JP2653220B2 - Anti-skid control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an anti-skid control that controls the hydraulic pressure of a braking cylinder disposed on each wheel during braking to prevent the wheels from locking. More particularly, the present invention relates to an anti-skid control device capable of performing good anti-skid control while preventing a malfunction due to a difference in rotation radius between inner and outer wheels when a vehicle turns.

[Conventional technology]

As a conventional anti-skid control device, for example, there is one described in Japanese Patent Publication No. 41-17082.

In this conventional example, since the highest wheel speed among the respective wheel speeds is closest to the vehicle speed, this select high wheel speed is selected as the pseudo vehicle speed. Even if this select high wheel speed is selected, since the wheel deceleration is large during rapid deceleration, the pseudo vehicle speed becomes smaller than the actual vehicle speed. The straight line is set to the pseudo vehicle speed.

[Problems to be solved by the invention]

However, in the above-described conventional anti-skid control device, when the inner wheel (especially the rear wheel) floats when the vehicle turns in the non-braking state, and the inner wheel generates wheel spin, the rotation of the inner wheel with the wheel spin is performed. Since the pseudo vehicle speed is calculated on the basis of the speed, the value of the pseudo vehicle speed becomes too high, and when the wheel lock is determined in comparison with the pseudo vehicle speed, the locked state is set even though the other wheels are not actually locked. In addition to performing unnecessary anti-skid control to depressurize the brake devices of the other wheels, yawing that occurs in the vehicle is not considered at all.For example, the right wheel has a high friction coefficient and the left wheel has low friction. When the yaw that occurs in the vehicle becomes large and the vehicle is in a limit state just before spinning, as in the case of traveling on a so-called split road surface, which is a coefficient road surface, a good condition is obtained. Unresolved problems shake can not be carried out, such anti-skid control had.

In view of the above, the present invention has been made by focusing on the unsolved problem of the conventional example, and it is possible to prevent unnecessary anti-skid control and perform anti-skid control optimal for yawing. It is intended to provide a control device.

[Means for solving the problem]

To achieve the above object, an anti-skid control device according to claim (1) includes, as shown in a basic configuration diagram of FIG. 1 (a), a wheel speed detecting means for detecting a speed of a plurality of wheels; Wheel speed selecting means for selecting a wheel speed detection value of each wheel speed detecting means; pseudo vehicle speed calculating means for calculating a pseudo vehicle speed based on the selected wheel speed of the wheel speed selecting means; and wheels of the wheel speed detecting means Braking pressure control means for comparing a detected speed value with a slip threshold value based on the pseudo vehicle speed, making a slip determination, and independently controlling a fluid pressure of a braking cylinder disposed on each wheel based on the determination result; An anti-skid control device comprising: a lateral acceleration detecting means for detecting a lateral acceleration of the vehicle; and a yaw momentum detecting means for detecting a yaw momentum of the vehicle, wherein the wheel speed selecting means is controlled by the braking pressure control means. For During anti-skid control for controlling the fluid pressure of the vehicle, a predetermined highest wheel speed is selected from the wheel speed detection values of the vehicle speed detection means, and during anti-skid non-control, the lateral acceleration of the lateral acceleration detection means is selected. Select a predetermined wheel speed lower than the predetermined wheel speed during the anti-skid control when the detected value is greater than or equal to the set value,
When the yaw momentum detection value of the yaw momentum detection means is equal to or larger than a set value, the highest wheel speed is selected from the wheel speed detection values of the wheel speed detection means.

Here, as the yaw momentum detecting means, two lateral acceleration sensors or a yaw angular velocity sensor provided in the front-rear direction of the vehicle with the yaw center interposed therebetween can be applied.

Further, the anti-skid control device according to claim (4), as shown in the basic configuration diagram of FIG. 1 (b), comprises: wheel speed detecting means for detecting the speed of a plurality of wheels; Wheel speed selection means for selecting a wheel speed detection value of the vehicle, pseudo vehicle speed calculation means for calculating a pseudo vehicle speed based on the selected wheel speed of the wheel speed selection means, and a wheel speed detection value of the wheel speed detection means An anti-skid control device comprising: a brake threshold control unit that performs a slip determination by comparing a slip threshold based on a vehicle speed and controls a fluid pressure of a brake cylinder disposed on each wheel based on the determination result. Turning mode detecting means for outputting a turning mode signal that changes in accordance with yaw motion of the vehicle during turning, and inner and outer wheel rotation corresponding to a vehicle turning locus based on the turning mode signal of the turning mode detecting section and the pseudo vehicle speed. speed A rotational speed difference correction value calculating means for calculating a correction value; and a threshold setting means for setting a slip threshold of the braking pressure control means based on the rotational speed difference correction value of the rotational speed difference correction value calculating means. It is characterized by.

Further, the anti-skid control device according to claim (5), as shown in the basic configuration diagram of FIG. 1 (c), includes wheel speed detecting means for detecting the speed of a plurality of wheels, and each wheel speed detecting means. Wheel speed selection means for selecting a wheel speed detection value of the vehicle, pseudo vehicle speed calculation means for calculating a pseudo vehicle speed based on the selected wheel speed of the wheel speed selection means, and a wheel speed detection value of the wheel speed detection means An anti-skid control device comprising: a brake threshold control unit that performs a slip determination by comparing a slip threshold based on a vehicle speed and controls a fluid pressure of a brake cylinder disposed on each wheel based on the determination result. A yaw angular velocity detecting means for detecting a yaw angular velocity of the vehicle; a lateral acceleration detecting means for detecting a lateral acceleration of the vehicle; and a vehicle turning trajectory corresponding to the lateral acceleration detection value of the lateral acceleration detecting means and the pseudo vehicle speed. A rotational speed difference correction value calculating means for calculating an outer ring rotational speed difference correction value; and the braking pressure based on the yaw angular speed detection value of the yaw angular speed detecting means and the rotational speed difference correction value of the rotational speed difference correction value calculating means. And a threshold setting means for setting a slip threshold of the control means.

[Action]

In the anti-skid control device according to claim 1, during anti-skid control in which the fluid pressure of the braking cylinder is controlled, a predetermined highest wheel speed is selected from the angular wheel speed detection values of the wheel speed detection means. However, during the non-anti-skid control, when the lateral acceleration detecting means detects the lateral acceleration equal to or higher than the predetermined set value, the wheel speed selecting means sets the wheel speed lower than the wheel speed selected value in the anti-skid control state. That is, during anti-skid control, when selecting the maximum value among the wheel speeds of the four wheels, the second and subsequent higher wheel speeds are selected. When selecting the higher wheel speed among the non-driven wheels in a two-wheel drive vehicle, the non-driving wheel is selected. When the second highest wheel speed is selected by ignoring the maximum value among the low wheel speeds and the four wheel speeds of the four wheels, wheel spin is generated by selecting the third and subsequent highest wheel speeds. Absent A pseudo vehicle speed that follows the actual vehicle speed can be determined based on the wheel speed of the wheels, and by using this pseudo vehicle speed to determine the lock state of each wheel, malfunction due to wheel spin of the inner wheel during turning can be prevented. The yaw movement detection means detects the magnitude of the yaw movement, and if the yaw movement is large, there is a possibility of spinning.Therefore, select the highest wheel speed to ensure steering stability. To perform accurate anti-skid control.

Further, in the anti-skid control device according to claim (4), when the vehicle is in a turning state, the turning state detecting means is provided in the front-rear direction with the turning state detection signal corresponding to the turning state including yawing, for example, across the yaw center. Lateral acceleration detection values from the two lateral acceleration sensors are output, and a correction value of the wheel speed difference between the inner and outer wheels due to the inner wheel difference of the fleet is calculated based on the turning mode signal and the pseudo vehicle speed from the pseudo vehicle speed calculation means. A wheel speed difference correction value corresponding to the turning locus of the vehicle can be obtained, and the wheel speed difference correction value is increased or decreased according to the yawing state of the vehicle, so that a slip determination is made based on the wheel speed difference correction value. By setting the slip threshold of the braking pressure control means, which is the reference for, the malfunction of the anti-skid control due to the speed difference between the inner and outer wheels during turning is prevented, When a large yawing occur in the vehicle during movement, perform good anti-skid control while ensuring the steering stability by suppressing yawing by increasing the slip threshold.

Furthermore, in the anti-skid control device according to claim (5), the yaw generated in the vehicle is detected by the yaw angular velocity sensor, and the slip threshold is set in accordance with the detected yaw angular velocity, so that the steering stability is also increased. Performs good anti-skid control while ensuring performance.

〔Example〕

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

FIG. 2 is a block diagram showing a first embodiment of the present invention.

In the figure, 1FL and 1FR are front wheels serving as non-driving wheels, 1RL and 1RR are rear wheels serving as driving wheels, and these wheels 1FL-1RR have wheel cylinders 2FL-2RR serving as braking cylinders, respectively.
Are mounted, and wheel speed sensors 3FL to 3RR that output pulse signals corresponding to the wheel rotation speeds of the wheels 1FL to 1RR.
Is installed.

Each wheel cylinder 2FL-2RR has a brake pedal 4
The master cylinder pressure from the master cylinder 5, which generates two systems of master cylinder pressures in accordance with the depression of the actuator, is supplied via the actuators 6FL to 6RR.

As shown in FIG. 3, each of the actuators 6FL to 6RR includes an electromagnetic inflow valve 8 interposed between a hydraulic pipe 7 connected to the master cylinder 5 and the wheel cylinders 2FL to 2RR. 8, a series circuit of an electromagnetic outflow valve 9, a hydraulic pump 10, and a check valve 11 connected in parallel with the outflow valve 9;
And an accumulator 12 connected to a hydraulic line between the hydraulic pumps 10.

Then, the electromagnetic inflow valves 8 of the actuators 6FL to 6RR,
The electromagnetic outflow valve 9 and the hydraulic pump 10 are provided with wheel speed sensors 3FL to 3FL.
With a wheel speed pulse signal P _FL to P _RR from RR is input, distribution in the longitudinal direction of the symmetrical positions sandwiching the longitudinal acceleration detection value X _G and Yosenta of the longitudinal acceleration sensor 13 for detecting a longitudinal acceleration which is attached to the vehicle body Two lateral acceleration sensors
The lateral acceleration detection values Y _G1 and Y _{G2 of} 14A and 14B are controlled by hydraulic pressure control signals EV, AV, and MR from the controller CR.

Here, as shown in FIG. 5 (a), when the acceleration / deceleration of the vehicle is not applied, the longitudinal acceleration sensor 13 has a positive neutral voltage _VN , and the forward acceleration (reverse deceleration) is applied. This proportion will voltage higher than the neutral voltage V _N, the forward deceleration (backward acceleration) longitudinal acceleration detection value X _G which is a positive voltage lower than the neutral voltage V _N in proportion thereto when acted upon Is output. Similarly, the lateral acceleration sensors 14A, 14B
As shown in FIG. 5 (b), when the vehicle lateral acceleration does not act, a positive neutral voltage V _N becomes, in proportion thereto when the lateral acceleration of the right direction by the left turn acts becomes a voltage higher than the neutral voltage V _N Te, a lateral acceleration detection value Y _G1, Y _G2 which is a positive voltage lower than the neutral voltage V _N in proportion thereto when the lateral acceleration of the left by the right turn acts Output.

