Patent ID: 7269494

Claim:
Method of estimating the slope of a road on which there is positioned a motor vehicle provided with rotational velocity sensor means for measuring the modulus of the velocity of the vehicle and with acceleration measuring means for measuring the acceleration in the longitudinal direction of the vehicle, characterized in that it comprises the following operations: a) providing a signal indicating the measurement of the velocity of the vehicle (V 1 , NCltFilV) by means of the said velocity sensor means; b) providing a signal indicating the measurement of the acceleration in the longitudinal direction of the vehicle (AxVehFilV) by means of the said acceleration measuring means; c) determining an estimated value of the slope of the road (StimaPend), the said determination of the estimated value comprising, subject to a condition of enabling the estimation, the processing of the velocity measurement signal (V 1 ) and of the acceleration measurement signal (AxVehFilV) by means of a mathematical model based on the relation A x ={dot over (ν)}+g sin α, where A x represents the measurement of acceleration in the longitudinal direction of the vehicle, {dot over (ν)} indicates the component of longitudinal acceleration of the vehicle along the road, g is the gravitational acceleration and α represents the angle of inclination of the road profile; d) processing the velocity measurement signal (V 1 , NCltFilV), the acceleration measurement signal (AxVehFilV) and the estimated value of the slope (StimaPend) in such a way as to determine the sign of the velocity of the vehicle (Segno); and e) repeating operations a) to d) recursively according to a predetermined rule, in which the sign of the velocity (Segno) determined in operation d) of a specific recursive step is used as an additional input for operation c) of a successive recursive step to update the estimated value of the slope of the road (StimaPend).