A control device for controlling the position of a rotor supported by active magnetic bearings supplied through power amplifiers (30A, 30B) whose outputs are connected to electromagnet coils (22A, 22B) of said active magnetic bearings, said control device comprising: a trajectory planning module for generating a requested position and speed, a observer for generating a position feedback value and a speed feedback value from measurements of at least a position (Z(t)) of said rotor and current intensities (I 1 (t), I 2 (t)) in said electromagnet coils, a first correction circuit connected to the trajectory planning module and to the observer for generating a first command signal (Z̈ feedback (t)) according to the difference between said requested position and speed and said position and speed feedback values respectively, a feedforward controller connected to the trajectory planning module for generating a second command signal (Z̈ feedforward (t)) according to a computation of said requested position and speed, an adder connected to the feedforward controller and to the first correction circuit for adding the first and second command signals and delivering a third command signal (Z̈ com (t)), a non-linear inversion circuit connected to the adder for generating flux command signals (Φ 1com (t), Φ 2com (t)) for said electromagnet coils from said third command signal, and a second correction circuit connected to the non-linear inversion circuit and to the observer for generating voltage command signals (U 1com (t), U 2com (t)) for said power amplifiers which control the current flowing in the electromagnet coils of the active magnetic bearings according to the difference between said flux command signals and observer flux values (Φ 1com (t), Φ 2com (t)). a trajectory planning module for generating a requested position and speed, a observer for generating a position feedback value and a speed feedback value from measurements of at least a position (Z(t)) of said rotor and current intensities (I 1 (t), I 2 (t)) in said electromagnet coils, a first correction circuit connected to the trajectory planning module and to the observer for generating a first command signal (Z̈ feedback (t)) according to the difference between said requested position and speed and said position and speed feedback values respectively, a feedforward controller connected to the trajectory planning module for generating a second command signal (Z̈ feedforward (t)) according to a computation of said requested position and speed, an adder connected to the feedforward controller and to the first correction circuit for adding the first and second command signals and delivering a third command signal (Z̈ com (t)), a non-linear inversion circuit connected to the adder for generating flux command signals (Φ 1com (t), Φ 2com (t)) for said electromagnet coils from said third command signal, and a second correction circuit connected to the non-linear inversion circuit and to the observer for generating voltage command signals (U 1com (t), U 2com (t)) for said power amplifiers which control the current flowing in the electromagnet coils of the active magnetic bearings according to the difference between said flux command signals and observer flux values (Φ 1com (t), Φ 2com (t)).