In this design, the anti-locking th

In this design, the anti-locking threshold is selected as the main threshold, and the slip rate is used as the auxiliary threshold. Because the separate acceleration and deceleration thresholds have great limitations, in the initial and high-speed emergency braking situations, it is possible to disable the anti-lock control logic in subsequent control. For non-driving wheels, premature locking may also occur and the anti-lock control logic may fail. However, if only the slip rate is used as a separate anti-lock braking threshold, it is difficult to obtain an optimal control effect for different road conditions. Therefore, the two thresholds of angular velocity and slip rate need to be combined to identify different road conditions for adaptive control. This control system can limit the speed of the wheels within a certain range when braking, so that the speed of the wheels fluctuates up and down around the optimal value.It is relatively easy for the controller to calculate the angular deceleration and angular acceleration based on the signal of the wheel speed sensor, but to obtain the actual slip rate, it is necessary to use Doppler radar or an acceleration sensor to measure the vehicle speed. Very high. Therefore, the reference slip rate is calculated by using the wheel speed signal and the set one vehicle deceleration value. Threshold deceleration, threshold acceleration and vehicle braking deceleration values ​​are determined through experiments. Different models and different ABSs are generally not universal.The system control logic adopts the threshold control method, which is very important for the selection of the comparison value (threshold value). Generally speaking, there are several types of comparison values: angular acceleration and deceleration of wheels: rate of change of angular velocity Acceleration to angular velocity ratio and reference slip rate, etc. By selecting different comparison amounts, you can get different pre-selection and re-selection conditions. The pre-selection condition refers to the tendency of the wheel to lock when this condition is met, and the braking pressure should be reduced to increase the wheel speed, while the check condition is the tendency of the wheel to avoid locking when this condition is met, and the braking pressure should be Rise.