Improvements of passenger car-trailer behaviour by a trailer based control system

The implementation of a trailer based control system can very much help tb stabilize the overall behaviour of a passenger car-trailer system. For corresponding simulations complex models of car and trailer are established that include the features of relative body motion, steering system, driving and braking systems and tyre characteristics up to the limit of combined longitudinal and lateral slip values. The trailer based control system includes an observer for the estimation of the side slip angle while other quantities are assumed to be measured. By the sliding mode algorithm the necessary unilateral braking torques are determined, that via actuators provide the longitudinal tyre force at the trailer wheels for the desired stabilizing moment. So e.g. the trailer swing after a lane change manoeuvre can by reduced substantially. Moreover this kind of feedback control proves to be robust e.g. in respect to the mass of the towing car or CG(T)-height of the trailer. a newly defined oscillation index (combining maximum swing amplitude and fading out behaviour) shows that driving up to higher velocities is no further safety problem.