JPH01212654A - Device for controlling skid - Google Patents

Abstract

PURPOSE:To control the output of an engine to be as minimum as possible by weighing the importance of skid conditions, assuming control in fluid pressure at the time of slight skid, and also assuming control in both fluid pressure and engine output at the time of serious skid. CONSTITUTION:In a device provided with both a booster 1 producing fluid pressure in a master cylinder 3 and a change-over valve 23 which applies and releases negative pressure to a negative pressure feeding system related with an inlet system 20, and concurrently equipped with valves 7, 7', 15 and 15' opening/closing a fluid pressure system for respective wheel brakes, the degree of the skid conditions of both driving wheels is judged by a controller 27 based on the circumferential speed and acceleration of the driving wheels and vehicle speeds. Then, negative pressure is applied to the booster 1 with the change-over valve 23 actuated regardless of the degree of the skid conditions of the driving wheels, and control of each valve is assumed only in the fluid pressure of the driving wheels at the time of slight skid. But control is assumed in both fluid pressure and an inlet air flow rate by auxiliary accelerators 24-26 at the time of serious skid.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a skid control device that prevents wheel skidding during both braking and acceleration, and particularly relates to a skid control device that prevents wheel skidding during both braking and acceleration. This invention relates to a skid control device that minimizes the amount of damage.

``Prior Art'' Traditionally, traction control devices, which have been used to prevent wheel skidding when a vehicle suddenly starts, detect wheel skid by some means and reduce the accelerator opening.
Alternatively, the mainstream method has been to reduce the engine output by delaying the ignition timing, or in other words, to control the engine output.

To explain the principle of this control, if the angular acceleration is X, the rotation of the wheel is determined by the torque T3 received from the road surface, the braking torque TB, the driving torque T^, and the inertia of the axle system. It is determined as follows.

I A ” T A -T RT a ・・
...(1) (However, TR is negative during braking) Here, assume that the wheels are in an acceleration state and consider wheel slip. A relative speed occurs between the wheel peripheral speed and the vehicle speed, and from that relative speed, λ=! −Rω/v
(2) A slip ratio λ is determined (where Rω is the wheel circumferential speed and V is the vehicle speed), and the road surface friction coefficient μ is determined from this slip ratio λ and the road surface condition. In addition, the value of μ above changes depending on the road surface condition, but its maximum value is -
It is known that this occurs in the range of 0.1 to -0.3.

Therefore, when the vehicle speed V- is known, the -0
, λ of about 0.2 as an approximately intermediate value between 1 and -0,3
If the wheel circumferential speed Rω is controlled so as to obtain the following, skids can be prevented more accurately.

From the above equation (1), if λ is larger than -0.2, the driving torque TA is increased, and if it is smaller than 0.2, the driving torque TA is decreased or the braking torque T
By increasing B, λ can be controlled to a predetermined value, so in the conventional skid control (traffic control) method, the accelerator opening, ignition timing, etc. can be adjusted as described above. By doing so, the engine is controlled to reduce the drive torque TA.

``Problem to be solved by the invention'' However, in general automobiles, a differential gear is interposed between the engine and the axle of the drive wheels, so the left and right wheels are in contact with the road surface with different coefficients of friction μ. Problems may occur in the split μ state.

That is, when one wheel is on the road surface of L' oμ,
When this wheel attempts to spin and the skid control system detects this (for example, it can be detected by an increase in wheel circumferential acceleration Rλ), the engine is controlled to reduce the drive torque TA, and accordingly, one of the above-mentioned The driving torque of the other wheel on the H iμ side, which is connected to the other wheel via the differential gear, also decreases. Therefore, there is a problem in that acceleration is inevitably slowed down due to a lack of drive torque on the Hiμ side where a larger drive force should be obtained, resulting in a decrease in drivability.

The present invention has been proposed in view of the above circumstances, and an object of the present invention is to provide a skid control device that can prevent skids while minimizing a decrease in engine output.

