Skid control apparatus

Claim 3

An apparatus as in claim 1, wherein said portions are connected in parallel to each other.

Claim 6

An apparatus as in claim 3, wherein said memory means includes energy storage means.

Claim 7

An apparatus as in claim 3, wherein said memory means includes capacitor means and unidirectional means for applying a voltage corresponding to the wheel velocity across said capacitor means.

Claim 8

An apparatus as in claim 5, wherein said first control means includes linear amplifying means for forming a path of constant current flow.

Claim 9

An apparatus as in claim 5, wherein said second control means includes a resistor.

Claim 10

An apparatus as in claim 5, wherein said adding means includes a circuit connecting each of said control means in parallel across said capacitor means.

Claim 11

An apparatus as in claim 8, wherein said first control means includes linear amplifying means for forming a path of constant current flow.

Claim 12

An apparatus as in claim 9, wherein said second control means includes a resistor.

Claim 13

An apparatus as in claim 10, wherein said first control means includes linear amplifying means for forming a path of constant current flow.

Claim 14

An apparatus as in claim 11, wherein said comparator means includes a differential amplifier.

Claim 15

An apparatus as in claim 12, further comprising pressure modulating means for modulating the braking force applied to the wheel.

Claim 16

A skid control system for a vehicle having a wheel and brakes for applying a braking force to the wheel, comprising a wheel velocity detector for detecing the velocity of the wheel, an initial velocity memory circuit for memorizing the wheel velocity when a braking force is applied to the wheel, first detector means for obtaining an output corresponding to the vehicle deceleration, second detector means for obtaining an output corresponding to the braking force applied to the wheel, differentiator means coupled to said second detector means to differentiate the output of said second detector means, multiplier means connected to said differentiator means for producing an output proportional to the product of the output of said differentiator means and the velocity of the vehicle and the product of the gradient of the characteristic curve determined by the coefficient of friction between a road surface and a wheel and a wheel slip ratio in the range of slip ratios less than that at which the characteristic curve is curved, adder means coupled to said first detector means and said multiplier means for adding the outputs of said first detector means and said multiplier means to obtain a value corresponding to a safe wheel deceleration, integrator means coupled to said adder means for integrating the value corresponding to the safe deceleration, subtractor means coupled to said memory means and said integrator means for subtracting the time integration of the value corresponding to the safe deceleration from the output of said wheel velocity detector, comparator means coupled to said velocity detector and said subtracting means for producing a pressure reducing signal when the output of said subtracting means exceeds the output of said detector, and pressure modulator means responsive to said comparator means for regulating the braking force in accordance with an output signal from said comparator means.

Claim 17

A skid control system for a vehicle having a wheel and brakes for applying a braking force to the wheel, comprising a wheel velocity detector for detecing the velocity of the wheel, an initial velocity memory circuit for memorizing the wheel velocity when a braking force is applied to the wheel, first detector means for obtaining an output corresponding to the vehicle deceleration, second detector means for obtaining an output corresponding to the braking force applied to the wheel, differentiator means coupled to said second detector means to differentiate the output of said second detector means, multiplier means connected to said differentiator means for producing an output proportional to the product of the output of said differentiator means and the velocity of the vehicle and the product of the gradient of the characteristic curve determined by the coefficient of friction between a road surface and a wheel and a wheel slip ratio in the range of slip ratios less than that at which the characteristic curve is curved, adder means coupled to said first detector means and said multiplier means for adding the outputs of said first detector means and said multiplier means to obtain a value corresponding to a safe wheel deceleration, integrator means coupled to said adder means for integrating the value corresponding to the safe deceleration, subtractor means coupled to said memory means and said integrator means for subtracting the time integration of the value corresponding to the safe deceleration from the output of said wheel velocity detector, comparator means coupled to said velocity detector and said subtracting means for producing a pressure reducing signal when the output of said subtracting means exceeds the output of said detector, and pressure modulator means responsive to said comparator means for regulating the braking force in accordance with an output signal from said comparator means.

