Patent ID: 7471057

Claim:
A system for servo-controlling a vibrator on a force setpoint signal (COEF) presenting an amplitude and a frequency that vary over time, the vibrator comprising a first pair (A) of unbalanced rotors ( 10 , 11 ) and a second pair (B) of unbalanced rotors ( 12 , 13 ), the four unbalanced rotors being driven in rotation by a first electric motor (M 1 ), the system comprising a second electric motor (M 2 ) arranged to drive a phase shifter mechanism, thereby mechanically adjusting a phase difference between the first pair of rotors and the second pair of rotors of the vibrator, the system further comprising: a first sensor (C 1 ) sensitive to the angular position of a rotor of the first pair of unbalanced rotors; a second sensor (C 2 ) sensitive to the angular position of a rotor of the second pair of unbalanced rotors, or else to the position of the phase shifter mechanism; a first control means (MC 1 ) sensitive to the force setpoint signal and to the signals delivered by the first sensor and the second sensor, the first control means being arranged to control the first motor as a function of the phase and the frequency of the force setpoint signal, and also as a function of the signals delivered by the first and second sensors; and a second control means (MC 2 ) sensitive to the force setpoint signal and to the signals delivered by the first sensor and by the second sensor, the second control means being arranged to control the second motor as a function of the phase, the frequency, and the amplitude of the force setpoint signal and also of the signals delivered by the first and second sensors.