JPH08332940A - Anti-skid control device - Google Patents

Abstract

PURPOSE: To avoid mis-determination of gear engagement as a bad road to prevent execution of improper anti-skid control. CONSTITUTION: In the case of two-wheel driving, gear engagement is determined as detected when a rotation speed increase/decrease frequency of a drive wheel is larger than that of a driven wheel by a set frequency difference or more (S305, 306). In the case of four-wheel driving, gear engagement is determined as detected when an estimated car body speed is less than a set car body speed (S308), and in the case where a road surface friction coefficient is determined to be low because of a small car body deceleration during anti-skid control (S309, 310). In a normal condition where gear engagement is not detected, in the case where wheel rotation speed increase/decrease frequency is large, it is detected as a bad road, and control conditions of anti-skid control are changed to control brake cylinder pressure to be higher than that on a good road, while if gear engagement is determined as detected, the control conditions are not changed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antiskid control device for a vehicle equipped with a manual transmission, and more particularly to optimizing control when a gear is engaged.

[0002]

2. Description of the Related Art When braking a vehicle equipped with a manual transmission, if the braking is continued with the clutch engaged while the reduction ratio is small, the driving torque fluctuations of the drive wheels increase when the vehicle speed decreases. This phenomenon is called gear engagement. Gearing occurs because the engine rotation speed is forcibly reduced by the drive wheels via the manual transmission, the engine cannot rotate smoothly, and the drive torque fluctuates, and the friction coefficient of the road surface is low. In this case, the drive wheel easily slips on the road surface as the drive torque fluctuates, and appears as vibration of the rotation speed. The vibration at this rotation speed is referred to as geared vibration. The vibration with gears causes various inconveniences such as making passengers feel uncomfortable and adversely affecting the durability and anti-skid control accuracy of the vehicle. It is obvious that the passengers are uncomfortable and the durability of the vehicle is adversely affected, but the reason why the antiskid control accuracy is adversely affected is as follows.

For example, in the anti-skid control device disclosed in Japanese Patent Laid-Open No. 2-310159, a bad road / a good road is determined depending on the frequency of increase / decrease of wheel rotational acceleration, and the control suitable for each is performed. However, if the rotation speed of the drive wheels is disturbed by the vibrations in the gears, if it is erroneously determined that it is caused by a bad road, improper anti-skid control will be performed. Will be lost. If the gear enters when anti-skid control is being performed, or if the anti-skid control is triggered by the occurrence of gear engagement, the rotational frequency of the drive wheels increases and decreases frequently. Is judged to be a bad road even though it is a good road, and control is performed to make the hydraulic pressure of the brake cylinder of the hydraulic brake device (called the brake cylinder pressure) higher than that of a good road. Become. However, since the gear entering vibration occurs when the road surface friction coefficient is relatively small as described above, the control for increasing the brake cylinder pressure is the control in the opposite direction to the desired direction, and the gear entering is suppressed. It is not desirable to be mistakenly judged as a bad road. Further, the occurrence of gear vibration reduces the wheel rotation acceleration calculated or estimated based on the wheel rotation speed, the road friction coefficient, the size of unevenness, and the accuracy of road surface step determination, and is executed based on these. Reduce the accuracy of anti-skid control.

[0004]

Therefore, it is detected whether or not gear engagement has occurred, and if gear engagement is detected, the control conditions for anti-skid control are changed to those suitable for gear engagement, etc. It is desirable to take the measures of. Then, the subject of the 1st invention of this application is to obtain the anti-skid control device which can satisfactorily avoid the fall of control accuracy by gear entering vibration.

[0005]

In order to solve the above problems, the present invention relates to a brake for suppressing the rotation of a wheel of a vehicle equipped with a manual transmission based on a slip state of the wheel and a predetermined control condition. When the anti-skid control device that controls the hydraulic pressure of the brake cylinder to keep the slip ratio of the wheels near an appropriate value, the gear engagement detection device that detects gear engagement and the gear engagement detection device detects gear engagement. The control condition changing means is provided for changing the control condition to a control condition in which the hydraulic pressure of the brake cylinder is controlled to be low as compared with the case where the gear engagement is not detected.

[0006]

The anti-skid control device according to the present invention has a gear engagement detecting device for detecting gear engagement. When gear engagement is detected by the gear engagement detection device, as compared with the case where gear engagement is not detected. Lower the brake cylinder pressure. For example, when the anti-skid control device includes a means for detecting a bad road and controls the brake cylinder pressure to be higher on a bad road than on a good road,
If the control to raise the brake cylinder pressure is stopped when a gear engagement is detected, or if the anti-skid control device does not have a means for changing the control of the brake cylinder pressure between a bad road and a good road. , If a gear engagement is detected, it is highly possible that the road surface friction coefficient is low,
The brake cylinder pressure is controlled to be lower than usual. To lower the hydraulic pressure in the brake cylinder, accelerate the decompression start time of the anti-skid control, control the decompression gradient to be steep, delay the decompression end timing or the pressure increase start timing, and gradually increase the pressure increase gradient. There are various methods, such as the setting, and any method may be used.

As the gear engagement detecting means of the gear engagement detecting device, for example, the following can be used. (1) A low speed / low μ-dependent gear engagement estimating means for estimating gear engagement based on a wheel rotation speed increase / decrease frequency, a vehicle speed, and a road surface friction coefficient. If gear vibration occurs, the wheel rotation speed increases and decreases rapidly, so it is natural to consider the wheel rotation speed increase / decrease frequency in estimating gear engagement. However, the frequency of wheel rotation speed increase / decrease increases even on a rough road. Therefore, the vehicle speed and the road surface friction coefficient are considered in addition to the frequency of wheel rotation speed increase / decrease. As mentioned above, gear engagement is a phenomenon that occurs when the vehicle speed becomes low, and even if gear engagement occurs, gear engagement vibration is a problem if the road surface friction coefficient is not small. Is not generated, it is effective to consider the vehicle speed and the road surface friction coefficient in estimating the gear engagement. Even on bad roads
It is possible that the vehicle speed and the road surface friction coefficient both become low by accident. Therefore, if the gear engagement is estimated on the basis of the wheel rotation speed increase / decrease frequency, the vehicle speed, and the road surface friction coefficient, it cannot be said that there is no error. But the bad road,
Since there is no direct relationship between the low vehicle speed and the low friction coefficient, the probability that these three accidentally overlap is not high, and if the vehicle speed and the friction coefficient are taken into consideration in estimating the occurrence of gear engagement, It is possible to significantly reduce the possibility of accidentally determining that the gear is engaged even though the road is actually bad.

