Method for anti-skid brake control

A method for anti-skid brake control comprising:

• detecting a wheel speed by a wheel speed sensor,
• comparing the detected wheel speed with an anti-skid brake control lower limit speed at which anti-skid brake control is initiated,
• determining locking of the wheel on the basis of,said wheel speed when said wheel speed is higher than said anti-skid brake control lower limit speed, and
• controlling, when it is determined that said wheel is showing a tendency to lock, braking force for at least said wheel so that the locking tendency is cancelled,
• said method additionally comprising determining whether said wheel sensor is defective by the steps of:
• setting a first reference speed which is higher than said anti-skid brake control lower limit speed,
• detecting a start-up wheel speed of rear wheels by said wheel speed sensor when the wheel speed gradually increases during starting of a vehicle,
• comparing said start-up wheel speed with said first reference speed, and
• determining said wheel speed sensor is defective, when said start-up wheel speed is higher than said first reference speed, and
• said method further comprising:
• modifying said anti-skid brake control by changing said anti-skid brake control lower limit speed to said start-up wheel speed, when said start-up wheel speed is higher than said first reference speed.

A method for anti-skid brake control performed in a vehicle having non-driving front wheels and driving rear wheels comprising:

• detecting wheel speeds for said front and rear wheels of a vehicle by a respective wheel speed sensor therefor,
• comparing the detected wheel speeds with an anti-skid brake control lower limit speed at which anti-skid brake control is initiated,
• determining locking of any one of said wheels on the basis of said wheel speeds when at least one of said wheel speeds is higher than said anti-skid brake control lower limit speed, and
• controlling, when it is determined that said at least one wheel is showing a tendency to lock, braking force for said at least one wheel so that the locking tendency is cancelled,
• said method additionally comprising determining whether any one of said wheel sensors is defective by the steps off
• setting a first reference speed which is higher than said anti-skid brake control lower limit speed and a second reference speed higher than said first reference speed representing an abnormal sensor,
• detecting start-up wheel speeds by each said wheel speed sensor when said wheel speeds gradually increase during starting of said vehicle,
• comparing said start-up wheel speeds with said first reference speed, and
• determining any one of said wheel speed sensors is defective when any one of said start-up wheel speeds is higher than said first reference speed, and
• said method further comprising:
• controlling said anti-skid brake control as follows:
• (1) when one of said front wheel start-up speeds is higher than said first reference speed and lower than said second reference speed, performing said anti-skid brake control by selecting a highest wheel speed of left and right front wheels speeds for executing anti-skid brake control,
• (2) when one of said front wheel start-up speeds is higher than said second reference speed, suspending said anti-skid brake control,
• (3) when one of said rear wheel start-up speeds is higher said first reference speed and lower than said second reference speed, changing said anti-skid brake control lower limit speed to said one of said rear wheel startup speeds, and
• (4) when one of said rear wheel start-up speeds is higher than said second reference speed, suspending said anti-skid brake control.