Control system for a motor vehicle provided with a semiautomatic gearbox with discrete ratios

The control system (CS) comprises - detectors or estimators (S1, S2, S3, D, TE) capable of supplying electrical signals or data indicative of the values of predetermined state variables including the angular velocity (É E, meas ) of the crankshaft (ES) of the engine (E), the difference (É D, meas ) between this angular velocity and the angular velocity of the primary shaft (PS) of the gearbox (GS), and the torque (C E ) delivered by the engine (E) crankshaft and the torque (C F ) transmitted by the friction clutch (FC); - calculating devices (SD1) capable of supplying signals or data (e) indicating the differences or errors between the values detected or otherwise determined of the state variables and respective reference values (r); - filter devices (FB) capable of incrementing, within a predetermined frequency band, the relative weight selectively of the error of angular velocity of the crankshaft (ES) of the engine (E), and of the error of the abovementioned difference of angular velocity (É D, meas ); - processing devices (SD2; SYSE, SYSF) capable of receiving as input the signals or data coming from the calculating devices (SD1) partly through the filter devices (FB), and capable of generating, in accordance with predetermined transfer functions, output signals or data indicating a torque partial value or contribution (C E, CL ) to be delivered by the engine (E) and a torque partial value or contribution (C F, CL ) to be transmitted to the primary shaft (PS) of the gearbox (GS) by the friction clutch (FC); and - an adder (AD) capable of adding the torque partial values or contributions (C E, CL, C F, CL ) to corresponding other torque partial values or contributions (C E, OL, C F, OL ), to be delivered or transmitted as relevant, determined by predetermined methods, in order to supply in the total output signals or data indicating the torque (C ET ) to be generated in the engine (E) crankshaft and signals or data indicating the torque (C FT ) to be transmitted by the friction clutch (FC).