JP3352496B2 - Anti-skid brake system for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-skid brake device for suppressing an excessive braking force at the time of braking of a vehicle, and particularly to an anti-skid brake device which performs an initial pressure increase with a sudden pressure increase and a gradual pressure increase. The present invention relates to one that is set based on a pressure increase amount of a cycle and information obtained from a wheel speed detected by a wheel speed detecting unit.

[0002]

2. Description of the Related Art As a vehicle brake system, an anti-skid brake device has been put to practical use in which a locked or skid state of a wheel during braking is prevented. This type of anti-skid brake device controls a wheel speed sensor that detects wheel speeds of four wheels, an electromagnetic control valve that adjusts brake oil pressure, and an electromagnetic control valve based on the wheel speed detected by the wheel speed sensor. A control device.
This control device determines the acceleration / deceleration of the wheel based on the detected wheel speed, for example, and when the wheel deceleration becomes equal to or less than a predetermined value, reduces the braking pressure by controlling the pressure of the electromagnetic control valve, and
When the wheel speed increases due to a decrease in the braking pressure and the wheel acceleration reaches a predetermined value, the braking pressure is increased by controlling the pressure of the control valve.

[0003] Such a series of braking pressure control (hereinafter referred to as AB
S control) is continued until the vehicle stops, for example, to prevent the wheels from being locked or skid during sudden braking, and to stop the vehicle at a short braking distance while ensuring the directional stability of the vehicle. Becomes

In the ABS control, control of a plurality of cycles in which four phases of pressure increase, pressure increase hold, pressure decrease, and pressure decrease hold are performed as one cycle, or two phases of pressure increase and pressure decrease are defined as one cycle.
It is executed by control of multiple cycles as a cycle, but in order to minimize the time required for the pressure increase phase as much as possible, a rapid pressure increase is performed at the beginning of the pressure increase phase, and then a gentle pressure increase is proposed. I have. For example, Japanese Patent Publication No. 57-45
No. 44 discloses that the initial rapid pressure increase amount of the current cycle is set in accordance with the increase of the duration, with the duration of the pressure increase phase of the previous cycle or the average duration of the pressure increase phase of the preceding plurality of cycles as a parameter. An anti-skid brake device which is set to be large has been proposed.

[0005]

In the anti-skid brake device disclosed in the above publication, the initial rapid pressure increase amount of the current cycle is set only by setting the duration of the pressure increase phase of the previous cycle or a plurality of preceding cycles as a parameter. It is not configured to set the initial rapid pressure increase amount of the current cycle in consideration of speed, vehicle acceleration, road surface friction state, etc., so the rapid pressure increase amount of the current cycle is considered in consideration of the behavior of the vehicle, road surface conditions, etc. And can not be set properly. An object of the present invention is to provide an anti-skid brake device,
The purpose of the present invention is to appropriately set the initial rapid pressure increase amount of the pressure increase phase in consideration of not only the pressure increase time of the previous cycle but also the behavior of the vehicle body, the road surface condition, and the like.

[0006]

According to a first aspect of the present invention, there is provided an anti-skid brake system for a vehicle, comprising: a wheel speed detecting unit for detecting a rotation speed of a wheel; a hydraulic pressure adjusting unit for adjusting a brake oil pressure; and a wheel speed detecting unit. Anti-skid control means for operating the hydraulic adjustment means based on the wheel speeds provided,
In an anti-skid brake device for a vehicle in which the pressure increase in one cycle of anti-skid control is performed by an initial rapid pressure increase and a subsequent gentle pressure increase, the anti-skid control means includes a pressure increase amount of a previous cycle, Based on the information obtained from the wheel speed detected by the wheel speed detection means,
Initial pressure increasing amount setting means for setting an initial pressure increasing amount of the current cycle , wherein the initial pressure increasing amount setting means includes a wheel speed detecting means.
The vehicle speed calculated from the wheel speed detected by
The initial pressure increase amount is set to be small according to the above .

An anti-skid brake for a vehicle according to claim 2
The device includes: a wheel speed detection unit that detects a rotation speed of the wheel;
Hydraulic pressure adjusting means for adjusting the brake hydraulic pressure, and a wheel speed detecting means
Activating the hydraulic adjustment means based on the wheel speed detected by the gear
Anti-skid control means for
The pressure increase in chip skid control is performed by
Anti-skid brake of vehicle adapted to run with slow boost
In the rake device, the anti-skid control unit includes:
The pressure increase amount of the previous cycle and the wheel speed detection means
Based on the information obtained from the wheel speed,
Initial pressure increasing amount setting means for setting the initial pressure increasing amount, wherein the initial pressure increasing amount setting means detects a road surface friction state based on the wheel speed detected by the wheel speed detecting means. It is provided with friction state detecting means and upper limit regulating means for setting an upper limit value to the initial pressure increase amount according to the road surface friction state detected by the friction state detecting means .

An anti-skid brake for a vehicle according to claim 3.
The device includes: a wheel speed detection unit that detects a rotation speed of the wheel;
Hydraulic pressure adjusting means for adjusting the brake hydraulic pressure, and a wheel speed detecting means
Activating the hydraulic adjustment means based on the wheel speed detected by the gear
Anti-skid control means for
The pressure increase in chip skid control is performed by
Anti-skid brake of vehicle adapted to run with slow boost
In the rake device, the anti-skid control unit includes:
The pressure increase amount of the previous cycle and the wheel speed detection means
Based on the information obtained from the wheel speed,
Initial pressure increasing amount setting means for setting the initial pressure increasing amount, wherein the initial pressure increasing amount setting means calculates the initial pressure increasing amount from the wheel speed detected by the wheel speed detecting means. And an upper limit regulating means for setting an upper limit according to the vehicle speed .

