Proportional skid control system

Claim 2

A control system for the brake system for at least one wheel of a wheeled vehicle comprising: sensing means for sensing the acceleration of the wheel and for providing a first signal representation of the acceleration of the wheel and control system means including means responsive to a preselected magnitude of said first signal representative of a preselected magnitude of wheel deceleration for providing an error signal representative of the difference between said first signal and the preselected magnitude of said first signal, said control system means further including brake control means for maintaining the magnitude of said first signal proximate to said preselected magnitude of said first signal so that the wheel will continue to decelerate proximate said preselected magnitude of wheel deceleration, whereby wheel departure is controlled to a desired magnitude.

Claim 3

A control system for the brake system for at least one wheel of a wheeled vehicle comprising: sensing means for sensing the acceleration of the wheel and for providing a first signal representation of the acceleration of the wheel and control system means including means responsive to a preselected magnitude of wheel deceleration for controlling the brakes to partially relieve braking, said means responsive to a preselected magnitude of wheel deceleration including means for generating a reference signal representative of said preselected magnitude of said first signal, and error signal means for providing an error signal having a magnitude determined by the difference between said first signal and said reference signal, said means responsive to a preselected magnitude of wheel deceleration further including brake control means for maintaining the magnitude of said first signal so that the wheel will continue to decelerate proximate said preselected magnitude of wheel deceleration by modulating the brakes to a degree which varies in accordance with the magnitude of said error signal.

Claim 4

A control system for the brake system for at least one wheel of a wheeled vehicle comprising: sensing means for sensing the acceleration of the wheel and for providing a first signal representation of the acceleration of the wheel and control system means including means responsive to a preselected magnitude of wheel deceleration for controlling the brakes to partially relieve braking, said means responsive to a preselected magnitude of wheel deceleration including means for generating a reference signal representative of said preselected magnitude of said first signal, and error signal means for providing an error signal having a magnitude determined by the difference between said first signal and said reference signal, said means responsive to a preselected magnitude of wheel deceleration further including brake control means for maintaining the magnitude of said first signal so that the wheel will continue to decelerate proximate said preselected magnitude of wheel deceleration by modulating the brakes to a degree which varies in accordance with the magnitude of said error signal.

Claim 5

A control system for the brake system for at least one wheel of a wheeled vehicle comprising: sensing means for sensing the acceleration of the wheel and for providing a first signal representation of the acceleration of the wheel and control system means including means responsive to a preselected magnitude of said first signal representative of a preselected magnitude of wheel deceleration for providing an error signal representative of the difference between said first signal and the preselected magnitude of said first signal, said control system means further including brake control means for maintaining the magnitude of said first signal proximate to said preselected magnitude of said first signal by partially relieving braking so that the wheel will continue to decelerate proximate said preselected magnitude of wheel deceleration, with said control system means including skid signal means for providing a skid control signal in response to the occurrence of an incipient skid condition at the wheel and for controlling the brakes, initially at least, to relieve braking to a greater extent than the first said partially relieved braking.

Claim 6

A control system for the brake system for at least one wheel of a wheeled vehicle comprising: sensing means for sensing the acceleration of the wheel and for providing a first signal representation of the acceleration of the wheel and control system means including means responsive to a preselected magnitude of said first signal representative of a preselected magnitude of wheel deceleration for providing an error signal representative of the difference between said first signal and the preselected magnitude of said first signal, said control system means further including brake control means for maintaining the magnitude of said first signal proximate to said preselected magnitude of said first signal by partially relieving braking so that the wheel will continue to decelerate proximate said preselected magnitude of wheel deceleration, with said control system means including skid signal means for providing a skid control signal in response to the occurrence of an incipient skid condition at the wheel and for controlling the brakes, initially at least, to relieve braking to a greater extent than the first said partially relieved braking.

Claim 7

The system of claim 3 with said error signal means responsive to said skid control signal for providing said error signal having a magnitude determined by the difference between the rate of change of velocity of the wheel and a preselected magnitude of rate of change of wheel velocity which is different than said preselected magnitude of wheel deceleration.

Claim 8

The system of claim 4 with said preselected magnitude of rate of change being a preselected magnitude of wheel acceleration, with said preselected magnitude of wheel acceleration selected to provide controlled spin-up of the wheel.

Claim 9

The system of claim 5 with said control system means further including means for providing a clamp signal subsequent to the initiation of spin-up to permit only increases and holding in braking to maintain spin-up at no greater than a selected magnitude.

Claim 10

The system of claim 6 with said selected magnitude of spin-up being the same as said preselected magnitude of wheel acceleration.

Claim 11

The systEm of claim 7 with said skid signal means providing said skid signal in response to the slip between the wheel velocity and the vehicle velocity exceeds a preselected slip magnitude.

Claim 12

The system of claim 8 with said clamp signal being provided during spin-up in response to the wheel slip being less than said preselected slip magnitude.

Claim 13

The system of claim 9 with said clamp signal being terminated in response to the wheel attaining a preselected minimum acceleration indicative of the wheel being proximate to synchronous.

Claim 14

The system of claim 2 with said error signal including a first component indicative of the instantaneous difference between the wheel deceleration and said preselected magnitude of wheel deceleration and a second component indicative of the integral of the difference between the wheel deceleration and said preselected magnitude.

Claim 15

The system of claim 4 with said error signal including one component indicative of the instantaneous difference between said rate of change of velocity of the wheel and said preselected magnitude of rate of change of wheel velocity and another component indicative of the integral of the difference between said rate of change of velocity of the wheel and said preselected magnitude of rate of change of wheel velocity.

