Skid control system

Claim 2

In a skid control system for controlling fluid pressure actuated brakes of at least one wheel of a wheeled vehicle by controlling the fluid pressure to the brakes via a modulating valve actuated to one condition for relieving the fluid pressure and to another condition for applying the fluid pressure, the invention comprising: control circuit means for actuating the modulating valve to the one condition in response to a deceleration of the wheel of a first determinable magnitude, said control circuit means comprising first acceleration means responsive to the acceleration of the wheel following actuation of the modulating valve to the one condition for varying said first determinable magnitude in accordance with variations in the magnitude of the acceleration.

Claim 3

The system of claim 1 with said control circuit means actuating the modulating valve to the other condition in response to a different condition having a different determinable magnitude and further comprising velocity means for providing a velocity signal representative of the velocity of the vehicle and varying said different determinable magnitude in response to variations in the magnitude of said velocity signal.

Claim 4

The system of claim 2 with said velocity means including means for increasing said different determinable magnitude in response to magnitudes of said velocity signal representative of higher vehicle velocities whereby actuation of the modulating valve to said other condition will be delayed at higher vehicle velocities.

Claim 5

The system of claim 3 with said velocity means comprising electrical storage means for storing an electrical charge with said charge being said velocity signal and having a magnitude representative of vehicle velocity with the magnitude of the charge varying in accordance with a preselected time rate.

Claim 6

The system of claim 1 with said control circuit means comprising second acceleration means responsive to the acceleration of the wheel of a second determinable magnitude following actuation of the modulating valve to the one condition for actuating the modulating valve to the other condition.

Claim 7

The system of claim 1 with the modulating valve being actuated to the one condition in response to initiation of a control signal and to the other condition in response to termination of said control signal and with said control circuit means comprising output circuit means for initiating said control signal in response to the deceleration of the wheel of said first determinable magnitude.

Claim 8

The system of claim 6 with said output circuit means including means for terminating said control signal a determinable time after the deceleration decreases to a selected magnitude below said first determinable magnitude.

Claim 9

The system of claim 7 with said control circuit means further comprising velocity means for providing a velocity signal representative of the velocity of the vehicle and varying said first determinable time in response to variations in magnitude of said velocity signal.

Claim 10

The system of claim 8 with said velocity means including means for increasing said determinable time in response to magnitudes of said velocity signal representative of higher vehicle velocities.

Claim 11

The system of claim 9 with said velocity means comprising electrical storage means for storing an electrical charge with said charge being said velocity signal and having a magnitude representative of vehicle velocity with the magnitude of the charge varying in accordance with a preselected time rate.

Claim 12

The system of claim 1 with the modulating valve being actuated to the one condition in response to a first control signal and to the other condition in response to a second control signal, said control circuit means comprising output circuit means for providing said first control signal in response to the deceleration of the wheel of said first determinable magnitude, said control circuit means comprising second acceleration means for providing said second control signal in response to the acceleration of the wheel attaining a second determinable magnitude following actuation of the modulating valve to the one condition.

Claim 13

The system of claim 11 with said control circuit means further comprising velocity means for providing a velocity signal representative of the velocity of the vehicle and varying said second determinable magnitude in response to variations in magnitude of said velocity signal.

Claim 14

The system of claim 12 with said velocity means including means for increasing said second determinable magnitude in response to magnitudes of said velocity signal representative of higher vehicle velocities whereby actuation of the modulating valve to said other condition will be delayed at higher vehicle velocities.

Claim 15

The system of claim 12 with the modulating valve being actuated to the one condition in response to initiation of said first control signal and to the other condition in response to termination of said first control signal and with said control circuit means comprising output circuit means for initiating said first control signal in response to the deceleration of the wheel of said first determinable magnitude.

Claim 16

The system of claim 14 with said output circuit means including means for terminating said first control signal a determinable time after the deceleration decreases to a selected magnitude below said first determinable magnitude.