The controller CR receives wheel speed pulse signals P _{FL to} P _RR from the wheel speed sensors 3 _{FL to 3 RR} , and inputs these signals to each wheel 1 FL.
From the turning radius of ~ 1RR and the peripheral speed of the wheel (wheel speed) Vw _FL ~ V
Wheel speed calculation circuits 15FL to 15RR for calculating w _RR, and wheel speeds Vw _{FL to} Vw _RR of these wheel speed calculation circuits 15FL to 15RR are selected based on lateral acceleration detection values Y _G1 and _G2 of lateral acceleration sensors 14A and 14B. Wheel speed selection circuit 16 and the wheel speed selection circuit 16
Select wheel speed Vw _s and the longitudinal acceleration sensor 13 in the selected
Is input and the longitudinal acceleration detection value X _G of the wheel and pseudo vehicle speed calculating circuit 17 for calculating the pseudo vehicle speed V _i on the basis of these, the pseudo vehicle speed V _i output from the pseudo vehicle speed calculation circuit 17 A braking pressure control circuit 18 for performing anti-skid control during braking based on the speeds Lw _FL , Lw _RR and Vw _R, and a control signal output from the braking pressure control circuit 18 is supplied to a drive circuit 22a.
Are supplied to the actuators 6FL to 6RR via .about.22c.

Wheel speed selecting circuit 16, as shown in FIG. 4, when the select signal S _E has the logical value "1", the maximum wheel speed among the wheel speeds Vw _FL ~Vw _RR (select high wheel speed) Vw _H select, as the wheel speed Vw _FL ~Vw minimum wheel speed (select low wheel speed) Vw _L select wheel speed this by selecting the Vw _s of _RR when the select signal S _E is logic value "0" and it includes a select switch SS as wheel speed selecting means for outputting, and a select signal forming circuit 19 for forming the select signal S _E for the select switch SS. Here, the select signal forming circuit 19 calculates the lateral acceleration detection values of the lateral acceleration sensors 14A and 14B.
Y _G1 and Y actual lateral acceleration representing the positive and negative by subtracting the neutral voltage V _N from _G2 Y _GR1 and Y _GR2 lateral acceleration conversion circuit 19a for calculating a,
19b and an average value circuit 19c for calculating these lateral acceleration conversion circuit 19a, the lateral acceleration Y _GR1 and signed mean value Y _GM of Y _GR2 output from 19b, the absolute average value Y _GM of the average value circuit 19c An absolute value circuit 19d for taking a value, and an absolute value output of the absolute value circuit 19d are supplied to one input side, and for example,
A set value Y _GS corresponding to 0.3 g is supplied, and when Y _GM <Y _GS , that is, when the turning radius is large in a straight running state or a turning state, or when the rotation speed difference between the inner and outer wheels is small at a low speed running, a logical value “ 1 ", a comparator that outputs a comparison output of logical value" 0 "when Y _GM ≥ Y _GS , that is, when the rotation speed difference between the inner and outer wheels is large in the turning state.
19e, an output of the comparator 19e and a braking pressure control circuit described later.
Taking the logical sum of the control in the signal MR from 18 consists of an OR circuit 19f, the output of the OR circuit 19f is supplied to the select switch SS as a select signal S _E.

As shown in FIG. 4, the pseudo vehicle speed calculation circuit 17 includes an output correction circuit 20 for correcting the longitudinal acceleration detection value output from the longitudinal acceleration sensor 13 and a corrected acceleration detection value _C output from the output correction circuit 20. , the pseudo vehicle speed generating circuit for calculating the pseudo vehicle speed V _i from the select wheel speed Vw _S and the control in the signal MR
And a 21, the pseudo vehicle speed V _i output from the pseudo vehicle speed generating circuit 21 is inputted to the braking pressure control circuit 18.

Here, the output correction circuit 20, a longitudinal acceleration conversion circuit 20a for calculating the actual longitudinal acceleration V _GR by subtracting the neutral voltage V _N from the longitudinal acceleration detection value X _G output from the longitudinal acceleration sensor 13, this The longitudinal acceleration V _GR of the longitudinal acceleration conversion circuit 20a
And an offset value output circuit 2
And 0c, and an adding circuit 20d for adding the output of the absolute value circuit 20b and the offset value output circuit 20c, subtracts the neutral voltage V _N from the acceleration detection value X _G of the longitudinal acceleration sensor 13 in the longitudinal acceleration converter 20a By calculating the forward acceleration (reverse deceleration) as a positive voltage proportional thereto, and the forward deceleration (reverse acceleration) as a negative voltage proportional thereto, an actual acceleration / deceleration X _GR is calculated. The absolute value circuit 20b
Inputting the acceleration X _GR of the longitudinal acceleration conversion circuit 20a into an absolute value to the adding circuit 20d. Also, the offset value output circuit 20c
Is for outputting the arbitrary predetermined offset value to correct the absolute value was deceleration X _GR to an adder circuit 20d, to correspond to the offset value, for example 0.3 g. Adder circuit 20
d is the absolute value of the acceleration / deceleration X _GR
The acceleration / deceleration correction value X _GC offset by 0.3 g is output.

Pseudo vehicle speed generating circuit 21, as shown in FIG. 5, the comparator 21a to select wheel speed Vw _S output from the select switch SS is input, and 21b, a dead zone of ± 1km / h to the pseudo vehicle speed V _i Adder 21c to set and supply to other inputs of comparators 21a and 21b
And a subtractor 21d and a NOR gate 21e to which output signals C ₁ and C _{2 of} the comparators 21a and 21b are supplied. The comparator 21a determines that Vw _H ≧
Outputs a high-level output C ₁ at V _i +1 km / h and outputs
1b outputs the output C ₂ high level when the _{Vw H <V i -1km / h} . Accordingly, NOR gate 21e, the outputs C _1, C ₂ and outputs an output signal S ₅ of high level when _{V i -1km / h ≦ Vw H} <V i + 1km / h which both become low level. Output signal of NOR gate 21e
S _5, the off-delay timer 21f, are input to the OR gate 21g and a shot pulse generator circuit 21h. Off-delay timer 21f is started by the fall of the signal from the NOR gate 21e, and outputs a high level signal by a predetermined time T _3, this
Supply to OR gate 21g.

The output of the OR gate 21g is supplied to the gate of the analog switch 21i as a select signal S _3, the AND gate 21k is inverted by an inverter 21j, it is supplied to one input side of 21l. The other input of the AND gate 21k, C ₁ signal, also C ₂ signal is supplied to the other input of the AND gate 21l, select AND gate 21k, the output of 21l signals S _2, S ₄ Are supplied to the gates of the analog switches 21m and 21n. Analog switch 21i is to zero the supply voltage E to the integrator circuit 21o goes high during the on state of the select signal S _3, the analog switch 21m becomes a high level during the on state of the select signal S _2, possible vehicle acceleration ( maximum value of the vehicle speed increasing rate of change), for example, + 0.4 g negative voltage E corresponding to, or + 10 g a negative voltage E corresponding to the supplied to the integration circuit 21o, an analog switch 21n is a high level of the select signal S ₄ In the middle ON state, the voltage E corresponding to the acceleration / deceleration correction value _C from the addition circuit 20d is supplied to the integration circuit 21o. In addition, the selection of + 0.4g and + 10g is made by the changeover switch 21p
The switch 21p is set to +0.4 g while the control-in-progress signal MR from the anti-skid control circuit 17 has the logical value “0”.
Is selected during anti-skid control in which the control signal MR has the logical value “1”.

Integrator circuit 21o is intended an amplifier 21q, known consisting of a capacitor 21r and an analog switch 21s, is reset when the analog switch 21s is turned on by the high level reset signals S ₁ to its gate, the reset signal S ₁
After disappearing, the voltage E is continuously integrated. Reset signals S ₁ is to obtain by-shot pulse from the shot pulse generating circuit 21h, the shot pulse generating circuit 21
h outputs first one shot pulse when the engine starts as a reset signals S ₁ by an ignition-on signal IG, then outputs the shot pulse for each output signal S ₅ of NOR gate 21e rises as a reset signals S ₁ I do.

Reset signals S ₁ is Other Sapuru hold circuit 21t
This circuit is also used for buffer amplifier 21u,
21v, and well known consisting capacitor 21w and an analog switch 21x, select wheel speed Vw _S is input. Sample-and-hold circuit 21t is a high-level reset signals S ₁ is reset when the analog switch 21x is turned on, the wheel speed sampling values V the wheel speed Vw _S at that time
_It keeps storing as _S , and inputs this to the adding circuit 21y. Adder circuit 21y is the integrated value V _e = ▲ ∫ ^t of the integration circuit 21o ₀ ▼ (-
E) · dt is added to the wheel speed sampling value V _S , and the added value V _S
+ A V _e is input to the brake pressure control circuit 18 as a pseudo vehicle speed V _i.

The braking pressure control circuit 18 determines the wheel speeds Vw _{FL to} Vw _R and the pseudo vehicle speed V
Wheel cylinder 2 provided on each wheel 1FL-1RR based on _i
Actuators 6FL to 6R that control the supply pressure to FL to 2RR
As shown in FIG. 2, the microcomputer 25 includes a microcomputer 25 having at least an input interface circuit 25a, an output interface circuit circuit 25d, an arithmetic processing unit 25b, and a storage device 25c. The following anti-skid control processing is executed.

This anti-skid control processing is performed for a predetermined time, for example, 20 ms.
This is executed as a timer interrupt process for each ec. In this process, AS indicates a control flag, L indicates a decompression timer, and these are shifted from step to step at the end of the previous inch skid control and cleared to zero, While the control flag AS is set to “1”, the controlling signal MR having the logical value “1” is output to the select signal forming circuit 19 and the pseudo vehicle speed generating circuit 21.

That is, when the processing in FIG. 6 is started, first, in step, the current wheel speed detection value Vw _jN output from the wheel speed calculation circuit 15j (j = FL, FR, RL, RR) is read, and then in step And the wheel speed change amount per unit time, that is, the wheel acceleration / deceleration w _j, is _obtained by subtracting the wheel speed detection value Vw _jN read in the step from the wheel speed detection value Vw _jN-1 read in the previous processing. and stores the calculated in a predetermined storage area of the storage device 25c, and then proceeds to step reads the pseudo vehicle speed V _i from the pseudo vehicle speed calculating circuit 17, then the following (1) the process proceeds to step type Calculation is performed to calculate the slip ratio _Sj .

