JP2903553B2 - Anti-skid control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-skid control device that controls a braking force on a wheel during vehicle braking to prevent locking of the wheel.

[Related Art] If the wheels lock when the vehicle is suddenly braked, running may become unstable depending on the road surface condition. Therefore, the brake fluid pressure to the wheel cylinder is reduced or restored so that the wheels are not locked during the sudden braking. Accordingly, an anti-skid control device that controls the braking force is used.

In this anti-skid control device, in consideration of the fact that when the brake fluid pressure to the wheel cylinder is increased, the wheel speed sharply decreases immediately before the friction coefficient μ against the wheel becomes maximum, the change in the wheel speed and the wheel acceleration is considered. The brake fluid pressure is controlled accordingly, resulting in a wheel slip rate of 20%
The braking force is controlled so as to be before and after, that is, to obtain the maximum friction coefficient. In particular, according to all-wheel control for controlling the brake fluid pressure of the wheel cylinder for each wheel, not only stability but also maneuverability can be ensured.

In such all-wheel control, for example, the rotational speed of each wheel, that is, the wheel speed, is detected, an estimated vehicle speed is calculated from the maximum wheel speed of all the wheels, a reference speed is obtained from the estimated vehicle speed, and The wheel speed of each wheel is compared, and the brake fluid pressure of the wheel cylinder of each wheel is controlled according to the comparison result. According to this method, for example, when the vehicle shifts to the anti-skid control while turning to the left, the estimated vehicle speed is calculated based on the wheel speed of the front right wheel that is the maximum wheel speed, and a reference speed is obtained from this.
For example, if the braking force of the rear left wheel is controlled on the basis of this, the braking is performed based on the estimated vehicle speed calculated based on the maximum wheel speed of the front right wheel, even though the rear left wheel speed is low. The fluid pressure control will be performed. Therefore, the brake fluid pressure of the wheel cylinder of the rear left wheel is excessively reduced. If the reference speed is set small to prevent this, the deceleration rate of each wheel becomes large during braking during normal straight running, and the stability of the vehicle may be impaired.

In this regard, as described in Japanese Patent Application Laid-Open No. 61-36052 as a prior art, the higher (larger) one of the wheel speed of the steered wheels and the wheel speed of the non-steered wheels is selected, and the pseudo vehicle speed, that is, the estimated vehicle body Techniques for calculating speed are known. In the same publication, the prior art described above erroneously, because the wheel speed of the inner wheel or the average speed of the two rear wheels, that is, the non-steered wheels, becomes smaller than the wheel speed of the outer wheel of the left and right steering wheels at low speed rotation. A problem is cited that a high (large) pseudo vehicle speed is generated and the slip ratio becomes too high and the brake pressure may decrease.

In the above publication, select low means for selecting a lower (smaller) wheel speed of the steered wheels, and a pseudo (higher) wheel speed of the output and the non-steered wheels for the non-steered wheels. There has been proposed a technology provided with a select high means for selectively outputting a vehicle speed.

[Problems to be Solved by the Invention] In the technology described in the above-mentioned publication, the brake fluid attributable to the difference between the inner and outer wheels of the wheel speed is set by setting the estimated vehicle speed as described above with respect to the braking operation during turning of the vehicle. It is intended to prevent the pressure from being excessively reduced. However, in the technique described in the above publication, for example, the wheel speeds of the other wheels are not taken into consideration for control of the steered wheels, so that the estimated vehicle speed may be significantly lower than the actual vehicle speed, causing early locking. In particular, when the steered wheels are drive wheels, this tendency becomes large when the low-speed gear is connected.

Therefore, the present invention relates to an anti-skid control device,
An object of the present invention is to calculate an estimated vehicle speed for each wheel, and to appropriately correct a difference between the inner and outer wheels of the wheel speed when the vehicle turns, thereby preventing early locking of each wheel during the vehicle turning.

