JPS59209945A - Anti-skid control device - Google Patents

Abstract

PURPOSE:To prevent the anti-skid control at a low speed from becoming unreliable by fixing the calculated output of the wheel acceleration/deceleration at a constant value when the calculated wheel speed is decreased to a fixed speed or lower in a low-speed area. CONSTITUTION:A wheel speed VW is calculated by an arithmetic unit (AU) 31 in a wheel speed information AU30 based on the output of a wheel speed sensor 1, and also the wheel acceleration/deceleration alphaW is calculated by an AU32. At this time, if VW<VO (VO: low-speed value) is judged by a low-speed judging unit 33, a transfer switch 35 is held at a mode I , and the acceleration/ deceleration alphaW is outputted to an output signal deciding unit 6. On the other hand, if VW<VO, the switch 35 is switched to a mode II, and the fixed deceleration alphaO stored in a deceleration memory 34 is outputted. In addition, when VW<VO and the system performs the anti-skid control and a motor control signal is outputted from the motor control unit 8 of a brake liquid recovering motor M, a prohibiting unit 36 is operated to hold the switch 35 at the mode I .

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an anti-skid control device that starts anti-skid control when wheel deceleration during braking reaches a set deceleration.

Conventionally, when the wheel acceleration/deceleration reaches the set deceleration, the slip rate λ
For example, as an Andesian control system that controls jblJ dynamic hydraulic pressure based on wheel acceleration/deceleration αW and wheel acceleration/deceleration αW,
1-89096 is known. This is C, when the vehicle suddenly brakes, the wheel acceleration/deceleration αW is the set wave Mr.
KαsK is controlled based on the slip rate λ determined based on the vehicle speed ■ and the wheel speed Vw and the wheel acceleration/deceleration αW! Switch Iiv liquid tfE to pressure increase, hold, and pressure decrease! 1! I control the slip ratio λ0 at which the wheel speed Vw reaches the maximum braking efficiency.
The objective is to shorten the braking distance without impairing the steering stability of the vehicle by adjusting the braking distance to a value that corresponds to the surrounding area by 7.l.

Here, the wheel acceleration/deceleration αW is, for example, in Japanese Patent Application Laid-Open No. 56-1.
As shown by OO363, from the periodic change of the sensor pulse output from the wheel speed sensor, Ill! The next thing to calculate is the slip ratio λ value 1, for example, the wheel speed Vw calculated from the sensor pulse period from the wheel speed sensor, and the wheel acceleration/deceleration αW at that point when it reaches the set deceleration αS. It is calculated according to the following equation based on the wheel speed and the pseudo vehicle speed Vi determined to have a predetermined deceleration characteristic.

In addition, such an anti-skid control system has to repeatedly control the brake fluid pressure at high speed by increasing and holding the brake fluid pressure until the vehicle comes to a stop after a sudden braking operation is performed. 49-32494, a hydraulic motor IVI? quickly recovers the brake fluid pressure in the foil cylinder when the brake fluid pressure is reduced. Il: Operation type,
Furthermore, it is effective to operate the hydraulic motor continuously during anti-skid control.

By the way, a wheel speed sensor for detecting wheel speed and wheel acceleration/deceleration generally consists of a toothed rotor that rotates integrally with the axle, a permanent magnet, and a bisokang coil. The big amplifier coil outputs an AC signal with a frequency proportional to the wheel speed.This wheel speed sensor is activated at low speeds (mph).
h8 degrees or less), the magnetic flux change per unit time is /
Since the wheel speed decreases by J%, the output tends to become unstable, and there is a possibility that a pulse dropout may occur in the output wheel speed pulse. For this reason, the hydraulic motor for hydraulic pressure recovery is
In an anti-skid control system like the one above, the sudden deceleration RBH and the different decelerations are equal to the fixed deceleration α
As shown in Figure 1, the wheel speed changes based on the sensor pulse output from the wheel speed sensor, and as a result of that change, the wheel speed changes. The calculated wheel acceleration/deceleration may instantaneously exceed the set deceleration αs 2Z, which is the condition for starting anti-speed control. In that case, the Annasgind '11ilJ control is started, a pressure reduction signal is output, and the hydraulic motor M, which is not necessary during normal braking, is operated.