Then, it outputs a control signal for controlling the actuator 6j based on the slip ratio S _j calculated by the wheel acceleration w _j and the step calculated in step.

That is, the slip ratio _Sj is a predetermined value S
₀ (for example, 15%), the control flag AS and the pressure reduction timer L are both zero, and the wheel acceleration / deceleration w _j is between the preset deceleration threshold α and acceleration threshold β, ie, α <
At the time of non-braking and the initial stage of braking in which w _j <β, the process proceeds to step through step to set a rapid pressure increase mode in which the pressure of the actuator 6j is a pressure corresponding to the pressure of the master cylinder 5. In this rapid pressure increase mode, the control signals EV and AV for the actuator 6j are both set to the logical value “0”, the inflow valve 8 of the actuator 6j is opened, and the outflow valve 9
Are respectively controlled to be in the closed state.

Therefore, when the vehicle is in the non-braking state in which the brake pedal 4 is not depressed, the pressure of the master cylinder 5 is substantially zero, so that the pressure of the wheel cylinder 2j also maintains substantially zero, and the non-braking state is maintained. At the initial stage of braking when the pedal 4 is depressed, the pressure of the wheel cylinder 2j corresponding to the increase in the pressure of the master cylinder 5 is rapidly increased, and a braking state is established.

Then, when the braking state, decreases the wheel speed Vw _j gradually, wheel deceleration w _j is increased as shown by curve l of FIG. 7 in response to this, the wheel deceleration w _j is the deceleration threshold If it exceeds α, the process shifts from step to step to enter a high pressure side holding mode in which the pressure of the actuator 6j is held at a constant value. In the high-pressure side holding mode, the control signal EV to the actuator 6j is set to the logical value “1” and the control signal AV is set to the logical value “0” to close the inflow valve 8 and the outflow valve 9 of the actuator 6j. Each state is controlled to maintain the internal pressure of the wheel cylinder 2j at the immediately preceding pressure.

However, even in this holding mode, with the braking force to the wheel is acting, the wheel deceleration w _j as indicated by the curve l of FIG. 7 increases, the slip ratio S _j
Increase.

When the slip ratio S _j exceeds a predetermined value S _0, and the wheel deceleration w _j is maintained less than the acceleration threshold value β is
The process proceeds from step to step through step, sets the pressure reduction timer L to a predetermined value L _0, sets the control flag AS to “1”, and controls the logical value “1” approximately based on this. The signal MR is output to put the hydraulic pump 10 of the actuator 6j into an operating state. For this reason, the process shifts from step to step through step, and a pressure reduction mode is set in which the pressure of the actuator 6j is gradually reduced.
In this pressure reduction mode, the control signals EV and AV for the actuator 6j are both set to the logical value “1”, and the actuator 6j
With the inflow valve 8 closed and the outflow valve 9 open, the pressure held in the wheel cylinder 2j is returned to the master cylinder 5 via the outflow valve 9, the hydraulic pump 10 and the check valve 11, and the wheel cylinder Decrease the internal pressure of 2i.

When this becomes a decompression mode, the braking force to the wheel is reduced, the wheel speed detected value Vw _j a while maintaining the reduced state, and therefore the wheel deceleration w _j and slip ratio S _j seventh view of a curve l continuing the upward trend as shown by, but then decreasing rate of the wheel speed detected value Vw _j shifts to the accelerating state decreases.

This increases the wheel acceleration w _j is the forward direction in accordance with, the wheel acceleration w _j is equal to or higher than the acceleration threshold value beta, the process proceeds to step through step from step.

In this step, the pressure reduction timer L is cleared to "0", and then the process proceeds to the above step.

Therefore, in the determination at the step, L = 0, and the process proceeds to the step. Since w _j ≧ β, the process proceeds to the step, and the control flag AS is set to “1”. Then, the mode shifts to the low pressure side holding mode in which the pressure of the actuator 6j is held on the low pressure side. In the low pressure side holding mode, the control signal EV is controlled to the logical value “1” and the control signal AV is controlled to the logical value “0” in the same manner as in the high pressure side holding mode, so that the internal pressure of the wheel cylinder 2j is immediately before. Hold at pressure.

Thus, when the holding mode of the low-pressure side, the inner pressure of the wheel cylinder 2j becomes constant value in the low-pressure side, the wheel speed detected value Vw _j continues to accelerated conditions. For this reason, wheel acceleration / deceleration
w _j increases in the positive direction, and the slip ratio S _j decreases.

When the slip ratio S _j is less than the set slip ratio S _0, the process proceeds from step to step, since pressure reduction timer L is the last low-pressure side holding mode is cleared to "0", and proceeds directly to step, The low pressure side holding mode is continued.

Also in the low-pressure side holding mode, for the wheels, the braking force acts, the rate of increase in the wheel speed detected value Vw _j gradually decreases, the wheel acceleration w _j is the acceleration threshold value β
When it is less than, it moves from step to step,
Since w _j > α, the process proceeds to the step where the control flag AS
Is “1”, the process proceeds to the step.

In this step, the pressure oil from the master cylinder 5 is intermittently supplied to the wheel cylinders 2j, and the internal pressure of the wheel cylinders 2j is increased in a stepwise manner, so that the mode is set to a gradual pressure increasing mode. In this gradual pressure increase mode, the control signal EV for the actuator 6j is alternately repeated at a predetermined interval with a logical value “0” and a logical value “1”, and the control signal AV is set to a logical value “0”, and the inflow valve of the actuator 6j 8, open and close at predetermined intervals,
By closing the outflow valve 9, the wheel cylinder
The internal pressure of 2j is gradually increased stepwise.

In the gradual pressure increase mode, the pressure increase of the wheel cylinder 2j becomes gradual, so that the braking force on the wheel 1j gradually increases, the wheel 1j is in a deceleration state, and the wheel speed detection value Vw
_j decreases.

Thereafter, when the wheel acceleration w _j is equal to or less than the deceleration threshold alpha, the process proceeds from step to step, becomes the hold mode of the high-pressure side, then the slip ratio S _j is set slip ratio
When the S ₀ or more, the process proceeds to step through step from step, then step, the so proceeds to step through, become reduced pressure mode, subsequent low pressure holding mode, slow increase mode, the high pressure side holding mode, vacuum mode repeated Thus, an anti-skid effect can be exhibited.

Incidentally, when the speed of the vehicle has decreased to some extent, may slip ratio S _j in a vacuum mode is restored to below the set slip ratio S _0, at this time, the process proceeds from step to step, setting the pressure decrease mode, as described above since vacuum timer L in the step of is set to a predetermined setting value L _0, the process proceeds to step, so that the process proceeds to step since by subtracting the predetermined set value "1" of the vacuum timer L. Therefore, when the process of shifting from step to step is repeated and the pressure reduction timer L becomes "0", the process shifts to step through step to step, shifts to the gradual pressure increase mode, and shifts to the high pressure side holding mode. Then, the mode is shifted to the gradual pressure increase mode.

Then, when the vehicle satisfies the control ending condition such as when the vehicle speed becomes close to the stop or when the number of times of selection of the gentle pressure increasing mode becomes a predetermined value or more, it is determined that the control is completed by the determination of the step. Then, the process proceeds from this step to the step, where the pressure reduction timer L and the control flag AS are cleared to "0", and then proceeds to the step to set the rapid pressure increase mode and terminate the anti-skid process.
Therefore, when the vehicle is stopped with the brake pedal depressed, the hydraulic pressure of the master cylinder 5 is applied to the wheel cylinder 2j as it is, so that the vehicle can be kept stopped, and when the brake pedal 4 is released, Since the oil pressure of the master cylinder 5 becomes zero, the internal pressure of the wheel cylinder 2j is maintained at zero, and no braking force is applied to the wheel 1j.

 Next, the operation of the above embodiment will be described.

Now, assuming that the vehicle is parked and the key switch is turned on in this state, power is supplied to the controller CR. Therefore, the output correction circuit 20 of the pseudo vehicle speed calculating circuit 17, be zero as the longitudinal acceleration X _GR obtained by subtracting the neutral voltage V _N from the acceleration detection value X _G of the longitudinal acceleration sensor 13 is shown in Figure No. 8 (f) The acceleration / deceleration correction value X _{GC obtained} by adding the absolute value of the acceleration / deceleration X _{GR by} the offset value 0.3 g to the pseudo vehicle speed generation circuit 21 is output from the addition circuit 20d as shown in FIG. 8 (g). .

On the other hand, the anti-skid control is not performed in the braking pressure control circuit 18, and the control-in-progress flag AS is reset to “0”.
The control-in-progress signal MR becomes a logical value "0" to maintain the rapid pressure increase mode, the inflow valve 8 of the actuators 6FL to 6RR is controlled to be open, and the outflow valve 9 is controlled to be closed, and the hydraulic pump is controlled. 10 is stopped, and the brake fluid pressure output from the master cylinder 5 in accordance with the amount of depression of the brake pedal 4 is supplied to the wheel cylinders 2FL to 2RR as they are via the actuators 6FL to 6RR.

At this time, since the vehicle is stopped, the lateral acceleration sensor
14A and 14B lateral acceleration detection values Y _G1 and Y _G2 are both neutral voltages
It has a V _N, a select signal lateral acceleration Y _GR1 and Y _GR2 lateral acceleration conversion circuit 19a and 19b of the forming circuit 19 are both becomes zero, the average value circuit 19c, and the absolute value circuit 1 according to this
Since the absolute value output also becomes zero in 9d, the comparison output of the comparator 19e is at a logic value "1", the select signal S _E output from the OR circuit 19f has the logical value "1", the select switch SS is in a select high state in which the maximum value is selected from the wheel speeds Vw _{FL to} Vw _RR .

Once t ₀ shown from the state in FIG. 8, when the ignition switch to the ON state, the ON signal IG is input to the shot pulse generator circuit 21h of the pseudo vehicle speed generating circuit 21. Therefore, the output-shot pulse S ₁ as shown in Figure 8 from shot pulse generating circuit 21h (i), which it was reset and is connected to the sample hold circuit 21t, which is selected by the select switch SS in this case The select high wheel speed Vw _S (= 0) is held as a wheel speed sampling value V _S. Further, shot pulse S ₁ is the integration circuit 21o
The also supplied, the integrating circuit 21o is reset, since the integral output V _e becomes zero, the pseudo vehicle speed V _i is also zero output from the addition circuit 21y. Thus, since the pseudo vehicle speed V _i and elect the high wheel speed Vw _S is zero equally both
The comparator 21a and the output C ₁ and C ₂ of 21b is in the low level as shown in FIG. 8 (b) and (c), the output from the NOR gate 21e of the high level as shown in Figure 8 (d) signal S ₅ is outputted, a high level as shown in select signal S ₃ also Figure 8, which is output from the OR gate 21g (e) accordingly.