[Means for Solving the Problems] In order to achieve the above object, the anti-skid control device of the present invention is mounted on each wheel FR, FL, RR, RL of the vehicle as shown in FIG. The wheel cylinders 51 to 54 that are mounted to apply braking force, wheel speed detecting means S for detecting the wheel speed of each wheel such as the wheel FR, and the wheel speed detecting means S
Estimated vehicle speed setting means M1 for calculating an estimated vehicle speed based on each of the detected wheel speeds;
Is provided with braking force control means M2 for controlling the brake fluid pressure supplied to each of the wheel cylinders 51 to 54 in accordance with the result of comparison between the estimated vehicle speed set by the vehicle and the wheel speed of each wheel. Further, a road surface state detecting means M4 for outputting a signal corresponding to a friction coefficient of a road surface on which the vehicle travels, and a wheel speed correction for correcting the wheel speed of each wheel according to the output of the road surface state detecting means M4 and the turning characteristics of the vehicle. Estimated vehicle speed setting means M1 including means M3 calculates an estimated vehicle speed for each wheel based on a wheel speed corrected by the wheel speed correcting means M3 for wheel speeds of the wheels except for the wheel to be calculated. It is configured as follows.

The wheel speed correction means M3 may be configured to set a correction value according to the average vehicle speed calculated based on the wheel speed of the driven wheel among the wheels FR and the like.

Then, in the anti-skid control device, an estimated vehicle speed to be set for the drive wheel among the wheels FR and the like,
It may be provided with a limiting means M5 for limiting the speed to a predetermined speed or less set based on the average vehicle speed.

In the above anti-skid control device,
It is provided with acceleration slip detecting means M6 for detecting an acceleration slip of a drive wheel among FRs and the like.When the acceleration slip detection means M6 detects an acceleration slip of a drive wheel, the estimated vehicle speed setting means M1 is provided for each wheel. Calculate the estimated vehicle speed for the driven wheels of FR etc. based on the wheel speeds of the target wheel and the driven wheels, and calculate the estimated vehicle speed for the driven wheels of each wheel FR etc. based on the wheel speed of only the driven wheels Can be configured.

[Operation] In the anti-skid control device having the above configuration,
The rotational speed of each wheel such as the wheel FR, that is, the wheel speed is detected by the wheel speed detecting means S.

Based on the wheel speeds of these wheels, the estimated vehicle speed setting means M1 calculates the estimated vehicle speed for each wheel. At this time, the wheel speed of the calculation target wheel itself, for example, the wheel speed of the wheel FR is unchanged, and the other wheels, for example, the wheel
The wheel speeds of RL and FL are corrected by the wheel speed correcting means M3 at least according to the output signal of the road surface state detecting means 4 and the turning characteristics of the vehicle, and the estimated vehicle speed is calculated based on the corrected wheel speed. Thus, the estimated vehicle body speed is set according to the vehicle turning characteristics that fluctuate with changes in the road surface condition. The brake fluid pressure supplied to each of the wheel cylinders 51 to 54 is controlled by the braking force control means M2 according to the comparison result between the estimated vehicle body speed set in this way and each wheel speed.

In the wheel speed correction means M3, for example, each wheel FR
The average vehicle speed is calculated based on the wheel speeds of the driven wheels, and the wheel speeds of the wheels excluding the calculation target wheels are corrected based on the average vehicle speed, the output of the road surface state detecting means M4, and the turning characteristics of the vehicle. A value is set and added to the target wheel speed.

In the vehicle equipped with the limiting means M5, since the estimated vehicle speed set for the drive wheels among the wheels FR and the like is limited to a predetermined speed set based on the average vehicle speed, the drive wheel Even when the wheel speed is recovered from the acceleration slip state, the brake fluid pressure in the wheel cylinder is not excessively reduced.

