speed detecting means. A reference speed setting unit for setting a reference speed, corresponding to each of a plurality of wheels, and a wheel speed for the control target wheel and the reference speed for optimizing a slip state of each wheel. And a braking force adjusting means for adjusting a wheel braking force applied to the control target wheel by the wheel braking force applying means. 2. The wheel braking force applying means according to whether the brake fluid pressure is increased by hydraulic pressure from a master cylinder, the brake fluid pressure is reduced, or the brake fluid pressure is maintained. 2. The vehicle according to claim 1, wherein the braking force adjusting unit is configured to perform adjustment by controlling a pressure increase, a pressure decrease, and a holding state of the brake fluid. 3. Motion characteristic control device. 3. A wheel braking force applying means for applying a wheel braking force to a wheel, a wheel speed detecting means for detecting a wheel speed, and a wheel braking force based on the wheel speed detected by the wheel speed detecting means. A reference speed setting unit for setting a reference speed, corresponding to each of a plurality of wheels, and a wheel speed for the control target wheel and the reference speed for optimizing a slip state of each wheel. Braking force adjusting means for adjusting a wheel braking force applied to the control target wheel by the wheel braking force applying means; and estimating a vehicle body speed of the vehicle based on a wheel speed of each wheel detected by the wheel speed detecting means. Vehicle body speed estimating means, and calculating a vehicle body deceleration which is a temporal change of the vehicle body speed estimated by the vehicle body speed estimating means, based on the vehicle body deceleration. A deceleration side guard value setting means for setting a deceleration side guard value, wherein the reference speed setting means is detected by the deceleration side guard value calculated by the deceleration side guard value degree calculating means, and by the wheel speed detecting means. And a reference speed for each wheel is set based on the wheel speed of each wheel. 4. The deceleration-side guard value setting means is configured to add a predetermined value to the calculated vehicle body deceleration and perform a correction operation as the deceleration-side guard value. The vehicle motion characteristic control device according to claim 3. 5. An accelerating guard value setting means for setting a predetermined value as an accelerating guard value, wherein the reference value setting means comprises: a decelerating guard value set by the decelerating guard value setting means; 5. The vehicle according to claim 3, wherein a reference speed is set based on an acceleration-side guard value set by the acceleration-side guard value setting means and a wheel speed of each of the wheels. Motion characteristic control device. 6. Wheel speed detecting means for detecting wheel speed, and setting means for setting a reference speed for the wheel based on the wheel speed detected by the wheel speed detecting means.
A plurality of means corresponding to each of a plurality of wheels, and a wheel driving force applying means for applying a driving force to the wheels, a wheel speed with respect to a control target wheel for optimizing a slip state of each wheel. And a driving force adjusting means for adjusting a driving force applied by the wheel driving force applying means based on the reference speed. 7. Wheel speed detecting means for detecting a wheel speed, and setting means for setting a reference speed for the wheel based on the wheel speed detected by the wheel speed detecting means.
A plurality of means corresponding to each of a plurality of wheels, and a wheel driving force applying means for applying a driving force to the wheels, a wheel speed with respect to a control target wheel for optimizing a slip state of each wheel. And a driving force adjusting means for adjusting a driving force applied by the wheel driving force applying means based on the reference speed; and estimating a vehicle body speed of the vehicle based on a wheel speed of each wheel detected by the wheel speed detecting means. Vehicle speed estimation means, and acceleration side guard value setting means for calculating a vehicle acceleration which is a temporal change of the vehicle speed estimated by the vehicle speed estimation means, and setting an acceleration side guard value based on the vehicle acceleration. Wherein the reference speed setting means is detected by the acceleration side guard value calculated by the acceleration side guard value degree calculation means and the wheel speed detection means. And a reference speed for each wheel is set based on the wheel speed of each wheel. 8. The acceleration-side guard value setting means is configured to set a value obtained by adding a predetermined value to the calculated vehicle body acceleration and performing a correction operation as the acceleration-side guard value. The vehicle motion characteristic control device according to claim 7. 9. A deceleration-side guard value setting means for setting a predetermined value as a deceleration-side guard value, wherein the reference value setting means includes an acceleration-side guard value set by the acceleration-side guard value setting means, 9. The vehicle according to claim 7, wherein a reference speed is set based on a deceleration side guard value set by the deceleration side guard value setting means and a wheel speed of each wheel. Motion characteristic control device.