Since the select signal S ₃ is supplied to the analog switch 21i, the analog switch 21i is turned on, the other select signal S ₃ is supplied inverted to the low level by the inverter 21j and the AND gates 21k and 21l, these inhibits the generation of the select signals S ₂ and S _4. At this time, since the input side of the analog switch 21i is grounded, the input voltage E of the integration circuit 21o becomes as shown in FIG.
And the integral output _Ve is also maintained at zero. As a result, the pseudo vehicle speed V _i output from the addition circuit 21y
Is maintained at the same zero as the wheel speed sampling value V _S.

Thereafter, when the vehicle is started to be in an acceleration state in which the vehicle keeps a linear state, the lateral acceleration sensors 14A and 14B output the neutral voltage _VN.
To maintain the lateral acceleration detection value Y _G1 and Y _G2 of the select signal S _E output from the selection signal generation circuit 19 maintains the logic value "1", the select switch SS also maintains a select-high state.

Then, rising as the select high wheel speed Vw _H is a bold line shown in FIG. 8 (a), at time t ₁ as the _{Vw L ≧ V i + 1km /} h,
Comparison output C ₁ of the comparator 21a turns to a high level. However, the output of the off-delay timer 21f is until the set time T ₃ from time t ₁ elapses maintaining a high level is converted at time t ₂ after the set time T ₃ has elapsed at a low level. Thus, between time t ₁ to time t _2, the pseudo vehicle speed V _i is still kept at the same constant value as the previous wheel speed sampling values V _S (= 0), is output at time t ₂ from the OR gate 21g that the select signal S ₃ is converted to the low level as shown in Figure No. 8 (e), by the output of the same time the aND gate 21k when the analog switch 21i is turned off becomes the high level in response to this, the analog switch 21m Is turned on and +0.4
A negative voltage corresponding to g is supplied as input voltage E.
Therefore, integration output V _e of the integration circuit 21o increases at a speed corresponding to + 0.4 g, the addition value or the pseudo vehicle speed V _i also Figure 8 by the addition circuit 21y between this and the wheel speed sampling value V _S (a ), As shown by the dotted line.

Then, a pseudo vehicle speed V _i is substantially equal to the select high wheel speed _{Vw H (Vw H = V i} +1) time t _3, the comparison output C ₁ of the comparator 21a is converted to a low level, in response to this NOR the output S ₅ of the gate 21e is converted to a high level, the integration circuit 21o and the sample hold circuit 21t is reset together, which an analog switch 21i is turned on instead of the analog switch 21m same time, the integration input of the integrator circuit 21o if the voltage E becomes zero, the integrated output V _e becomes zero, the pseudo vehicle speed V _i is the time t ₃
It is held in the sampling speed V _S at.

Thereafter, since the vehicle continues to accelerate, the time t ₄
In comparison output C ₁ of the comparator 21a is converted to a high level, the timer 2
The output S of the OR gate 21g at t ₅ the set time T ₃ of the 1f has elapsed
₅ is changed to a low level, and the analog switch 21m is turned on again in place of the analog switch 21i.
Pseudo vehicle speed V _i is increased at a speed corresponding to the integral value of the acceleration corresponding to + 0.4 g, the output of the comparator 21a at the time point t ₆ of the pseudo vehicle speed V _i is substantially equal to the select high wheel speed Vw _H is low by converting to, the integration circuit 21o and the sample hold circuit 21t is reset to hold the select high wheel speed Vw _H at that time by the sample-and-hold circuit 21t.
After that, select-high wheel speed pseudo vehicle speed V _i is in the period from the time point t ₆ ~t ₇
Holding the Vw _H, time t ₇ ~t increased at a speed corresponding to + 0.4 g between _8, select-high wheel speed Vw at time t ₈ in the period from the time point t ₈ ~t ₉
Holding the _H, rises at a speed corresponding to + 0.4 g in the period from the time point t ₉ ~t _10, select high wheel speed at the time t ₁₀ in the period from the time point t ₁₀ ~t ₁₁ V
holds w _H, rises at a speed corresponding to + 0.4 g in the period from the time point t ₁₁ ~t _12, holds the select-high wheel speed Vw _H at time t ₁₂ in the period from the time point t ₁₂ ~t _13, time t ₁₃ ~t increased at a speed corresponding to + 0.4 g between _14, a constant speed running condition after the time t ₁₄ the acceleration state is ended, holding the select-high wheel speed Vw _H at time t _14.

However, for example, at time t when the vehicle is running at a constant speed straight ahead
₁₄ after time t _15, represented the vehicle when the transition from the straight running state to the left (or right) turning, the following from the lateral acceleration sensor 14A and 14B the lateral acceleration occurs (2) and (3) neutral higher than the voltage V _N (or lower) the lateral acceleration detected value becomes a positive voltage Y _G1 and Y _G2 is outputted.

Y _G1 = + l ₁ ... (2) Y _G2 = −l ₂ ... (3) where (= + V _X ) represents the lateral acceleration at the yaw center, represents the lateral acceleration, V _X Is the vehicle speed and is the yaw angular speed. Further, l ₁ and l ₂ is the distance between the lateral acceleration sensor 14A and 14B and Yosenta, it is yaw angular acceleration.

Then, these lateral acceleration detection values Y _G1 and Y _G2 are converted into actual lateral accelerations Y _GR1 and Y _GR2 by the lateral acceleration conversion circuits 19a and 19b, and these are subjected to signed average processing by the average value circuit 19c. The average acceleration value Y _GM is Becomes For this reason, the lateral acceleration average value Y _GM is l ₂ > l ₁ , and the sign of the lateral acceleration and the sign of the yaw angular acceleration or the same sign when turning when the vehicle is turning, so that the yaw angular acceleration increases. Becomes smaller according to

Since the lateral acceleration average value Y _GM is supplied to the absolute value has been comparator 19e at an absolute value circuit 19d, the yawing less abrupt turning state, the absolute value | Y _GM | the set value Y _GS more and Then, the comparison output of the comparator 19e becomes a logical value “0”,
Since it is in the non-braking state, the control signal of the braking pressure control circuit 18 is being controlled.
Since MR continues the logical value "0", the select signal S _E output from the OR circuit 19f is inverted to logic value "0". For this reason, the select-low state where the selection switch SS to select the minimum value in the wheel speed Vw _FL ~Vw _RR. Therefore, the inner wheels 1 of the rear wheels 1RL and 1RR which are the driving wheels when turning left (or right) are turned.
Fig. 8 (a) when wheel spin occurs in RL (or 1RR)
As shown in the one-dot chain line, even when the wheel speed Vw _RL increases rapidly, the inner wheel 1RL (or 1
The wheel speed Vw _RL (or Vw _RR ) of the drive outer wheel 1RR (or 1RL) shown in a two-dot chain line in FIG. Vw _RR (or Vw
_RL ), and ignores the inner wheel 1FL (or 1
Wheel speed Vw _FL of FR) (or Vw _FR) will be is selected, since calculating the pseudo vehicle speed V _i to the select low wheel speed Vw _L in groups Dzute pseudo vehicle speed calculating circuit 17, the pseudo vehicle speed V _i Can be prevented from becoming abnormally high. Therefore, the anti-skid treatment of FIG. 6 in the braking pressure control circuit 18, without slip ratio S _j to be calculated becomes a set value S ₀ or more in accordance with the equation (1) in step, the step-by step , Or from the step to the step through the step 〜, the rapid pressure increase mode is maintained, and the start of the anti-skid control due to a malfunction can be avoided.

After that, when the vehicle returns to the straight traveling state, the lateral acceleration sensor 14A
And the lateral acceleration detection values Y _G1 and Y _G2 detected at 14B become zero, the select signal _SE becomes a logical value “1”, and the select switch SS selects the select high wheel speed Vw _H , Based on this, the pseudo vehicle speed calculation circuit 18 calculates the pseudo vehicle speed.
V _i is calculated.

Then, to release the depression of the accelerator pedal at time t _16,
When braking state depress the brake pedal 4 Alternatively, the select-high wheel speed Vw _H is reduced with respect to the pseudo vehicle speed V _i, as the comparison output of the comparator 21b is shown in Figure No. 8 (c) , inverted to high level, setting the timer 21f time T ₃
Once t ₁₇ but have passed, the output of the OR gate 21g is inverted to the low level as shown in Figure No. 8 (e), AN
The output of the D gate 21l is inverted to a high level, and the analog switch 21n is turned on. This allows the output correction circuit 2
Since the acceleration / deceleration correction value _C output from the 0 addition circuit 20d is supplied to the integration circuit 21o as the input voltage E, the integrated output increases in the negative direction according to the acceleration / deceleration correction value _C ,
Since this is supplied to the adding circuit 21y, pseudo vehicle speed V _i decreases gradually as the dotted line shown in FIG. 8 (a).

Then, the pseudo-vehicle speed V _i at time t ₁₈ the select high wheel speed V
When substantially equal to w _H, the comparison output C ₂ of the comparator 21b is inverted to the low level, the output S ₅ of NOR gate 21e in response to this eighth
Because inverted to the high level as shown in FIG. (D), as shown from the shot pulse generator circuit 21h in FIG. 8 (i), shot pulse S ₁ is output, together with the integration circuit 21o is reset, the sample-and-hold holding the select-high wheel speed Vw _H at that time in the circuit 21t, then adding circuit 2 outputs the correction circuit 20 at time t ₁₉ the set time T ₃ of the timer 21f has elapsed
Pseudo vehicle speed V _i is reduced acceleration and deceleration correction value _C output integrated to the integration circuit 21o from 0d, select the time at t ₂₀ to the pseudo vehicle speed V _i is substantially equal to the select high wheel speed Vw _H The high wheel speed Vw _H is held by the sample hold circuit 21t.

In this braking state, the braking pressure control circuit 18 is activated, and the wheel cylinder 2FL provided on each wheel 1FL-1RR is provided.
Anti-skid control is applied to the braking force for ~ 2RR individually.

On the other hand, in the turning state where the lateral acceleration of the vehicle is large,
Inner wheel is a state of traveling on a so-called split road outer ring side is low coefficient of friction surface with a high friction coefficient road surface, depress the brake pedal 4 at t ₂₁ in FIG. 9, when shifting to the braking state, the braking initial state In the processing shown in FIG. 6, the arithmetic processing unit 25b of the braking pressure control circuit 18 proceeds to the step to select the rapid pressure increase mode, and the anti-skid control from the pressure reduction mode is not executed.
MR keeps the logical value "0" as shown in FIG. 9 (d), and the wheel speed selection circuit 16 selects the select low wheel speed Vw _L as shown by the broken line in FIG. 9 (a). ing. For this reason, the brake fluid pressure generated in the master cylinder 5 is directly supplied to each of the wheel cylinders 1FL to 1RR to be in a braking state. However, since the turning outer wheel side has a low friction coefficient road surface, the braking force is reduced. The turning inner wheel side has a high coefficient of friction on the road surface, but the rear wheel side, which is the driving wheel, generates wheel spin, so the braking force is similarly small and the braking force is large only on the front wheel side, which is the non-driving wheel. Power will be generated. Therefore, in the right turning state (or the left turning state), large yaw occurs in the clockwise direction (or the counterclockwise direction) as viewed from the plane.

