Electronic antiskid control device
First Claim
1. An electronic antiskid control device for a motor vehicle brake system, comprising in combination, a frequency multiplier circuit responsive to a speed signal, the frequency of which represents the peripheral speed of one wheel of a vehicle and supplying an output signal whose frequency is such that the ratio between the frequency of the output signal and the frequency of the speed signal normally assumes a predetermined value equal to the multiplication factor of the multiplier when the peripheral speed of the said one wheel is substantially constant, the ratio between the frequencies of the output signal and speed signal being capable of deviating temporarily from its normal value in response to a variation in the frequency of the speed signal, the improvement wherein a calculating means 14 supplies at intervals of time a number which is a function of the ratio between the frequencies of the output signal and speed signal and which represents the wheel slip, an actuating means 20 is responsive to the value of the number supplied by the calculating means 14 so as to generate an antiskid signal to control an antiskid cycle, the calculating means 14 comprises a counting circuit 16 of which the input receives the output signal from the frequency multiplier circuit 12 and of which the counting period equals the period of the speed signal, and a storage element 18 connected to the output of the counting circuit 16, the storage element 18 being capable of storing the value contained in the counting circuit in response to the supply of a store signal whose frequency equals the frequency of the speed signal, the storage element 18 supplying the number representing the wheel slip, and the store signal being supplied by a first monostable circuit 34 responsive to one edge of the speed signal.
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Accused Products
Abstract
An electronic antiskid control device which comprises a frequency multiplier of the phase locked-loop type, which receives repetitive pulses of predetermined frequency representing the speed of one wheel. The phase locked-loop multiplier normally outputs a second pulse signal, the frequency of which is normally equal to the frequency of the wheel speed signal multiplied by a given number. A digital counter which is periodically reset at a frequency equal to that of the wheel speed signal measures the number of pulses of the second pulse signal during each period. The measured number is transfered into a memory element and calculating apparatus responsive to the value stored in the memory element control an antiskid cycle. In operation under normal conditions, the number stored in the memory element is constant and has no action on the calculating apparatus. In case of high deceleration or acceleration, the stored number momentarily deviates from its constant value so as to indicate a predetermined skid and control actuation of the antiskid device.
14 Citations
12 Claims
- 1. An electronic antiskid control device for a motor vehicle brake system, comprising in combination, a frequency multiplier circuit responsive to a speed signal, the frequency of which represents the peripheral speed of one wheel of a vehicle and supplying an output signal whose frequency is such that the ratio between the frequency of the output signal and the frequency of the speed signal normally assumes a predetermined value equal to the multiplication factor of the multiplier when the peripheral speed of the said one wheel is substantially constant, the ratio between the frequencies of the output signal and speed signal being capable of deviating temporarily from its normal value in response to a variation in the frequency of the speed signal, the improvement wherein a calculating means 14 supplies at intervals of time a number which is a function of the ratio between the frequencies of the output signal and speed signal and which represents the wheel slip, an actuating means 20 is responsive to the value of the number supplied by the calculating means 14 so as to generate an antiskid signal to control an antiskid cycle, the calculating means 14 comprises a counting circuit 16 of which the input receives the output signal from the frequency multiplier circuit 12 and of which the counting period equals the period of the speed signal, and a storage element 18 connected to the output of the counting circuit 16, the storage element 18 being capable of storing the value contained in the counting circuit in response to the supply of a store signal whose frequency equals the frequency of the speed signal, the storage element 18 supplying the number representing the wheel slip, and the store signal being supplied by a first monostable circuit 34 responsive to one edge of the speed signal.
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12. An electronic antiskid control device for a motor vehicle brake system, comprising in combination, a frequency multiplier circuit responsive to a speed signal the frequency of which represents the peripheral speed of one wheel of a vehicle and supplying an output signal whose frequency is such that the ratio between the frequency of the output signal and the frequency of the speed signal normally assumes a predetermined value equal to the multiplication factor of the multiplier when the peripheral speed of the said one wheel is substantially constant, the ratio between the frequencies of the output signal and speed signal being capable of deviating temporarily from its normal value in response to a variation in the frequency of the speed signal, the improvement wherein a calculating means 14 supplies at intervals of time a number which is a function of the ratio between the frequencies of the output signal and speed signal and which represents the wheel slip, an actuating means 20 is responsive to the value of the number supplied by the calculating means 14 so as to generate an antiskid signal to control an antiskid cycle, the calculating means 14 comprise a counting circuit 16 of which the input receives the output signal from the frequency multiplier circuit 12 and of which the counting period equals the period of the speed signal, and a storage element 18 connected to the output of the counting circuit 16, the storage element 18 being capable of storing the value contained in the counting circuit in response to the supply of a store signal whose frequency equals the frequency of the speed signal, the storage element 18 supplying the number representing the wheel slip, the counting circuit 16 being arranged so that the value entered in said circuit cannot exceed a given value which is greater than the multiplication factor of the multiplier and less than the maximum counting capacity of said circuit, the operating means 20 comprising a circuit 24 for decoding the given value so as to supply a first decoded signal when the number entered in the storage element 18 possesses the given value, and the actuating means also comprising an output circuit 28 capable of supplying an antiskid signal in response to the appearance of the first decoded signal.
Specification