(2) Drive wheel / non-drive wheel comparison type gear engagement estimating means for estimating gear engagement based on the frequency of increase / decrease in rotational speed between the drive wheel and the non-drive wheel. The gear vibration occurs on the drive wheels and not on the non-drive wheels. On the other hand, it is common to the driving wheels and the non-driving wheels that the rotation speed increases and decreases more frequently due to the bad road. Therefore, if the rotational speed increase / decrease frequency of the drive wheels is high and the rotational speed increase / decrease frequency of the non-drive wheels is low, it is appropriate to estimate that gear engagement has occurred. However, it is possible that the road surface on which the driving wheels are riding is a bad road and the road surface on which the non-driving wheels are riding is a good road. However, the rotational speed increase / decrease frequency of the drive wheels is large, and the rotational speed increase / decrease frequency of the non-drive wheels is small. For other reasons, the rotational speed of the non-driving wheels increases / decreases more frequently due to the vibration of the driving wheels with gears. It's not impossible. In these cases, the second gear engagement estimating means makes an incorrect estimation, and as described above, there is a possibility that the first gear engagement estimating means may make an estimation error. Therefore, it is meaningful to provide both the first and second gear engagement estimating means.

When both gear engagement estimating means are provided,
It is also possible to independently use the estimation results of the gear engagement estimating means for different purposes. In that case, it is sufficient if the gear engagement detecting device has both gear engagement estimating means. When the estimation results of the means are used together, a gear engagement detection device is provided in addition to both gear engagement estimation means, and an estimation result processing means for determining whether gear engagement has occurred from those estimation results is provided. Will be required. The estimation result processing means may be an AND type processing means that determines that the gear is engaged when both the gear engagement estimating means estimate the occurrence of the gear engagement, and does not determine that the gear is engaged in other cases. It is also possible to use an OR type processing means that determines that the gear is engaged if at least one of the both gear engagement estimating means estimates the gear engagement. If it is important to avoid accidentally detecting gear engagement even when gear engagement is not occurring, use the AND type processing means. Conversely, if gear engagement is occurring, it is not detected. When it is important to avoid this, the OR type processing means is used. Furthermore, it is possible to provide both the AND-type processing means and the OR-type processing means, and use them properly according to the purpose.

However, the second gear engagement estimating means can be provided only in a vehicle having both driving wheels and non-driving wheels. For example, in the case of a two-wheel drive vehicle, one of FF (front engine / front drive), FR (front engine / rear drive), MR (midship engine / rear drive), and RR (rear engine / rear drive) can be used. A four-wheeled vehicle can also be provided with a second gear engagement estimating means, and even a four-wheeled vehicle can be regarded as a non-driving wheel if there is a time when it is in a non-driving state if it is a part-time system. Although the entrance estimation means can be provided, it cannot be provided because there are no non-driving wheels in a full-time four-wheel drive vehicle.

The wheel rotation speed increase / decrease frequency detecting means is
For example, the number of times the rotational speed itself increases and decreases per hour (a combination of an increase and a decrease each time may be counted as 1, and each increase or decrease may be counted as 1). May be detected). In this case, it is desirable to use, as the rotation speed of each wheel, the output of the wheel speed sensor from which noise has been removed. It is also possible to ignore the increase or decrease in which the amount of increase or decrease in one time does not exceed the set amount and not count it. The wheel rotation speed increase / decrease frequency detection means also
It is also possible to detect the increase / decrease frequency based on the rotational acceleration obtained by differentiating the rotational speed. For example, the number of times per hour when the rotational acceleration or the absolute value of the rotational acceleration exceeds the set acceleration value is counted.

The vehicle speed detecting means includes a wheel speed sensor and a vehicle speed estimating means for estimating the vehicle speed based on the rotational speed of the wheel detected by the wheel speed sensor. The detecting means may also be a dedicated vehicle speed detecting means such as a Doppler type ground vehicle speed sensor that detects the relative moving speed of the vehicle body with respect to the road surface based on the Doppler effect of the transmitted wave and the received wave reflected on the road surface. Is also possible.

The road surface friction coefficient detecting means is, for example, a vehicle deceleration acquiring means for acquiring the vehicle deceleration during the anti-skid control, and the road surface friction coefficient is increased as the vehicle deceleration acquired by the vehicle deceleration acquiring means increases. It is possible to include a road surface friction coefficient estimating means for largely estimating. The vehicle deceleration can be acquired by detecting it with an acceleration sensor attached to the vehicle body or by differentiating the vehicle speed. Further, the road surface friction coefficient estimating means may estimate the vehicle deceleration from a vehicle deceleration at a predetermined specific time such as at the time of starting the antiskid control, and the slip ratio increases to about 10 to 30% during the antiskid control. It is also possible to use the value at the point of taking the maximum value (so-called μ peak point) as the value of the road surface friction coefficient. In addition, the road surface reflectance detecting means for detecting the regular reflectance or irregular reflectance on the road surface of transmission signals such as ultrasonic waves and light, and the smaller the regular reflectance detected by the road surface reflectance detecting means, or the irregular reflectance is Including a road surface reflectance-based road surface friction coefficient estimating means for estimating a larger road surface friction coefficient, a relative rotation suppressing device for gently suppressing relative rotation of left and right wheels, and a turning radius for detecting a turning radius of a vehicle. Detecting means, vehicle speed detecting means for detecting the vehicle speed, rotating speed difference detecting means for detecting the rotating speed difference between the left and right wheels, and a rotating speed difference based on the detected turning radius, vehicle speed and rotating speed difference. In combination with a turning road surface friction coefficient estimating means for estimating the road surface friction coefficient as it becomes larger, the diameters of the left and right wheels are slightly different in the above.
Various road surface friction coefficient detecting means, such as one capable of detecting the road surface friction coefficient even when the vehicle goes straight, can be adopted.
The relative rotation suppressing device preferably suppresses relative rotation of the left and right wheels only when the road surface friction coefficient needs to be detected.

(3) Front / rear wheel comparison type gear engagement estimating means for estimating gear engagement based on the difference between the rotational vibration states of the front wheels and the rear wheels. In the two-wheel drive vehicle, as described above, the gear-induced vibration is generated in the drive wheels, whereas it is not generated in the non-drive wheels, so that the rotational vibration state is different between the front wheels and the rear wheels.
Even in a four-wheel drive vehicle, the rotational vibration may differ between the front wheels and the rear wheels due to the difference in load. For example, a front engine vehicle usually has a large load on the front wheels, and in particular, during braking, the load increases due to the inertia of the vehicle body. When geared vibration occurs in this state, the degree of slippage differs between the front wheels and the rear wheels due to the difference in surface pressure between the tire and the road surface. Furthermore, since there is a difference in the driving force transmission system between the front wheels and the rear wheels, this difference may cause a difference in the occurrence state of gear-induced vibration. Therefore, the rotational vibration states of the front wheel and the rear wheel such as the rotational speed and the amplitude of the rotational acceleration are different from each other, and the gear engagement can be detected. (4) Suspension vibration-based gear entry estimating means for estimating gear entry based on the fact that the vibration state of the drive wheel suspension during braking varies due to gear entry. In most cases, gear vibration does not occur at the beginning of the braking period. Therefore, when gear engagement occurs during the braking period, the vibration state of the suspension usually changes at the same time that gear engagement occurs, and it is possible to detect gear engagement. In this case, the vibration state means amplitude, frequency, vibration acceleration, etc., and at least one of these values is adopted. For example, each of these values fluctuates by more than a set value with reference to these values at the start of braking. Sometimes it is determined that gearing has occurred.