As described above, when the vehicle is in the yawing state, the yaw angular acceleration becomes a large value. Therefore, the average lateral acceleration Y _GM calculated by the above equation (4) becomes a small value, and its absolute value | Y _GM |
There at t ₂₂ to be less than the set value Y _GS, the comparison output of the comparator 19e becomes the logic "1". Therefore, select switch SS
In such a thick line shown in FIG. 9 (a), the highest wheel speed (select high wheel speed) Vw _H or drive wheels of the inner ring that occurs wheelspin 1RR (or 1RL) is selected, the pseudo vehicle speed calculating pseudo vehicle speed V _i of the broken line shown is formed on the basis of the circuit 17 to select high wheel speed Vw _H.

Therefore, the pseudo vehicle speed calculated by the pseudo vehicle speed calculation circuit 17
Once t ₂₃ where V _i has passed the set time T ₃ of the off-delay timer 21f, as shown by the broken line shown in Fig. 9 (a), slowly at a speed corresponding to the integral value of the acceleration corresponding to + 0.4 g To increase.

On the other hand, since the brake fluid pressure of the wheel cylinders 2FL to 2RR of the wheels 1FL to 1RR continues to increase as shown in FIG. 9 (c), first, the low friction coefficient of the turning outer wheel side in contact with the road surface The wheel speed detection value Vw _FL of the front wheel 1FL becomes the lowest as shown by the thick broken line in FIG. 9A, and the wheel speed detection value Vw _FL
Transition to a sixth view of a slip ratio S _FL set value S ₀ or more words Figure 9 (a) in step a step at a time t ₂₄ to be less than 0.85V _i dashed illustrated calculated in the processing of steps based on Then, since the wheel acceleration / deceleration w _{FL at} that time is on the deceleration side as shown by the thick broken line in FIG. 9 (b), by shifting from step to step, the pressure reduction mode is set and anti-skid control is performed. Will start. In this pressure reduction mode, as described above, the inflow valve 8 of the actuator 6FL is controlled to be closed, the outflow valve 9 is controlled to be open, and the hydraulic pump 10 is driven to rotate.
The brake fluid pressure of the wheel cylinder 2FL is gradually reduced as shown by the thick broken line in FIG. 9 (c), thereby preventing the wheel 1FL on the turning outer wheel that is in contact with the low friction coefficient road surface from locking. be able to.

Thus, by the anti-skid control is started with respect to the wheel cylinders 2FL at t _24, the control in the signal MR is Figure 9 theory as shown in (d) "1", and the response to this The changeover switch 21p of the pseudo vehicle speed calculation circuit 16 is +1
By being switched to the negative voltage side corresponding to the acceleration of 0 g, pseudo vehicle speed V _i output from the addition circuit 21y rises sharply, the rear wheel has occurred a wheel spin as the select high wheel side Vw _H 1RR (Or 1RL) wheel speed detection value Vw
_RR (or Vw _RL ), at time t ₂₅ , the wheel speed detection value Vw _RR (or Vw _RL ) at that time is maintained, and thereafter, at time t ₂₇ when the set time T ₃ of the off-delay timer 21f has elapsed. It decreases according to the integrated value of the correction value X _GC of the longitudinal acceleration detection value X _G of the longitudinal acceleration sensor 13.

Therefore, the slip ratio of the inner side of the front wheel 1FR S _FR also time t
Becomes the set value S ₀ or at time t ₂₄ 'to slightly lag than _24, similarly pressure reducing mode is set will be anti-skid control is started, the brake force is weakened. Further, as for the rear wheel 1RR serving as the driving wheel, the brake fluid pressure of the wheel cylinder 2RR is maintained at a high level, so that the wheel speed detection value Vw _RL is reduced and the wheel spin is eliminated.
As a result, the braking force on the front wheel side of the turning inner wheel for yawing the vehicle is reduced, so that the yaw angular acceleration can be reduced before the vehicle reaches the spin state, and the steering stability of the vehicle can be ensured.

Then, as the yaw angular acceleration decreases, the comparison circuit 19
The comparison output of e returns to the state of the logical value "0". At this time, since the anti-skid control has been started for each of the wheel cylinders 2FL to 2RR, the control is performed as shown in FIG. medium signal MR is the fact that a logic "1", the state continues to select a select high wheel speed Vw _H in the wheel speed selecting circuit 16, the optimal anti-skid control is continued.

That is, at time t _26, as the wheel acceleration w _RR of wheel 1RR after the drive wheel by a chain line shown in FIG. 9 (b),
When the processing shown in FIG. 6 is executed when the deceleration threshold value is equal to or less than the deceleration threshold α, the holding mode is set by shifting from step to step, whereby the wheel cylinder is set.
The brake fluid pressure for 2RR is maintained at a constant value as shown by the dashed line in FIG. 9 (c), and the wheel speed detection value Vw _RR continues to decrease.

Then, at time t _28, from the front when the wheel acceleration w _FL wheel speed detected value Vw _FL becomes the acceleration state to recover by vacuum mode of the left wheel 1FL is higher acceleration threshold beta, step in the process of FIG. 6 The process proceeds to step to clear the pressure-reducing timer L to zero, and then to step and through step to set the holding mode, whereby the brake fluid pressure for the wheel cylinder 2FL is maintained at a constant value on the low pressure side. . Thereafter, when the wheel acceleration / deceleration w _FL becomes smaller than the acceleration threshold value β at time t ₂₉ , the process proceeds from the step of FIG. 6 to the wheel acceleration / deceleration w _FL
Is greater than or equal to the deceleration threshold value α, the flow proceeds to step through step, and the slow pressure increase mode is set. This slow increase mode, by the inflow valve 8 is intermittently opened, the brake fluid pressure in the wheel cylinders 2FL is gradually increased, whereby the wheel speed detected value Vw _FL is decreased.

In addition, at the time point t _30, the wheel acceleration and deceleration of the front right wheel 1FR w _FL
As shown by the thin line in FIG. 9 (b), when the acceleration threshold β or more is set, the holding mode is set, whereby the pressure reduction of the brake fluid pressure to the wheel cylinder 2FR is stopped, and the pressure becomes a constant value on the low pressure side. Will be retained.

Then, at time t _31, the wheel acceleration and deceleration w _FL of the front left wheel 1FL
Is equal to or less than the deceleration threshold α, the holding mode is set, and the brake fluid pressure for the wheel cylinder 2FL is held at a constant value on the high pressure side.

Thereafter, the front right wheel 1FR sequentially at time t ₃₂ the wheel cylinder 2F
R is set to the slow increase mode, the wheel cylinder 2RR of the rear right wheel 1RR by t ₃₃ is the first time the anti-skid control is started is set to a vacuum mode, pressure reduction wheel cylinders 2FL in the front-left wheel 1FL at time t ₃₄ Mode set, front right wheel at t ₃₅
With wheel cylinders 2FR of 1FR is set to the holding mode of the high-pressure side, front wheel cylinder 2FL the left wheel 1FL is set to the holding mode of the low-pressure side, at time t ₃₆ of the front left wheel 1FL wheel cylinders 2FL is slow increase mode is set to the wheel cylinder 2RR of the rear right wheel 1RR at t ₃₇ is set to the hold mode of the low-pressure side, then the wheel cylinders 2FL~2RR is sequentially reduced pressure mode, the holding mode of the low-pressure side, slow increase mode and pressure By repeating the side hold mode, a favorable braking state is maintained while ensuring steering stability.

As described above, according to the first embodiment, the vehicle is in a turning state, the detected value of lateral acceleration is a large value (for example, 0.3 g or more), and wheel spin occurs on the driving wheel on the turning inner wheel side. In this case, the wheel speed selection circuit 16 ignores the wheel speed detection value of the driving wheel causing the wheel spin and selects the lowest wheel speed detection value, so that the anti-skid control malfunctions due to the wheel spin. When the vehicle travels on an anti-skid road in this turning state and yawing occurs, the wheel speed selection circuit 16 selects the wheel speed detection value of the driving wheel that is causing wheel spin. By doing so, it is possible to reduce the braking force of the wheels, which causes yawing when the vehicle is in the braking state, to secure steering stability.

Next, a second embodiment of the present invention will be described with reference to FIG.

In the second embodiment, two lateral acceleration sensors are disposed at symmetrical positions in the front-rear direction across a yaw center to detect yaw movement.

That is, as shown in FIG.
Is the actual lateral acceleration Y _GR1 output from the lateral acceleration conversion circuits 19a and 19b in addition to the configuration of FIG. 4 of the first embodiment.
A subtraction circuit 19g for calculating a yaw angle acceleration component, and by taking the absolute value by subtracting the Y _GR2, the subtraction circuit 1
A yaw angular velocity conversion circuit 19h that integrates the yaw angular acceleration component calculated in 9g and converts it into a yaw angular velocity, a yaw angular velocity output from the yaw angular velocity conversion circuit 19h, and a preset yaw angular velocity set value _S (for example, 4 ゜/ sec), and outputs a comparison output of a logical value “1” when ≧ _S and a logical value “0” when < _S.
Except that the OR circuit 19f is a three-input type and the comparison output of the comparator 19i is supplied to the OR circuit 19f.
Corresponding parts in the drawings are denoted by the same reference numerals, and a detailed description thereof will be omitted.

According to the second embodiment, the lateral acceleration sensors 14A and 14B
Are located at symmetrical positions in the front-rear direction with the yaw center interposed therebetween, the actual lateral acceleration detection values Y _GR1 and Y _GR2 output from the lateral acceleration conversion circuits 19a and 19b are given by the following equations (5) and (6). It is expressed by an equation.

Y _GR1 = + 1 (5) Y _GR2 = −1 (6) where 1 is the yaw center and the lateral acceleration sensors 14A and 14B.
Is the distance between

Therefore, the average lateral acceleration value Y _GM output from the average value circuit 19c is Becomes, becomes only the transverse acceleration component in Yosenta, therefore, the comparator 19e logic value on the inner ring drive wheel is a lateral acceleration component is less than the set value Y _GS when no wheel spin from "1", the horizontal When wheel spin occurs on the inner wheel drive wheel whose directional acceleration component is greater than or equal to the set value _YGS , a comparison output of a logical value “0” is output. When wheel spin occurs on the inner wheel drive wheel, select is performed. By selecting the lowest wheel speed detection value with the switch SS and ignoring the wheel speed detection value of the driving wheel on the turning inner wheel side where wheel spin has occurred, malfunction of the anti-skid control is prevented as in the first embodiment described above. can do.