[0009]

According to the anti-skid brake device for a vehicle of the first aspect, the pressure increase in the anti-skid control in one cycle is executed by an initial rapid pressure increase and a subsequent gentle pressure increase. The initial pressure increasing amount setting means provided in the means sets the initial pressure increasing amount of the current cycle based on the pressure increasing amount of the previous cycle and the information obtained from the wheel speed detected by the wheel speed detecting means. . Further
The initial pressure increasing amount setting means is detected by the wheel speed detecting means.
The vehicle speed calculated from the wheel speeds
Set the initial pressure increase amount small. Therefore, in addition to taking into account the pressure increase amount of the previous cycle, the initial pressure increase amount of the current cycle is appropriately adjusted by taking into account information (vehicle speed, vehicle acceleration, road surface friction state, etc.) obtained from the detected wheel speed. Setting can improve the performance of the anti-skid brake device.
Furthermore, as the vehicle speed increases, the initial pressure increase
Roads that are proportional to the increase in vehicle speed
Initial pressure increase taking into account the decrease in decompression amount according to the surface reaction force
The amount can be set appropriately.

[0010] An anti-skid brake for a vehicle according to claim 2.
In equipment, anti-skid control of one cycle
Pressure increase is performed with an initial sudden pressure increase and a subsequent gentle pressure increase.
However, the initial pressure increase amount provided in the anti-skid control means
The setting means includes the pressure increase amount of the previous cycle and the wheel speed detecting means.
This time, based on the information obtained from the wheel speed detected in
Set the initial pressure increase of the cycle. In addition, friction state detection
The informing means is based on the wheel speed detected by the wheel speed detecting means.
The road surface friction state is detected, and the upper limit regulating means sets the initial pressure increase amount
Depending on the road surface friction state detected by the friction state detection means.
Set the upper limit. Therefore, the pressure increase in the previous cycle
In addition to taking into account the information obtained from the detected wheel speed (car
Body speed, body acceleration, road surface friction, etc.)
Properly set the initial pressure increase in
The performance of the brake system can be improved. further
By setting the upper limit value according to the road surface friction state by the upper limit regulating means, it is possible to suppress excessive rapid pressure increase while adapting to the road surface friction state.

An anti-skid brake for a vehicle according to claim 3.
In equipment, anti-skid control of one cycle
Pressure increase is performed with an initial sudden pressure increase and a subsequent gentle pressure increase.
However , the initial pressure increase amount provided in the anti-skid control means
The setting means includes the pressure increase amount of the previous cycle and the wheel speed detecting means.
This time, based on the information obtained from the wheel speed detected in
Set the initial pressure increase of the cycle. Furthermore, upper limit regulation
The means includes a vehicle detected by the wheel speed detecting means in the initial pressure increase amount.
An upper limit is set according to the vehicle speed calculated from the wheel speed.
Therefore, in addition to taking into account the pressure increase in the previous cycle,
Information obtained from the detected wheel speeds (vehicle speed, vehicle acceleration, road
Initial pressure increase in this cycle, taking into account the surface friction state, etc.)
Set the amount appropriately and anti-skid brake device performance
Can be increased. Further, by setting the upper limit value according to the vehicle speed by the upper limit regulating means, it is possible to suppress excessive sudden pressure increase while adjusting to the vehicle body speed.

[0012]

Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, in the vehicle according to this embodiment, left and right front wheels 1 and 2 are driven wheels, left and right rear wheels 3 and 4 are driving wheels, and the output torque of an engine 5 is Propeller shaft 7, differential gear 8 and left and right drive shafts 9,
It is configured to be transmitted to the right and left rear wheels 3 and 4 via 10. Each of the wheels 1 to 4 is provided with a disc 11a to 14a which rotates integrally with the wheel, and a brake device 11 to which calipers 11b to 14b which brake the rotation of the discs 11a to 14a when braking pressure is supplied. 14 are provided, and a brake control system 15 for operating these brake devices 11 to 14 is provided.

The brake control system 15 includes a booster 17 for increasing the depression force of the brake pedal 16 by the driver.
When, and a master cylinder da 18 for generating a braking pressure corresponding to the stepping force that is increased by the booster 17. The front wheel brake pressure supply line 19 from the master cylinder da 18
Is branched into two paths, and these front wheel branch braking pressure lines 19
a and 19b are respectively connected to calipers 11a and 12a of brake devices 11 and 12 of left and right front wheels 1 and 2, respectively.
A first valve unit 20 comprising an electromagnetic on-off valve 20a and an electromagnetic relief valve 20b is provided on one of the front-branch branch braking pressure lines 19a leading to the brake device 12 for the right front wheel 2. Branch braking pressure line 19 for the other front wheel
Similarly to the first valve unit 20, b also has a second valve unit 21 including an electromagnetic on-off valve 21a and an electromagnetic relief valve 21b.

On the other hand, the first and second valve units 20, 2 are connected to the brake pressure supply line 22 for the rear wheels from the master cylinder 18.
Similarly to 1, a third valve unit 23 including an electromagnetic on-off valve 23a and an electromagnetic relief valve 23b is provided. The rear wheel braking pressure supply line 22 is branched into two paths on the downstream side of the third valve unit 23, and these rear wheel branch braking pressure lines 22a, 22b are connected to the brake devices 13 for the left and right rear wheels 3, 4. , 14 are connected to calipers 13b, 14b, respectively. The brake control system 15 includes a first channel for variably controlling the braking pressure of the brake device 11 of the left front wheel 1 via the first valve unit 20, and a brake channel 12 for the right front wheel 2 via the second valve unit 21. A left and right rear wheel via a second channel for variably controlling the braking pressure and a third valve unit 23;
There is provided a third channel for variably controlling the braking pressure of both the brake devices 13 and 14, and the first to third channels are controlled independently of each other.