Claim 18

A skid control system as in claim 14, wherein said multiplier means responds to the output of said subtracting means for responding to a value corresponding to the vehicle velocity.

Claim 19

A skid control system for a vehicle having a wheel and a brake for applying a braking force to the wheel, comprising a wheel velocity detector means for detecting the wheel velocity, initial velocity memory circuit means for memorizing the wheel velocity at the initiation of braking, braking force detector means for producing an output proportional to the vehicle deceleration, braking force speed means for producing an output corresponding to the rate of change of the braking force, multiplier means coupled to said braking force speed means for producing a signal corresponding to the product of the vehicle velocity and the output of said braking force speed means as well as the gradient of the characteristic curve determined by the coefficient of friction between a road surface and a wheel and the wheel slip ratio in the range of slip ratios less than that at which said characteristic curve is curved, adder means coupled to said multiplier means for adding both outputs of said braking force detecotr means and said multiplier means for obtaining a value corresponding to a set deceleration, integrator means coupled to said adder means for producing a value corresponding to the integral of the set wheel acceleration, subtractor means connected to said memory circuit means and said integrator means for producing a signal corresponding to the difference between the output of said memory means and the output of said integrator means, comparator means coupled to said subtractor means and said detector means for producing a braking force reducing signal when the output of said subtractor means exceeds the output of said detector means, and force modulator means coupled to said comparator means for regulating the braking force with a constant force application rate of change in accordance with the output signal of said comparator means.

Claim 20

A skid control system for a vehicle having a wheel and a brake for applying a braking force to the wheel, comprising a wheel velocity detector means for detecting the wheel velocity, initial velocity memory circuit means for memorizing the wheel velocity at the initiation of braking, braking force detector means for producing an output proportional to the vehicle deceleration, braking force speed means for producing an output corresponding to the rate of change of the braking force, multiplier means coupled to said braking force speed means for producing a signal corresponding to the product of the vehicle velocity and the output of said braking force speed means as well as the gradient of the characteristic curve determined by the coefficient of friction between a road surface and a wheel and the wheel slip ratio in the range of slip ratios less than that at which said characteristic curve is curved, adder means coupled to said multiplier means for adding both outputs of said braking force detecotr means and said multiplier means for obtaining a value corresponding to a set deceleration, integrator means coupled to said adder means for producing a value corresponding to the integral of the set wheel acceleration, subtractor means connected to said memory circuit means and said integrator means for producing a signal corresponding to the difference between the output of said memory means and the output of said integrator means, comparator means coupled to said subtractor means and said detector means for producing a braking force reducing signal when the output of said subtractor means exceeds the output of said detector means, and force modulator means coupled to said comparator means for regulating the braking force with a constant force application rate of change in accordance with the output signal of said comparator means.

Claim 21

A system as in claim 16, wherein the output of said subtractor means is coupled to said multiplier means.

Claim 22

A skid control system for a vehicle having a brake arrangement for applying a braking pressure to a wheel of the vehicle, comprising wheel velocity detector means for detecting the velocity of the wheel, initial velocity memory means for memorizing the wheel velocity at the time of the start of a braking action, subtractor means responsive to said memory means for obtaining a set wheel velocity by substracting a time integration of a set deceleration from an initial velocity, braking pressure sensing means for detecting the braking pressure, linear amplifier means coupled to the output of said subtractor means and to said sensing means for amplifying the set wheel velocity to obtain an output substantially corresponding to the product of the vehicle velocity and the rate of change of the braking pressure as well as the gradient of the characteristic curve determined by the coefficient of friction between a road surface and a wheel and the wheel slip ratio in the range of slip ratios less than that at which the characteristic curve is curved, comparator means for comparing the wheel velocity and the set wheel velocity for issuing a braking pressure reducing signal when the wheel velocity is less than the set wheel velocity, and pressure modulator means for reducing the braking pressure in accordance with said signal by providing the characteristic to the pressure modulating speed so that the sum of the value representing the braking pressure and the value representing the change in braking pressure become constant.

