JPS5871246A - Anti-skid control device - Google Patents

Abstract

PURPOSE:To obtain a reference speed in accordance with road friction conditions without using a car deceleration sensor by correcting the deceleration to calculate the reference speed in accordance with the decreasing rate of the reference speed. CONSTITUTION:The signal from a wheel speed sensor 1 is input into a control means 4 through a shaping circuit 2, and the output drives an actuator 6 through a current amplifier 5. The control means 4 is composed of a microcomputer and is provided with a free-run counter 3. The output signal to release a brake force is obtained by comparing the wheel speed signal with a reference speed signal, and the reference speed is determined by decreasing the wheel speed at a predetermined deceleration. The deceleration hereof is corrected based on the decrease rate of the reference speed during the previous cycle, thereby the reference speed in accordance with road friction conditions can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an anti-skid control device that prevents wheel locking that occurs during sudden braking.

Normally, this type of device calculates the approximate vehicle speed () degree from the wheel speed, creates a reference speed from which to set wheel slip with a predetermined speed difference, and then adjusts the brake hydraulic pressure based on the comparison output with the wheel speed. It's in control. Therefore, in order to improve controllability, it is necessary to bring the approximate vehicle speed closer to the actual vehicle speed, and to do so, the deceleration α used at the valley of the wheel speed must be corrected depending on the road surface.

As a countermeasure, conventional devices have installed a vehicle deceleration sensor that detects vehicle deceleration during braking in order to detect the road surface condition, and corrected the rate of decrease in approximate vehicle speed according to the detection signal. be.

However, special sensors must be provided to obtain the approximate vehicle speed.

The present invention has been developed in view of the above problems, and it is possible to obtain a reference speed that matches the friction condition of the road surface during braking without installing a special sensor, and based on this, the anti-skid by adjusting the appropriate braking force in °C. The purpose is to control.

In order to achieve this object, the present invention obtains a reference speed corresponding to an approximate vehicle speed that is reduced by a predetermined deceleration (2) from the memorized value of the wheel speed immediately before braking, and uses this reference speed and the wheel speed. The braking force is repeatedly adjusted by loosening and reapplying it depending on the speed relationship, and the subsequent deceleration is corrected in accordance with the rate of decrease of the reference speed in one cycle of the indirect braking force.

The present invention will be described below with reference to embodiments shown in the drawings.

Fig. 1 is an overall configuration diagram showing one embodiment of the invention, in which 1 is a wheel speed sensor that generates a detection signal with a frequency proportional to the rotational speed of the wheel, and 2 is a wheel speed sensor that shapes the detection signal from the wheel speed sensor 1 into a pulse signal. 3 is a free run counter for counting the time interval of the wheel speed pulse signal; 4 calculates the wheel speed from the a1 value of the counter 3, calculates the approximate vehicle speed and reference speed, and calculates the loosening signal. , a microcombicoater which serves as a control means that generates a brake hydraulic control output including a reapply signal; 5 is a current amplifier; 6 is a solenoid coil installed in a brake hydraulic control actuator of the drive means; when energized, the brake hydraulic pressure is reduced. do.

(3) Then, the microcomputer 4 executes the arithmetic processing shown in the flowcharts of FIGS. 3 and 4, and as shown in FIG.
By correcting the deceleration α by the average deceleration obtained from the difference △■α between the approximate vehicle speed at the intersection P□ and the time difference ′Fα in the next cycle, the approximate vehicle speed is adjusted to match the friction condition of the road surface. In addition, if the deceleration α is calculated too low due to road noise etc., problems such as an elongation of the braking distance will occur, but in order to correct the deceleration α, it is necessary to take into account the characteristic that increases over time as shown in the following equation. Because of this, this problem does not continue for a long time, and the problem is prevented.

α-K・△VFire/0. ＋△α・ However, K is a constant.

Fig. 2 is an explanatory diagram showing the control state, where ■mi is the vehicle speed, v
To represents the approximate vehicle speed, Vs represents the reference speed, Vw represents the wheel speed, and PB represents the change in brake oil pressure.