On the other hand, the subtraction output of the subtraction circuit 19g becomes Y _GR1 −Y _GR2 = + 1 − (− l) = 2l, and only the yaw angular acceleration component generated in the vehicle is obtained.
When the yaw angular velocity generated in the vehicle is equal to or greater than the set value _S , the comparator 19i outputs a comparison output of a logical value “1”, which is a select signal.
Since supplied to the select switch SS as S _E, select the wheel speed detected value of the turning inner wheel side driving wheels has occurred the highest wheel speed i.e. the wheel spin in this select switch SS, the pseudo vehicle speed calculating circuit based on this by calculating the pseudo vehicle speed V _i at 17, when the braking state in a state in which the yawing of the vehicle as in the first embodiment described above has occurred, good anti-skid control while ensuring driving stability It can be performed. Moreover, the yaw angular velocity generated in the vehicle can be accurately detected.

In the second embodiment, the case where the yaw angular velocity is detected based on the acceleration detection values of the two lateral acceleration sensors 14A and 14B has been described. However, the present invention is not limited to this. The yaw angular velocity detection value may be directly input to the comparator 19i.

In the first and second embodiments, the select low wheel speed Vw _L is selected in the turning traveling state in which the lateral acceleration equal to or higher than the set value is generated as the wheel speed selection value, and in the other traveling states. The case where the select high wheel speed Vw _H is selected has been described. However, the present invention is not limited to this. For example, during the anti-skid control, the select high wheel speed Vw _H is selected.
Vw _H is selected and the highest wheel speed Vw _H
In a vehicle that selects the second highest select second wheel speed, the third highest select third wheel speed may be selected as well as the select low wheel speed when a lateral acceleration equal to or greater than the set value occurs. Further, in the case of a two-wheel drive vehicle having rear wheels or front wheels as in the above-described embodiment, a higher wheel speed of non-drive wheels that substantially follow the vehicle speed may be selected. Therefore, it is preferable to select the select low wheel speed from the viewpoint of safety.

Next, a third embodiment of the present invention will be described with reference to FIG.

This third embodiment has two lateral acceleration sensors 14A and 14B.
The yaw motion occurring in the vehicle is detected based on the detected value of the lateral acceleration of the vehicle, the left-right turning inner wheel difference correction amount at the time of turning is calculated based on the detected value, and the slip determination is performed based on the left / right turning inner wheel difference correction amount. By changing the slip ratio threshold value, good anti-skid control is performed while ensuring the steering stability of the vehicle.

That is, as shown in FIG. 11, in the configuration of FIG. 2 of the first embodiment described above, the actuators 6RL and 6RR are omitted, a common actuator 6R is provided in place of them, and the wheel speed is reduced. The sensors 3RL and 3RR are omitted, and instead of these, a common wheel speed sensor 3R receives the rotational driving force from the engine EG via the transmission T, and transmits the rotational driving force to the differential gear DF on the rear wheel side. A wheel speed calculation circuit 15 provided on the shaft PS and further having one of the wheel speed calculation circuits 15RL and 15RR omitted and the other wheel wheel speed detection circuit 3R receiving the wheel speed detection value of the wheel speed sensor 3R.
R, the wheel speed selection circuit 16 is further omitted, and the highest wheel speed detection value among the wheel speed detection values Vw _{FL to} Vw _R output from the wheel speed calculation circuits 15FL to 15R is selected instead. select-high switch 31 for selecting a high wheel speed Vw _H is provided, the select-high switch 31
With select-high wheel speed Vw _H is supplied to the pseudo vehicle speed computing circuit 17, the lateral acceleration detected value of the pseudo vehicle speed V _i and the lateral acceleration sensor 14A and 14B, which are calculated by the pseudo vehicle speed calculating circuit 17 Y _G1
And Y _G2 is supplied to the wheel speed difference correction value calculation circuit 32, the wheel speed difference correction value wherein the wheel speed difference correction value ΔV outputted from the arithmetic circuit 32 pseudo vehicle speed V _i and each actuator 6FL~6R
Are supplied to the threshold setting circuits 33FL to 33R corresponding to the slip thresholds Vs _{FL to} Vs set by the threshold setting circuits 33FL to 33R.
except that s _R is supplied to the braking pressure control circuit 18.
It has the same configuration as in the figure, and the same reference numerals are given to the parts corresponding to FIG. 2, and the detailed description thereof will be omitted.

The wheel speed difference correction value calculation circuit 32, as shown in FIG.
A signed average value circuit 32e to which the lateral acceleration detection values Y _G1 and Y _G2 of the lateral acceleration sensors 14A and 14B are input to one input side via noise filters 32a and 32b and lateral acceleration conversion circuits 32c and 32d, respectively. with lateral acceleration average value Y _GM outputted from the mean value circuit 32e is supplied to one input side, the pseudo vehicle speed V _i from the pseudo vehicle speed computing circuit 17 is supplied to the other input side, the wheels on the basis of these a correction value computing circuit 32f for calculating a velocity difference correction value [Delta] V _H, is composed of a limiting circuit 32g for limiting the correction value calculating circuit wheel speed difference correction value [Delta] V _H calculated in 32f.

The correction value calculation circuit 32f calculates the lateral acceleration average value Y _GM and the pseudo vehicle speed V _i and the wheel speed difference correction value [Delta] V _H corresponding to the pivot trajectory by performing the calculation of the following equation (7) based on . That is, when the relationship between the front inner wheel speed and the wheel speed difference between the outer wheel and the inner wheel on the front wheel side is measured using the lateral acceleration detection value Y _G in the steady circular turning state as a parameter, the result is as shown in FIG. The wheel speed difference ΔV _H corresponding to the turning radius R (turning locus) can be calculated from the speed and the average lateral acceleration value Y _GM, and the relationship in FIG. 13 can be expressed by an approximate expression (7). .

Also, limiting circuit 32g includes an absolute value circuit 32h for taking the absolute value of the vehicle speed correction value [Delta] V _H, a wheel speed correction limit value [Delta] V _L comprising a polygonal line function shown in FIG. 13 according to the pseudo vehicle speed V _i occurs A function generator 32i, a wheel speed correction limit value ΔV _{L of the} function generator 18i, and an inverted wheel speed correction limit value −ΔV _L obtained by inverting the wheel speed correction limit value −ΔV _L by the inverting circuit 32j are input, and the selection signal S _E1 becomes high. Select switch 32k for selecting ΔV _L when the level is at the level and selecting −ΔV _L when the selection signal S _E1 is at the low level, and at the high level when the wheel speed correction value ΔV _H is positive or zero, Selection signal S that goes low when the speed correction value ΔV _H is negative
A comparator 32l that outputs _E1 to the selection switch 32k, and a comparator 32m that compares the wheel speed difference correction value | ΔV _H | output from the absolute value circuit 32h with the wheel speed correction speed value ΔV _{L of the} function generator 32i.
When, the comparison output of the comparator 32m is input as a selection signal S _E2, and a selection switch 32n for selecting the wheel speed correction value [Delta] V _H and the wheel speed limit value [Delta] V _L. Where the comparator 32m
Outputs a selection signal S _E2 that becomes high level when ΔV _H ≦ ΔV _L and becomes low level when ΔV _H > ΔV _L , and the analog switch 32n performs wheel speed correction when the selection signal S _E2 is high level. The value ΔH _H is selected, and the wheel speed limit value ΔV _L is selected when the selection signal S _E2 is at a low level, and the selected output is used as the wheel speed correction value Δ
It is output as V to the threshold setting circuits 33FL, 33FR and 33R.

Threshold setting circuit 33FL are pseudo vehicle speed V _i and the wheel speed difference correction value Δ
By calculating the following equation (8) based on V,
The slip threshold Vs _FL (km / h) for the front left wheel 1FL is calculated.

_{Vs FL = V i × 0.95-4 +} MIN (0, ΔV) ...... (8) like the threshold setting circuit 33FR and 33R also threshold setting circuit 33FL, on the basis of the pseudo vehicle speed V _i and the wheel speed correction value [Delta] V below ( By performing the calculations of the expressions 9) and (10), the front right wheel
Slip threshold values Vs _FR , Vs _R (km for 1FR and rear wheels 1RL, 1RR)
/ h).

Vs _FR = V _i × 0.95-4-MAX (0, ΔV) (9) Vs _R = V _i × 0.95-4- | ΔV | (10) The braking pressure control circuit 20 determines the wheel speed Vw _FL ~ Vw _R and pseudo vehicle speed V
Wheel cylinder 2 provided on each wheel 1FL-1RR based on _i
Actuators 6FL to 6R that control the supply pressure to FL to 2RR
As shown in FIG. 2, for example, the input interface circuit 25a and the output interface circuit 25
d, each wheel speed Vw _FL , Vw _FR , Vw _R and slip threshold Vs _FL , Vs _FR , Vs _R which are constituted by a microcomputer 25 having at least an arithmetic processing unit 25 b and a storage unit 25 c and are inputted to the input interface circuit 25 a. The braking pressure control process shown in FIG. 14 is executed individually for each wheel by the arithmetic processing unit 25b based on the calculation.

Here, in the braking pressure control routine in FIG. 14, steps in the first embodiment described above, the process of omitting the slip threshold Vs _FL ~Vs _R outputted from the threshold setting circuit 33FL~33R instead of these Is provided, and the wheel speed detection value Vw _j read in the step is the slip threshold V read in the step.
s _j is changed to a step of determining whether or not
The step when it is Vw _j <Vs _j, except that the process proceeds to the step when it is Vw _j ≦ Vs _j 6
The same processing as in the figure is executed.

 Next, the operation of the third embodiment will be described.

Assuming that the vehicle is in a parking state and the key switch is turned on (for example, the ignition key is in the accessory position) from this state, power is supplied to the controller CR. In this case, the pseudo vehicle speed V _i output from the pseudo vehicle speed computing circuit 17 is in the state of zero.

Then, the pseudo vehicle speed V _i of zero outputted from the pseudo vehicle speed computing circuit 17 is inputted to the wheel speed difference correction value calculation circuit 32, the lateral acceleration sensor 14A and 14B to the wheel speed difference correction value calculation circuit 32
Since the lateral acceleration detection value Y _G1 and Y _G2 zero is supplied from the correction value calculating circuit 32f wheel speed difference correction value [Delta] V _H also becomes zero output from, this wheel speed difference correction value [Delta] V _H supplied The wheel speed difference correction value ΔV of the limiting circuit 32g also becomes zero.

Therefore, the zero wheel speed difference correction value ΔV and the wheel speed Vw _FL .
Slip threshold Vs _FL ~Vs _R together -4km / h Nearby Vw _R is supplied from the threshold setting circuit 33FL~33R input, they are input to the brake pressure control circuit 20.