Further, in the apparatus provided with the acceleration slip detection means M6 for detecting the acceleration slip of the drive wheel, when the acceleration slip of the drive wheel is detected, the estimated vehicle The estimated vehicle speed for the driving wheel is calculated based on the wheel speed of the calculation target wheel and the driven wheel,
The estimated vehicle speed for the driven wheel among the wheels FR and the like is calculated based on the wheel speed of only the driven wheel.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 3 shows a vehicle provided with an anti-skid control device according to one embodiment of the present invention, and a tandem master cylinder 2a.
And a booster 2b, which is connected to the hydraulic pressure generating device 2 driven by the brake pedal 3 and the wheel cylinders 51 to 54 disposed on each of the wheels FR, FL, RR and RF. Actuators 31 to 34 are provided.
Wheel FR indicates a front right driving wheel as viewed from the driver's seat, wheel FL indicates a front left driving wheel, wheel RR indicates a rear right driven wheel, and wheel RL indicates a rear left driven wheel. That is, in this embodiment, a front-wheel drive system is adopted, and front wheels FR and FL are connected to a transmission 5 connected to the internal combustion engine 4.
The turning radii of the wheels FR, RR, FL, RL when turning the vehicle (hereinafter referred to as turning radii) are respectively r4, r3, r2, r1 as shown in FIG. Is r. As is clear from FIG. 2, when the vehicle turns left, r4
The radius gradually decreases from r1 to r1.

Regarding the turning radii r1 to r4 of each wheel shown in FIG. 2, a coefficient r1 / r2, r2 / r3, r2 / r4, r1 / r3, r1 representing a difference between inner and outer wheels generated at the time of turning of the vehicle by a ratio of the turning radii to each other. If you ask for / r4, the eighth
As shown in the figure, a predetermined relationship is obtained with respect to the turning radius r of the vehicle. Particularly, when the turning radius r is small, the difference between the inner and outer wheels is large, so that each coefficient is small. Also, as shown in the lower part of FIG. 8, the allowable turning radius of the vehicle is determined according to the vehicle speed,
Different characteristics are shown depending on the road surface condition, that is, the friction coefficient μ. Therefore, a turning radius r that can turn with respect to the vehicle speed at a predetermined friction coefficient μ (hereinafter simply referred to as μ) is determined, and a predetermined correspondence relationship between the respective coefficients r1 / r2 and the like can be obtained accordingly. Based on the predetermined correspondence, a correction value ΔV (r1 / r2) described later is set as shown in FIGS. 9 and 10.

The actuators 31 to 34 constituting the pressure control valve device according to the present invention have solenoids 31a to 34a, and can control the energization and non-energization of these solenoids to increase or decrease the brake fluid pressure in the wheel cylinders 51 to 54. it can.
That is, when the solenoids 31a to 34a are energized, the brake fluid pressure in the wheel cylinders 51 to 54 is reduced, and when the solenoids 31a to 34a are not energized, the brake fluid pressure is supplied from the fluid pressure generator 2 to increase the pressure.
That is, the pressure is restored.

The solenoids 31a to 34a are connected to the electronic control unit 100, and energization and non-energization of each solenoid are controlled. The wheels FR, FL, RR, and RF are provided with wheel speed sensors 41 to 44 as wheel speed detecting means according to the present invention, respectively, and these are connected to the electronic control unit 100. That is, the wheel speed signal is input to the electronic control unit 100. Wheel speed sensors 41 to 44 are toothed rotors that rotate with the rotation of each wheel,
It is a well-known device that has an electromagnetic induction type spot type detection unit provided opposite to the teeth of the rotor and outputs a voltage having a frequency proportional to the rotation speed of each wheel.

The vehicle in this embodiment is equipped with an acceleration sensor 6, and detects acceleration (including deceleration) of the vehicle.
Specifically, for example, a well-known mercury switch is used in which mercury moves when the acceleration of the vehicle becomes equal to or less than a predetermined value and electrically connects the electrodes to output an ON signal. A signal corresponding to the road surface state is output from the acceleration sensor 6 and supplied to the electronic control unit 100, and as described later, the road surface has a high μ or a low μ.
Is determined. That is, the acceleration sensor 6 functions as road surface state detecting means.