The brake control system 15 includes first to first
A control unit 24 for controlling the third channel is provided. The control unit 24 receives a brake signal from a brake switch 25 for detecting ON / OFF of the brake pedal 16 and a brake signal from a steering angle sensor 26 for detecting the steering angle of the steering wheel. Receiving the steering angle signal and the wheel speed signals from the wheel speed sensors 27 to 30 respectively detecting the rotation speeds of the respective wheels, a braking pressure control signal corresponding to these signals is transmitted to the first to third valve units.
20, 21 and 23, respectively, to control the braking of the left and right front wheels 1 and 2 and the rear wheels 3 and 4 against slip, that is, AB
The S control is performed in parallel for each of the first to third channels.

The control unit 24 controls the opening / closing valves 20a, 21a, 23a and the relief valves 20b, 21b in the first to third valve units 20, 21, 23 based on the wheel speeds detected by the wheel speed sensors 27 to 30, respectively. , 23b, respectively, so that the front wheels 1, 2 and the rear wheels 3, 4 can be controlled by the braking pressure according to the slip condition.
To apply a braking force. In addition, the first to third
Each relief valve 20b, 21b, in the valve unit 20, 21, 23,
The brake oil discharged from 23b is supplied to the reservoir tank 18 of the master cylinder 18 via a drain line (not shown).
Returned to a.

In the ABS non-control state, the control pressure signal is not output from the control unit 24, and the relief valves 20b, 21b, 23b in the first to third valve units 20, 21, 23 are respectively operated as shown in FIG. Since the open / close valves 20a, 21a, 23a of the units 20, 21, 23 are held open, respectively, the braking pressure generated in the master cylinder 18 in accordance with the depressing force of the brake pedal 16 increases the braking pressure for the front wheels. Left and right front wheels 1 and 2 via a pressure supply line 19 and a rear wheel braking pressure supply line 22.
The braking force is supplied to the braking devices 11 to 14 of the rear wheels 3 and 4, and the braking force according to these braking pressures is directly applied to the front wheels 1 and 2 and the rear wheels 3 and 4.

Next, an outline of the brake control performed by the control unit 24 will be described. Control unit 24
Are the wheel speeds Vw1 to Vw1 indicated by the signals from the wheel speed sensors 27 to 30.
Based on Vw4, decelerations DVw1 to DVw4 and accelerations AVw1 to AVw4 are calculated for each wheel. The calculation method of the acceleration or the deceleration will be described. The control unit 24 divides the difference between the current value of the wheel speed and the previous value of the wheel speed by the sampling period Δt (for example, 7 ms), and converts the result into a gravitational acceleration. Is updated as the current acceleration or deceleration.

The control unit 24 executes a predetermined rough road determination process to determine whether or not the traveling road surface is a rough road. To explain the outline of the rough road determination process, for each wheel corresponding to each channel, count the number of times the wheel acceleration or wheel deceleration becomes equal to or greater than a predetermined rough road determination threshold value during a predetermined period, When the number of times is equal to or less than a predetermined value, the bad road flag Fak is set to 0, and when the number is larger than the predetermined value, the bad road flag Fak is set to 1.

Further, the control unit 24 controls the rear wheels 3, 3 representing the wheel speed and acceleration / deceleration for the third channel.
4 is selected, the smaller of the two wheel speeds is selected as the rear wheel speed in consideration of the detection errors of the two wheel speed sensors 29, 30 of the rear wheels 3, 4 during slip. The acceleration and the deceleration obtained from the wheel speed are selected as the rear wheel acceleration and the rear wheel deceleration.

Further, the control unit 24 calculates the road surface friction coefficient for each of the three channels and the pseudo vehicle speed Vr at predetermined small time intervals. The control unit 24 calculates a first wheel speed based on the rear wheel speed obtained from the signals from the wheel speed sensors 29, 30 and the wheel speeds of the left and right front wheels 1, 2 detected by the wheel speed sensors 27, 28 and the vehicle speed Vr.
To calculate the slip ratio for the third channel. In this case, the slip ratio is calculated by the following relational expression. Slip ratio = (wheel speed / pseudo vehicle speed) x
Therefore, as the deviation of the wheel speed from the vehicle speed Vr increases, the slip ratio decreases, and the tendency of the wheels to slip increases.

Next, the control unit 24
Various control threshold values used for control of the third channel are respectively set, and the lock determination process for each channel is performed using these control threshold values, and the first to third valve units 2 are set.
A phase determination process for defining a control amount for 0, 21, and 23 and a cascade determination process are performed.

Here, the lock determination processing will be described. For example, in the lock determination processing for the first channel for the left front wheel, the control unit 24
First, the current value of the continuation flag Fcn1 for the first channel is set as the previous value, and then the vehicle speed Vr and the wheel speed Vcn are set.
w1 is a predetermined condition (for example, Vr <5 km / H, Vw1 <7.
5Km / H) is determined, and when these conditions are satisfied, the continuation flag Fcn1 and the lock flag Flok1
Are reset to 0, respectively, and if they are not satisfied, it is determined whether or not the lock flag Flok1 is set to 1. If the lock flag Flok1 is not set to 1, the lock flag Flok1 is set to 1 under a predetermined condition (for example, when the wheel deceleration becomes -3G).

On the other hand, when the lock flag Flok1 is set to 1, the control unit 24 sets the phase flag P1 of the first channel to the phase V
And the continuation flag Fcn when the slip ratio S1 is larger than the 5-1 slip ratio threshold value Bsz.
Set 1 to 1. Note that the lock determination process is similarly performed on the second and third channels.