To prevent this, as shown in Figure 2, when the calculated wheel speed or the wheel speed sensor output drops below a constant speed IVυ in the low speed range where it is expected to become unstable, the calculated wheel acceleration/deceleration output is is fixed to a constant value, for example, zero, which is smaller than the set deceleration αS of the anti-skid control start condition, and is usually set to 1b.
1. Even if the output of the wheel speed sensor becomes unstable when the vehicle is about to stop during excitation, it is desirable to prevent the calculated output of wheel acceleration/deceleration from reaching the set deceleration αsK of the anti-skid control start condition.

However, as mentioned above, when the calculated wheel speed drops below a certain speed in the low speed range, if the calculated output of the wheel acceleration/deceleration is fixed at a constant value, the hydraulic motor M Although it is possible to prevent this from occurring,
Even when anti-skid control is being executed during sudden braking, if the calculated wheel speed drops below the above-mentioned constant speed Vt+, the calculated output of wheel acceleration/deceleration is fixed at a constant value, so wheel acceleration/deceleration and slip rate are There is a risk that the anti-skid control, which determines the control mode of the brake fluid pressure based on this, may become inappropriate when the vehicle is stopped.

This specification was made with personal considerations in mind; if the calculated wheel speed decreases below a constant speed in the low speed range during sudden braking when performing anti-skid control, the calculated output of wheel acceleration/deceleration will become even more unstable. The entire purpose is to prevent accuracy. Then, based on this sensor pulse, the control mode of the brake fluid pressure is completely determined.
i, speed and (i) 2 deceleration, 5 22, and anti-skid control starts fully when the set deceleration is exceeded by braking operation.In the anti-skid control device, the upper is automatically calculated wheel speed or low speed. When the speed falls below a certain speed in the speed range, the calculated output of the acceleration/deceleration of the vehicle mentioned above is fixed to a constant value, and during anti-skid control, the fixed output of the wheel acceleration/deceleration described in "2" is prohibited. 2].

The following is based on all the drawings of "Kienori".
do.

FIG. 3 is a block diagram showing an embodiment of the entire system according to the present invention.

First, regarding the overall configuration 1, based on the sensor pulses converted into pulse signals by the detection signal full waveform shaping circuit 2 from the 11th wheel en route 1, the Oki 6 en route and the small '1m/Jll deceleration are calculated respectively. T/) A wheel speed information calculation unit 30 including a base calculation unit 31 and a wheel acceleration/deceleration calculation unit 32 starts outputting a pseudo vehicle speed Vi when the calculated wheel acceleration/deceleration reaches a target deceleration. A simulated vehicle speed determination section 4, a slip rate operator section 5 that calculates the slip rate λ based on the pseudo vehicle speed Vi and the calculated wheel speed Vw, and a slip rate operator section 5 that calculates the slip rate λ based on the pseudo vehicle speed Vi and the calculated wheel speed Vw; According to the predetermined control pattern of the brake fluid pressure, the output signal determining unit 6 outputs 8 pressures (iu, holding signal, and depressurization 'fV-ke'), and each output from the output/code determining unit 6. 11. An actuator 7 which is switched and controlled based on the curve 11 and which switches the hydraulic pressure state of a foil cylinder for braking, and a hydraulic motor M for gray liquid recovery based on a pressure reduction signal from an output signal determining section 6. and a motor control section 8 which outputs a motor fli!I control signal.

Here, the wheel speed control unit 30r according to the present invention, in addition to the wheel speed calculation unit 31 and the wheel acceleration/deceleration calculation unit 32, operates in a low speed range where the output of the wheel speed sensor 1 is expected to become unstable. Constant speed ■Discrimination 4 when the calculated wheel speed decreases below 0
a low speed discrimination unit 33 that outputs a full signal, and a constant deceleration α0 that is smaller than the set deceleration that is the anti-skid control start condition.
For example, the deceleration memory 34 which stores α0-0 and the determination signal from the low speed determination unit 33 are used to determine if i
Set the deceleration αυ stored in step 4 to 7-to-11 (toggle changeover switch 35 and motor 1lrl).
Created based on motor control No. 45 that continues to output 8 ka!
t6+L, this Mortal 1] Go, (bow' is in output mode Jt!g, 'S・F border 35 is mode 1 from 7-do I!
1. Please switch from the prohibited section 36 to 1. ing.

Next is the work of δl530: Part I
J diagram (a) C? )) Flowchart 1-6 shown in FIG.

As shown in Fig. 4(a), the wheel speed 'jLj '1l-
11i 31 is output from the waveform shaping circuit 2, the wheel 1ζ
flj Sequentially calculates the final Vw from the 7% pulse period of the sensor pulse based on the detection signal of the AM sensor 1, and outputs the theoretical speed Vw of each calculation amount at a predetermined period.

