DE2553000A1 - ANTI-LOCK CONTROL SYSTEM - Google Patents

Description

6900 Heidelberg 1
Grenzhöfer Weg 3ö

Heidelberg, 1d. November 1975 PJJ-Ku / Ba E-379

Anti-lock control systems

The invention relates to an anti-lock control system in which the digital value of a wheel in successive periods of predetermined length At at the beginning of each of the existing Digi talwert or a dependent value stored, uuu Lei the within the period of the Augeriblickswert luit compared to the stored digital value is, v.uoei with a predetermined deviation of the current uigitalwerts from the stored value a switching stepul for from Βτααχ- pressure control device is generated, with eier ürzw ^ juriis of this switching signal immediately investigate the runae i ^j ei ^- ic.de and start a new period urui the üocuuigung of the switching signal by the nächtitfol - ^^ dua AuIüul "Jor period duration takes place.

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The invention represents a further development of the invention according to claim. 9 of the patent

(Patent application P 23 42 350.7).

Based on the embodiment of Figures 1, 2, 3 should the invention of the main patent will be explained, wherein

Fig. 1 - a circuit example for implementation. tion of the method according to the invention according to the main patent and

Fig. 2 - Diagrams to explain the operation of the arrangement according to FIG. 1 is used

Fig. 3 - a circuit in which the in the

Circuit of Fig. 1 generated signals are further processed.

In the embodiment example dor I ¹ Ig. 1, the digital value representing the vehicle speed is present at the terminal bundle 1 (shown as follows for the sake of simplicity). This digital value reaches the memory 3 via a trunk group 2, into which the digital value is accepted in response to a corresponding signal. The digital value stored in the memory reaches the input A of a comparator 4 via a bundle of lines; its input ß is fed via a bundle of lines of the moment. ^ · L of the digital value. It is assumed here that an acceleration signal is to be generated, the comparator emits a signal if the outside lick value exceeds the stored value by a threshold value / \ ν üuer et.

At output 5 of the bistable Uiiüdea ο one receives an acceleration signal, when the bistable element 6 has been toggled via a signal from the output C. Hucked the bistable element via a 3i ^ nal dcü delay element of the 7th

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This delay element 7 is activated via the AND gate 8, e.g. when the brake light switch is actuated (signal on Terminal 9) put into operation. After the delay time T- of e.g. 50 msec has elapsed, a signal is emitted which by blocking the AND gate .8 interrupts the input signal of the delay element 7 and thus its Makes the output signal disappear. The delay element 7 thus starts up again. Its short-term output signal triggers storage in memory 3. If the bistable element 6 is tilted, the output signal switches of the delay element 7 this back into the starting position. Via the control line 10, the one Contains differentiating element 13, it is achieved that each time the bistable element 6 is tilted back and when it appears an output signal on output C of the comparator 4 via OR gate 16 the delay element just like restarting through its output signal and the storage of the current digital value is effected.

With the aid of FIG. 2, the mode of operation of the arrangement of FIG. 1 will now be described.

In Fig. 2a, however, the wheel speed is only shown in the acceleration phase because it is only of interest in connection with the invention. The course of the wheel speed is denoted _{by v R.} As a result of the pressure drop that has taken place, the wheel is accelerated again in the area shown. At t _Q , the timer 7 is to restart (randomly). The threshold Λ ν is not exceeded within Δ Τ, that is to say that it is only when the time constant Δ Τ of the element has expired that it is reset (at t.). Within the period Δ T starting at t ... the threshold Δ ν is exceeded _{at t o.}

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th, the output C emits a signal and thus sets the bistable element 6, which emits the acceleration signal + ■ b (see FIG. 2b) at terminal 5. The pressure is thus kept constant, as it has been since the end of the delay signal (see dashed curve) (see FIG. 2c). Simultaneously with the setting of the bistable element 6, the timer 7 starts again. In the following periods up to time t ^ the threshold Δ ν is exceeded and thus Δ T does not expire and the element 6 remains tilted. However, since the threshold Λ ν is not exceeded in the period that starts again at t, the following period Δ T expires and at the end of this period the element 6 is reset and the element 7 starts up again At terminal 12, the comparator emits a signal when a wheel deceleration threshold is exceeded. This signal can set the arrangement of FIG. 1 in motion in the same way as the signal at output C. For the present case, however, only the appearance of the delay signal at 12 is of interest.