"Means for Solving the Problems" In order to achieve the above object, the present invention provides wheel speed detection means that is provided at least on the drive wheels and measures the circumferential speed of each wheel, and a vehicle speed based on detection data of the wheel speed detection means. an estimating means for estimating the acceleration of the wheel from the detection data of the wheel circumferential speed; a hydraulic system for transmitting the hydraulic pressure generated from the master cylinder to the brake caliper of the driving wheel and the driven wheel, respectively; A valve that opens and closes each hydraulic pressure system toward the driving wheels, a valve that opens and closes the hydraulic system toward the driven wheels, and a booster that generates hydraulic pressure in the master cylinder by receiving a supply of negative pressure. a switching valve provided in a negative pressure supply system between the booster and the intake system to intermittent the supply of negative pressure to the booster; and a switching valve provided in the intake system of the engine to limit the intake flow rate. An auxiliary accelerator to
It is comprised of a control circuit that operates the auxiliary accelerator to adjust the intake flow rate, a valve provided in each of the hydraulic pressure system and the negative pressure system, and a controller that controls the control circuit of the auxiliary accelerator. The controller determines the degree of skidding of both driving wheels from the circumferential speed of the driving wheels and the estimated vehicle speed, and operates the switching valve to apply negative pressure to the booster regardless of the degree of skidding. At the same time, the valve is operated to supply hydraulic pressure to the brake hydraulic system of the driving wheel that is skidding and to disconnect the brake hydraulic system of the driven wheel from the brake hydraulic system of the driving wheel, and the valve is operated to reach the limit where skidding occurs. The auxiliary accelerator is configured to limit the intake flow rate when the engine progresses beyond this point.

"Operation" With the above configuration, when the driving wheels are in a skid state, pressure is applied to the brake hydraulic system, and pressure is not applied to the brake hydraulic system of the driven wheels, and in this state, the above-mentioned In the case of relatively mild skid conditions, such as when only one drive wheel is skidding, the brakes on that drive wheel are applied, and in the case of severe skid conditions, such as when both drive wheels are skidding, If so, the engine speed can be reduced to allow the affected wheel to recover from the skid.

"Example" Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

First, the configuration of the skid control system will be explained with reference to FIG.

This control system is used for anti-skid control applied to a 4-sensor, 4-channel vehicle braking system (a system in which each wheel is provided with a vehicle speed sensor and each wheel is braked by an independent hydraulic system). The configuration includes additional engine output control.

The code l is, for example, a patent application filed in 1982, which is the applicant's earlier application.
This is a booster equipped with a so-called control chamber, as described in No. 14063. This booster l performs the normal boosting function of amplifying the depression force of the brake pedal 2 and transmitting it to the master cylinder 3 when connected to a negative pressure source such as an engine intake system, which will be described later. By disconnecting from the negative pressure source and creating a state of communication with the air and air, the function of generating braking force regardless of the operation of the brake pedal 2, in other words, regardless of the driver's intention during skid control. It is something you have. In other words, in the above-mentioned booster, when atmospheric pressure is applied to the working pressure chamber indicated by No. 1 B, the master cylinder can be automatically operated to generate hydraulic pressure based on the pressure difference. .

The master cylinder 3 applies pressure applied from the booster 1 to the brake calipers 4 of each of the front left, front old, rear left, and rear right wheels (in the embodiment, the front wheel is the driving wheel).
The brake calipers 4A to 4D apply braking force corresponding to the hydraulic pressure to the brake discs 5A to 5D that rotate together with the axle. It has become. Also, changes in the rotational speed of the brake discs 5A to 5D (changes in wheel circumferential speed)
are detected by wheel speed sensors 6A to 6D, respectively.

Next, the configuration of the hydraulic system from the master cylinder 3 to the left front wheel brake caliper 4A will be explained.

The brake caliper 4A is connected to the output side of the master cylinder 3 via a normally open valve 7. This normally closed valve 9 is always kept in an "open" state, and can be switched to "closed" by being energized during anti-skid control. Further, a check valve 8 is provided in parallel with the normally open valve 7 to allow pressure oil to return from the caliper 4A side to the master cylinder 3 side. A conduit between the caliper 4A and the normally open valve 7 is connected to a reservoir (accumulator) via a normally closed valve 9 and a check valve lO. ! , and is connected to the suction side of the hydraulic pump 12 to constitute a hydraulic pressure release system that releases the hydraulic pressure supplied to the brake caliper 4A and stops its operation.

Further, the discharge side of the hydraulic pump 12 is connected via a check valve 13 to a pipe line from the master cylinder 3 to the caliper 4A, and the liquid released by the hydraulic pressure release system is connected to the hydraulic system for driving. It is supposed to be returned.

