Slip-Deceleration Control in Anti-Lock Braking Systems

In road vehicles, wheel locking can be prevented by means of closed-loop Anti-lock Braking Systems (ABS). Two output measured variables are usually considered for regulation: wheel- deceleration and wheel longitudinal slip. The traditional controlled variable used in ABS is the wheel deceleration, since it can be easily measured with a simple wheel encoder; however, it can be dynamically critical if the road-surface rapidly changes. On the other hand, the regulation of the longitudinal slip is much robust from the dynamical point of view, but the slip measurement is critical, since it requires the estimation of the longitudinal vehicle speed. In this work a control strategy is proposed, where the regulated variable is a convex combination of wheel deceleration and longitudinal slip.