Whirl Mode Suppression for AMB-Rotor Systems in Control Moment Gyros Considering Significant Gyroscopic Effects

For a magnetically suspended control moment gyroscope with strong gyroscopic effects, the whirl mode (nutation and precession) stability control of the active magnetic bearing (AMB) rotor system has always been a challenging problem. This article proposes a robust control method combined with regional pole assignment to achieve the stability control of the whirl mode in the AMB-rotor system. First, the physical model of multi-degree-of-freedom magnetic bearing system is analyzed in detail, and the state-space model of the system is established. Then, the gyroscopic effects varying with the rotor speed are considered as a bounded parameter perturbation of the system, and the constraints on the controller to achieve the system stability are obtained. Furthermore, in order to increase the system stability margin and the whirl mode damping, the additional constraints on the controller are derived through the regional pole assignment method. Finally, all constraints are converted into the form of linear matrix inequalities (LMIs), and a controller satisfying all the constraints can be obtained by solving the LMIs. Experimental results demonstrate that the designed robust controller can achieve the stability control of nutation and precession as well as keeping a satisfactory system performance.