The electronic control unit 100 includes a microprocessor C (not shown).
There is provided a one-chip microcomputer 130 having a PU, a memory ROM, a RAM, and the like, connected to the input port 110 and the output port 120 via a common bus, and performing input / output with the outside. The detection signals of the acceleration sensor 6 and the wheel speed sensors 41 to 44 are connected to input ports 110 via amplification circuits 101 to 105, respectively. The output port 120 is connected to actuators 31 to 34 via drive circuits 106 to 109, respectively.

The electronic control unit 100 performs a series of processes for anti-skid control, which will be described below with reference to FIGS. 4 to 10.

FIGS. 4 to 7 are flowcharts showing the control of an embodiment of the anti-skid control device of the present invention, which is repeatedly executed at predetermined time intervals. First, as a preliminary process, a timer or the like is cleared in step 201, and an initial value of the memory RAM is set. Then, the front wheel FL based at step 202 the output signal of the wheel speed sensors 42, 41, the wheel speed Vw _FL of FR, Vw _FR is calculated. Similarly, wheel speed sensors 44, 43
_RL , Vw of the rear wheels RL, RR based on the output signal of
_RR is calculated, and the routine proceeds to step 203.

Step of serving driven wheel behind the 203 present embodiment the wheel RL, the estimated vehicle speed Vs _RL based on RR, the average value of Vs _RR is calculated, the average vehicle speed Vv is set. The estimated vehicle speed
Calculations of Vs _RL and Vs _RR will be described later.

Next, in steps 211 to 213, a correction value corresponding to the road surface μ is selected. That is, in step 211, it is determined whether the road surface is high μ or low μ according to the output of the acceleration sensor 6. Here, when it is determined to be high μ, the process proceeds to step 212, where the correction values ΔV (r1 / r2), ΔV (r1 / r3), ΔV (r1 / r) for high μ are determined according to the average vehicle speed Vv based on a predetermined map. r
4), ΔV (r2 / r3) and ΔV (r2 / r4) are selected.
FIG. 9A shows an example of a map, ΔV (r1 / r3),
FIG. 9 (b) shows a map of ΔV (r2 / r3). As is clear from the figure, each of the correction values ΔV (r1 / r3) and the like is set at the speed (km / h). Step 211
When it is determined that the road surface is low μ, the process proceeds to step 213, and the correction value ΔV (r1 / r
2), ΔV (r1 / r3), ΔV (r1 / r4), ΔV (r2 / r3) and ΔV (r2 / r4) are selected. FIG. 10 (a) shows ΔV (r1 / r3) at low μ, and FIG. 10 (b) shows ΔV (r
2 / r3) shows an example of a map.

In the present invention, the estimated vehicle speed is set for each wheel. In steps 221 to 228 in FIG. 5 following the above process, first, the estimated vehicle speed VsFL for the wheel _FL is calculated.
In step 221, the correction values ΔV are obtained from the wheel speeds Vw _RR and Vw _FR , respectively.
(R2 / r3), ΔV (r2 / r4) minus the wheel speed Vw _RL , V
The maximum value of w _FL is obtained, and the maximum wheel speed Vm _FL is set. MAX (A, B, C) is a function for selecting the maximum value among A, B, C.

Then, the process proceeds to step 222 and 223, the second set speed V obtained by subtracting the second set speed V _FL (K1) and a predetermined speed K2 obtained by adding a predetermined speed K1 to the estimated vehicle speed Vs _FL of the previous wheel FL
_FL (K2) is required. Maximum wheel speed V in step 224
m _FL is compared with the first set speed V _FL (K1), and when it is determined that the speed is higher than the first set speed V _FL (K1), the _routine proceeds to step 226, where the first set speed V _FL (K1)
Is the estimated vehicle speed Vs _FL for the wheel FL. If the maximum wheel speed Vm _FL is lower than the first set speed V _FL (K1), the process proceeds to step 225, and the magnitude is compared with the second set speed V _FL (K2). In step 225, the maximum wheel speed Vm _FL becomes the second set speed V
_If it is determined that the speed is higher than _FL (K2), the value of the maximum wheel speed Vm _FL is set to the estimated vehicle speed Vs _FL in step 227. If the value is equal to or less than the second set speed V _FL (K2), in step 228 The second set speed V _FL (K2) is set as the estimated vehicle speed Vs _FL .

