As shown in Figure 4-1, at the init

As shown in Figure 4-1, at the initial stage of braking, as the brake pressure rises, the wheel speed v decreases, and the wheel deceleration increases. When the wheel deceleration reaches the threshold value -a (at the end of stage 1), the calculated slip rate does not reach the threshold value s. Therefore, the control system puts the brake pressure into the holding phase (the second phase) to fully brake the wheels. When the slip rate is greater than the threshold value s, then enter the brake pressure reduction stage (stage 3)) As the brake pressure decreases, the wheels begin to accelerate under the action of inertial force. When the speed decreases to the threshold value -a, it enters the brake pressure maintenance stage (stage 4). At this stage, due to the inertia of the vehicle, the wheels are still accelerating. When the wheel acceleration reaches the acceleration threshold + a, the brake pressure is still maintained until the wheel acceleration exceeds the second threshold + a (+ a is the adaptation adhesion coefficient suddenly Increase the setting). This is because the brake pressure is increased again (stage 5) to accommodate the increase in the adhesion coefficient. As the brake pressure increases, the wheel acceleration decreases. When the wheel acceleration is lower than + a, it enters the brake pressure maintenance stage (stage 6) until the wheel acceleration falls below + a again. At this time, the brake pressure is slightly insufficient, and the control of the brake pressure is a fast transition of boosting and maintenance (the seventh step, the brake pressure has a small step increase rate), so that the wheel slip rate is ideal The slip rate fluctuates up and down. When the wheel deceleration exceeds -a again, it begins to enter the brake pressure reduction stage (stage 8). At this time, the brake pressure reduction no longer considers the reference slip rate threshold and enters the next control cycle process.