An investigation of digital filter technology on ABS wheel speed signal

The wheel speed signals measured from ABS wheel speed sensors must be processed in advance before they are used to calculate the acceleration and deceleration of the wheel and the reference vehicle velocity. Owning to not considering the time varying noise characteristics of measured signals, the exponential smoothness filter cannot fulfill the requirements of ABS system. According to the data measured by test, the system measurement standard variance is obtained by two order polynomial data fit. On the basis of linear system equation assumed, the structure of Kalman filter is introduced in the process of wheel velocity signal. Test results show that the filter designed in this paper can be applied in the calculation of other ABS control items because of its high accuracy and small lag.