An outline of the phase determination process will be described. The control unit 24 compares the respective control thresholds set according to the running state of the vehicle with the wheel acceleration / deceleration and the slip ratio to determine whether the ABS is in the non-control state. 0, phase I in a pressure increasing state during ABS control, phase II in a holding state after pressure increase, phase III in a pressure reducing state, phase IV in a rapid pressure reducing state, and a holding state after pressure reduction. Phase V is selected. The cascade determination process is for determining a cascade lock state in which the wheel lock state occurs continuously in a short time because the wheel is easily locked even with a small braking pressure particularly on a low friction road surface such as an ice burn. The cascade flag Fcs is set to 1 when a predetermined condition that cascade lock is likely to occur is satisfied.

Thus, the control unit 24 outputs a braking pressure control signal corresponding to the phase designated by each phase flag P1 to each of the first to third valve units 20, 21, and 23 for each channel. Thereby, the first
-The braking pressure of the front wheel branch braking pressure lines 19a, 19b and the rear wheel branch braking pressure lines 22a, 22b downstream of the third valve units 20, 21, 23 is increased or decreased, or increased or decreased. Or at a later pressure level.

A method of calculating the road surface friction coefficient (road surface μ) will be described. First, when calculating the road surface friction coefficient Mu1 of the first channel, the road surface friction coefficient Mu1 is calculated based on the wheel speed Vw1 of the front wheel 1 and its acceleration Vg.
Using the 00 ms timer and the 100 ms timer, the acceleration Vg is calculated by the following equation from the change in the wheel speed Vw1 during 100 ms every 100 ms until the acceleration Vg does not become sufficiently large after the acceleration starts.

Vg = K1 × [Vw1 (i) -Vw1 (i-100)] After 500 ms when the acceleration Vg has become sufficiently large, the change in the wheel speed between 500 ms every 100 ms,
The acceleration Vg is calculated by the following equation. Vg = K2 × [Vw1 (i) -Vw1 (i-500)] In the above equation, Vw1 (i) is the current wheel speed, Vw1
(I-100) is the wheel speed 100 ms before, Vw1 (i-5)
00) is the wheel speed 500 ms before, and K1 and K2 are predetermined constants. The road surface friction coefficient Mu1 is calculated by three-dimensional interpolation from the μ table shown in FIG. 2 using the wheel speed Vw1 and the acceleration Vg obtained as described above. However, road friction μ = 1.0 to 2.5 corresponds to low friction, and road friction μ = 2.
5 to 3.5 corresponds to medium friction, and road surface μ = 3.5 to 5.0 corresponds to high friction. Next, the road surface friction coefficient M of the second channel
When calculating u2, the same calculation is performed using the wheel speed Vw2, and the surface friction coefficient Mu3 of the third channel is set equal to the smaller value of the road surface friction coefficient Mu1 and the road surface friction coefficient Mu2. . However, road surface μ detected by three dedicated road surface μ sensors corresponding to the first to third channels may be applied.

Next, the calculation process of the vehicle speed Vr will be described with reference to FIG.
This will be described with reference to the flowchart of FIG. First, the control unit 24 reads various data (S20), then calculates the maximum wheel speed Vwm from the wheel speeds Vw1 to Vw4 indicated by the signals from the sensors 27 to 30 (S21), and then calculates the maximum wheel speed. The maximum wheel speed change amount ΔVwm per Vwm sampling period Δt is calculated (S22). Next, the control unit 24 reads the vehicle speed correction value CVr corresponding to the friction state value Mu (the minimum value of the road surface friction of the first to third channels) from the map shown in FIG. It is determined whether or not the change amount ΔVwm is equal to or less than the vehicle speed correction value CVr.

If it is determined that the wheel speed change amount .DELTA.Vwm is equal to or less than the vehicle speed correction value CVr, the program proceeds to S2.
5, the vehicle speed correction value CVr from the previous value of the vehicle speed Vr
Replace the subtracted value with the current value. Therefore, the vehicle speed Vr
Decreases at a predetermined gradient corresponding to the vehicle speed correction value CVr. On the other hand, when the control unit 24 determines in S24 that the wheel speed change amount ΔVwm is larger than the vehicle speed correction value CVr, that is, when the maximum wheel speed Vwm shows an excessive change, in S26, the control proceeds from the pseudo vehicle speed Vr to the maximum wheel speed. It is determined whether the value obtained by subtracting the speed Vwm is equal to or greater than a predetermined value V0.

That is, it is determined whether or not there is a large difference between the maximum wheel speed Vwm and the vehicle speed Vr. When there is a large difference, in S25, the value obtained by subtracting the vehicle speed correction value CVr from the previous value of the vehicle speed Vr is replaced with the current value. Further, the control unit 24 controls the maximum wheel speed Vwm.
When there is no large difference between the vehicle speed Vr and the vehicle speed Vr, S2
In step 7, the maximum wheel speed Vwm is replaced with the vehicle speed Vr.
Thus, the vehicle body speed Vr of the vehicle is gradually updated every sampled in g cycle Δt in accordance with the wheel speeds Vw1～Vw4.

Next, the processing for setting various control thresholds will be described with reference to the flowchart of FIG. 5 and FIGS. The control threshold value setting process is executed independently for each channel. In this case, the first process for the left front wheel is performed.
A control threshold value setting process for a channel will be described. The control unit 24 reads various data in S30, and then in S31, according to the friction state value Mu and the vehicle speed Vr, from a table in which the vehicle speed range and the road surface μ are set as parameters as shown in FIG. Selected running state parameter. For example, when the friction state value Mu is 1, which indicates a low friction road surface, and the vehicle speed Vr is in the medium speed range, LM2 for a medium speed low friction road surface is selected as the traveling state parameter. The friction state value Mu is determined from the smallest one of the friction coefficients Mu1 to Mu3. In FIG. 6, Mu = 1 is a low friction state, Mu = 2 is a medium friction state, and Mu = 3 is a high friction state. It corresponds to a friction state.

