Anti-lock brake control system

Claim 2

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 deceleration 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 3

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 deceleration 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 4

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 deceleration 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 5

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 high 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 lower value when the positive wheel acceleration remains below a predetermined value 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 6

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 high 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 lower value when the positive wheel acceleration remains below a predetermined value 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 7

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 during initial brake application has a first value representing optimum wheel deceleration for vehicle braking on a high 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, means responsive to the brake control signal for changing the reference signal to a second value lower than the first value when brake pressure relief is requested, and means responsive to positive wheel acceleration in each cycle for maintaining the reference signal for the subsequent cycle at the second value when the positive wheel acceleration remains below a predetermined value during wheel speed recovery, and for changing the reference signal for the subsequent cycle back to the first value when the positive wheel acceleration exceeds the predetermined value 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 8

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 during initial brake application has a first value representing optimum wheel deceleration for vehicle braking on a high 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, means responsive to the brake control signal for changing the reference signal to a second value lower than the first value when brake pressure relief is requested, and means responsive to positive wheel acceleration in each cycle for maintaining the reference signal for the subsequent cycle at the second value when the positive wheel acceleration remains below a predetermined value during wheel speed recovery, and for changing the reference signal for the subsequent cycle back to the first value when the positive wheel acceleration exceeds the predetermined value 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 9

An anti-lock brake control system for a wheeled vehicle comprising means for generating first and second electrical signals proportional to wheel acceleration, means including a logic circuit for producing a deceleration reference electrical signal which during initial brake application has a first value representing optimum wheel deceleration for vehicle braking on a high coefficient of friction surface, the logic circuit contributing a portion of the reference signal, 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, the logic circuit including means responsive to the brake control signal for disabling the logic circuit output to change the reference signal to a second value lower than the first value when brake pressure relief is requested, and means including a signal level detector responsive to the second signal in each cycle and connected to the logic circuit for disabling the logic circuit output to maintain the reference signal for the subsequent cycle at the second value when the positive wheel acceleration remains below a predetermined value during wheel speed recovery, and for enabling the logic circuit to change the reference signal for the subsequent cycle back to the first value when the positive wheel acceleration exceeds the predetermined value 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 10

An anti-lock brake control system for a wheeled vehicle comprising means for generating first and second electrical signals proportional to wheel acceleration, means including a logic circuit for producing a deceleration reference electrical signal which during initial brake application has a first value representing optimum wheel deceleration for vehicle braking on a high coefficient of friction surface, the logic circuit contributing a portion of the reference signal, 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, the logic circuit including means responsive to the brake control signal for disabling the logic circuit output to change the reference signal to a second value lower than the first value when brake pressure relief is requested, and means including a signal level detector responsive to the second signal in each cycle and connected to the logic circuit for disabling the logic circuit output to maintain the reference signal for the subsequent cycle at the second value when the positive wheel acceleration remains below a predetermined value during wheel speed recovery, and for enabling the logic circuit to change the reference signal for the subsequent cycle back to the first value when the positive wheel acceleration exceeds the predetermined value 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 11

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 high 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, 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, means responsive to wheel acceleration for sensing transient wheel hop signals and for increasing the deceleration reference signal to render the brake control signal means less sensitive to the wheel hop signals.

Claim 12

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 high 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, 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, means responsive to wheel acceleration for sensing transient wheel hop signals and for increasing the deceleration reference signal to render the brake control signal means less sensitive to the wheel hop signals.