Proof-phase-margin design of nutation cross-feedback control in magnetically suspended high-speed rotor system with large rotary inertia

A parameter design method of nutation cross-feedback control is investigated.Based on nutation stability analysis of a large-inertia and high-speed rotor using two-frequency Bode diagram,a new proof-phase-margin method of cross-feedback parameter design based on two-frequency Nyquist contour is proposed.The proportional coefficient and High-pass Filter(HPF) cutoff frequency of cross-feedback are determined by vectors combination to accomplish the robust design of nutation stability.Utilizing designed cross-feedback controller,nutation stability of rotor in the magnetically suspended control moment gyroscope is significantly improved and the critical speed of rotor increases from 10 500 r/min to 20 040 r/min.It can be concluded that the proposed method is effective for cross-feedback parameter design,which provides important foundation for rotor suspension stability of control moment gyroscope and momentum flywheel.