On the other hand, the rough road flag Fak indicates 1 on a rough road.
When the vehicle speed is set to, as shown in FIG. 6, a traveling state parameter corresponding to the vehicle speed Vr is selected. In this case, for example, when the vehicle speed Vr belongs to the middle speed range, the HM2 for the middle speed low friction road surface is forcibly selected as the traveling state parameter. That is, the road surface μ tends to be estimated to be small because the fluctuation of the wheel speed is large when traveling on a rough road.

After the selection of the driving state parameters, the control unit 24 reads various control threshold values corresponding to the driving state parameters from the control threshold value setting table shown in FIG. 7 in S32. Here, as shown in FIG. 7, the various control thresholds include a 1-2 intermediate deceleration threshold B for determining switching from phase I to phase II.
12, 2- for judging switching from phase II to phase III
3 Intermediate slip ratio threshold value Bsg, 3-5 intermediate deceleration threshold value B3 for determining switching from phase III to phase V
5. 5-1 for determining switching from phase V to phase I
A slip ratio threshold value Bsz and the like are set for each traveling state parameter.

In this case, the deceleration threshold value which has a large effect on the braking force is determined by the following equation: to achieve a high level of both the braking performance when the road surface μ is large and the control responsiveness when the road surface μ is small. The value is set so as to approach 0 G as the level of the state value Mu decreases, that is, as the road surface μ decreases. Here, when LM2 for a medium-speed low-friction road surface is selected as the traveling state parameter, the control unit 24 reduces the LM2 by 1-2 intermediate as shown in the column of LM2 in the control threshold value setting table of FIG. Speed threshold B12, 2-3 intermediate slip rate threshold Bsg, 3-5 intermediate deceleration threshold B35, 5-1 slip rate threshold Bsz
, Each value of -0.5G, 90%, 0G, and 90% is read out.

Next, the control unit 24 executes S33
In step S34, it is determined whether or not the friction state value Mu is set to 3 indicating a high friction road surface. If the determination is Yes, it is determined in step S34 whether or not the bad road flag Fak is set to zero. As a result of the determination, the rough road flag Fak becomes 0
In step S35, the process proceeds to S35 to determine whether the absolute value of the steering angle θ detected by the steering angle sensor 26 is smaller than 90 °. If the absolute value of the steering angle θ is not smaller than 90 °, S3
In step 6, a correction process of the control threshold value according to the steering angle θ is performed. This control threshold value correction process is performed based on the control threshold value correction table illustrated in FIG.

That is, in the control threshold value correction table shown in FIG. 8, when the road is not a bad road with low friction, medium friction, and high friction, and the steering performance is large when the steering wheel operation amount is large, 2- The values obtained by adding 5% to the 3 intermediate slip ratio threshold value Bsg and the 5-1 intermediate slip ratio threshold value Bsz are
The final 2-3 slip rate threshold value Bsg and the final 5-
The threshold value is set as one slip ratio threshold value Bsz, and the other intermediate threshold values are set as they are as final threshold values.

On a rough road with high friction (flag Fak = 1),
In order to ensure running performance when the steering wheel operation amount is small,
The values obtained by subtracting 5% from the 2-3 intermediate slip ratio threshold Bsg and the 5-1 intermediate slip ratio threshold Bsz are the final 2-3 slip ratio threshold Bsg and the final 5-1.
The slip ratio is set as a threshold value Bsz. next,
When the determination result in S35 is No, each of the intermediate threshold values is set as a final threshold value as it is.

On the other hand, the control unit 24 executes S34
When it is determined that the rough road flag Fak is set to 1, the process proceeds to S37, and based on the control threshold correction table of FIG. 3 Intermediate slip ratio thresholds Bsg and 5-
The corrected values of the 1 slip ratio threshold value Bsz are respectively used as the final 2-3 intermediate slip ratio threshold value Bsg and the final 5-1.
A correction process for setting the slip ratio as the threshold value Bsz is executed. Next, in step S38, based on the control threshold value correction table shown in FIG.
The value obtained by subtracting 1.0 G is used as the final 1-2 deceleration threshold value B12.
Is performed.

This is because, when a bad road is determined, the wheel speed sensors 27 to 30 are likely to make an erroneous detection, so that the response of the control is delayed to secure a good braking force. The other intermediate thresholds are set as final thresholds. Further, when the control unit 24 determines that the friction state value Mu is not 3 in S33,
Move to 35. It should be noted that control threshold values are set for the second and third channels in the same manner as in the case of the first channel.

Next, the control signal output processing for setting the phases and outputting the braking control signal of each phase to the valve unit will be described with reference to the flowcharts of FIGS. 9 to 11 and FIGS. 17 will be described. First, various data are read (S40),
Next, it is determined whether or not the brake switch 25 is ON. If the determination is No, the process returns through S42. If the determination is Yes, the vehicle speed Vr is increased to a predetermined value C1 in S43.
(For example, 5.0 Km / H) or less and whether or not the wheel speed Vw1 is equal to or less than a predetermined value (for example, 7.5 Km / H). The judgment is
If Yes, the process returns through S42 because the ABS control is not necessary in a state where the vehicle is sufficiently decelerated. However, if the determination in S43 is No, the process proceeds to S44.

