The invention relates to a power assisted steering system (21) that includes an electric assist motor (22) arranged to assist the manual force exerted by a driver on the steering wheel of the automobile, a processing means (23) arranged to control the electric assist motor (22), the processing means (23) including a means (28) for predetermining a signal (S3) for controlling the electric assist motor on the basis of a first operation signal (S1) determined on the basis of the angular position of the electric assist motor, and a second operation signal (S2) determined on the basis of the measurement or calculation of the angular acceleration of the electric assist motor and the measurement or calculation of the assistance torque output by the electric assist motor.