Claim 17

The system of claim 15 with said control circuit means further comprising velocity means for providing a velocity signal representative of the velocity of the vehicle and varying said determinable time in response to variations in magnitude of said velocity signal.

Claim 18

The system of claim 16 with the modulating valve controlling the fluid pressure to the brakes of a plurality of wheels and further comprising wheel velocity means responsive to the velocity of the wheels for preventing actuation of the valve to said one condition unless the velocity of the wheels is below a preselected magnitude.

Claim 19

The system of claim 1 with the modulating valve controlling the fluid pressure to the brakes of a plurality of wheels and further comprising wheel velocity means responsive to the velocity of the wheels for preventing actuation of the valve to said one condition unless the velocity of the wheels is below a preselected magnitude.

Claim 20

In a skid control system for controlling fluid pressure actuated brakes for at least one wheel of a plurality of wheels of a wheeled vehicle by controlling the fluid pressure to the brakes via a modulating valve actuated to one condition for relieving the fluid pressure and to another condition for applying the fluid pressure, the invention comprising: control circuit means for actuating the modulating valve to the one condition in response to a selected occurrence, said control circuit means comprising wheel velocity means responsive to the velocity of at least one of the wheels for preventing actuation of the valve to said one condition unless the velocity of the wheel is below a preselected magnitude with said control circuit means including disabling means for disabling said wheel velocity means when the modulating valve is in the one condition.

Claim 21

In a skid control system for controlling fluid pressure actuated brakes for at least one wheel of a plurality of wheels of a wheeled vehicle by controlling the fluid pressure to the brakes via a modulating valve actuated to one condition for relieving the fluid pressure and to another condition for applying the fluid pressure, the invention comprising: control circuit means for actuating the modulating valve to the one condition in response to a selected occurrence, said control circuit means comprising wheel velocity means responsive to the velocity of at least one of the wheels for preventing actuation of the valve to said one condition unless the velocity of the wheel is below a preselected magnitude with said control circuit means including disabling means for disabling said wheel velocity means when the modulating valve is in the one condition.

Claim 22

An anti-lock brake control system for a wheeled vehicle adapted to the coefficient of friction between a braked wheel and the surface on which the vehicle is supported, comprising means for generating a first electrical signal proportional to acceleration of a braked wheel, means for producing a deceleration reference electrical signal which represents optimum wheel decleration for vehicle braking on a given surface, means responsive to the reference signal and the first signal for cyclically producing a brake control signal when said first and reference signals attain predetermined relationships, brake pressure modulating means responsive to the brake control signal for cyclically relieving and applying brake pressure, whereby the brake pressure modulating means relieves brake pressure to permit wheel speed recovery and thereafter reapplies brake pressure, and means responsive to positive wheel acceleration in each cycle for altering the reference signal value for the subsequent cycle according to the value of the positive wheel acceleration during wheel speed recovery, so that the control system is conditioned to the value of wheel acceleration and hence to the coefficient of friction between the wheel and the surface.

Claim 23

An anti-lock brake control system for a wheeled vehicle adapted to the coefficient of friction between a braked wheel and the surface on which the vehicle is supported, comprising means for generating a first electrical signal proportional to acceleration of a braked wheel, means for producing a deceleration reference electrical signal which represents optimum wheel decleration for vehicle braking on a given surface, means responsive to the reference signal and the first signal for cyclically producing a brake control signal when said first and reference signals attain predetermined relationships, brake pressure modulating means responsive to the brake control signal for cyclically relieving and applying brake pressure, whereby the brake pressure modulating means relieves brake pressure to permit wheel speed recovery and thereafter reapplies brake pressure, and means responsive to positive wheel acceleration in each cycle for altering the reference signal value for the subsequent cycle according to the value of the positive wheel acceleration during wheel speed recovery, so that the control system is conditioned to the value of wheel acceleration and hence to the coefficient of friction between the wheel and the surface.