The object on which the invention is based is to reduce the subsequent pressure build-up in a manner known per se should proceed gradually, so that the evaluation circuit the reaction of the wheel to each pressure build-up level can capture.

According to the invention, this object is achieved in that at

switching means, which are known per se and stepwise increase in the brake pressure, are provided which, after the acceleration signal + b generated in this way has ended, in each case with the expiry of the time period Λ. ¹ S cause a pressure increase by a specified pressure level.

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In the invention it is therefore essential that the gradual pressure increase is defined at the end of the + b signal begins immediately and the subsequent pressure build-up and pressure maintenance periods, each of which is the Make up time Δ t, with the monitoring periods for the occurrence of a deceleration or acceleration of the Match the wheel, as this means that the reaction of the wheel is monitored for each pressure increase stage. as As a side effect, there is also the advantage that the timing element for Δ T is used twice and thus an additional one Timer is saved.

For the invention, it does not matter whether the successive periods for the pressure increase are variable, whether - as in the preferred embodiment of the main patent, the time / \ T and the threshold ^ ν are switchable or whether the first pressure stage according to the teaching of the German patent application P 24 60 904.9 is measured.

In Pig. 3 is the circuit of the Pig. 1 as block 20 with outputs 5 'and 12' corresponding to outputs 5 and 12 the Pig. 1 (i.e. + b and -b signal) and another Output 21, which supplies the output signal of the timing element 7, i.e., needle pulses at a distance Δ T, if the acceleration threshold (and, if applicable, the delay threshold) has not been exceeded. The inlet valve is controlled 22j the associated outlet valve is not shown here.

When a delay signal occurs, the inlet valve 22, not shown, is via the line 12 *

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The outlet valve and the bistable element 24 are activated and the pressure is thus reduced.

Subsequently, the pressure is applied until the end of the + b signal held constant (see Fig. 2b). The + b-3 signal sets, however in addition, the bistable element 24, which is then the gate 25 for output pulses from the monostable multivibrator 26 makes permeable. As long as the monostable multivibrator is not tilted, the line 27 carries output signal j however, since valve 22 has responded anyway because of the acceleration signal, the signal has no effect. With each pulse on the line 21, i.e. at intervals of Δ T, the monostable element 26 is tilted and then gives there is no output signal for a given time.

This also happens at the end of the acceleration signal, so at t, generated output pulse of the timer 7. With the associated switching the one-shot disappears for a time ^ \ (= time constant of the one-shot 26), the output signal; thus the inlet valve 22 is not activated and pressure is built up for the time Δ. Thereafter (at te) the monostable multivibrator tilts back and then controls the inlet valve 22 again, ie the pressure is kept constant. In this constant maintenance phase (T .. = Αϊ - Δ) the evaluation circuit now has time to monitor the loading behavior based on the previous pressure stage. This is followed by further pressure increase steps, the step height here increasing with time by the time constant of the monostable multivibrator being changed by element 27, which is set to its starting position by the trailing edge deu -tb-Ji ^ nals. The pressure increase is continued until a delay (doi 12 ') occurs and the bistable element 24 tilts back so that the output signals on line 27 can no longer reach valve 22.

- patent claims -

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Claims (2)

E-379/7 Claims Anti-lock control system in which the as a digital value present speed of a wheel or a value dependent on it in successive periods predetermined length T at the beginning of each is saved and for which within the period the instantaneous value is saved with the respectively saved Digital value is compared, with a given deviation de3 instantaneous digital value from the stored value a switching signal for the brake pressure Your device is generated, the current period is immediately interrupted when this switching signal is generated and a new period is started and the switching period is ended by the next following one The period duration expires according to claim 9 of the Patents (patent application P 23 42 35Ö.7), characterized in that, when the brake pressure is increased gradually, switching means are provided which, after the time interval / \ T, cause the acceleration signal + b generated in this way to increase the pressure by a predetermined pressure level. 2. Anti-lock control system according to claim 1, characterized in that that the pressure levels are different. Heidelberg, November 18, 197 ^
E-379 PT-Ka / Ba 709822/0513 BATH ORIGINAL