What is described is a control system for controlling the coupling between a driveshaft of a motor vehicle propulsion system and a primary input shaft of a gearbox by means of a servo-assisted friction clutch.A control unit receives at its input signals indicating a command imparted by the driver of the motor vehicle by operating the accelerator pedal in a driving-away or gear-changing manoeuvre, and generates--on the basis of a mathematical reference model--reference torque request signals indicating the reference torques requested from the driveshaft and from the friction clutch, the said request signals or data varying in time in such a way as to cause synchronization between the angular velocities of the driveshaft and of the primary gear shaft to be reached at the same moment as the difference between the angular accelerations of the said shafts becomes zero.