Claim 23

A skid control system for a vehicle having a brake arrangement for applying a braking pressure to a wheel of the vehicle, comprising wheel velocity detector means for detecting the velocity of the wheel, initial velocity memory means for memorizing the wheel velocity at the time of the start of a braking action, subtractor means responsive to said memory means for obtaining a set wheel velocity by substracting a time integration of a set deceleration from an initial velocity, braking pressure sensing means for detecting the braking pressure, linear amplifier means coupled to the output of said subtractor means and to said sensing means for amplifying the set wheel velocity to obtain an output substantially corresponding to the product of the vehicle velocity and the rate of change of the braking pressure as well as the gradient of the characteristic curve determined by the coefficient of friction between a road surface and a wheel and the wheel slip ratio in the range of slip ratios less than that at which the characteristic curve is curved, comparator means for comparing the wheel velocity and the set wheel velocity for issuing a braking pressure reducing signal when the wheel velocity is less than the set wheel velocity, and pressure modulator means for reducing the braking pressure in accordance with said signal by providing the characteristic to the pressure modulating speed so that the sum of the value representing the braking pressure and the value representing the change in braking pressure become constant.

Claim 24

A skid control system for varying the braking pressure applied by a brake to the wheel of a vehicle, comprising velocity measuring means for measuring the velocity of the wheel, storage means for storing a value corresponding to the output of said measuring means, first control means capable of changing the level of the value in said storage means linearly, second control means capable of changing the level of the value in said storage means exponentially, adding means for connecting said first and second control means to said storage means so as to change the value in said storage means on the basis of the sum of the linear and exponential change, comparator means responsive to said adding means and said measuring means for comparing the value in said adding means and said measuring means and producing an output signal when the value in said storage means exceeds the value in said measuring means, and braking force modulating means responsive to said comparator means for regulating the braking force applied by the brake to the wheel.

Claim 25

A skid control system for varying the braking pressure applied by a brake to the wheel of a vehicle, comprising velocity measuring means for measuring the velocity of the wheel, storage means for storing a value corresponding to the output of said measuring means, first control means capable of changing the level of the value in said storage means linearly, second control means capable of changing the level of the value in said storage means exponentially, adding means for connecting said first and second control means to said storage means so as to change the value in said storage means on the basis of the sum of the linear and exponential change, comparator means responsive to said adding means and said measuring means for comparing the value in said adding means and said measuring means and producing an output signal when the value in said storage means exceeds the value in said measuring means, and braking force modulating means responsive to said comparator means for regulating the braking force applied by the brake to the wheel.

Claim 26

A system as in claim 19 wherein said braking force modulating means includes a negative feedback system for delaying the effect said modulating means has upon the braking force in response to said comparator means.

Claim 27

A system as in claim 20 wherein said braking force modulating means has a characteristic obeying the expression (C0t/c1t + C2) + C3, where t represents time and C0, C1, C2 and C3 are constants.

Claim 28

A system as in claim 20 wherein said first control means includes linear aplifying means for forming a path of constant current flow and wherein said second control means includes a resistor.

Claim 29

A system as in claim 22 wherein said braking force modulating means includes a pressure control system, said pressure control system having an output, said pressure control system having an input, said pressure control system having a throttling valve responsive to said output and forming a feedback in said system.

Claim 30

A system as in claim 19 wherein said storage means includes capacitor means and unidirectional means for applying a voltage corresponding to the wheel velocity across said capacitor means.

Claim 31

A system as in claim 24 wherein said first control means includes linear amplifying means for Forming a path of constant current flow.

Claim 32

A system as in claim 24 wherein said second control means includes a resistor.

Claim 33

A system as in claim 24 wherein said adding means includes a circuit connecting each of said control means in parallel across said capacitor means.

Claim 34

A system as in claim 27 wherein said first control means includes linear amplifying means for forming a path of constant current flow and wherein said second control means includes a resistor.

Claim 35

A system as in claim 19, wherein said control means include means for prolonging the modulaton of said braking force when the value in said storage means no longer exceeds the value in said measuring means.