In S42, the phase flag P1, the lock flag Flok1, and the continuation flag Fcn1 are each reset to 0, and thereafter, the flow returns to S40. Next, in S44,
It is determined whether or not the lock flag Flok1 is 0. If the flag Flok1 is 0 before the start of the ABS control, the process proceeds to S45,
Deceleration DVw1 of wheel speed Vw1 (however, DVw1 ≦ 0)
Is less than or equal to a predetermined value D0 (for example, -3G),
If the determination is Yes, the process moves to S46. On the other hand, S4
When the determination of No. 4 is No, the process proceeds to S49.

Next, if the judgment in S45 is Yes, the program proceeds to S4
In 6 the lock flag Flok1 is set to 1 and then in S47 the flag P1 is set to 2 and the phase
The phase shifts to II (a phase of holding after pressure increase), and then a braking control signal preset for phase II is output to the first valve unit 20 in S48, and then the process returns.

After the start of the ABS control, since the flag Flok1 is set to 1, the flow shifts from S44 to S49 to determine whether or not the flag P1 is 2, and when the flag P1 is 2, the flow goes to S5.
The process proceeds to 0, and if the flag P1 is not 2, the process proceeds to S54. In S50, it is determined whether or not the slip ratio S1 is equal to or smaller than the 2-3 slip ratio threshold value Bsg. Since it is initially determined as No, the process shifts from S50 to S48. Is less than or equal to the threshold value Bsg, the process moves from S50 to S51. In S51,
The flag P1 is set to 3, and the process shifts to phase III (decompression phase).

Next, in step S52, the timer T3 for counting the decompression time in phase III is started after resetting. Next, in step S53, a braking control signal preset for phase III is output to the first valve unit 20. And then return. If the flag P1 is not 2, the process proceeds from S49 to S54 to determine whether the flag P1 is 3. If the determination is Yes, the process proceeds to S55, and if the determination is No, the process proceeds to S59.

Next, in S55, the deceleration DVw1 is set to 3-5.
It is determined whether or not it is equal to the intermediate deceleration threshold value B35. Since it is initially determined as No, the process shifts from S55 to S53, but this is repeated until the deceleration DVw1 becomes equal to the threshold value B35. , S56, the flag P1 is set to 5 in S56, and the process shifts to phase V.
Next, in S57, the decompression time Td is calculated from the count value of the timer T3 and stored.

Next, at S58, a braking control signal preset for phase V is output to the first valve unit 20, and thereafter, the routine returns. Next, in the determination of S54
If No, it is determined whether or not the flag P1 is 5 in S59, and if the determination is Yes, the process shifts to S60.
In the case of o, the process proceeds to S67. When the flag P1 is 5, in S60, it is determined whether or not the slip ratio S1 is equal to or more than the 5-1 slip ratio threshold Bsz.

At first, since it is determined as No, S6
The transition from 0 to S58 is repeated. Then, in the phase V, when the slip ratio S1 increases and the determination in S60 becomes Yes, the process shifts to S61, and in S61,
The flag P1 is set to 1, the process proceeds to the phase I (pressure increase phase), and the continuation flag Fcn1 is set to 1.

Next, in S62, a rapid pressure increase time Tpz of the initial rapid pressure increase executed at the beginning of the phase I is calculated. This subroutine will be described later with reference to FIG. Next, in S63, the timer T1 for counting the elapsed time after the start of the phase I is reset and started, and then in S64, the count time T of the timer T1 is counted.
It is determined whether or not 1 is equal to or less than the rapid pressure increase time Tpz set in S62.
Then, in S65, a braking control signal preset for the initial rapid pressure increase in Phase I is output to the first valve unit 20, and the process returns.

Next, after the shift to the phase I, the determination in S59 becomes No.
In 67, it is determined whether the flag P1 is 1 or not.
When 1 is 1, the deceleration DVw1 is set to 1−1 in S68.
(2) It is determined whether or not it is equal to or lower than the intermediate deceleration threshold value B12. At first, since the determination is No, the process proceeds from S68 to S64, and before the rapid pressure increase time Tpz elapses, the process proceeds from S64 to S65.
Repeat to move to. While repeating this, after the transition to Phase I, when the surge pressure boosting period Tpz has passed, S64
Is determined to be No, the process proceeds from S64 to S66, and a braking control signal set in advance for the gradual pressure increase of the phase I is output to the first valve unit 20, and thereafter, the return is repeated.

Next, if the judgment in S68 is Yes, S6
9, the flag P1 is set to 2, and then in S70, based on the time measured by the timer T1, the pressure increase time Ti
(That is, the phase I period) is calculated and stored,
Thereafter, the flow shifts to S48. Thus, after the start of the ABS control, the control is executed over a plurality of cycles in the order of phase II, phase III, phase V, phase I, phase II, phase III,... When the switch 25 is turned off, A
The BS control ends (see FIG. 18).

Next, the rapid pressure increase time Tpz executed in S62
Will be described with reference to the flowchart of FIG. 11 and FIGS. 12 to 17. After the start of this subroutine, various data as shown in the figure are first read (S80), and then the return acceleration AVw1 at the time of shifting to the phase I is calculated (S81).
From the map shown in FIG. 17, the coefficient k as various correction coefficients
1 to k4 and the upper limit values Tuμ and Tuv are calculated.

Here, the coefficients k1 to k4 are set as characteristics as shown in FIGS. 12 to 15, using the return acceleration, the vehicle speed Vr, the road surface μ, and the pressure reduction time Td as parameters. The upper limits Tuμ and Tuv that regulate the upper limit of the rapid pressure increase time Tpz are set as characteristics as shown in FIGS. 16 and 17 using the road surface μ and the vehicle speed Vr as parameters, respectively.

