System and method for maneuvering a vehicle-trailer unit in reverse travel

A method of maneuvering a vehicle-trailer unit in reverse travel comprising the steps of:

• providing a trailer having a front with a trailer tongue and a vehicle having a rear with a trailer hitch, the trailer tongue being connected to the trailer hitch allowing a horizontal swivel movement of the trailer around the hitch;
• providing an electronic processing unit having a back-up assistant module and power steering control feature integrated into the electronic processing unit;
• providing at least one distance sensor connected to the vehicle and configured to send information to the at least one electronic processing unit;
• providing an active power steering system in the vehicle;
• determining that the vehicle-trailer unit is backing up;
• measuring with said at least one distance sensor a quantity representing a relative position between the vehicle rear and the trailer front;
• generating output information from said at least one distance sensor to the electronic processing unit, wherein said output information is representative of the distance between the front of the trailer and the rear of the vehicle at least at a location that is laterally offset from the location of the trailer hitch, by establishing at least one distance value in determining the difference between the distance value and a reference value;
• comparing the measured quantity with a reference value using the electronic processing unit;
• determining in the electronic processing unit an intended path of the trailer with respect to the vehicle based upon an input that is independent of a steering wheel for the vehicle;
• using the electronic processing unit to determine whether the trailer deviates from the intended path with respect to the vehicle and calculating the deviation;
• determining with the electronic processing unit whether the deviation exceeds a predetermined threshold and using the electronic processing unit to control;
• and
• implementing a path-correcting measure using the electronic processing unit to command a steering system to correct the course of at least one of the vehicle and the trailer while the vehicle-trailer unit is in reverse travel when the deviation exceeds the predetermined threshold.