Adaptive Vibration Control of a Rigid Rotor Supported by Active Magnetic Bearings

In this paper a digital numerical simulation is carried out in which active magnetic bearings (AMB) are applied to control nonlinear and non-synchronous vibrations of a rigid rotor excited by non-conservative cross-coupling mechanisms. Through an adaptive control algorithm of the AMB-controller, unknown cross-coupling parameters of a rotor are estimated on-line by a standard least square estimator along with a time-varying so-called forgetting factor. The parameters of the AMB controller are adapted in order to compensate the cross-coupling effects and to stabilize the rotor system. Transient cross coupling response characteristics are calculated by numerical simulation of a rigid rotor supported by two active magnetic bearings. With this kind of control strategy the stability of the system can be guaranteed for much higher values of cross-coupling coefficients than with common non-adaptive feedback controllers, designed with pole placement or least square algorithms.