Next, in S83, the rapid pressure increase time Tpz
Is calculated by the following equation from the pressure increase time Ti in the previous cycle calculated and stored in S70 and the coefficients k1 to k4. Rapid pressure increase time Tpz = Ti × k1 × k2 × k3 × k4
Next, at S84, it is determined whether or not the previous road surface μ is high and the current road surface μ is low.
86, and in S86, it is determined whether or not the previous road surface μ is low and the current road surface μ is high. If the determination is No, the process proceeds to S88.

On the other hand, if the result of the jump of the road surface μ is that the determination in S84 is Yes, a value obtained by subtracting a predetermined value Δ from the rapid pressure increase time Tpz in S85 is set as the current rapid pressure increase time Tpz. To S88, and S8
If the determination in step S6 is Yes, the rapid pressure increase time T
The value obtained by adding the predetermined value Δ to pz is set as the current rapid pressure increase time Tpz, and the flow shifts to S88. That is, the rapid pressure increase time Tpz is corrected so as to conform to the road surface μ of the current cycle. Next, in S88, it is determined whether or not the rapid pressure increase time Tpz is equal to or less than the upper limit value Tuμ. If the determination is Yes, it is determined in S90 whether or not the rapid pressure increase time Tpz is equal to or less than the upper limit value Tuv. At this time, the rapid pressure increase time Tpz is stored in the memory, and the process returns.

If the determination in S88 is No, in S89, the rapid pressure increase time Tpz is set equal to the upper limit Tuμ,
The rapid pressure increase time Tpz is stored in the memory, and the routine returns. If the determination in S90 is No, in S91, the rapid pressure increase time Tpz is set equal to the upper limit Tuv, the rapid pressure increase time Tpz is stored in the memory, and the routine returns.

Next, as shown in FIG. 12, the coefficient k1 is
Since it increases in accordance with an increase in the return acceleration AVw, the initial pressure increase amount can be set by indirectly considering the vehicle speed and the road surface μ.
As shown in FIG. 13, the coefficient k2 increases as the vehicle speed Vr increases, and thus the initial pressure increase amount takes into account that the pressure reduction amount decreases in accordance with the road surface reaction force proportional to the increase in the vehicle speed. Can be set appropriately. As shown in FIG. 14, the coefficient k3 decreases as the road surface μ decreases, so that the braking performance can be improved while controlling the lock. As shown in FIG. 15, the coefficient k4 becomes smaller as the decompression time Td becomes longer, so that the lock control can be achieved by suppressing an excessive sudden increase in pressure when the road surface μ is low.
As shown in FIG. 16, the upper limit value Tuμ decreases as the road surface μ decreases, so that an excessive rapid pressure increase can be suppressed by adapting to the road surface μ. As shown in FIG.
Since uv decreases as the vehicle speed Vr increases, excessive rapid pressure increase can be suppressed in accordance with the vehicle speed.

Next, the operation of the above-described ABS control will be described by taking the ABS control for the first channel as an example.
This will be described with reference to the time chart of FIG. In the ABS non-control state at the time of deceleration, the braking pressure generated by depressing the brake pedal 16 gradually increases, and the left front wheel 1
When the change rate (deceleration DVW1) of the wheel speed Vw1 of the first channel reaches -3G, the lock flag Flok1 of the first channel becomes 1
Is set, and the operation shifts to the ABS control from the time ta. In the first cycle immediately after the start of the control, the friction state value Mu is set to 3 indicating a high friction state,
Various control thresholds are set according to the traveling state parameters.

Next, the slip ratio S obtained from the wheel speed Vw1
1. The wheel deceleration DVw1 and the wheel acceleration AVw1 are compared with various control thresholds, the phase is changed from phase 0 to phase II, and the braking pressure is maintained at the level immediately after the pressure increase. When the slip rate S1 falls below the 2-3 intermediate slip rate threshold value Bsg, the phase shifts from phase II to III, the relief valve 20b is turned ON / OFF in a predetermined open / close mode, and the braking pressure is reduced to a predetermined gradient from time tb. , The braking force gradually decreases, and the rotational force of the front wheels 1 starts to recover. Further, the brake pressure is continuously reduced, and the wheel deceleration DVw1 is reduced to the threshold value B35 (0
When the pressure drops to G), the phase shifts from phase III to V, and from time tc, the braking pressure is maintained at the reduced level.

In this phase V, when the slip ratio S1 exceeds the 5-1 slip ratio threshold value Bsz, the continuation flag Fcnl is set to 1, and the ABS control shifts to the second cycle from time td. At this time, the process forcibly shifts to the phase I. Immediately after the shift to the phase I, as described above, the on-off valve 20a operates the pressure increasing time Ti
And various data obtained from the wheel speed Vw1 (return acceleration,
During the rapid pressure increase time Tpz set using the vehicle speed, the road surface μ) and the pressure reduction time Td of the previous cycle as parameters, the on-off valve 20a is opened at a duty ratio of 100% with the relief valve 20b closed and the braking pressure is increased. Is increased at a steep gradient, and after this rapid increase time Tpz has elapsed, the on-off valve 20a is operated at a predetermined duty ratio.
It is turned ON / OFF, and the braking pressure gradually increases with a gentler gradient. Thus, immediately after the transition to the second cycle, the braking pressure is reliably increased, and a good braking pressure is secured.

On the other hand, after the second cycle, an appropriate friction state value Mu is determined, and these friction state values Mu are determined.
Since various control threshold values corresponding to the traveling state parameters according to the vehicle speed Vr and the vehicle speed Vr are selected from the control threshold value setting table in FIG. 7, the precise control of the braking pressure according to the traveling state is performed. become. Thereafter, in the phase V of the second cycle, for example, when it is determined that the slip ratio S1 is larger than the threshold value Bsz, the process proceeds to the phase I of the third cycle.