(5) Front / rear suspension vibration comparison type gear engagement estimating means for estimating gear engagement based on a difference in vibration states of suspensions of front and rear wheels during a braking period. In the two-wheel drive vehicle, as described above, the vibration with the gear is generated in the drive wheel, whereas the vibration is not generated in the non-drive wheel, and therefore the suspension vibration is also different. Even in a four-wheel drive vehicle, as described above, the rotational vibration state varies due to the difference in load between the front wheels and the rear wheels and the difference in the driving force transmission system. As a result, the vibration of the suspension between the front wheels and the rear wheels occurs. Differences occur in the state, and it becomes possible to detect gear engagement.

(6) Load torque vibration-dependent gear engagement estimating means for estimating gear engagement based on the vibration state of the load torque of the driving force transmission system during the braking period. The vibration generated in the drive system due to the occurrence of gear engagement can be detected as, for example, the vibration of the load torque value of the driving force transmission shaft. As a method of detecting torque, a torque sensor including a strain gauge attached to the driving force transmission shaft and a slip ring for supplying energy to the strain gauge and acquiring a detected torque signal, the surface of the driving force transmission shaft is coated. A torque sensor using photoelasticity, which utilizes the fact that the deflection direction of light passing through the photoelastic body changes according to the magnitude of the strain on the surface of the driving force transmission shaft, that is, the magnitude of the torque There is a non-contact magnetic torque sensor that utilizes deflection in the easy magnetization direction due to the inverse magnetostrictive effect that occurs when an external force is applied to the magnetic body, and any of these may be used. In addition to the driving force transmission shaft, the gear engagement may be detected based on the output value of a stress detection means such as a strain gauge attached to another component affected by vibration.
The gear vibration detection means described in (3) to (6) above can be used regardless of whether the drive system is two-wheel drive or four-wheel drive.

[0017]

As is apparent from the above description, according to the present invention, more appropriate anti-skid control can be performed by incorporating the information on the gear engagement acquired by the gear engagement detection device into the anti-skid control. It will be possible.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments of each invention will be listed and related explanations will be given if necessary. (1) The gear engagement detection device detects a vehicle speed, a vehicle speed detection unit, a wheel rotation speed increase / decrease frequency detection unit that detects an increase / decrease frequency of the rotation speed of each wheel, and friction of a road surface while the vehicle is traveling. Having a road surface friction coefficient detecting means for detecting a coefficient, and a low speed / low μ dependent type gear entering estimating means for estimating gear entering based on the detection result of these detecting means,
It has a drive wheel rotational speed increase / decrease frequency detection means for detecting the rotational speed increase / decrease frequency of the drive wheel and a non-drive wheel rotational speed increase / decrease frequency detection means for detecting the rotational speed increase / decrease frequency of the non-driving wheel. The anti-skid control device according to claim 1, further comprising at least one of driving wheel / non-driving wheel comparison type gear engagement estimating means for estimating gear engagement based on a frequency of increase / decrease in rotational speed with the wheel. Aspect 1 also includes an aspect in which a plurality of set values are provided for at least one of vehicle speed, wheel rotation speed increase / decrease frequency, and road surface friction coefficient, and the possibility of gear engagement is estimated in more stages. . If multiple set values are provided for the vehicle speed, the wheel rotation speed increase / decrease frequency, and the road surface friction coefficient, the possibility of gear engagement is set at multiple levels based on the combination of the magnitude relationship for each set value of each amount. It will be possible to do. Aspect 1 further includes an aspect in which the magnitude of the possibility of gear engagement is continuously estimated corresponding to the combination of the vehicle speed, the wheel rotation speed increase / decrease frequency, and the road surface friction coefficient. ing. (2) The low speed / low μ-dependent geared estimation means is used by the vehicle speed V _S , the wheel rotation speed increase / decrease frequency H, and the road friction coefficient μ.
But each setting value V _SS, H _S, with respect mu _S, V _S
The anti-skid control device according to claim 1 or claim 1, wherein when <V _SS , H> H _S and μ <μ _S , it is presumed to be geared. The low speed / low μ-based gear engagement estimating means calculates the vehicle speed V _S , the wheel rotation speed increase / decrease frequency H, and the road surface friction coefficient μ
When V _S <V _SS , H> H _S and μ <μ _S with respect to the respective set values V _SS , H _S and μ _S preset using a priori information, gear engagement Presumed to be This mode 2 corresponds to the simplest embodiment of the gear engagement estimating means. (3) The low-speed / low-μ-based gear engagement estimating means uses the first set (V _S1 , H ₁ , μ ₁ ) of the vehicle speed, the wheel rotation speed increase / decrease frequency, and the road surface friction coefficient and the second value. Pair (V _S2 , H ₂ ,
μ ₂ ) and V _S1 ≦ V _S2 , H ₁ ≧ H ₂ , μ ₁ ≦ μ ₂
Are respectively satisfied, and | V _S2 −V _S1 |, |
_3. It is estimated that the larger the value of at least one of H ₁ −H ₂ | and | μ ₂ −μ ₁ | is, the greater the possibility of gear engagement is. Anti-skid control device described in one. The possibility of gear engagement is estimated so that the size changes in response to changes in at least one of the vehicle speed, the wheel rotation speed increase / decrease frequency, and the road surface friction coefficient. The change may be continuous or stepwise. (4) The drive-wheel / non-drive-wheel comparison type geared estimation means is in gear when the rotational speed increase / decrease frequency for the drive wheels is larger than the rotational speed increase / decrease frequency for the non-drive wheels by a preset frequency difference or more. The antiskid control device according to claim 1, wherein the antiskid control device is estimated as follows. The larger the setting frequency difference, the smaller the possibility of accidentally estimating that the gear is engaged even though the gear is not engaged. (5) The drive wheel / non-drive wheel comparison type gear engagement estimating means estimates the possibility of gear engagement as the rotational speed increase / decrease frequency for the drive wheel is greater than the rotational speed increase / decrease frequency for the non-drive wheel. Claim 1, Aspect 1
4. The anti-skid control device according to any one of 4 above. It is highly estimated that gearing is likely to occur depending on the change in the frequency difference between the rotational speed increase / decrease frequency for the drive wheels and the rotational speed increase / decrease frequency for the non-drive wheels. The change between the frequency difference and the possibility of being in gear may be continuous or stepwise. (6) The gear engagement detection device has both the low speed / low μ-dependent gear engagement estimation means and the drive wheel / non-drive wheel comparison gear engagement estimation means, and the drive system of the drive wheels is changed. 2. The estimating means effective state changing means for changing the effective states of the low speed / low μ dependent type geared estimating means and the driving wheel / non-driving wheel comparison type geared estimating means in accordance with
The anti-skid control device according to any one of to 5.
The estimating means effective state changing means may be, for example, one that selectively activates the low speed / low μ-dependent gear entering estimating means and the driving wheel / non-driving wheel comparing type gear entering estimating means, or both gear entering estimation. Alternatively, it is possible to selectively select a state in which both means are effective and a state in which only the low speed / low μ-based gear engagement estimating means is effective. The timing of changing the valid state by the estimating means valid state changing means may be variously changed. For example, in a part-time four-wheel drive vehicle, the effective state may be changed according to switching between the four-wheel drive state and the two-wheel drive state. Further, a gear entering detection device common to a four-wheel drive vehicle and a two-wheel drive vehicle is manufactured, and a low speed / low μ dependency is obtained by the estimating means effective state changing means depending on which drive method the vehicle is equipped with. It is possible to change the effective states of the type gear inset estimation means and the drive wheel / non-drive wheel comparison type gear inset estimation means, in which case the effective state is changed at the time of manufacturing the vehicle. (7) The control condition changing means includes a decompression start timing advancing means for changing the control condition so that the decompression start timing of the anti-skid control is advanced when the gear engagement is detected, as compared to when the gear engagement is not detected. The anti-skid control device according to any one of claims 1 and 1 to 6. (8) The control condition changing means changes the control condition so that the depressurization gradient of the anti-skid control becomes steeper when the gear engagement is detected than when the gear engagement is not detected. An anti-skid control device according to any one of claims 1 to 7 including. (9) The control condition changing means changes the control condition so that the pressure increasing gradient of the anti-skid control becomes gentler when the gear engagement is detected than when the gear engagement is not detected. 9. The antiskid control device according to claim 1, further comprising: (10) The anti-skid control device according to any one of claims 1 and 1 to 9, further comprising an informing unit for informing the outside of the occurrence of the gear engagement when the gear engagement is detected. The output of the notification means is used, for example, as a trigger signal for turning on an indicator for notifying the operator of occurrence of gear engagement, ringing of a buzzer, operation of an automatic clutch disengagement device when gear engagement occurs in a manual transmission, and the like. be able to. In the latter, a clutch that is normally disengaged by an operator is provided with an actuator such as an air cylinder, a hydraulic cylinder, or an electric cylinder to provide an automatic clutch disengagement device that disengages the clutch automatically.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. In the present embodiment, a function for detecting gear engagement is added to an anti-skid control device that can perform different control depending on whether the road surface is a bad road or a good road. It is possible to perform anti-skid control.