On the other hand, the output of the master cylinder 3 is branched before the normally open valve 7, and after being adjusted to a pressure lower than that of the front wheel hydraulic system by the pressure control valve 14, the output is sent via the normally open valve 15. It is designed to be supplied to the caliper 4D of the right rear wheel. In addition, the normally open valve 15 is provided with a bypass passage provided with a check valve 8 in parallel, similar to the case of the normally open valve 7 for the left front wheel system. A pipe line between the caliper 4D and the normally open valve 15 is connected to the reservoir 711 and the hydraulic pump 12 in parallel with the normally closed valve 9 of the hydraulic system for the left front wheel via the normally closed valve 16 and the check valve lO. It is connected to the.

With the above configuration, the front left wheel 4A and the rear right wheel 4D are individually limited in hydraulic pressure to prevent skidding by controlling the normally closed valves 9 and 16, respectively, and also have a common hydraulic pressure. The reservoir 11 and the hydraulic pump 12 constitute a hydraulic control system in which hydraulic pressure is restored.

On the other hand, the calipers 4B and 4C for the front right wheel and the rear left wheel are controlled by a hydraulic system having the same configuration as the front left wheel and the rear right wheel. That is, the caliper 4B of the right front wheel is connected to the master cylinder 3 via the normally open valve 7', and the caliper 4C of the left rear wheel is connected to the master cylinder 3 via the normally open valve 15', and the normally closed valve provided for each is connected to the master cylinder 3. 9° and 1
It is connected to a reservoir 11[deg.] and a hydraulic pump 12[deg.] through 6[deg.], thereby forming a hydraulic system similar to the left front wheel to right rear wheel system.

In addition, the intake pipe 20 connected to the intake valve to the engine adjusts the intake amount of air by operating the main intake damper 22 via the accelerator 21, thereby adjusting the amount of air-fuel mixture supplied to the engine. It also has the function of being connected to the booster l via the switching valve 23 and applying negative pressure to the booster l. Further, an auxiliary damper 24 is provided in the intake pipe 20, and the auxiliary damper 24 is operated by a servo motor 26 that is controlled by a motor control circuit 25 to correct an increase or decrease in the air flow rate caused by the damper 22. It has the function of In other words, when the main intake damper 22 is released due to sudden depression of the accelerator pedal 21, the auxiliary damper 24 is released after a certain time delay after the main intake damper 22 is depressed, thereby increasing the air-fuel mixture as the engine output increases. The flow rate is increased appropriately.

Furthermore, the brake pedal 1 includes a switch BSW,
The accelerator pedal 21 is provided with a switch ASW,
It is designed to detect each step. Note that the signals from these switches are used for system checks or fail-safe purposes, but the details of the signal processing are not related to the present invention and will not be described here.

Furthermore, the detection signals of the wheel speed sensors 6A to 6D, brake sensor BSW, and accelerator sensor ASW are supplied to a controller 27 consisting of a microprocessor, and the controller 27 processes the signals from each of the sensors. Each solenoid valve (normally closed valve, normally open valve, and switching valve) 7, 9, 15, 16, 7°
・9'・15' ・! 6°・23, pump 12・1
2. By supplying control signals to the motor control circuit 25, each brake caliper 4 is controlled during braking and starting.
A to 4D or the servo motor 26 is operated to prevent skids. In addition, each of the above-mentioned solenoid valves 7, 9, 15,! 6・7° ・9° ・15
° · 16' · 23 are switched to the opposite position to the illustrated state by turning on electricity, and OF
By reaching F, the state shown in the figure is restored.

In other words, to explain the principle of skid prevention, the pressure oil supplied from the master cylinder 3 passes through the normally open valves 7, I5,
Brake caliper 4 via 7° and 15° respectively.
A to 4D, and this brake caliper 4A to 4D
Braking force is applied to the wheels. At this time, pressure control valves 14 are installed in the hydraulic pressure systems toward the rear wheel brake calipers 4G and 4D, respectively, to limit the braking force on the rear wheels, thereby reducing the load distribution toward the front due to braking. In response to the change, a large braking force is generated in the brake calipers 4A and 4B on the front wheel side, which are subject to a larger load. Further, a decrease in wheel circumferential speed due to braking is detected by the wheel speed sensors 6A to 6D, and based on this detection data, for example, if the speed suddenly decreases beyond a certain limit, the wheels tend to lock. Something and Controller 2
It is now judged as 7. Then, by operating the normally closed valves 9, 9°, 16, and 16°, the controller 27 transfers the pressure oil from the brake calipers 4A to 4D of the wheels judged to have a locking tendency to the reservoirs 11-11.
' to reduce braking force. Further, when the wheel circumferential speed is recovering, the normally closed valve is closed to recover the braking force. Furthermore, the pressure oil released into the reservoir 11-11' is pumped 12.! 2° and then returned to the master cylinder 3.

