Longitudinal Vehicle Speed Estimation for Traction and Braking Control Systems

Accurate estimation of longitudinal vehicle speed is crucial for effective design and implementation of Anti-lock Braking Systems (ABS) and Traction Control Systems (TCS). The knowledge of the current value of the vehicle speed, in fact, is the key for computing the longitudinal wheel slip, i.e., the main control variable in most advanced braking and traction control logics. This work presents a new algorithm for the estimation of longitudinal vehicle speed, based on the measurements of the four wheel rotational speeds and of the longitudinal vehicle acceleration. The main advantages of this approach are the low computational burden - which makes implementation on a commercial vehicle Electronic Control Unit (ECU) effective, and the accuracy of the final estimation results - which makes the tire slip current value available with small uncertainty. The algorithm has been extensively tested on an instrumented test car in different driving and road conditions.