First, the hardware configuration of this embodiment will be described. In FIG. 1, reference numeral 10 is a brake pedal, which is linked to a master cylinder 14 via a booster 12. The master cylinder 14 is a tandem type in which two pressurizing chambers are arranged in series with each other, and the brake pressures of the same height are generated in the pressurizing chambers. This brake circuit is an X piping type in which two independent brake systems are arranged in an X shape. In the first brake system, one pressurizing chamber of the master cylinder 14 is connected to the brake cylinder 26 of the brake for the left rear wheel RL via the liquid passage 20, the normally open type electromagnetic opening / closing valve 22 and the liquid passage 24. The liquid passages 20 and 30, the normally open type electromagnetic on-off valve 32, and the liquid passage 34 are connected to the brake cylinder 36 of the brake for the right front wheel FR. On the other hand, in the second brake system, the other pressurizing chamber passes through the liquid passage 40, the normally open type electromagnetic on-off valve 42 and the liquid passage 44, and then the left front wheel F.
The brake cylinder 46 of the L brake is connected to the brake cylinder 46 of the right rear wheel RR via the liquid passages 40, 48, the normally open type solenoid valve 50 and the liquid passage 52. Has been done.

Further, in the first brake system, the liquid passage 24 is a normally closed type electromagnetic on-off valve 60.
The liquid passage 34 is also connected to the reservoir 64 via a normally closed electromagnetic opening / closing valve 62. The reservoir 64 is connected to the suction port of the pump 66, and the discharge port thereof is connected to the liquid passage 20. On the other hand, in the second brake system, the liquid passage 44 passes through the normally closed electromagnetic on-off valve 68,
The liquid passage 52 is also a normally closed solenoid valve 7
Each of them is connected to the reservoir 72 via 0. The reservoir 72 is connected to the suction port of the pump 74, and the discharge port thereof is connected to the liquid passage 40. Then, the two pumps 66 and 74 share a common motor 76.
Driven by Therefore, for example, with respect to the brake pressure of the left rear wheel RL, a pressure-increased state is realized by making the electromagnetic opening / closing valves 22 and 60 both non-energized.
The holding state is realized by energizing only the electromagnetic on-off valve 22, and the depressurized state is realized by energizing both the electromagnetic on-off valves 22 and 60. The same applies to the brake pressures of the other wheels. That is, the brake pressure of each wheel is selectively realized by the combination of the open / closed states of the two electromagnetic opening / closing valves, that is, the pressure increasing state, the holding state, and the pressure reducing state. The signals supplied to the respective electromagnetic on-off valves for realizing the pressure increasing state, the holding state and the pressure reducing state are referred to as a pressure increasing signal, a holding signal and a pressure reducing signal, respectively.

The electromagnetic on-off valve 22 and the like are the electronic control unit 8
Controlled by 0. As shown in FIG. 2, the electronic control unit 80 is mainly composed of a computer 82, and has a CPU 84, a ROM 86, a RAM 88, and a timer 9.
0, an input interface circuit 92 and an output interface circuit 94. The output interface circuit 94 is connected to the motor 7 via each driver 96.
6 and the solenoid on-off valve 22 are connected to each other.
On the other hand, the input interface circuit 92 is provided with four wheel speed sensors 100, 10 via each buffer amplifier 98.
2, 104, 106, a stop lamp switch 110, and an acceleration sensor 120 are connected to each other. Each wheel speed sensor 100, 102, 104, 106 detects the rotation of the rotor that rotates with each wheel.
The stop lamp switch 110 is for acquiring the depression of the brake pedal 10 by the driver. Further, the acceleration sensor 120 measures the deceleration applied to the vehicle being braked. The acceleration sensor used in this embodiment classifies the magnitude of acceleration into three levels of high, medium, and low, and a sensor that can be further finely classified and a continuous output corresponding to the magnitude of acceleration are obtained. The sensor may be used.