Next, the details of the control executed by the controller 27 will be explained in connection with skid control operations during braking and acceleration.

5 tepl: Based on the signals obtained from each rotation sensor 6A to 6D (generally determined by pulses counted over a certain period of time), wheel circumferential speed Rωi (where i = 1 to 4, left front wheel, right front wheel, left rear wheel, respectively) (assumed to correspond to the right rear wheel).

5tap2: Calculate the rate of change Rλi by differentiating the calculated Rωi with respect to time. In reality, the average rate of change within a certain period of time is calculated by dividing the difference between the count value n at a certain time and the count value n+1 after Δ has elapsed by Δt, and this average value is calculated as the rate of change. It is used for subsequent control.

5tap3: Find the simulated vehicle speed Vref. In other words, to explain the concept of simulated vehicle speed, during anti-skid braking, the wheel circumferential speed Rωi repeatedly rises and falls and gradually decreases in a pulsating manner, and the deceleration is a curve that changes in a pulsating manner as described above. is given as the slope of the tangent at a certain time. This gradient gradually increases as braking progresses, but it never becomes Ig
It will not be decelerated beyond that. Therefore, when the change in wheel circumferential speed is captured and the rate of change (deceleration) approaches a certain (usually -1g) slope, the speed change is set when decelerating at this slope (usually , a tangent line is drawn to the change curve at that point in time) to obtain a simulated vehicle speed V ref, and skid control is executed to bring the wheel vehicle speed Rωi closer to this simulated vehicle speed V ref.

5tep4: Wheel circumferential speed Rω8,4 of the left and right rear wheels and a constant coefficient (0.8 in the case of the example) to the simulated vehicle speed Vref
) to determine the presence or absence of skids, and if either one is skidded, the 5t
Proceed to ep8, and if not, proceed to 5step5.

Step 5: If none of the rear wheels are skidding, it is determined whether acceleration skid control is being performed for both front wheels. That is, FLAGl and FLAG2 are set with "!" when skid control is being executed for the left front wheel and the right front wheel, respectively (the process of setting these flags will be described later). If it is not the mode to be executed (FLAG1=
0, FLAG2=0), proceed to 5step 6; otherwise proceed to 5step 7.

5tep6: If acceleration skid control is not in progress, the normally open valves 15 and 15° of the rear wheel hydraulic system are turned OFF to maintain the normally open state.

5tap7: When the acceleration series skid control is in progress, the normally closed valve I6, 16° of the rear wheel hydraulic pressure system is turned OFF to be in the normal closed state, and then the process proceeds to 5tep9, which will be described later.

5tep8: In order to reduce the braking force of calipers 4C and 4D on both rear wheels, open the normally open valves 15 and 15 degrees, and
After closing the normally closed valve 16/16°, 5tep described later
Proceed to 9.

Therefore, when one of the rear wheels skids during deceleration, the hydraulic pressure in the calipers 4C and 4D on the rear wheel side is reduced. In this case, in consideration of the fact that the skid of the rear wheels greatly affects the directional stability of the vehicle, a pressure control valve 14 is installed in the hydraulic pressure system going to the rear wheel calipers 4C and 4D to ensure that the pressure is lower than that of the front wheels. This is the so-called rear low select. In addition, if none of the rear wheels are skidding, it is determined whether or not the front wheels are under acceleration skid control, and if they are not under acceleration skid control, each of the rear wheels' hydraulic system is Valve 15・15゛・16・!
6゛ is kept in the normal state by turning it off regardless of the presence or absence of the control signal, and when the acceleration skid is under control,
Skid control CNT is applied to one front wheel after only the valve 16.
RL (Rω1)...Execute 5step9,
Furthermore, skid control CN T for the other front wheel
RL (Rω,)...Execute 5teplO.

The details of the control in the skid control CNTRL (Rω1) will be explained below with reference to FIG.

5tepH:) Determine whether traction (skid phenomenon of the drive wheels during acceleration) is occurring.

That is, based on Rω, ≧1.2V ref, it is determined whether the wheel circumferential speed Rω1 of one front wheel exceeds the simulated vehicle speed V ref by a certain amount or more, and if YES, the process is performed by 5 tep.
12, if no, step 1. ．． Proceed to step 8.

