Force-Based ABS Control Using Lateral Force Measurement

In this paper a hybrid force-based Anti Locking Braking System (ABS) is presented. The proposed control system directly considers the lateral tyre behaviour during heavy braking. In this way it is possible to guarantee drivability and stability also when braking on surfaces without a clear tyre characteristic peak. The goal of the paper is to show the potentialities of load-based vehicle dynamics control. It is shown that, thanks to the availability of the lateral and longitudinal tyre force measurements, a stable braking can be achieved with a minimal increase of complexity of the algorithm in conditions that are critical for traditional ABS. The general control concept is that of reducing the longitudinal slip if the measured lateral force is smaller than a desired minimum. Two different ways of computing the minimum lateral forces are presented: one for the front axle with the objective of guaranteeing steerability and one for the rear axle to guarantee stability. Simulations on a nonlinear vehicle simulator confirm that the controller can maintain the desired steering behaviour and vehicle yaw stability in case of heavy braking.