Next, the software configuration of this embodiment will be described. Various programs necessary for the control of this embodiment are stored in the ROM 86 in advance. The representative ones will be described below. (1) Anti-skidding domain routine This routine is continuously executed while the ignition switch is ON unless a system abnormality described later occurs. As shown in FIG. 3, first, an initialization process is performed in step S101 (hereinafter, simply referred to as S101. The same applies to other steps). In this step, timer interrupts 1 and 2 and a vehicle speed sensor interrupt, which will be described later, are enabled, and the values of flags, counters, and registers, which will be described later, are initialized. At this time, the flag is turned off, the counter is cleared, and the register is set to zero. These flags, counters and registers are provided in the RAM 88. Note that turning the flag ON / OFF means, specifically, writing a value indicating ON / OFF by the CPU in the address of the RAM 88 defined as the flag.
To simplify the description, it is simply noted that the flag is turned ON / OFF. In the case of a counter, the contents of the address in the RAM 88, which is defined as a counter, is incremented / decremented or cleared by one by the CPU 84, but the counter is simply incremented / decremented or reset. Is written. In the case of a register, it is almost the same as the counter, but it is used as an area for storing an arbitrary value. The flags that are turned off in S101 are the braking flag F _ACT and the system abnormality flag F _AB.
The counter that is _N and is reset is the clock counter C.
_TIM , each wheel road surface state detection counter C _SF (i), each wheel vehicle speed sensor pulse counter C _VS (i), and the registers that are set to zero are each wheel anti-skid state display register R.
_CON (i), road surface state display register R _SF , front wheel road surface state display register R _SFF , rear wheel road surface state display register R _SFR
Is.

Next, in S102, it is determined whether or not the stop lamp switch is ON. If the stop lamp switch is ON, it means that braking is in progress, and the following S
In 103, a braking flag F indicating whether or not braking is being performed.
_ACT is turned on. Stop lamp switch is off
In case of, the braking flag F _ACT is turned off in S104. In the process of the present embodiment, the state of the stop lamp switch is detected only in S102 for determining whether or not braking is being performed. When it is detected in another step whether or not braking is being performed, the ON / OFF state of the braking flag F _ACT is detected. Next, S105, S106, and S107 executed are a road surface state determination process, an estimated vehicle body speed calculation process, and a reference speed calculation process, which will be described later, respectively.

Thereafter, in S108, it is determined whether or not the system abnormality flag F _ABN is ON. The system abnormality flag F _ABN is turned ON when a system abnormality is recognized in the pressure reduction time monitoring process in the timer interrupt 1 process described later. If no abnormality is recognized, the process from S102 is restarted. If an abnormality is found in the system, system abnormality processing is executed in S109. In the system error processing, the error indicator lamp is turned on to notify the operator, and timer interrupts 1 and 2
Also, acceptance of all external interrupts is prohibited. Then, a continuous pressure increase process is performed in S110. Therefore, when the system abnormality is detected, the anti-skid control is not executed, and the pressure continuously increases.

(2) Road Surface State Discrimination Routine In this routine, the value of the road surface state display register R _SF corresponding to the road surface state is set to 0 for a good road and 1 for a bad road. It is set to 2 in case of a terrible road, and is executed for each wheel. The road surface state display register R _SF has only three values, 0, 1, and the initial value is zero. As shown in FIG. 4, first, in S201, a branch is made to the process according to the value of the road surface state display register R _SF set last time. In the case of a good road, it is judged whether or not the road has changed to a bad road or a bad road. If it is judged as a bad road or a bad road, the value of the road surface state display register R _SF is incremented by 1 to 1 And will represent a bad road. Specifically, in S202, it is determined whether or not the value of the clock counter C _TIM is greater than or equal to the set count value Cα,
If the result is NO, the road surface state determination processing ends. S
If the result of 202 is YES, the counter C _SF (i) for detecting each road surface condition is set to the first counter set value C in S203.
It is determined whether _TH1 or more. However, an asterisk in the figure indicates that each wheel road surface state detection counter C _SF (i) whose determination corresponds to at least one of the front wheels and at least one of the rear wheels is the first counter set value C _TH1.
It is indicated that the determination is YES when the above is the case.
Also in S209, S210, and S212 described below, in order for the determination result to be true, the value of each wheel road surface state detection counter C _SF (i) corresponding to at least one of the front wheels and at least one of the rear wheels is Both must be values that make each judgment expression true. If the result of S203 is YES, it is determined that the road is a bad road, the road surface state register R _SF is incremented in S204, and then the gear engagement estimation process described below is performed in S205. Subsequently, in S206, each wheel road surface state detection counter C _SF (i) is cleared, and in S207, the clock counter C _TIM is cleared, and the road surface state determination processing ends. If the result of S203 is NO, S206, S
After performing the process of 207, the road surface state determination process ends.

Next, in the case of a bad road, it is judged whether or not the road has changed to a good road or a bad road, and if it is a good road, the road surface state display register R _SF is decremented to 0,
It becomes a state showing a good road. If the road is a terrible road, the road surface state display register R _SF is incremented to 2 and becomes a state indicating a terrible road. Specifically, first in S208, it is determined whether or not the value of the clock counter C _TIM is greater than or equal to the set count value Cβ, and if the result is NO, the road surface state determination process ends. Therefore, the road surface status display register R _SF remains 1. If the result of S208 is YES, S
At 209, it is determined whether each wheel road surface state detection counter C _SF (i) is greater than or equal to the first counter set value C _TH1 . S
If the result of 209 is NO, it is determined that the road has changed from a bad road to a good road, and the road surface state display register R _SF is decremented to 0 in S213 and then S206, S20.
The processing of No. 7 is performed, and the road surface state determination processing ends. S2
If the result of 09 is YES, in S210, each wheel road surface state detection counter C _SF (i) is further set to the second counter set value C.
It is determined whether _TH2 or more. If the result of S210 is NO, it is determined that the road is not a bad road, and S206, S
After the processing of 207 is performed, the road surface state determination processing ends. If the result of S210 is YES, after the road surface state display register R _SF is set to 2 in S204, S205, S2
06 and S207 are sequentially executed, and the road surface state determination processing ends.

In the case of a terrible road, in S211, the clock counter
C_TIMIs greater than or equal to the set count value Cγ.
If the result is NO, the road surface condition determination processing is finished as it is.
Complete. If the result of S211 is YES, in S212
Each road surface condition detection counter C _{science fiction}(I) is the second counter setting
Fixed value C_TH2 It is determined whether or not the following, and the result is NO.
If there is a bad road, the road surface status display register R_{science fiction}
The value of remains unchanged at 2, and S206 and S207 are sequentially
After that, the road surface state determination process ends. Result of S212
Is YES, the road surface condition display register R is determined in S213.
_{science fiction}After the value of is set to 1, the processing of S206 and S207
The next execution is performed, and the road surface state determination processing ends.

Therefore, basically, if each wheel road surface state detection counter C _SF (i) is less than the first counter setting value C _{TH1, the} value of the road surface state display register R _SF is set to 0, and the first counter setting is made. Second counter set value C when the value is C _TH1 or more
If it is less than _TH2, it is set to 1 and the second counter set value C _TH2
If it is above, the value is set to 2, and the larger the value of the road surface state display register R _SF , the worse the road surface state is displayed.
However, if it is estimated that there is a high possibility of gear engagement in S205 (gear engagement estimation processing), which will be described in detail later,
The value of the road surface state display register R _SF is decremented during execution of S205, and the increment of the value of the road surface state display register R _SF performed in S204 is invalidated. Therefore, even if the value of each wheel road surface state detection counter C _SF (i) is large, the value of the road surface state display register R _SF does not change when the possibility of gear engagement is high, and the brake cylinder when gear engagement occurs Excessive increase in pressure is suppressed.

