Hybrid ABS Control Using Force Measurement

The anti-lock braking system (ABS) is the most important active safety system for passenger cars. Thanks to tire force measurement, provided for example by the new SKF load sensing hub bearing units, hybrid ABS algorithms can be made simpler and more robust than when only using wheel acceleration measurement. A two-phase algorithm is presented, where the wheel acceleration is controlled in closed-loop and the longitudinal force measurement is used to fire phase switching. Load transfer is accounted for using the vertical force measurement. Realistic simulations show that this simple algorithm can handle changes in vehicle velocity and tire-road friction without extra logic or adaptation of the controller parameters. Stability analysis provides tuning indications. Finally, the algorithm is validated on a tire-in-the-loop experimental facility.