Anti-locking systems for vehicle brakes

Claim 2

A anti-locking braking device for controlling the braking of at least one wheel of a vehicle; means for producing a first pulsating electric signal the frequency of which is proportional to the speed of rotation of the wheel, means for producing a second pulsating electric signal representing a predetermined fraction of the speed of the vehicle, digital comparing means for comparing the first and the second signals and issuing an electrical wheel slip error signal which is a function of the difference between the speed of the wheel and the predetermined fraction of the speed of the vehicle, pressure-operated braking means for said wheel, control means for controllably limiting the maximum pressure that can be applied to the braking means to brake said wheel, and means for producing as a function of said error signal a pulsating control signal driving the control means to reduce the pressure applied to the braking means in the event of wheel slip exceeding a predetermined value, and further comprising a clock generating pulses at a fixed frequency lower than the minimum frequency of said first and second signals, comparison means comprising counting means counting the number of pulses of the first and second signals between two consecutive clock pulses and producing a digital error signal which is a function of the difference between the number of pulses of the first signal and that of the second, and said means for producing the control signal from the digital error signal comprising a converter supplying at each clock pulse a pulsed signal the duration of which is a function of the digital error signal, and further comprising a logic circuit programmed to supply a pilot number which is a function of the difference between the number of pulses of the first and that of the second signal arranged to drive said converter, the pilot number lying between zero and a constant given value, the converter issuing at each clock pulse a signal the length of which is a fraction of the period of the clock pulses equal to the ratio of the pilot number to the given value.

Claim 3

A braking device according to claim 1, in which the converter comprises a frequency multiplier arranged to multiply by 2n-1 the frequency of the clock pulses, a memory with n bits connected with the multiplier, a transfer device which is controlled by the clock and connects the memory to said counting means, and an OR gate which is connected to the memory to issue a signal as long as at least one bit of the latter is equal to 1.

Claim 4

A anti-locking braking device for controlling the braking of at least one wheel of a vehicle; means for producing a first pulsating electric signal the frequency of which is proportional to the speed of rotation of the wheel, means for producing a second pulsating electric signal representing a predetermined fraction of the speed of the vehicle, digital comparing means for comparing the first and the second signals and issuing an electrical wheel slip error signal which is a fuNction of the difference between the speed of the wheel and the predetermined fraction of the speed of the vehicle, pressure-operated braking means for said wheel, control means for controllably limiting the maximum pressure that can be applied to the braking means to brake said wheel, and means for producing as a function of said error signal a pulsating control signal driving the control means to reduce the pressure applied to the braking means in the event of wheel slip exceeding a predetermined value, and further comprising a clock generating pulses at a fixed frequency lower than the minimum frequency of said first and second signals, comparison means comprising counting means counting the number of pulses of the first and second signals between two consecutive clock pulses and producing a digital error signal which is a function of the difference between the number of pulses of the first signal and that of the second, and said means for producing the control signal from the digital error signal comprising a converter supplying at each clock pulse a pulsed signal the duration of which is a function of the digital error signal, and in which said means for producing said second signal comprise a generator which receives a numerical signal representing the speed of the vehicle and transmits said numerical signal without alteration to said means of comparison if this signal increases or remains constant, but imposes upon said second signal a maximum reduction when said second signal decreases and a logic circuit which is connected to the generator and multiplies the signal received from the latter by a factor of less than one, and in which the generator comprises a shift register having a first output of a number being entered into the register and a second output of a number being shifted from the register, a comparator to which both outputs of the shift register are connected, and a logic circuit connected to the shift register, the comparator and the clock.

Claim 5

A anti-locking braking device for controlling the braking of at least one wheel of a vehicle; means for producing a first pulsating electric signal the frequency of which is proportional to the speed of rotation of the wheel, means for producing a second pulsating electric signal representing a predetermined fraction of the speed of the vehicle, digital comparing means for comparing the first and the second signals and issuing an electrical wheel slip error signal which is a fuNction of the difference between the speed of the wheel and the predetermined fraction of the speed of the vehicle, pressure-operated braking means for said wheel, control means for controllably limiting the maximum pressure that can be applied to the braking means to brake said wheel, and means for producing as a function of said error signal a pulsating control signal driving the control means to reduce the pressure applied to the braking means in the event of wheel slip exceeding a predetermined value, and further comprising a clock generating pulses at a fixed frequency lower than the minimum frequency of said first and second signals, comparison means comprising counting means counting the number of pulses of the first and second signals between two consecutive clock pulses and producing a digital error signal which is a function of the difference between the number of pulses of the first signal and that of the second, and said means for producing the control signal from the digital error signal comprising a converter supplying at each clock pulse a pulsed signal the duration of which is a function of the digital error signal, and in which said means for producing said second signal comprise a generator which receives a numerical signal representing the speed of the vehicle and transmits said numerical signal without alteration to said means of comparison if this signal increases or remains constant, but imposes upon said second signal a maximum reduction when said second signal decreases and a logic circuit which is connected to the generator and multiplies the signal received from the latter by a factor of less than one, and in which the generator comprises a shift register having a first output of a number being entered into the register and a second output of a number being shifted from the register, a comparator to which both outputs of the shift register are connected, and a logic circuit connected to the shift register, the comparator and the clock.

