Effects of Tire Slip on the Handling Performance of Tractor-Semitrailers in Braking Maneuvers

Automatic braking control systems for trucks and tractor-semitrailers have become the subject of a sizeable research and development effort. These devices can provide improved vehicle stability and control characteristics in braking maneuvers. An analysis utilizing a mathematical model of a tractor-semitrailer vehicle yielded the following results: Favorable stability and control characteristics in braking maneuvers are maintained when front wheels do not lock, tractor rear-wheel longitudinal slip remains less than front-wheel longitudinal slip, and semitrailer rear wheels do not lock. Effects of kingpin (fifth wheel) location and introduction of coulomb friction at the kingpin are also discussed.