Thus, the brake pressure control circuit 20, since the processing of Figure 14 is executed as a timer interrupt processing for each predetermined time (e.g. 50 msec), the determination in step Vw _i (=
0)> Vs _i (= −4), and a rapid pressure increase mode is achieved by going through the steps 1 to 3 and then proceeding to the step. At this time, assuming that the brake pedal 4 is depressed when the vehicle is stopped, the pressure of the wheel cylinder 2j becomes a pressure corresponding to the brake pressure output from the master cylinder 5, and a braking state is established.

Once t ₀ shown from the state in FIG. 15, when the ignition switch to the ON state, as in the first embodiment described above, a sample hold circuit 21t of the pseudo vehicle speed calculating circuit 17
To hold the select high wheel speed Vw _S (= 0) selected by the select high switch 31 as the wheel speed sampled value V _S , reset the integration circuit 21o, and reduce its integrated output V _e to zero. pseudo vehicle speed V _i also becomes zero output from the circuit 21y, select-high wheel speed Vw _S pseudo vehicle speed V
_It is within the dead band width of _i . For this reason, the analog switch 21i
To select a zero voltage, which is input to the integration circuit 21o as an integration input voltage E, so that the integration output V _{e of the} integration circuit 21o
Is also kept at zero. As a result, the pseudo vehicle speed V _i output from the addition circuit 21y is maintained at the same zero wheel speed sampling value V _S.

After that, if you start the vehicle and go straight ahead,
In the same manner as in the first embodiment, the select high wheel speed selected by the select high switch 31 from the wheel speed calculation circuit 17 is used.
Vw _H Figure 15 that follows: (a) the pseudo vehicle speed V _i of the broken line shown in are calculated.

On the other hand, the wheel speed difference calculating circuit 32, in relation vehicle between time t ₀ ~ time t ₁₄ is traveling straight, the lateral acceleration sensor
The lateral acceleration detection values Y _G1 and Y _G2 of 14A and 14B are substantially zero,
Since the lateral acceleration average value Y _GM also zero output from the averaging circuit 32e, the equation (7) becomes zero wheel speed correction value [Delta] V _H is an operation result. Therefore, the threshold value setting circuits 33FL to 33R
In will be calculated slip threshold Vs _FL, s _FR and Vs _R performs operation on the pseudo vehicle speed _{V i (8) ~ (10} ) equation, these slip threshold Vs _FL, s _FR and Vs _R pseudo vehicle speed V _i
Only as shown in FIG. 15 (a).

However, when the vehicle is turning right at t ₁₅ after time t _14, the lateral acceleration detection value Y _G1 and Y _G2 is Figure 15 is output from the lateral acceleration sensor 14A and 14B in accordance with this (b)
Since increasing both in the positive direction as shown in, by performing the calculation of the correction value calculation circuit 32f in (7) of the wheel speed difference calculating circuit 32 and to the pseudo vehicle speed V _i and the lateral acceleration average value Y _GM The corresponding wheel speed correction value + ΔV _H is output, and this is
g, the absolute value of the wheel speed correction value ΔV _{H and} the pseudo-vehicle speed V output from the function generator 32i.
is compared with the limit value ΔV _L determined by _i , and | ΔV _H | ≦ Δ
In the case of _VL , ΔV _H is output as it is to the threshold setting circuits 33FL, 33F and 33R as the wheel speed difference correction value ΔV, and | ΔV _H |>
At ΔV _L , the limit value ΔV _L is output to the threshold setting circuits 33FL, 33FR, and 33R as the wheel speed difference correction value ΔV.

For this reason, the threshold setting circuit 33 corresponding to the turning outer wheel of the front wheel
In FL, since the wheel speed difference correction value ΔV is a positive value,
In the third term on the right side of the above equation (8), zero is selected when zero or the smaller ΔV is selected.
Vs _FL has the same value as in the straight traveling state. Further, in the threshold setting circuit 33FR corresponding to the turning inner wheel of the front wheel, in the third term on the right side of the above equation (9), ΔV is selected and subtracted when zero or ΔV is selected, so that the slip threshold is reduced. Vs _FR
Is smaller by ΔV than in the straight running state. Further, in the threshold setting circuit 33R corresponding to the rear wheel, the above (10)
Since the absolute value | ΔV | of the wheel speed difference correction value ΔV is subtracted by the third term on the right side of the equation, the slip threshold Vs _R becomes a value smaller by ΔV than in the straight running state.

When the vehicle makes a left turn, the lateral acceleration sensor 14
Lateral detection value Y _G1 that increases in the negative direction from both A and 14B
And Y _G2 are output, the wheel speed difference correction value ΔV output from the wheel speed difference calculation circuit 32 becomes a negative value, and −ΔV is selected by the threshold setting circuit 33FL corresponding to the turning inner wheel of the front wheel, The slip threshold Vs _FL becomes a value smaller by ΔV than in the straight running state, zero is selected by the threshold setting circuit 33FR corresponding to the front turning outer wheel, and the slip threshold Vs _FR becomes the same value as in the straight running state. Threshold setting circuit 33R corresponding to the wheel
, The slip threshold value Vs _R becomes smaller by ΔV than in the straight running state.

As described above, when turning without braking, the slip thresholds Vs _FL (or Vs _FR ) and Vs of the front turning inner wheel and the rear wheel are turned.
_{Since R} becomes a value smaller by the wheel speed difference correction value ΔV than when traveling straight, the turning inner wheel side wheel speed Vw _FL (or Vw _FR ) and the rear wheel speed are determined in the steps in the processing of FIG.
Vw _R can be prevented from falling below the slip thresholds Vs _FL (or Vs _FR ) and Vs. Unnecessarily start anti-skid control, close the inflow valves 8 of the actuators 6FL and 6FR, and shift to the pressure reduction mode. Therefore, malfunction of the anti-skid control can be reliably prevented.

Further, when the vehicle is in a braking state during a right (or left) turn, the front right wheel speed Vw _FR (or front left wheel speed Vw
_FL ) decreases as compared with the braking in the straight running state, but as described above, the front right wheel speed Vw _FR (or the front left wheel speed)
Since Vw _FL) slip threshold Vs _FR for (or Vs _FL) also decreases the wheel speed difference correction value ΔV min, rows slightly lower wheel speed transition from the holding mode of the high-pressure side to the pressure reduction mode is compared to the straight running As a result, it is possible to prevent the braking distance from being lengthened due to insufficient braking force.

However, for example, during a right turn, the left wheels run on a so-called split road surface having a low friction coefficient road surface and the right wheels have a high friction coefficient road surface.
When the vehicle is depressed to bring about a braking state, a large yawing occurs in the vehicle due to a difference in braking force between the wheels, as in the first embodiment described above.

Becomes this state, since the lateral acceleration average value Y _GM outputted from the mean value circuit 32g becomes possible to reduce the yaw angular acceleration component, the correction value calculation circuit wherein at 32h (7) calculated by the wheel speed correction value in accordance with formula + ΔV _H becomes a small value, and accordingly, the wheel speed difference correction value + Δ outputted from the limiting circuit 32i.
V also has a small value. Thus, the slip threshold Vs _FL calculated according to the previous wherein the threshold setting circuit 33FL corresponding to the left wheel 1FL (8) which is zero in the third term of the right side of equation (8) is selected, resulting yawing described above However, the threshold value setting circuits 33FR and 33R for the front right wheel 1FR and the rear wheels 1RL and 1RR have the slip threshold Vs _FR calculated according to the above equations (9) and (10). And Vs
_R is a large value as compared to the above-described right turning state in which yawing does not occur. Therefore, in the process of FIG.
Front right wheel 1FR and rear wheels 1RL, these wheel speed detection value Vw _FR and Vw _R is smaller than the slip threshold Vs _FR and Vs _R for 1RR, so that the program proceeds from step to step. As a result, similarly to the above-described first embodiment, the front right wheel 1F
The decompression mode is set for the R and the wheel cylinders 2FR and 2RL, 2RR of the rear wheels 1RL, 1RR, which suppresses yawing that occurs in the vehicle and ensures good anti-skid control while ensuring steering stability It can be performed.

In the third embodiment, the pseudo vehicle speed calculation circuit is used.
By 17, by adding or subtracting the correction value ΔV to the pseudo vehicle speed V _i, which is calculated, has been to seek a slip threshold, not limited to this, the pseudo vehicle speed V _i
The calculation one slip threshold value setting circuit for adding the correction value ΔV may be used conventional ones (which performs calculation of 0.85 × V _i).

Next, a fourth embodiment of the present invention will be described with reference to FIGS.

In the fourth embodiment, a yaw angular velocity sensor is applied to detect yawing of a vehicle, instead of detecting yaw with the two lateral acceleration sensors 14A and 14B in the third embodiment. The threshold value is changed.

That is, as shown in FIG. 16, the lateral acceleration detection value Y _G output from one of the lateral acceleration sensor 14 is supplied to the wheel speed difference correction value calculation circuit 32, and the output from the yaw angular velocity sensor 40 provided in the vehicle The detected yaw angular velocity value is an absolute value circuit.
The signal is supplied to a weighting circuit 42 via the
Is multiplied by a predetermined weighting coefficient a, and the weighted yaw angular velocity detection value a is supplied to threshold setting circuits 33FL to 33R.

Then, the wheel speed difference correction value calculation circuit 32, as shown in FIG. 17, the correction value calculated lateral acceleration detected value Y _G from the lateral acceleration sensor 14 via the filter 32a and the lateral acceleration conversion circuit 32c for noise removal It is configured to be supplied to the circuit 32f.

Further, the threshold value setting circuits 33FL to 33R perform the calculations of the following equations (11) to (13) based on the input wheel speed difference correction value ΔV and the weighted yaw angular velocity a to perform the slip threshold Vs _FL to It is configured to calculate Vs _R.

_{Vs FL = V i × 0.95-4 +} MIN (0, ΔV) + a ...... (11) Vs FR = V i × 0.95-4-MAX (0, ΔV) + a ...... (12) Vs R = V i × 0.95- 4- | ΔV | + a (13) According to the fourth embodiment, the yaw angular velocity detection value output from the yaw angular velocity sensor 40 is zero when yawing does not occur when the vehicle is turning, so As in the third embodiment, it is possible to prevent a malfunction of the anti-skid control by estimating a wheel rotation speed difference according to the vehicle trajectory at the time of turning, and to detect a yaw angular velocity sensor 40 when yawing occurs in the vehicle. The yaw angular velocity detection value corresponding to the yaw angular velocity is output from the controller, and the yaw angular velocity detection value is converted into an absolute value by an absolute value circuit 41, and is then multiplied by a weighting coefficient a by a weighting circuit 42 and supplied to threshold setting circuits 33FL to 33R. Therefore, the slip threshold Vs set by these threshold setting circuits 33FL to 33R
_{FL to} Vs _R become larger by the weighted yaw angular velocity a, and the brake pressure control process of FIG. 14 shifts from step to step to set the pressure reduction mode in the same manner as in the third embodiment described above. As a result, good anti-skid control can be performed while suppressing yawing generated in the vehicle. Moreover, the yaw angular velocity sensor 40 can accurately detect the yawing of the vehicle, so that more accurate control can be performed.