With respect to the estimated vehicle speed Vs _FL obtained in this manner,
In steps 231 and 232, an upper limit value is set and the speed is limited to a predetermined speed. That is, the estimated vehicle speed Vs _FL is _calculated in step 231.
Is compared with the upper limit value obtained by adding the predetermined speed K3 (km / h) to the average vehicle speed Vv obtained in step 203. If the upper limit value is larger than this value, the process proceeds to step 232, where the estimated vehicle speed Vs _FL is set to the upper limit value. If the value is equal to or smaller than this value, the process directly proceeds to step 241.

Reference speed Vk _FL for the wheels FL is calculated based on the following formula (1) in step 241.

_{Vk FL = K4 × Vs FL -K5} ... (1) where, K4, K5 0.97 is a constant, for example as K4, K5
Is used as 1 km / h.

Then, the process proceeds to steps 251 to 253 in FIG. 6 to perform the brake fluid pressure control for the wheel cylinder 52 of the wheel FL. That is, at step 251, the wheel speed Vw _FL becomes the reference speed V
is compared with k _FL, Step 2 if less than the reference speed Vk _FL
At 52, a pressure reduction signal is output to the wheel cylinder 52 of the wheel FL, and the pressure reduction operation of the brake fluid pressure is performed. If the wheel speed Vw _FL is the reference speed Vk _FL or proceeds to step 253, is output the pressure increase signal to the wheel cylinder 52 of the wheels FL, brake fluid pressure is boosted圧即Chi condensate.

The processing from the wheel speed detection to the brake fluid pressure control for the wheel FL has been described above. However, since the same processing is performed for the other front wheel FR, the processing is shown as step 300 of the subroutine in FIG. .

Steps 421 to 443 show the processing for the rear wheel RL. The wheel RR is shown as step 500 of the subroutine in FIG. 7, and the description is omitted. Note that, for the wheels RL and RR, unlike in the case of the wheel FL described above, the acceleration slip does not occur, so that the restriction processing of steps 231 and 232 is not performed, but the remaining processing is substantially the same as the processing for the wheel FL. .

In FIG. 6, in step 421, the wheel speeds Vw _RR , V
correction values ΔV (r1 / r3) and ΔV (r1 / r3) from w _FL and Vw _FR , respectively.
2), the maximum value of the value obtained by subtracting ΔV (r1 / r4) and the wheel speed Vw _RL is calculated, and the maximum wheel speed Vm _RL is obtained.

Next, the process proceeds to steps 422 and 423, and a third set speed obtained by adding a predetermined speed K1 to the previous estimated vehicle speed Vs _RL for the wheel RL.
V _RL (K1) and the fourth set speed V _RL (K
2) is required. If it is determined in step 424 that the maximum wheel speed Vm _RL is equal to or higher than the third set speed V _RL (K1), step 426
The value of the third set speed V _RL (1K) is set as the estimated vehicle speed Vs _RL for the wheel RL. If the maximum wheel speed Vm _RL is lower than the third set speed V _RL (K1), the process proceeds to step 425. If it is determined that the maximum wheel speed Vm _RL is higher than the fourth set speed V _RL (K2), the process proceeds to step 427. maximum value of the wheel speed Vm _RL is the estimated vehicle speed Vs _RL, if the fourth set speed V _RL (K2) or less, the fourth set speed V _RL (K2) is the estimated vehicle speed Vs _RL at step 428 Te It is said. Then, in step 433, the reference speed Vk _RL for wheel RL is calculated based on equation similar to the equation (1).

Thus, the process proceeds to steps 441 to 443, where the wheel speed Vw _RL is compared with the reference speed Vk _RL, and the wheel cylinder 54 of the wheel RL is
, A brake pressure reduction operation is performed, or a pressure increase signal is output to the wheel cylinder 54 of the wheel RL, and the brake hydraulic pressure is increased, that is, restored.