On the other hand, as shown in Fig. 4('b), wheel acceleration/deceleration performance 1-
2: The unit 32 calculates the wheel acceleration/deceleration αW according to the cycle change of the sensor pulse. When calculating this okiwa force 11 deceleration αW, the wheel speed calculation: AB 31 is performed. When the discrimination signal is not outputted from the discrimination section 33 and becomes below the extra low speed value VO, if the system is not performing anti-skid control and the hydraulic motor for hydraulic pressure recovery is not operating, the low speed discrimination section 33 will output the discrimination signal. The selector switch 35 is switched to the seventh mode 11 by the discrimination signal.
The constant deceleration α0 stored in the deceleration memory 34 is output. Here, in a state where the calculated wheel speed Vw is below the low speed value,
When the system performs anti-skid control and a motor control signal is output from the motor 1b and the oblique portion 8, the prohibition section 36 is activated, and the changeover switch 35 is changed from mode I to mode ■ by the discrimination signal from the low speed discrimination section 33. Switching to mode is completely prohibited and turned off, and the chivalry switch 35 maintains mode ■'.
Then, the vehicle will be powered.

In this way, according to this embodiment, fang 1. During normal braking, that is, when the motor control signal from the motor control unit 8 is fixed, and when the anti-skid control unit, that is, the motor +1ilJ control 4K M is output from the motor control unit 8, the calculated wheel speed is Since the calculated wheel acceleration/deceleration αW is output in its entirety even when the low speed value is 0 or more, the thrust motor hi for brake fluid recovery is reduced to 1'1. In addition, the anti-slip throat control is performed based on the calculated wheel speed and calculated wheel acceleration/deceleration even at low speeds below the above-mentioned VO. Become so.

As explained above, uninventively, l: ′i'L,
Output from midway sensor (AG to nin-ν-pulse
When the brake fluid pressure is controlled by the FIIFJ motor, the wheel speed and wheel acceleration/deceleration are determined by the front loader, and when the redundant resistance speed for 1ull dynamic operation is obtained, the anti-skid city is activated.
Install an anti-skid suppression device on the RN-11 for 2 hours. : fil-: 'When the fitf calculated wheel speed decreases beyond a constant continuous intake in the low speed range, the calculated amount of wheel acceleration/deceleration is fixed to a constant value, and furthermore, during anti-skid control, the wheel acceleration/deceleration is fixed to a constant value. 1xJJ constant output Constant output - 4 - Because it is based on 1xJJ constant output constant output -4-, even if the calculated wheel speed drops below a constant speed in the low speed region during sudden braking when performing anti-skid control, the output of wheel acceleration/deceleration will not be output from the wheel speed sensor. With the calculated value based on the sensor pulse, it is possible to completely prevent the anti-skid control from becoming inappropriate during the low continuous period.

[Brief explanation of the drawing]

FIGS. 1 and 2 (d) are graphs showing an example of calculated wheel speed and calculated wheel acceleration/deceleration states during normal braking; FIG. Block diagram showing the example of the ritual, Fig. 4(a) (
b) is a flowchart showing the operation of wheel speed information calculation 's30 shown in FIG. 3; 1... Wheel speed sensor 2... Waveform shaping circuit 4...
- Approximate vehicle speed determination section 5... Sling rate calculation capital 6...
Output signal determination section 7...Actuator 8...Motor control section 30...Wheel speed information calculation section 31...Wheel speed calculation section 32...Wheel acceleration/deceleration calculation section 33...
Low speed discrimination section 34...Deceleration memory 35...Switch switch 36...Prohibition section M...Hydraulic motor patent applicant: Nissan Motor Co., Ltd. Patent attorney, Hajime Dobashi

Claims (1)

[Claims] Based on the sensor pulse output from the wheel speed sensor, the wheel speed and wheel acceleration/deceleration that determines the control mode of the brake fluid pressure are calculated, and when the set deceleration is obtained by the braking operation, the anti-skin brake is activated. In the anti-skid control device that starts the control, the calculated output of the wheel acceleration/deceleration is fixed at a constant value when the calculated wheel speed falls below a constant speed in the low speed region, and furthermore, during anti-skid control, the calculated output of the wheel acceleration/deceleration is fixed at a constant value. An anti-skid control device comprising a means for inhibiting fixed output k IA of wheel acceleration/deceleration.