(3) Gear engagement estimation routine This routine is included in the road surface condition determination routine and
Processing can be changed depending on whether it is dynamic or four-wheel drive
It is something. As shown in FIG. 5, first, in S301,
The motion method is determined. Specifically, in the case of a two-wheel drive vehicle
It is always judged to be a two-wheel drive, and it is a part-time system 4
In a wheel drive vehicle, for example, a manual switch
Determined by switching between 4 wheel drive state and 2 wheel drive state
It will be configured. When the determination result of S301 is two-wheel drive
If so, in S302, the road surface condition detection counter C for each wheel_{science fiction}
(I) is cleared, and the clock counter C in S303_TIMBut
Cleared. Each road surface condition detection counter C_{science fiction}(I) Oh
And clock counter C_TIMSee later for the tie
Ma interrupt 2 routine and rough road counter processing in FIG.
It will be described in relation to the routine. Clock counter in S304
C_TIMIs greater than or equal to the set count value Cδ, in S305
Front wheel road condition display register R_SFF， Rear road surface condition display
Dista R_SFRThe value to be stored in
Wheel condition display register R_SFFAnd rear wheel road condition display cash register
Star R_SFRThe absolute value of the difference between and is the counter set value C_THSince
It is determined whether or not it is above. Here, the front wheel road surface condition table
Indicating register R_SFFAnd rear wheel road condition display register R_SFRof
Although various methods can be considered for calculating the value, here, the front wheel is used.
Each road surface condition detection counter C_{science fiction}The average value of (i) is the front wheel
Road condition display register R_SFFStored in each rear wheelway
Surface status display register C_{science fiction}The average value of (i) is the rear road surface condition
Display register R _SFRShall be stored in. S306
If the result is YES, the road surface status register is displayed in S307.
R_{science fiction}After decrementing the value of
Reason ends. If the result of S306 is NO, it is as it is.
The gear engagement estimation process ends. In short, two-wheel drive
In case of geared vibration only on the drive wheels,
Of the count value in the road surface condition display register for the front and rear wheels.
If the difference is large, it is determined that the gear is engaged, and the road condition
State display register R_{science fiction}The value of is decremented
It A rough road in 203 of the road surface state determination routine of FIG.
Is determined, or in S210, in a bad road
As a result of determining that there is a road surface state display register R_{science fiction}The value of the
Is set to 1 indicating a bad road or 2 indicating a bad road
However, in this routine, it is determined that the gear is engaged.
For example, the road condition display register R_{science fiction}The value of is decremented
Therefore, the judgment of the bad road or the bad road is invalidated.

Next, in the case of four-wheel drive, first in S308
Estimated vehicle speed V_S0Is set vehicle speed V _THWhether or not
Is determined. Set vehicle speed V_THThe value of is, for example, 15k
m / h. V_S0<V_THIf so, the processing after S309
Is done, V_S0≧ V_THIf so, the gear entering estimation process
Reason ends. S309 and S310 are anti-ski
Processing for determining whether or not the vehicle is in control
This is a process of determining whether or not the output of the controller is low G. S30
Each wheel anti-skid status display cash register used for 9 judgment
Star R_CONFor (i), the timer interrupt in FIG. 8 will be described later.
A description will be given in connection with one routine. During anti-skid control
It is continuously judged whether or not it is and whether or not it is low G.
It does not start the anti-skid control.
When the output of the acceleration sensor is low G,
This is because the friction coefficient is not always small.
That is, the braking force (brake cylinder pressure) is the friction of the road surface.
During anti-skid control that is controlled to a size suitable for the coefficient
Therefore, the output value of the acceleration sensor is
To respond. In short, in the case of four-wheel drive, vehicle body estimation
When the speed is low and the road friction coefficient is small, the gear
Road surface status register R_{science fiction}
Value is decremented and the road surface condition determination
The judgment of bad roads or terrible roads in
Is.

(4) Estimated vehicle speed calculation routine In this routine,
The maximum number of wheel turns of four wheels at each run.
Rolling speed V_{W MAX}And the previous estimated vehicle speed V_S0Is the upper body
Acceleration α_UPWhen changing with (for example, + 0.5G)
Limited vehicle speed V_{S UP}And the previous estimated vehicle speed V_S0Is the lower limit car
Body acceleration α_DOWNWhen it changes in (for example, -1.5G)
Lower limit vehicle speed V_{S DOWN}And are obtained respectively
Of the middle magnitude of those three parameters
Is the estimated vehicle speed V this time_S0It is a routine to be.
Specifically, as shown in the flow chart of FIG.
First, in S401, the upper limit vehicle body acceleration α_UPAnd the calculation cycle t
Product and previous estimated vehicle speed V_S0Upper limit vehicle speed as the sum of
V_{S UP}Is calculated, and subsequently, in S402, the lower limit vehicle
Body acceleration α_DOWNAnd the calculation cycle t and the previous estimated vehicle speed
Degree V_S0Lower limit vehicle speed V as the sum of_{S DO WN}Is calculated
It Then, in S403, the maximum wheel rotation speed V
_{W MAX}Is calculated. Then, the maximum vehicle in S404
Wheel rotation speed V_{W MAX}And the upper limit vehicle speed V _{S UP}And lower limit car
Body speed V_{S DOWN}The intermediate one of these is the estimated vehicle speed this time
Degree V_S0Is decided. The determination result is stored in RAM88
It

(5) Reference speed calculation routine In this routine, the start condition for the anti-skid control is set.
The reference speed that is the case is the road surface state display register R_{science fiction}To the value of
Will be changed accordingly. As shown in FIG. 7, first in S501
Road condition display register R_{science fiction}Branch to the process according to the value of
Done. Ryoji (R_{science fiction}= 0), S502 and S50
A rough road (R_{science fiction}= 1), S504 and 505
Then, the bad road (R_{science fiction}= 2), S506 and S507
Then, the first set vehicle speed V_SNAnd the second set vehicle speed V_SHThe value of the
Are set respectively. Settings in S502 to S507
Constant speed V₀₀, V₀₁, V_Ten, V ₁₁, V₂₀, V_{twenty one}The value of
For example, 1, 5, 3, 7, 5, 10 [km / h]
It is said that

(6) Timer Interrupt 1 Routine This routine is a timer interrupt process which is activated by a timer interrupt generated at fixed time intervals (for example, 10 ms), and anti-skid for each wheel depending on the state of the wheel. The control state is changed. As shown in FIG. 8, first, in S601, it is determined whether or not the system abnormality flag F _ABN is ON. If it is ON, it is determined that the antiskid control system has an abnormality, and the continuous pressure increase processing is performed in S617. Then, the timer interrupt 1 routine ends. If the system error flag F _ABN is OFF, S
At 602, it is determined whether or not braking is being performed by referring to the braking flag F _ACT . If braking is not in progress, after all the wheel anti-skid state display registers R _CON (i) are set to zero in S616, continuous pressure increase processing is performed in S617, and the timer interrupt 1 ends. If the vehicle is braking, the wheel anti-skid state display register R is displayed in S603.
A branch is made to the anti-skid control processing according to the value of _CON (i). After S603, each wheel is independently executed. Anti-skid status display register for each wheel R _CON (i)
The value of indicates a continuous pressure increasing state when 0, a pulse pressure reducing state when 1, a holding state when 2, a pulse pressure increasing state when 3, respectively.