In the fourth embodiment, the case where yaw occurring in the vehicle is detected by the yaw angular velocity sensor 40 has been described. However, the present invention is not limited to this.
Similarly to the embodiment, the yaw angular acceleration component is detected by using two lateral acceleration sensors 14A and 14B to take the absolute value of the difference between the lateral acceleration detection values Y _G1 and Y _G2. The yaw angular velocity component may be calculated by differentiating.

In the third and fourth embodiments, the case where the wheel speed of each wheel is detected has been described. However, the present invention is not limited to this, and a common wheel speed sensor may be provided for the left and right wheels on the driving wheel side. Good.

Further, in the first to fourth embodiments, the case where the pseudo vehicle speed calculation circuit 17 is constituted by an electronic circuit has been described. However, the present invention is not limited to this, and the calculation processing is performed using a microcomputer. You may.

Further, in the first to fourth embodiments, the case where the lateral acceleration sensor 14 is applied as the lateral acceleration detecting means has been described. However, the present invention is not limited to this, and the vehicle speed and the steering angle may be detected. The lateral acceleration may be estimated based on these.

Further, in the above-described embodiment, the description has been given of the rear-wheel drive vehicle.

Further, in the above-described embodiment, the case where a microcomputer is applied as the braking pressure control circuit 18 has been described. However, the present invention is not limited to this, and electronic circuits such as a comparison circuit, an arithmetic circuit, and a logic circuit are combined and configured. You can also.

Further, in each of the embodiments described above, the case where the present invention is applied to a drum type brake is shown, but this can be similarly applied to a disk type brake.

Further, in each of the above embodiments, the case where the wheel cylinder is controlled by the hydraulic pressure has been described. However, the present invention is not limited to this, and it goes without saying that other defaults such as liquid or air can be applied.

〔The invention's effect〕

As described above, according to the anti-skid control device according to claim (1), during the anti-skid control for controlling the fluid pressure of the braking cylinder, the predetermined value of the angular wheel speed detection value of the wheel speed detection means is determined. Choose a higher wheel speed,
During the non-anti-skid control, when the lateral acceleration of the vehicle detected by the lateral acceleration detecting means is equal to or more than a predetermined set value,
It is determined that the wheel spin of the drive inner wheel is caused by the difference in the rotation speeds of the inner and outer wheels, and the wheel speed selection means selects a wheel speed smaller than the wheel speed selection value in the anti-skid control state. Since the pseudo vehicle speed is calculated by the pseudo vehicle speed calculation means based on the wheel speed, when a wheel spin occurs in the driving inner wheel during turning of the vehicle, other wheel speeds except the wheel speed of the wheel that generated the wheel spin are calculated. From the selection, the pseudo vehicle speed can be prevented from being affected by the wheel spin, and the malfunction of the anti-skid control can be reliably prevented.
When a large yawing occurs during braking of the vehicle, setting the depressurization mode has an effect of suppressing the yawing and performing good anti-skid control while ensuring steering stability.

According to the anti-skid control device according to claim (2), the turning state is detected using two lateral acceleration sensors installed in the front-rear direction with the yaw center interposed therebetween. Is obtained, and there is an advantage that a complicated arithmetic circuit is not required.

Further, according to the anti-skid control device according to claim (3), since the yawing state is detected using the yaw angular velocity sensor, the accurate yaw angular velocity can be detected, and more accurate steering stability is ensured. There is an advantage that anti-skid control can be performed.

Further, according to the anti-skid control device according to claim (4), the turning state detecting means outputs a turning state signal including the yaw movement of the vehicle, and a rotational speed difference based on the turning state signal and the pseudo vehicle speed. The correction value calculating means calculates an inner / outer wheel rotational speed difference correction value according to the vehicle turning locus, and corrects a slip threshold for making a slip determination of the braking pressure control means based on the rotational speed difference correction value. Therefore, even when the pseudo vehicle speed is obtained by selecting the select high wheel speed, the wheel speed of the rear inner wheel due to the inner wheel difference in the turning state of the vehicle at low speed running or the front inner wheel due to the flow of the rear wheel side at high speed running It is possible to reliably prevent the decrease from being determined as a slip state, and when a large yaw occurs in the vehicle during braking, set the pressure reduction mode to suppress the yaw and operate the vehicle. Effect capable of performing good anti-skid control while ensuring stability.

Still further, according to the anti-skid control device according to claim (5), the yaw state of the vehicle is detected by the yaw angular velocity sensor, and the slip threshold is changed based on the detected yaw angular velocity value. Similar effects can be obtained.

[Brief description of the drawings]

1 (a) to 1 (c) are basic configuration diagrams showing a schematic configuration of the present invention, FIG. 2 is a block diagram showing a first embodiment of the present invention, and FIG. 3 is a configuration diagram showing an example of an actuator. ,
FIG. 4 is a block diagram showing an example of a pseudo vehicle speed calculation circuit, and FIGS. 5 (a) and (b) show the relationship between the longitudinal acceleration and the output voltage of the longitudinal acceleration sensor and the lateral acceleration and the output voltage of the lateral acceleration sensor, respectively. , FIG. 6 is a flowchart showing an example of the processing procedure of the braking pressure control circuit, FIG. 7 is a diagram showing a control map of the braking pressure control circuit, and FIGS. Waveform diagrams in an acceleration state and a deceleration state for explaining the operation of one embodiment, FIG. 10 is a block diagram showing a second embodiment of the present invention, FIG. 11 is a block diagram showing a third embodiment of the present invention, FIG. 12 is a block diagram showing a wheel speed difference correction value calculating circuit of the third embodiment, and FIG. 13 is a characteristic diagram showing a relationship between front wheel inner wheel rotation speeds and wheel speed differences between inner and outer wheels using lateral acceleration as a parameter. FIG. 14 shows the processing procedure of the braking pressure control circuit of the third embodiment. Flow chart showing an example, fifteenth
FIG. 16 is a waveform diagram for explaining the operation of the third embodiment, FIG. 16 is a block diagram showing a fourth embodiment of the present invention, and FIG.
It is a block diagram showing a wheel speed difference correction value calculation circuit of an example. In the figure, 1FL and 1FR are front wheels, 1RL and 1RR are rear wheels, 2FL to 2RR are wheel cylinders (braking cylinders), 3FL to 3RR are wheel speed sensors, 4 is a brake pedal, 5 is a master cylinder, and 6F.
L to 6RR are actuators, 8 is an inflow valve, 9 is an outflow valve, 10
Is a hydraulic pump, 14A and 14B are lateral acceleration sensors, CR is a controller, 15FL to 15RR are wheel speed calculation circuits, 16 is a wheel speed selection circuit (wheel speed selection means), 17 is a pseudo vehicle speed calculation circuit (pseudo vehicle speed calculation means) , 18 is a brake pressure control circuit, SS is a select switch, 19 is a select signal forming circuit, 19c is an average value circuit, 19e is a comparator, 19g is a subtraction circuit, 19i is a comparator, 20 is a correction circuit, and 21 is pseudo vehicle speed. A generation circuit, 25 is a microcomputer, 31 is a select high switch, 32 is a wheel speed difference correction value calculation circuit, 35FL to 33RR are threshold setting circuits, and 40 is a yaw angular velocity sensor.

Claims (5)

(57) [Claims] 1. A wheel speed detecting means for detecting the speed of a plurality of wheels, a wheel speed selecting means for selecting a wheel speed detected value of each wheel speed detecting means, and a wheel speed selecting means based on the selected wheel speed. A pseudo vehicle speed calculating means for calculating a pseudo vehicle speed, and a slip determination based on the wheel speed detection value of the wheel speed detecting means and a slip threshold based on the pseudo vehicle speed. The braking pressure control means for independently controlling the fluid pressure of the braking cylinder is provided, the yaw momentum detecting means for detecting the yaw momentum of the vehicle, the wheel speed selecting means, During the anti-skid control in which the fluid pressure of the brake cylinder is controlled by the braking pressure control means, a predetermined highest wheel speed among the wheel speed detection values of the vehicle speed detecting means is selected, and the anti-skid control is not performed. When the lateral acceleration detection value of the lateral acceleration detection means is equal to or more than a set value, a predetermined wheel speed lower than the predetermined wheel speed during the anti-skid control is selected, and the yaw momentum detection means detects the yaw momentum. An anti-skid control device, wherein when the value is equal to or more than a set value, the highest wheel speed is selected from the wheel speed detection values of the wheel speed detection means. 2. An anti-skid control device according to claim 1, wherein said yaw momentum detecting means comprises two lateral acceleration sensors arranged at a predetermined interval in the longitudinal direction of the vehicle. 3. The anti-skid control device according to claim 1, wherein said yaw momentum detecting means is a yaw rate sensor. 4. A wheel speed detecting means for detecting a speed of a plurality of wheels, a wheel speed selecting means for selecting a wheel speed detected value of each of the wheel speed detecting means, and a wheel speed selecting means based on the selected wheel speed. A pseudo vehicle speed calculating means for calculating a pseudo vehicle speed, and a slip determination based on the wheel speed detection value of the wheel speed detecting means and a slip threshold based on the pseudo vehicle speed. An anti-skid control device provided with braking pressure control means for controlling the fluid pressure of the braking cylinder, wherein a turning mode detecting means for outputting a turning mode signal that changes in accordance with the yaw motion of the vehicle when turning, A rotational speed difference correction value calculating means for calculating an inner and outer wheel rotational speed difference correction value corresponding to a vehicle turning locus based on the turning mode signal of the turning mode detecting means and the pseudo vehicle speed; and Times Anti-skid control apparatus characterized by comprising a threshold value setting means for setting a slip threshold of the brake pressure control device on the basis of the speed difference compensation value. 5. A wheel speed detecting means for detecting a speed of a plurality of wheels, a wheel speed selecting means for selecting a wheel speed detected value of each wheel speed detecting means, and a wheel speed selecting means based on the selected wheel speed. A pseudo vehicle speed calculating means for calculating a pseudo vehicle speed, and a slip determination based on the wheel speed detection value of the wheel speed detecting means and a slip threshold based on the pseudo vehicle speed. An anti-skid control device comprising braking pressure control means for controlling the fluid pressure of the braking cylinder, a yaw angular velocity detecting means for detecting a yaw angular velocity of the vehicle, a lateral acceleration detecting means for detecting a lateral acceleration of the vehicle, Rotation speed difference correction value calculation means for calculating an inner and outer wheel rotation speed difference correction value corresponding to a vehicle turning locus based on the lateral acceleration detection value of the lateral acceleration detection means and the pseudo vehicle speed;
Threshold value setting means for setting a slip threshold value of the braking pressure control means based on the rotation speed difference correction value of the rotation speed difference correction value calculation means and the yaw angular velocity detection value of the yaw angular velocity detection means. Characteristic anti-skid control device.