5 step 12 Proceed to the Niskit (traction) control flow TRC (Rωl). (See Figure 4) Step 13
Determine whether or not skid (skid phenomenon during deceleration) is occurring. That is, Rω, < 0.8V re
f, the wheel vehicle speed Rω of one front wheel becomes the simulated vehicle speed V
Determine whether it has fallen below ref' by a certain level, and then
If S, go to 5tep14; if NO, go to 5tep
Proceed to step 15.

5tap14: Anti-skid control flow ASC (R
Proceed to ω1). (See Figure 5) Step 15 Since one front wheel is not under either traction control or anti-skid control, clear FLAGI (see Figure 4) indicating that it is under control.

5tep16: Stop the engine output reduction command EG. In other words, if one front wheel does not show any skidding, the engine output reduction command EC is executed based on the judgment that even if the other front wheel skids, the skid can be prevented only by the braking force of the other wheel. It is determined that there is no need to reduce the output, and the output of the engine output reduction command EG is stopped.

Step 17: Determine whether FLAG 2 is zero, that is, whether the other front wheel is under traction control, and if it is under traction control (N
o), the process proceeds to step 5 step 18, and if it is not under the control of the truck shift fan (in the case of YES), the process proceeds to step 5 step 19.

5tep18: When the other front wheel is under Traxijin control, turn on the normally closed valve 9 of the hydraulic pressure release system of one front wheel to open it.

5tep19: If the other front wheel is not under traction control, normally open valve 1 installed in the hydraulic system to the rear wheel side.
5, 15, and the switching valve 23 provided between the booster and the intake system, respectively, are turned OFF, and the rear wheels can be braked by pressing the brake pedal normally.

5tep20D After turning off the normally open valve 7 and the normally closed valve 9 provided in the hydraulic pressure system for one of the front wheels, and making it possible to brake the front wheel with the hydraulic pressure from the master cylinder 3, as shown in FIG. Return to flowchart.

Next, the traction control T described in 5 step 12 above
RC(Rω,) will be explained.

5step 21: Turn on the normally open valves 15 and 15' provided in the hydraulic system for the rear wheels and switch them to "closed" to prevent pressure fluctuations in the hydraulic system due to traction control from affecting the rear wheels. Then, disconnect the rear wheel calipers 4C and 4D from the hydraulic system.

5tep22: Set 1 to FLAG l, which indicates that the front wheels are under Traxicon control.

5tep23 Determine whether RA>0 for the wheel circumferential acceleration RA of one front wheel, that is, whether traction is progressing further, and if YES, proceed to 5tep.
If the answer is No, proceed to step 25.

5top24: When in acceleration state, valves 7 and 9
are respectively turned OFF to allow hydraulic pressure to be supplied to the brake calipers 4A and 4B of the left and right front wheels.

5tep25: If not in acceleration state, turn valve 7 to O.
At the same time as shutting off the supply of hydraulic pressure by setting the valve 9 to
Leave it in FF to maintain the hydraulic pressure in the brake calipers 4A and 4B.

5tep26: Determine whether 1 is set in FLAG 2, which indicates that the other front wheel is in the Traxijin control state. If YES, proceed to 5tep27; if NO, proceed to 5tep28. Note that FLAG2 is set for the other front wheel under the same conditions as 5tep22 in the skid control performed in the same manner as for the one front wheel.

5tep27: If the other front wheel is also in the trough sill control state, it is determined that traction cannot be recovered without reducing the engine output in addition to controlling the brake force, and the servo motor 26 operates the auxiliary damper 24. In order to reduce the engine output, an engine control signal EG is output to the motor control circuit 25.

5tep28: If the other front wheel is not under traction control, valves 7 and 9. - are respectively turned on to lower the hydraulic pressure within the brake caliper of the other front wheel.

5tep29: Turn on the valve 23 to apply atmospheric pressure to the booster and increase the hydraulic pressure in the master cylinder.

Further, FIG. 5 shows details of the anti-skid control performed in step 514.

5tep30: The valve 23 is turned OFF and negative pressure is applied to the booster to maintain the normal operating state that assists the depression force of the brake pedal.

5tap31 It is determined whether one front wheel is in a deceleration state, that is, whether the wheel circumferential acceleration Rλ1 is Rλ1<0. If YES, the process proceeds to 5tep2, and if No, the process proceeds to 5tep33.