First, in the case of the continuous pressure increase state, it is determined in S604 whether the wheel rotation speed V _W (i) is less than the second set vehicle body speed V _{SH. If} it is not less than this, the timer interrupt 1 ends. However, the pressure is continuously increased. If it is less than the second set vehicle speed V _SH , pulse pressure reduction processing is performed in S605,
Anti-skid status display register R in S606
_CON (i) becomes 1. Next, in the case of the pulse pressure reducing state, it is determined in S607 whether the wheel rotation acceleration V _W 'exceeds the set acceleration G. If not, S6
At 10, the decompression time monitoring process is performed. In this process, if the pulse pressure reducing process continues for a set time or longer, it is determined that the system is in an abnormal state, and the system abnormal flag F _ABN is ON.
It is said. If the set acceleration G is exceeded, a holding process is performed in S608, and each wheel anti-skid state display register R _CON (i) is set to 2 in S609. The holding process is a process of prohibiting the inflow and outflow of the fluid in the brake cylinder to keep the fluid pressure in the brake cylinder constant.

In the case of the holding state, in S611, it is determined whether or not the wheel rotation speed V _W is decreasing (displayed by ↓) and is less than the first set vehicle body speed V _SN . S6
If the result of 11 is YES, processing for shifting to the pulse pressure reducing state in S605 and thereafter is performed. The result of S611 is N
If it is O, the wheel rotation speed V _W is increasing in S612 (↑
Is displayed) and the second set vehicle speed V _SH is exceeded. If the result of S612 is NO, the timer interrupt 1 is terminated and the holding state is continued. If the result of S612 is YES, S61
In step S614, the pulse pressure increasing process is performed, and in step S614, each wheel anti-skid state display register R _CON (i) is set to 3. In the case of the pulse pressure increasing state, it is determined in S615 whether the wheel rotation speed V _W is decreasing (↓) and is less than the first set vehicle body speed V _SN . If the result of S615 is YES, the process of transitioning to the pulse pressure reducing state of S605 and thereafter is performed. If the result of S615 is NO, the timer interrupt 1 ends as it is, and the pulse pressure increasing state continues.

In summary, in the timer interrupt 1 routine, if there is no abnormality in the system, the state of the anti-skid control is changed to an appropriate state and the rough road counter processing required for road surface state estimation is performed. Of. Further, the decompression time is monitored, and if it is determined that excessive decompression is performed, the system abnormality flag F _ABN is set to O.
By setting it to N, the subsequent timer interrupt is prohibited in the system abnormality processing of S109 of the anti-skidding domain routine, and the anti-skid control is practically not performed.

(7) Timer Interrupt 2 Routine This routine is a timer interrupt process activated by a timer interrupt generated at fixed time intervals (for example, 1 ms), and is counted by the process in the vehicle speed sensor interrupt described later. Wheel speed sensor pulse counter C
_The wheel rotation speed _VW (i) and the wheel rotation acceleration _VW '(i) are calculated for each wheel based on the value of _VS (i).
In this routine, the time counter C _TIM used for time measurement is incremented, and the rough road counter process described later is continuously performed. As shown in FIG. 13, first, S1101.
Then, the wheel rotation speed V _W (i) and the wheel rotation acceleration V _W ′
(I) and are calculated for each wheel. Next, S1102
After the value of the clock counter C _TIM is incremented by,
In S1103, the rough road counter process described later is performed.

(8) Rough Road Counter Processing Routine This routine is included in the timer interrupt 2 routine.
Wheel wheel rotation acceleration V_WThe size of ´ (i) is the set acceleration G
_THWhen it is above, each wheel rough road detection counter C _{science fiction}(I)
The value of is incremented and is independent for each wheel
And then executed. As shown in FIG. 9, first, in S701
Road condition display register R_{science fiction}S702, S depending on the value of
Branch to any one of 703 and S704
Be done. If it is a good road, the acceleration G set in S702_TH0 But evil
For road, set acceleration G in S703_TH1 But on a terrible road
In case of S704, set acceleration G_TH2 But each set acceleration
Degree G_THIt is said that Then, in S705, V_W´ (i) increases
Addition (↑) and set acceleration G_THIs it above
Is determined. If the result of S705 is YES, S
At 706, each wheel road surface state detection counter C_{science fiction}(I) is ink
If the result of S705 is NO after being remented,
Immediately, the rough road counter process ends. Road surface condition detection
Counter C_{science fiction}The value of (i) is the wheel rotation acceleration V of each wheel._W´
(I) is the set acceleration G_THThe number of times greater than
The larger is, the worse the condition of the road surface is.

The values of the set accelerations G _TH0 , G _TH1 , and G _TH2 may be the same, but may be changed according to the states of a good road, a bad road, and a bad road. For example, in order to obtain a determination result that the road is a bad road, the wheel rotation acceleration V _W ′
The value of each wheel road surface state detection counter C _SF (i) can be increased when (i) becomes a value larger than that at the time of rough road determination. That is, G _TH0 <G _TH1 . Thus, by setting at least two of the set accelerations G _TH0 , G _TH1 , and G _TH2 to have different magnitudes, it is possible to determine the road surface state in consideration of the amplitude of the wheel rotation speed.

(9) Pulse decompression processing routine This routine is in the timer interrupt 1 routine and
Surface status display register R _{science fiction}Duty ratio D corresponding to the value of
_GPulse depressurization process that repeatedly depressurizes and holds at
Is what is done. In this case, D_G= Decompression time / (decompression
Time + holding time). First, as shown in FIG.
In 801 the road condition display register R_{science fiction}Corresponding to the value of
Is branched to. If it is a good road, D at S802_G= D
_G0If it is a bad road, D in S803_G= D_G1And
In case of a terrible road, D in S804_G= D_G2It is said that Continued
Then, using the set duty ratio,
After the pressure reduction is performed, the pulse pressure reduction process ends. D
_G0, D_G1, D_G2Is D_G0> D _G1> D_G2Will be
Is preset. Therefore, the rougher the road
Depressurization is performed with a depressurization gradient.