Claim 6

A anti-locking braking device for controlling the braking of at least one wheel of a vehicle; means for producing a first pulsating electric signal the frequency of which is proportional to the speed of rotation of the wheel, means for producing a second pulsating electric signal representing a predetermined fraction of the speed of the vehicle, digital comparing means for comparing the first and the second signals and issuing an electrical wheel slip error signal which is a function of the difference between the speed of the wheel and the predetermined fraction of the speed of the vehicle, pressure-operated braking means for said wheel, control means for controllably limiting the maximum pressure that can be applied to the braking means to brake said wheel, and means for producing as a function of said error signal a pulsating control signal driving the control means to reduce the pressure applied to the braking means in the event of wheel slip exceeding a predetermined value, and further comprising a clock generating pulses at a fixed frequency lower than the minimum frequency of said first and second signals, comparison means comprising counting means counting the number of pulses of the first and second signals between two consecutive clock pulses and producing a digital error signal which is a function of the difference between the number of pulses of the first signal and that of the second, and said means for producing the control signal from the digital error signal comprising a converter supplying at each clock pulse a pulsed signal the duration of which is a function of the digital error signal, and further comprising means for differentiating said digital control signal, and a logic matrix which receives the digital control signal and the differentiated signal and is connected to said converter.

Claim 7

A anti-locking braking device for controlling the braking of at least one wheel of a vehicle; means for producing a first pulsating electric signal the frequency of which is proportional to the speed of rotation of the wheel, means for producing a second pulsating electric signal representing a predetermined fraction of the speed of the vehicle, digital comparing means for comparing the first and the second signals and issuing an electrical wheel slip error signal which is a function of the difference between the speed of the wheel and the predetermined fraction of the speed of the vehicle, pressure-operated braking means for said wheel, control means for controllably limiting the maximum pressure that can be applied to the braking means to brake said wheel, and means for producing as a function of said error signal a pulsating control signal driving the control means to reduce the pressure applied to the braking means in the event of wheel slip exceeding a predetermined value, and further comprising a clock generating pulses at a fixed frequency lower than the minimum frequency of said first and second signals, comparison means comprising counting means counting the number of pulses of the first and second signals between two consecutive clock pulses and producing a digital error signal which is a function of the difference between the number of pulses of the first signal and that of the second, and said means for producing the control signal from the digital error signal comprising a converter supplying at each clock pulse a pulsed signal the duration of which is a function of the digital error signal, and further comprising means for differentiating said digital control signal, and a logic matrix which receives the digital control signal and the differentiated signal and is connected to said converter.

Claim 8

A anti-locking braking device for controlling the braking of at least one wheel of a vehicle; means for producing a first pulsating elEctric signal the frequency of which is proportional to the speed of rotation of the wheel, means for producing a second pulsating electric signal representing a predetermined fraction of the speed of the vehicle, digital comparing means for comparing the first and the second signals and issuing an electrical wheel slip error signal which is a function of the difference between the speed of the wheel and the predetermined fraction of the speed of the vehicle, pressure-operated braking means for said wheel, control means for controllably limiting the maximum pressure that can be applied to the braking means to brake said wheel, and means for producing as a function of said error signal a pulsating control signal driving the control means to reduce the pressure applied to the braking means in the event of wheel slip exceeding a predetermined value, and further comprising a clock generating pulses at a fixed frequency lower than the minimum frequency of said first and second signals, comparison means comprising counting means counting the number of pulses of the first and second signals between two consecutive clock pulses and producing a digital error signal which is a function of the difference between the number of pulses of the first signal and that of the second, and said means for producing the control signal from the digital error signal comprising a converter supplying at each clock pulse a pulsed signal the duration of which is a function of the digital error signal, and further comprising means for integrating said digital control signal when it is positive, and a logic matrix which receives the digital control signal and the integrated signal.

Claim 9

A anti-locking braking device for controlling the braking of at least one wheel of a vehicle; means for producing a first pulsating elEctric signal the frequency of which is proportional to the speed of rotation of the wheel, means for producing a second pulsating electric signal representing a predetermined fraction of the speed of the vehicle, digital comparing means for comparing the first and the second signals and issuing an electrical wheel slip error signal which is a function of the difference between the speed of the wheel and the predetermined fraction of the speed of the vehicle, pressure-operated braking means for said wheel, control means for controllably limiting the maximum pressure that can be applied to the braking means to brake said wheel, and means for producing as a function of said error signal a pulsating control signal driving the control means to reduce the pressure applied to the braking means in the event of wheel slip exceeding a predetermined value, and further comprising a clock generating pulses at a fixed frequency lower than the minimum frequency of said first and second signals, comparison means comprising counting means counting the number of pulses of the first and second signals between two consecutive clock pulses and producing a digital error signal which is a function of the difference between the number of pulses of the first signal and that of the second, and said means for producing the control signal from the digital error signal comprising a converter supplying at each clock pulse a pulsed signal the duration of which is a function of the digital error signal, and further comprising means for integrating said digital control signal when it is positive, and a logic matrix which receives the digital control signal and the integrated signal.