5tep32: When in deceleration state, valves 7 and 9
are turned ON to reduce the hydraulic pressure inside the brake caliper 4A.

5tap33: If the deceleration is not in progress, turn on the normally open valve 7 of the hydraulic pressure supply system and switch it to "closed", and leave the normally closed valve of the pressure reduction system OFF to reduce the hydraulic pressure in the brake caliper 4A. Hold and wait for recovery from skid.

Then, the traction control for one front wheel (Ste pH
p21-5tep29) or anti-skid control (
After Step 30 to Step 33) are performed, skid control is performed on the other front wheel at 5 steps, and then the process returns to 5 steps and repeats the same control.

Next, a specific example of skid (traction) control will be explained in chronological order with reference to FIG.

That is, this example shows the operating state of the brake when the vehicle starts in a state of LOμ, where the road surface friction coefficient is small, and only one front wheel (left front wheel) becomes a state of Hiμ.

At time tl, one of the front wheels tends to skid, and when the circumferential speed of this wheel exceeds the simulated vehicle speed V ref by a certain amount or more, the valve 23 is turned on and hydraulic pressure is generated from the master cylinder 3. At this time, the brake caliper p<4A of one front wheel that has a tendency to skid is caused by valves 7 and 9.
Since both are OFF, the hydraulic pressure increases due to the operation of the master cylinder 3, producing a braking force. However, since the valves 7' and 9' are turned on, the hydraulic pressure in the brake caliper 4B of the other front wheel does not increase.

Also, both valves 15 and 15° are turned on and “closed”.
Therefore, no hydraulic pressure is applied to the brake calipers 4C and 4D of both rear wheels.

At time t2, when it is detected that the other front wheel also has a tendency to skid, both the valves 7° and 9' are turned OF.
F, and hydraulic pressure from the master cylinder is supplied to the brake caliper 4B of the other front wheel. Also, since both front wheels tend to skid (i.e. FRAGl=1.P
RAG2=2), it is determined that it is necessary to throttle the engine, and the engine control signal EG is turned ON.
The auxiliary damper 24 is rotated in the closing direction.

At time II t 3, one of the front wheels entered the deceleration state (i.e., RA, <0), so the brake caliper 4A
In order to maintain the hydraulic pressure, valve 7 is turned on and valve 9 is turned off.
It is set to F state and waits for recovery from skid.

At time t4, the other front wheel also enters the deceleration state (
That is, Rat<0), valve 7° is turned ON to maintain the hydraulic pressure of brake caliper 4B.

Turn off valve 9° and wait for recovery from skid.

At time t5, the peripheral speed Rω of one front wheel is Vref
When the pressure falls below Xl,2, both valves 7 and 9 are turned on to reduce the hydraulic pressure in the front wheels. Further, it is determined that there is no need to reduce the engine output any further, and the engine control signal EC is stopped, and the auxiliary damper 24 gradually rotates toward the horizontal position and opens.

At time t6, the wheel peripheral speed Rω of the other front wheel.

When the pressure becomes less than a predetermined value, both valves 7' and 9' are turned off and connected to the master cylinder 3, and the switching valve 23 is turned off, turning the negative pressure of the intake system into a booster! Therefore, the master cylinder 3 is in a state where it is operated only by the depression force of the brake pedal 2. Therefore, when the brake pedal 2 is not depressed, the hydraulic pressure from the master cylinder 3 also decreases, and the pressure of the brake caliper 4B connected thereto also decreases. On the other hand, the rear wheel hydraulic system valve I5
15° is turned off, both the front and rear hydraulic pressure systems are in communication with the master cylinder 3. Note that even if the rear wheel hydraulic pressure system is in communication with the master cylinder 3, the pressure of the rear wheel hydraulic pressure system is maintained at a slightly lower pressure than that of the front wheel hydraulic pressure system due to the action of the pressure control valve 14.

Thereafter, the same control as the above t+-ts is performed from t7 to tit and from t1! By repeating t III, t's to tts, the wheel circumferential speed Rω of the left and right front wheels, and Rω
, approaches the simulated vehicle speed V ref while the vehicle is accelerated.