In the ABS control according to the present embodiment, the pressure increase amount of the initial rapid pressure increase is set as the basic value with the pressure increase amount of the previous cycle.
In addition, return acceleration, vehicle speed Vr, road surface μ, decompression time T
To take into account not only the slip state of the wheels, but also the behavior of the vehicle and the road surface conditions, the initial pressure increase amount is set appropriately and with high accuracy, and braking is performed while suppressing locks. Performance can be enhanced. In addition, the initial pressure increase amount is limited by the upper limit set according to the road surface μ, and the upper limit is set by the upper limit set according to the vehicle speed. It is possible to suppress excessive initial pressure increase while adapting.

Here, it is needless to say that the present invention can be applied to a mode in which a part of the embodiment is changed as follows. 1) Although the initial pressure increase amount is set using the pressure increase time as a parameter, the braking pressure may be set as a parameter. However, in this case, the detection signal of the hydraulic pressure sensor that detects the braking pressure is used as needed. 2) In the brake control system of the embodiment, first to
Although it was configured to control three systems of the third channel,
An independent channel is provided for each of the four wheels so as to be controlled independently. 3) In the above embodiment, the cycle consisting of the four phases of pressure increase, pressure increase hold, pressure reduction, and pressure decrease hold is configured to be repeated. However, ABS control that repeats the cycle consisting of the pressure increase and pressure decrease two phases is performed. To be configured.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an anti-skid brake device for a vehicle according to an embodiment.

FIG. 2 is a chart of a μ table.

FIG. 3 is a flowchart of a pseudo vehicle speed calculation process.

FIG. 4 is a diagram of a map of a vehicle speed correction value.

FIG. 5 is a flowchart of a control threshold value setting process.

FIG. 6 is a table of a table in which traveling state parameters are set.

FIG. 7 is a table of a table in which various control thresholds are set.

FIG. 8 is a chart of a table in which correction values of various control thresholds are set.

FIG. 9 is a part of a flowchart of a control signal output process.

FIG. 10 is the remaining part of the flowchart of the control signal output process.

FIG. 11 is a flowchart of a sudden pressure increase time calculation subroutine.

FIG. 12 is a characteristic diagram of a coefficient k1 for setting a rapid pressure increase time.

FIG. 13 is a characteristic diagram of a coefficient k2 for setting a rapid pressure increase time.

FIG. 14 is a characteristic diagram of a coefficient k3 for setting a rapid pressure increase time.

FIG. 15 is a characteristic diagram of a coefficient k4 for setting a rapid pressure increase time.

FIG. 16 is a characteristic diagram of the upper limit of the rapid pressure increase time.

FIG. 17 is a characteristic diagram of the upper limit of the rapid pressure increase time.

FIG. 18 is an operation time chart of the anti-skid brake device.

[Explanation of symbols]

 1, 2 front wheel 3, 4 rear wheel 11-14 brake device 15 brake control system 27-30 wheel speed sensor 20, 21, 23 first to third valve unit 20a, 21a, 23a on-off valve 20b, 21b, 23b relief valve 24 control unit

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B60T 8/58

Claims (3)

(57) [Claims] 1. Anti-skid control for operating a wheel speed detecting means for detecting a rotation speed of a wheel, a hydraulic adjusting means for adjusting a brake oil pressure, and a hydraulic adjusting means based on a wheel speed detected by the wheel speed detecting means. And an anti-skid brake device for a vehicle in which the pressure increase in the anti-skid control of one cycle is performed by an initial rapid pressure increase and a subsequent gradual pressure increase. and pressure increase amount, based on the information obtained from the detected wheel speed by the wheel speed detecting means includes an initial pressure increase amount setting means for setting an initial pressure increase amount of the current cycle, the initial pressure increase amount setting means Is detected by the wheel speed detecting means.
The vehicle speed calculated from the wheel speeds
An anti-skid brake device for a vehicle, wherein the initial pressure increase amount is set to be small . 2. A wheel speed detecting means for detecting a rotational speed of a wheel.
Step, hydraulic adjustment means for adjusting the brake oil pressure, and wheel speed
Based on the wheel speed detected by the detector,
Anti-skid control means for moving
The pressure increase in the anti-skid control of
The anti-skip of the vehicle was made to run with a slow boost after
In the brake system, the anti-skid control means includes a pressure increase amount of a previous cycle.
And information obtained from the wheel speed detected by the wheel speed detecting means.
The initial pressure increase amount for the current cycle
The initial pressure increasing amount setting means, based on the wheel speed detected by the wheel speed detecting means, a friction state detecting means for detecting a road surface friction state, and the initial pressure increasing amount , vehicles antiskid brake system you characterized in that a an upper limit restricting means for setting an upper limit value corresponding to the road surface friction state detected by the friction state detecting means. 3. A wheel speed detecting means for detecting a rotational speed of a wheel.
Step, hydraulic adjustment means for adjusting the brake oil pressure, and wheel speed
Based on the wheel speed detected by the detector,
Anti-skid control means for moving
Of the pressure increase in Anchisuki head control, initial rapid pressure increase and its
The anti-skip of the vehicle was made to run with a slow boost after
In the brake system, the anti-skid control means includes a pressure increase amount of a previous cycle.
And information obtained from the wheel speed detected by the wheel speed detecting means.
The initial pressure increase amount for the current cycle
It includes a period pressure increase amount setting means, the initial pressure increase amount setting means, the initial pressure increase amount upper limit regulation for setting an upper limit value corresponding to the vehicle speed which is calculated from the detected wheel speed by the wheel speed detecting means vehicles antiskid brake system you <br/> characterized in that a means.