Antilock brake control method for four-wheel drive vehicle

An antilock brake control method for a four-wheel drive vehicle, said method comprising the steps of:

• (a) sensing a speed of each of four vehicle wheels;
• sensing a longitudinal acceleration/deceleration of the vehicle;
• (c) determining an offset value corresponding to an output error of said longitudinal acceleration/deceleration of the vehicle;
• (d) determining if the four vehicle wheels are in a spinning state;
• (e) calculating a first estimated vehicle speed for executing antilock brake control as a function of wheel speed and a sum of the longitudinal acceleration/deceleration and the offset value, when the four vehicle wheels are not in a spinning state;
• (f) calculating a second estimated vehicle speed for executing antilock brake control as a function of wheel speed and the longitudinal acceleration/deceleration when the four vehicle wheels are in a spinning state;
• and
• executing antilock brake control using one of said first and second estimated vehicle speeds.