Antiskid control with surface friction compensation by prolonged down-pressure operation

An antiskid control system for the hydraulic braking system of a wheeled vehicle, comprising:

• (a) wheel speed detecting means for detecting the speed of rotation of at least one of said wheels;
• and
• (b) wheel acceleration detecting means for detecting the acceleration of said wheel;
• (c) vehicle speed detecting means for detecting the speed of said vehicle;
• (d) brake control means for applying a brake release signal to said braking system when said wheel acceleration is lower than a first acceleration threshold until said wheel acceleration becomes higher than a second acceleration threshold which is higher than said first acceleration threshold;
• (e) threshold establishing means for deriving from said vehicle speed a speed threshold as an indication that the vehicle is on a low friction road surface;
• and
• (f) threshold correcting means for varying said second acceleration threshold to a higher level when said wheel speed is lower than said speed threshold.

An antiskid control system for the hydraulic braking system of a wheeled vehicle, comprising:

• (a) wheel speed detecting means for detecting the speed of rotation of at least one of said wheels;
• and
• (b) wheel acceleration detecting means for detecting the acceleration of said wheel;
• (c) vehicle speed detecting means for detecting the speed of said vehicle;
• (d) threshold establishing means for deriving from said vehicle speed a first speed threshold as an indication that said vehicle is on a low friction road surface, a second speed threshold lower than said first speed threshold by a predetermined amount and deriving from said vehicle speed a third speed threshold as an indication of a target slip rate when said wheel speed is lower than said second speed threshold, said third speed threshold being higher than said first speed threshold;
• and
• (e) brake control means for applying a brake release signal to said braking system when said wheel acceleration is lower than a first acceleration threshold until said wheel acceleration becomes higher than a second acceleration threshold which is higher than said first acceleration threshold if said wheel speed is higher than said second speed threshold following the application of said brake release signal to said braking system or until said wheel speed becomes equal to or higher than said third speed threshold if said wheel speed falls below said second threshold following the application of said brake release signal to said braking system.

An antiskid control system for the hydraulic braking system of a wheel vehicle, comprising:

• (a) a wheel speed detecting means for detecting the speed of rotation of at least one of said wheels;
• and
• (b) wheel acceleration detecting means for detecting the acceleration of said wheel;
• (c) vehicle speed detecting means for detecting the speed of said vehicle;
• (d) threshold establishing means for deriving from said vehicle speed a first speed threshold as an indication that said vehicle is on a low friction road surface and deriving from said vehicle speed a second speed threshold as an indication of a target slip rate when said wheel speed becomes lower than said first speed threshold, said second speed threshold being higher than said first speed threshold;
• and
• (e) brake control means for applying a brake release signal to said braking system when said wheel acceleration is lower than a first acceleration threshold until said wheel acceleration becomes higher than a second acceleration threshold which is higher than said first acceleration threshold if said wheel speed is higher than said first speed threshold following the application of said brake release signal to said braking system or until said wheel speed becomes equal to or higher than said second speed threshold if said wheel speed is lower than said first threshold following the application of said brake release signal to said braking system.