Claim 16

The system of claim 10 with said error signal including a first component indicative of the instantaneous difference between the wheel deceleration and said preselected magnitude of wheel deceleration and a second component indicative of the integral of the difference between the wheel deceleration and said preselected magnitude.

Claim 17

The system of claim 13 with said error signal including one component indicative of the instantaneous difference between said rate of change of velocity of the wheel and said preselected magnitude of rate of change of wheel velocity and another component indicative of the integral of the difference between said rate of change of velocity of the wheel and said preselected magnitude of rate of change of wheel velocity.

Claim 18

The system of claim 11 with said error signal including a third component indicative of the magnitude of slip between wheel speed and vehicle velocity.

Claim 19

The system of claim 12 with said error signal including a third component indicative of the magnitude of slip between wheel speed and vehicle velocity.

Claim 20

The system of claim 14 with said error signal including a third component indicative of the magnitude of slip between wheel speed and vehicle velocity.

Claim 21

The system of claim 1 with said preselected magnitude of wheel deceleration being approximately in the range of from 3 to 5 g''s.

Claim 22

The system of claim 12 for fluid actuated brakes with said preselected magnitude of wheel deceleration being approximately 3 to 5 g''s and with the brake pressure being relieved by approximately 30 percent for an incipient skid condition for the wheel under high mu surface conditions.

Claim 23

The system of claim 17 for fluid actuated brakes with said preselected magnitude of wheel deceleration being approximately 3 to 5 g''s and with the brake pressure being relieved by approximately 30 percent for an incipient skid condition for the wheel under high mu surface conditions.

Claim 24

The control system of claim 3 with said sensing means sensing the speed of the wheel and providing a wheel speed signal and with said control means responsive to said wheel speed signal providing a vehicle velocity signal having a magnitude simulating the vehicle velocity and with said skid signal means providing said skid control signal in response to the difference between the speed of the wheel and the simulated vehicle velocity attaining a preselected difference.

Claim 25

The control system of claim 3 comprising a second control system for a second wheel including second sensing means for providing a second wheel speed signal indicative of the speed of the second wheel and further including second control meanS for controlling the brakes for the second wheel, said second control system including error signal means responsive to said second wheel speed signal and said simulated vehicle velocity as generated by the first said control system having a magnitude indicative of the difference between the speed of the second wheel and the simulated vehicle velocity to control the brakes as a function of that difference.

Claim 26

The control system of claim 20 with said sensing means sensing the speed of the wheel and providing a wheel speed signal and with said control means responsive to said wheel speed signal providing a vehicle velocity signal having a magnitude simulating the vehicle velocity and with said skid signal means providing said skid control signal in response to the difference between the speed of the wheel and the simulated vehicle velocity attaining a preselected difference.

Claim 27

The control system of claim 23 comprising a second control system for a second wheel including second sensing means for providing a second wheel speed signal indicative of the sensing speed of the second wheel and further including second control means for controlling the brakes for the second wheel, said second control system including error signal means responsive to said second wheel speed signal and said simulated vehicle velocity as generated by the first said control system having a magnitude indicative of the difference between the speed of the second wheel and the simulated vehicle velocity to control the brakes as a function of that difference.

Claim 28

A control system for the brake system for at least one wheel of a wheeled vehicle comprising: sensing means for sensing the acceleration of the wheel and for providing a first signal representation of the acceleration of the wheel and control system means including means responsive to a preselected magnitude of said first signal representative of a preselected magnitude of wheel deceleration for providing an error signal representative of the difference between said first signal and the preselected magnitude of said first signal, said control system means further including brake control means responsive to said error signal for maintaining the magnitude of said first signal proximate to said preselected magnitude of said first signal so that the wheel will continue to decelerate proximate said preselected magnitude of wheel deceleration, said brake control means comprising actuator means actuable by the vehicle operator for controlling the hydraulic pressure to the brakes, said actuator means comprising valve means including pilot valve means actuable by the vehicle operator and being further actuable by said error signal for continuously varying an input hydraulic pressure over a first range of hydraulic pressures in accordance with continuous variations in actuation by said vehicle operator and continuous variations in said error signal, and main valve means responsive to said input hydraulic pressure for continuously varying an output hydraulic pressure over a second range of hydraulic pressures in accordance with continuous variations in said input hydraulic pressure which is substantially greater than said first range of hydraulic pressures so that said hydraulic output pressure represents a pressure amplification of the hydraulic input pressure.

Claim 29

A control system for the brake system for at least one wheel of a wheeled vehicle comprising: sensing means for sensing the acceleration of the wheel and for providing a first signal representation of the acceleration of the wheel and control system means including means responsive to a preselected magnitude of said first signal representative of a preselected magnitude of wheel deceleration for providing an error signal representative of the difference between said first signal and the preselected magnitude of said first signal, said control system means further including brake control means responsive to said error signal for maintaining the magnitude of said first signal proximate to said preselected magnitude of said first signal so that the wheel will continue to decelerate proximate said preselected magnitude of wheel deceleration, said brake control means comprising actuator means actuable by the vehicle operator for controlling the hydraulic pressure to the brakes, said actuator means comprising valve means including pilot valve means actuable by the vehicle operator and being further actuable by said error signal for continuously varying an input hydraulic pressure over a first range of hydraulic pressures in accordance with continuous variations in actuation by said vehicle operator and continuous variations in said error signal, and main valve means responsive to said input hydraulic pressure for continuously varying an output hydraulic pressure over a second range of hydraulic pressures in accordance with continuous variations in said input hydraulic pressure which is substantially greater than said first range of hydraulic pressures so that said hydraulic output pressure represents a pressure amplification of the hydraulic input pressure.