Antilocking controller or drive slip controller

Details Antilocking controller or drive slip controller Antilocking controller or drive slip controller

1991-11-13

1993-03-16

Butler, Douglas C.

Fluid-pressure and analogous brake systems

Speed-controlled

Having a valve system responsive to a wheel lock signal

303103, 303 96, B60T 832, B60K 2816, G01P 348

Patent

active

051938898

DESCRIPTION:

BRIEF SUMMARY
BACKGROUND OF THE INVENTION

From the DE-OS 25 18 190, a method is known by which to avoid wheel vibration in an ABS by preventing another pressure build-up for a predetermined period, after a pressure degradation and subsequent phase of holding a constant condition in which the wheel once more gains speed. This enables wheel vibrations to be prevented, but restricts the function of the controller which can no longer react as fast with this design.
From the EP-PS 00 73 198, a method is known in an ABS by which the wheel speed signal, in respect of physcially impossible changes, is filtered.


SUMMARY OF THE INVENTION

In the controller designed in accordance with the invention, no continuously effective method influences the controller function. Instead, a checking facility is provided to ascertain whether wheel vibration exists, and corrective action is initiated only when such vibration has been recognized. A corrective measure in an ASR, for example, is to influence the engine torque. However, it is also possible to intervene in the brake pressure variation, and this certainly applies to the ABS. It is possible to vary the duration of the control cycle, a required pressure build-up can be suppressed, and by a phase-shift, a pressure build-up or pressure holding can be initiated.
Several thresholds can be provided for triggering various actions for vibration suppression.


BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a block diagram of an ASR
FIG. 2 shows an associated diagram
FIG. 3 shows a block diagram of another embodiment
FIG. 4 is a block diagram of an embodiment for damping vibrations of driven and non-driven wheels


DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIG. 1, four transducers 1, 2 for the non-driven wheels and transducers 3, 4 for the driven wheels supply digital speed signals to an evaluation unit 5 which is designed as a microprocessor. This contains, in a known manner, filters 5a, 5b for the digital filtering of the wheel speed signals of the non-driven and driven wheels. In a known manner, the evaluation circuit produces control signals for brake control valves 6 which is assigned to the driven wheels, and for a control element 7 which can adjust the throttle.
In order to recognize wheel vibrations, a subtraction element 8 is provided which is supplied with the filtered (V.sub.RF) and the unfiltered speed signal (V.sub.R) of a driven wheel and which sends out a signal which corresponds to the difference of the two signals: .vertline.V.sub.R -V.sub.RF .vertline.. This signal is fed to a counter 9 which adds the differences generated in the time interval of the working cycle (control line 9a) of the evaluation circuit 5. With each cycle, the counter 9 is fed with a constant value from a block 10 which is substracted from the sum in counter 9. This value is rated such that with a small difference of the two speed signals, the counter is corrected downwards. If a first threshold is exceeded by the calculation result E of the counter 9, then a first control signal is produced which prevents the further supply of a control signal to a control element 7 (AND-gate 11).
If yet another threshold is exceeded, then a second control signal is coupled in via an OR-gate 12, which influences the control element so as to close the throttle. At the same time, the counter 9 is returned to the starting position. Moreover, resetting to a definite value or reduction by a definite amount would be possible.
FIG. 2 shows the unfiltered wheel speed V.sub.R and the filtered wheel speed V.sub.RF over the time period. The differences are shown partly as a dashed line. Below this, the result E of the calculating process of the counter 9 is presented. At t.sub.1, the first threshold S.sub.1 is exceeded and further movement of the throttle is prevented. At t.sub.2, the second threshold S.sub.2 is exceeded and the throttle is angled back, and the counter is cleared.
After a few such processes, the vibration decays in the vicinity of t.sub.3. For the other driven wheel, a second arrangement, which is not

REFERENCES:
patent: 3630578 (1971-12-01), Kaiser
patent: 4039227 (1977-08-01), Sivulka
patent: 4497026 (1985-01-01), Braschel et al.
patent: 4701855 (1987-10-01), Fennel
patent: 4762375 (1988-08-01), Maki et al.
patent: 4870582 (1989-09-01), Hoashi et al.
patent: 4992945 (1991-02-01), Kumpfmueller
patent: 5040120 (1991-08-01), Hoffmann
patent: 5099443 (1992-03-01), Higashima et al.

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