Active control of vibrations in the case of asymmetrical high-speed rotors by using magnetic bearings

Rotor-bearing systems with long, fast running rotors and rotational symmetry disturbed in stiffness, damping and moments of inertia are investigated. Since a magnetic bearing is used as an actuator in a control circuit, vibrations of the system can be influenced in a desired way, A feedback control is designed with emphasis to the endangered modes of oscillation of the rotor system caused by parametrical excitation. A small number of sensors and a controller with constant gain factors are used in order to obtain a low-cost system. For illustration an elastically supported gas centrifuge with 12 degrees of freedom and asymmetrical stiffness and damping properties is considered.