"Modified Embodiment" 5 In the above embodiment, a case where the present invention is applied to a front wheel drive system is shown, but it goes without saying that the present invention can also be applied to a rear wheel drive system. In other words, based on wheel peripheral speed data, it detects the presence or absence of skid for each of both rear wheels, and if only one is in a skid state, it attempts to recover from the skid by adjusting the braking force only, and when both rear wheels are in a skid state. If this occurs, you can also adjust the engine output.

b In the above embodiment, the skid weight is determined based on whether one of the drive wheels is in the skid state or both are in the skid state, but other means, for example,
The lightness and weight of the skid may be determined by determining how much the circumferential speed of the driving wheels exceeds the simulated vehicle speed, or by using this determination in combination with the determination of whether it is one wheel or both wheels. .

C In the above embodiment, a so-called 4-sensor 4 that measures the circumferential speed of each wheel and has an independent brake hydraulic pressure system is used.
Although we have shown the case where it is applied to the channel method, it is possible to at least measure the circumferential speed of the driving wheels and determine the weight and weight of the skid based on this, and it is also possible to measure the braking force of the driving wheels separately from the driven wheels. The present invention can also be applied to vehicles that have a controllable hydraulic system.

"Effects of the Invention" As is clear from the above explanation, according to the present invention, the lightness or weight of the skid state is determined based on the data obtained from the wheel speed sensor of the drive wheels, and regardless of the lightness or weight of the drive wheels, the When the brake is in a skid state, hydraulic pressure is generated in the master cylinder, and a valve is operated to cut off the influence of this hydraulic pressure on the braking system of the driven wheels. In order to recover the drive wheels from a skid, the brake fluid pressure of the drive wheels is controlled only, and if the skid is severe, the brake fluid pressure is controlled and the engine output is controlled in combination to recover the drive wheels from the skid. This has the effect of suppressing the output drop to a minimum and quickly recovering from a skid with a good response (accelerating the vehicle).

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention. Fig. 1 is a hydraulic system diagram of the control system constituting the skid control device, Fig. 2 is a flowchart of the entire control operation of the controller, and Fig. 3 is a diagram of the front wheel skid. Control flowchart, Figure 4 is a flowchart of traction control, Figure 5 is a flowchart of anti-skid control, Figure 6 is a flowchart of solenoid valve and engine control signal output status when the vehicle starts, braking fluid pressure, accelerator opening. 3 is a timing chart showing the correspondence between speed, simulated vehicle speed, and wheel circumferential speed over time. l... Booster, 2... Brake pedal, 3... Master cylinder, 4A/4B/4
C・4D・・・Brake caliper, 6A・6B・
6C・6D・・・Wheel speed sensor, 7.・7'・
15・15°・・・・・・Normal open valve, 9・9
° ・16・16°・・・Normally closed valve,
20... Intake pipe line, 21... Accelerator pedal, 22... Main intake damper, 23...
...Switching valve, 24...Auxiliary damper, 25.
...Motor control circuit, 27...Controller. Applicant Tokico Co., Ltd.

Claims (1)

[Claims] Wheel speed detection means provided at least on the drive wheels to measure wheel circumferential speeds, estimation means for estimating vehicle speed from detection data of the wheel speed detection means, and calculation of wheel acceleration from the detection data of the wheel circumferential speeds. a hydraulic system that transmits the hydraulic pressure generated from the master cylinder to the brake calipers of the driving wheels and the driven wheels, a valve that opens and closes each hydraulic system going to the driving wheels, and a hydraulic system that transmits the hydraulic pressure generated from the master cylinder to the brake calipers of the driving wheels. A valve that opens and closes the pressure system, a booster that generates hydraulic pressure in the master cylinder by receiving a supply of negative pressure, and a negative pressure supply system between the booster and the intake system. a switching valve that cuts off and on the supply of negative pressure to the booster;
an auxiliary accelerator provided in the intake system of the engine to limit the intake flow rate; a control circuit that operates the auxiliary accelerator to adjust the intake flow rate; and valves provided in the hydraulic pressure system and the negative pressure system, respectively; and a controller that controls the control circuit of the auxiliary accelerator, and the controller determines the degree of skid state of both drive wheels from the wheel circumferential speed and acceleration of both drive wheels and the estimated vehicle speed, Regardless of the degree of skidding, the switching valve is operated to apply negative pressure to the booster, and at the same time, hydraulic pressure is supplied to the braking hydraulic system of the skidding driving wheels to perform braking and to brake the driven wheels. A skid control device, characterized in that the valve is operated to separate the hydraulic system from the braking hydraulic system of the drive wheels, and when the skid advances beyond a certain limit, the auxiliary accelerator is made to restrict the intake flow rate.