Then, after the processing for the wheel RR is performed in step 500, in steps 601 to 603, usually 3 to 5 m
The calculation cycle of S is set. That is, the timer is set to the predetermined time T1
In the following cases, the value is incremented in step 603, and is cleared in step 602 after a predetermined time T1 has elapsed, and returns to step 202.

In the above flowchart, the maximum wheel speed required for calculating the estimated vehicle speed is the maximum wheel speed Vm _FL of the wheels FL and RL,
Although only the calculation formula of Vm _RL is shown, the table including the maximum wheel speeds Vm _RL and Vm _RR for the other wheels FR and RR is as shown in Table 1 below. Note that in the Table 1, although calculates the maximum wheel speed Vm _RL from the wheel speed Vw _RL of each wheel, the estimated vehicle speed of each wheel instead of the wheel speed Vw _RL like Vs _RL
Etc. may be used.

Further, the above embodiment relates to a vehicle of a front wheel drive system, that is, a front wheel drive vehicle. In the case of a rear wheel drive vehicle, since the rear wheels RR and RL are drive wheels, it is shown in Table 2 below. As described above, the process of speed limitation at the time of setting the estimated vehicle speed is different. That is, in a rear-wheel drive vehicle, the average vehicle speed is calculated based on the estimated vehicle speeds Vs _FL and Vs _FR of the front wheels FL and FR as driven wheels.
Vv is calculated. Also, the rear wheels RL, RR, which are driving wheels,
Has an upper limit (Vv + K3), and there is no limit on the front wheels FL and FR.

Incidentally, when the vehicle is accelerated during the turning operation and an acceleration slip occurs on the wheels on the driving wheel side, it is preferable that the wheel speed of the driving wheel is excluded from the calculation of the estimated vehicle body speed for the driven wheel. Also, in the calculation of the estimated vehicle body speed for the drive wheels, it is preferable to exclude the wheel speeds of the other drive wheels from the calculation, even if the wheel speeds of the drive wheels to be calculated have to be included in the calculation. Therefore, when calculating the maximum wheel speed for obtaining the estimated vehicle speed at the time of acceleration slip, in the case of a front wheel drive vehicle, the calculation is performed according to the following Table 3,
In the case of a rear-wheel drive vehicle, the calculation may be performed according to Table 4 below.

As the acceleration slip judging means of the present invention, for example, a means for determining on whether the driving wheels serving wheels FR, estimated vehicle speed Vs _FR of FL, Vs _FL exceeds the upper limit value (Vv + K3). That is, if it exceeds the upper limit (Vv + K3), it is determined that the vehicle is in the acceleration slip state. This processing is the fifth
In the flowchart shown in FIG.
It can be done with 41.

Although the road surface condition is determined by the acceleration sensor 6 in the above-described embodiment, well-known means for determining based on the wheel speed, the wheel acceleration (deceleration), and the brake fluid pressure control signal may be used.

[Effects of the Invention] The present invention is configured as described above, and has the following effects.

That is, according to the anti-skid control device of the present invention, the wheel speed of each of the wheels except for the wheel for which the estimated vehicle speed is to be calculated is determined by the wheel speed correction unit according to the output of the road surface state detection unit and the turning characteristics of the vehicle. The estimated vehicle speed is calculated for each wheel based on the corrected wheel speed, so that even if the turning characteristics of the vehicle fluctuate according to the road surface condition, excessive decompression of the brake fluid pressure due to the difference between the inner and outer wheels of the wheel speed is performed. Can be prevented and early locking can be prevented.

The wheel speed correcting means calculates an average vehicle speed based on the wheel speeds of the driven wheels, and calculates the average vehicle speed based on the average vehicle speed, the output of the road surface state detecting means, and the turning characteristics of the vehicle. If a correction value for the speed is set, for example, the abnormal speed of the drive wheel at the time of acceleration slip is not used for calculation, so that appropriate braking force control can be performed without requiring complicated adjustment.

