Boots – shoes – and leggings
Patent
1982-08-18
1985-01-29
Truhe, J. V.
Boots, shoes, and leggings
303 99, 303105, 180197, B60T 810
Patent
active
044970269
DESCRIPTION:
BRIEF SUMMARY
The invention relates to an anti-wheel-lock control system in which wheel speed signals are derived from rotation transducers for subsequent processing.
BACKGROUND
Various anti-wheel-lock control systems are known. In such known anti-wheel-lock control systems, frequency filters are used to suppress disturbance signals generated by frictional oscillations. Such frictional oscillations occur particularly in commercial vehicles at low speed (shortly before a standstill). Their frequency is in the range of a few hundred Hertz. The transducers of the anti-wheel-lock controller sense these oscillations and transmit them to a controller in the form of disturbance signals, which may evaluate them as high-speed signals. Thus, an excessively high wheel speed is simulated by the disturbance signal, causing malfunctioning of the controller.
Known controllers made to solve this problem have the disadvantage that they do not permit digital signal processing, at least in this speed range of the controller, and thus construction in integrated circuit form, e.g. as a microprocessor, is difficult.
THE INVENTION
It is an object of the invention to provide a means for suppressing disturbance signals, which also permits digital signal processing within the controller.
Briefly, it has been found that upon the occurrence of frictional oscillations, the wheel will behave in such a manner that the output signals which are generated by the transducer will be representative of signals which are actually physically impossible in the system if the wheel were to operate normally. To analyze these signals, then, threshold signals are generated which simulate such physically impossible behavior of the wheel speed signal, that is, simulate extreme variations in wheel speed, or, effectively, in wheel acceleration. This phenomenon, namely physically impossible wheel acceleration, is utilized and analyzed and the signal is then analyzed for outputs which would be physically impossible. If such physically impossible outputs are recognized, the signal from the transducer is not applied to the wheel slip control system but, rather, inhibited, and an auxiliary signal, based on a previously measured and normal signal is, instead, connected.
The system, thus, includes a memory to store, continuously, speed signals as they are derived from the transducer. A disturbance simulating signal is generated, representative of a physically impossible condition. If the transducer signal exceeds a minimum threshold, or falls within a threshold range of the distrubance signal--which would be physically impossible as a normal signal--then its effect on the wheel slip system is inhibited, for example by switching-over or blocking of a gate, and, instead, a previously stored wheel signal is connected to the wheel speed evaluation system.
The system has the advantage that it can eliminate distrubances by digital signal processing which can be monitored with a self-checking device; this is accomplished more easily than in apparatus which use analog filters.
DRAWINGS
The drawings show in:
FIG. 1: the fundamental structure of one exemplary embodiment of an anti-wheel-lock control system;
FIG. 2: a basic circuit diagram for the suppression of disturbances according to the invention;
FIG. 3: one exemplary embodiment of components for use in the system of FIG. 2; and
FIG. 4: a digram explaining the mode of operation.
DETAILED DESCRIPTION
A transducer 1 senses wheel speed as shown in FIG. 1. The signals from the transducer 1 are processed in block 2 and then delivered to an evaluation circuit 3, in which trigger signals for electro-magnetic valves 4 and 5 are obtained on the basis of the signals from the signal processing block 2, for instance signals relating to deceleration, acceleration or slip. Brake fluid pressure is controlled by the magnetic valves 4 and 5, reducing or increasing the pressure, or holding it constant.
In accordance with a feature of the invention, and in order to eliminate the disturbances appearing because of frictional oscillations a
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patent: 4136912 (1979-01-01), Hesse et al.
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patent: 4251118 (1981-02-01), Rothen et al.
D. G. Smedley, Second International Conference on Automotive Electronics, London, England, (Oct. 29-Nov. 2, 1979), pp. 33-37.
Braschel Volker
Emig Reiner
Gerstenmeier Jurgen
Leiber Heinz
Mendel Michael
Ro Bentsu
Robert & Bosch GmbH
Truhe J. V.
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