In this FIG. 2, PoXPl and P2 indicate correction points (4) for the deceleration α used to calculate the approximate vehicle speed.

First, the operation of the above configuration will be explained.

Now, while the lj cars are running, when the detection signal from the wheel speed sensor 1 is formed in the shaping circuit 2 and added to the interrupt input of the microcomputer 4, the interrupt in steps 100 to 103 in the interrupt routine of FIG. 81 value tn of the free run counter 3 at that time is inputted, and the pulse interval Tn is calculated from the difference from the total count value tn-1.

On the other hand, in the main routine of FIG. 3, after the initialization of calculation start and self-run in steps 11 and 12 when the power is turned on, the process is performed for 10 ms in step 13.
Various main operations are repeated for each e c.

That is, in step I4, the wheel speed Vw is calculated from the reciprocal of the pulse interval Tn obtained in the calculation y of the interrupt routine.
In step 15, the approximate vehicle speed VTO is evaluated, in step 16, the reference speed Vs is calculated as ei, and in step 17.1
Based on the comparison result between the base speed Vs and the wheel speed Vw by the calculation in 8.19.23, (5) Lenoid ON and solenoid OFF outputs are generated as a loosening signal and a reapplying signal.

Here, when the relationship of wheel speed Vw≦reference speed Vs is reached (points PoXPl and Pλ in FIG. 2), step 20
~22. Approximate vehicle speed VSTΔ stored in the previous cycle and current approximate vehicle speed VTO by calculations from 24 to 27
The speed difference ΔV+x and the time difference Ttc are determined, and the deceleration α is corrected based on the recalculated values, and VSTA and T y are reset for the next correction. In addition to this correction calculation, the deceleration is gradually increased in step 25.

Therefore, by the above calculation process, as shown in FIG.
At the start of the control, a large deceleration α0 (approximately 1 g) is set, but from the next cycle onwards, the deceleration α can be corrected to a value appropriate to the frictional state of the road surface. Furthermore, even if the deceleration is set to a low value due to road noise or the like, the deceleration has a characteristic of increasing over time, so it can be prevented from continuing for a long time.

This 9. (By controlling J, it is possible to control the modulation of braking force that constantly adapts to the road surface condition as an anti-skid operation (6).

In addition, in the example of "double series", one is shown in which one wheel speed sensor 1 is provided. -Can be used for skid control, etc.

Further, the peak point of the wheel speed may be detected as the deceleration correction point in FIG. 2, and even if the application of braking force is detected, the same control as in the above embodiment can be performed.

Further, although the microcomputer 4 is used as a control means, similar control can be realized using general digital circuits or analog circuits.

As mentioned above, according to the present invention, base! It is possible to correct the deceleration in the calculation of the V speed based on the friction condition of the road surface using only the lLW without installing a special sensor, and based on this, it is possible to always perform appropriate anti-skid control. This has an excellent effect.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram showing one embodiment of the present invention, (7) Fig. 2 is an explanatory diagram of its operation, Fig. 3 is a flowchart 1 of the main routine of the microcomputer, and Fig. 4 is a microcombi coater. This is a flowchart 1- of the side-in routine. 1... Wheel speed sensor, 2... Shaping circuit, 3...
Free run counter, 4... microcomputer as control means, 5... current amplifier, 6... solenoid forming drive means. Representative Patent Attorney Takashi Okabe (8)

Claims (1)

[Claims] A wheel speed sensor that detects the rotational speed of a wheel, and a wheel speed that is determined by receiving a detection signal from this sensor, and that decreases at a predetermined deceleration from a stored value of the immediately preceding wheel speed during braking. A reference speed corresponding to the approximate vehicle speed is obtained, and by comparing this reference speed with the wheel speed, a loosening signal and a reapplying signal are generated. An undesired control device comprising a control means for correcting deceleration, and a drive means for relaxing or reapplying braking force to wheels in response to the loosening signal or reapplying signal.