Further, in addition to the above, in the device provided with a limiting means for limiting the estimated vehicle speed for the drive wheel, malfunctions that can occur when the wheel speed is recovered from the acceleration slip state in the drive wheel are avoided, and a stable braking force is obtained. Can be secured.

Further, in the apparatus provided with the acceleration slip detecting means, when the acceleration slip of the driving wheel is detected, the estimated vehicle body speed is calculated by excluding the wheel speed of the driving wheel other than the calculation target wheel. The effect of the acceleration slip of the drive wheels during skid control can be minimized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an outline of an anti-skid control device of the present invention, FIG. 2 is an explanatory diagram showing a difference in inner and outer wheel turning radii during turning operation of a vehicle, and FIG. FIG. 4, FIG. 5, FIG.
FIG. 7 and FIG. 7 are flowcharts showing a process for controlling the braking force according to one embodiment of the present invention. FIG. 8 is a graph showing the relationship between the average vehicle speed, the vehicle turning radius, and the difference between the inner and outer wheel turning radii.
FIG. 9 is a graph showing the correction value at the time of high μ, and FIG. 9 (a)
Is a graph showing a change in Δv (r1 / r3), FIG. 9 (b) is a graph showing a change in Δv (r2 / r3), FIG. 10 is a graph showing a correction value at low μ, and FIG. (A) is Δv (r1 / r3)
And FIG. 10 (b) is a graph showing a change in Δv (r2 / r3). 2 ... Hydraulic pressure generator, 2a ... Master cylinder, 2b ... Booster, 3 ... Brake pedal, 6 ... Acceleration sensor (road surface detecting means), 31-34 ... Actuator, 31a-34a ... Solenoid 41-44 Wheel speed sensor (wheel speed detecting means) 51-54 Wheel cylinder 100 Electronic control unit (braking force control means) FR, FL, RR, RL Wheel

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-1-202565 (JP, A) JP-A-61-178256 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B60T 8/32-8/86

Claims (4)

(57) [Claims] 1. A wheel cylinder mounted on each wheel of a vehicle to apply a braking force, a wheel speed detecting means for detecting a wheel speed of each wheel, and an estimation based on each detected wheel speed of the wheel speed detecting means. Estimated vehicle speed setting means for calculating the vehicle speed, and a brake fluid pressure supplied to each of the wheel cylinders according to a comparison result between the estimated vehicle speed set by the estimated vehicle speed setting device and the wheel speed of each wheel. An anti-skid control device including a braking force control unit for controlling, wherein a road surface state detection unit that outputs a signal corresponding to a friction coefficient of a road surface on which the vehicle travels, and a wheel speed of each of the wheels, the road surface state detection unit Wheel speed correction means for correcting the vehicle speed in accordance with the output and turning characteristics of the vehicle, wherein the estimated vehicle body speed setting means determines a wheel speed of each of the wheels except for a wheel to be calculated. Antiskid control device according to claim in that for calculating the estimated vehicle speed above for each wheel based on the wheel speeds corrected by said wheel speed correction means. 2. The vehicle speed correction means calculates an average vehicle speed based on the wheel speed of a driven wheel among the wheels, and calculates the average vehicle speed, the output of the road surface state detection means, and the turning characteristics of the vehicle. 2. The anti-skid control device according to claim 1, wherein a correction value for the wheel speed of each of the wheels excluding the wheel to be calculated is set based on the wheel speed. 3. The vehicle according to claim 2, further comprising a limiter configured to limit an estimated vehicle speed to be set for a drive wheel of each of the wheels to a predetermined speed or less based on the average vehicle speed. An anti-skid control device as described. 4. An accelerating slip detecting means for detecting an accelerating slip of a driving wheel among the respective wheels, wherein the accelerating slip detecting means detects an accelerating slip of the driving wheel.
The estimated vehicle speed setting means calculates an estimated vehicle speed for a driven wheel among the wheels based on a wheel speed of a calculation target wheel and a driven wheel, and calculates an estimated vehicle speed for the driven wheel among the wheels. 3. The anti-skid control device according to claim 2, wherein the calculation is performed based on only the wheel speeds.