PURPOSE: To minimize trailer swing by receiving an input signal and an obtained value and processing them according to a predetermined rule so as to detect conditions indicative of at least an initial trailer swing event induced by trailer brake.

CONSTITUTION: At least an value indicative of an articulation angle AA and a time derivative dAA/dt thereof are computed, at least an articulation input signal indicative of them is generated, and a value is computed which is indicative of at least a curvature radius of tractor rotation, and a reference value is computed as a function of a time derivative of the curvature radius of tractor rotation. And then, the input signal and the computed values are received and are processed according to a predetermined logic rule so as to detect conditions indicative of at least an initial trailer swing induced by trailer brake.