Claim 24

An anti-lock brake control system for a wheeled vehicle comprising means for generating a first electrical signal proportional to wheel acceleration, means for producing a deceleration reference electrical signal which represents optimum wheel deceleration for vehicle braking on a predetermined coefficient of friction surface, means responsive to the reference signal and the first signal for cyclically producing a brake control signal when said first and reference signals attain predetermined relationships, brake pressure modulating means responsive to the brake control signal for cyclically relieving and applying brake pressure, whereby the brake pressure modulating means relieves brake pressure to permit wheel speed recovery and thereafter reapplies brake pressure, and means responsive to positive wheel acceleration in each cycle for altering the reference signal for the subsequent cycle to a different value when the positive wheel acceleration attains a predetermined value during wheel speed recovery, so that the control system is conditioned to the value of the wheel acceleration and hence to the coefficient of friction between the wheel and the surface.

Claim 25

An anti-lock brake control system for a wheeled vehicle comprising means for generating a first electrical signal proportional to wheel acceleration, means for producing a deceleration reference electrical signal which represents optimum wheel deceleration for vehicle braking on a predetermined coefficient of friction surface, means responsive to the reference signal and the first signal for cyclically producing a brake control signal when said first and reference signals attain predetermined relationships, brake pressure modulating means responsive to the brake control signal for cyclically relieving and applying brake pressure, whereby the brake pressure modulating means relieves brake pressure to permit wheel speed recovery and thereafter reapplies brake pressure, and means responsive to positive wheel acceleration in each cycle for altering the reference signal for the subsequent cycle to a different value when the positive wheel acceleration attains a predetermined value during wheel speed recovery, so that the control system is conditioned to the value of the wheel acceleration and hence to the coefficient of friction between the wheel and the surface.

Claim 26

An anti-lock brake control system for a wheeled vehicle comprising means for generating a first electrical signal proportional to wheel acceleration, means for producing a deceleration reference electrical signal which represents optimum wheel deceleration for vehicle braking on a predetermined coefficient of friction surface, means responsive to the reference signal and the first signal for cyclically producing a brake control signal when said first and reference signals attain predetermined releationships, brake pressure modulating means responsive to the brake control signal for cyclically relieving and applying brake pressure, whereby the brake pressure modulating means relieves brake pressure to permit wheel speed recovery and thereafter reapplies brake pressure, means responsive to positive wheel acceleration in each cycle for altering the reference signal value for the subsequent cycle according to the value of the positive wheel acceleration during wheel speed recovery, so that the control system is conditioned to the value of wheel acceleration and hence to the coefficient of friction between the wheel and the surface, said last means being responsive to wheel acceleration for sensing predetermined wheel acceleration signals and for increasing the deceleration reference signal to render the brake control signal means less sensitive to the predetermined wheel acceleration signals.

Claim 27

An anti-lock brake control system for a wheeled vehicle comprising means for generating a first electrical signal proportional to wheel acceleration, means for producing a deceleration reference electrical signal which represents optimum wheel deceleration for vehicle braking on a predetermined coefficient of friction surface, means responsive to the reference signal and the first signal for cyclically producing a brake control signal when said first and reference signals attain predetermined releationships, brake pressure modulating means responsive to the brake control signal for cyclically relieving and applying brake pressure, whereby the brake pressure modulating means relieves brake pressure to permit wheel speed recovery and thereafter reapplies brake pressure, means responsive to positive wheel acceleration in each cycle for altering the reference signal value for the subsequent cycle according to the value of the positive wheel acceleration during wheel speed recovery, so that the control system is conditioned to the value of wheel acceleration and hence to the coefficient of friction between the wheel and the surface, said last means being responsive to wheel acceleration for sensing predetermined wheel acceleration signals and for increasing the deceleration reference signal to render the brake control signal means less sensitive to the predetermined wheel acceleration signals.