(10) Pulse pressure boosting routine This routine is in the timer interrupt 1 routine and
Surface status display register R _{science fiction}Duty ratio D corresponding to the value of
_ZPulse pressure boosting process that repeatedly boosts and holds with
Is what is done. In this case, D_Z= Pressure increase time / (pressure increase
Time + holding time). As shown in FIG. 11, first, S
901: Road surface status display register R_{science fiction}Corresponding to the value of
Is branched to. If it is a good road, D at S902_Z= D
_Z0If it is a bad road, S903 returns D_Z= D_Z1And
In case of a terrible road, D at S904_Z= D_Z2It is said that Next
After the pulse boosting is executed in S905, the pulse boosting process is performed.
Ends. D_Z0, D_Z1, D_Z2Is D_Z0<D_Z1
<D_Z2Is set in advance. Therefore, on a bad road
The steeper the gradient, the higher the pressure.

(11) Vehicle Speed Sensor Interrupt Routine This routine is four independent interrupt routines that correspond one-to-one to the pulse signals from the wheel speed sensors attached to each wheel. FIG. 12 shows only one interrupt process corresponding to a certain wheel. When an interrupt occurs, at S1001, each wheel vehicle speed sensor pulse counter C provided in the RAM 88 for each wheel.
_VS (i) is incremented. Each wheel speed sensor pulse counter C _VS (i) is a rotary counter having a sufficiently large number of digits (it returns to zero when 1 is added to the maximum countable value) and is read by S1101 included in the timer interrupt 2 routine. The count value is output and used to calculate the wheel rotation speed and the like. Even if interrupts corresponding to a plurality of wheels occur at the same time, it is necessary to surely increment the counter. Therefore, the interrupt priority is assigned.

The present embodiment has the following features as a whole by using the above-described routines. (1) Content of anti-skid control Road surface conditions are classified into three stages: good roads, bad roads, and bad roads, and the control corresponding to each is performed. That is, the first set vehicle speed V _SN and the second set vehicle speed V _SH that define the decompression start condition, the set acceleration G _TH that defines the condition for incrementing each wheel road surface state detection counter C _SF (i), and the pulse. The anti-skid control is performed based on the values of the duty ratio D _{G of} pressure reduction and the duty ratio D _Z of pulse pressure increase. The above five control parameters are changed in three steps according to the value of the road surface state display register R _SF . Moreover, improper anti-skid control is not performed due to occurrence of gear engagement. Normally, the above-mentioned control parameters are changed according to the road surface condition to perform anti-skid control suitable for the road surface condition.However, when the gear engagement is detected, these control parameters are changed to values different from the normal values, and the gear engagement This is a configuration in which inappropriate antiskid control is not performed due to occurrence. In the present embodiment, the control parameters are changed into three levels according to the road surface condition, but they may be classified into two levels or, conversely, into more levels. Also,
The change in the road surface condition may be continuously detected, and the corresponding control parameter may be continuously changed.

(2) Antiskid control by interrupt processing In this embodiment, the state of antiskid control is changed in the timer interrupt 1 routine. Further, the pulse from the vehicle speed sensor for obtaining the wheel rotation information is input by an independent external interrupt for each wheel. The priority levels of these interrupts are that the four external interrupts from the vehicle speed sensor are the first to fourth highest levels, the timer interrupt 2 is the fifth level, and the timer interrupt 1 is the sixth level. . This means that when the vehicle speed increases and the frequency of external interrupts increases, the execution start times of the timer interrupts 1 and 2 are not equidistant or the processing is frequently interrupted. Therefore, the pulse input from the vehicle speed sensor is configured as an external interrupt to another CPU (referred to as a sub CPU, whereas the CPU 84 is referred to as a main CPU), and C _VS (i) is incremented by the sub CPU. It may be done. In this case, it is desirable that the value of C _VS (i) be transferred between the sub CPU and the main CPU asynchronously. Therefore, a dual port RAM may be provided between the sub CPU and the main CPU, and the storage location of C _VS (i) may be within the dual port RAM. Further, as a configuration in which four hardware counters that count up each pulse from the vehicle speed sensor are provided, and an arbitration function is added to ensure that the data is fixed when the CPU 84 reads the count value Good.

(3) Gear Entrainment Detection Method In this embodiment, the gear engagement detection method can be changed according to the drive system. In the case of two-wheel drive, gear engagement is estimated based on the difference in rotational speed vibration that occurs between the driving wheel and the non-driving wheel. In the case of four-wheel drive, in addition to rotational speed vibration, traveling speed and road surface friction The gear engagement is estimated in consideration of the coefficient. In the case of two-wheel drive, the processing for four-wheel drive is also used, and if both gears are estimated to be in gear or at least one of them is estimated to be in gear, the final gear It may be determined that the entry has occurred. Further, in the present embodiment, the means for detecting the gear engagement vibration uses means based on measured values such as vehicle speed, wheel rotation speed increase / decrease frequency, and road surface friction coefficient, but the gear engagement detection means is not limited to these. is not. For example, other means such as a means based on the magnitude of load fluctuation of the driving force transmission shaft can be used.

While the embodiments common to the inventions of the present application have been described in detail with reference to the drawings, various embodiments other than these will be described based on the knowledge of those skilled in the art without departing from the scope of the claims. It is possible to implement each invention in a modified and improved mode.

[Brief description of drawings]

FIG. 1 is a system diagram showing an anti-skid brake system including a gear engagement detection device that is an embodiment of the present invention.

FIG. 2 is a diagram conceptually showing the structure of the electronic control device in FIG.

FIG. 3 is a flowchart showing a main routine of anti-skid control performed by the electronic control unit.

FIG. 4 is a flowchart showing a road surface state determination process in S105 of FIG.

5 is a flowchart showing a gear engagement estimation process in S205 of FIG.

FIG. 6 is a flowchart showing an estimated vehicle body speed calculation process in S106 of FIG.

FIG. 7 is a flowchart showing a reference velocity calculation process of S106 of FIG.

FIG. 8 is a flowchart showing a timer interrupt process of anti-skid control performed by the electronic control unit.

9 is a flowchart showing a rough road counter process in S604 of FIG.

FIG. 10 is a flowchart showing a pulse pressure reducing process in S608 of FIG.

FIG. 11 is a flowchart showing a pulse pressure increasing process in S616 of FIG.

FIG. 12 is a flowchart showing vehicle speed sensor interrupt processing of anti-skid control performed by the electronic control unit.

FIG. 13 is a flowchart showing a timer interrupt process of anti-skid control performed by the electronic control unit.

Claims (1)

[Claims] 1. A wheel slip ratio of a vehicle equipped with a manual transmission is controlled by controlling a hydraulic pressure of a brake cylinder of a brake that suppresses the rotation of the wheel based on a slip state of the wheel and a predetermined control condition. This is an anti-skid control device that keeps the value close to the specified value.When the reduction ratio is small, braking continues with the clutch engaged, and when the vehicle speed becomes low, the drive torque fluctuation of the drive wheels becomes large. And a gear engagement detection device that detects a gear engagement, and when the gear engagement detection device detects a gear engagement, the control condition is controlled so that the hydraulic pressure of the brake cylinder is controlled to be lower than when the gear engagement is not detected. An anti-skid control device comprising control condition changing means for changing the condition.