磁悬浮球形飞轮不平衡振动前馈抑制与实验

Aiming at the unbalance vibration of a magnetic bearing spherical flywheel rotor, an unbalance vibration feedforward restraint method was presented by establishing the dynamic model of its spherical rotor-magnetic bearing. Based on the D'Alembert's principle, the unbalance mass moments was equivalent to two counterweights on the end planes of rotor, and the dynamic reaction of the magnetic bearing was obtained. To keep the shell gap its spherical configuration between stator and rotor and relieve the negative magnetic deflection moment induced by non-uniform magnetic field, the sphere centers of the rotor was made always coinciding with that of the stator. The centrifugal force caused by the deviation between the rotor mass center and spin axis was analysed. Considerning the electromagnetic levitation force always pointing to the sphere center, the caused negative moment was also calculated when the rotor mass center deviates from the rotor sphere center. When the two unbalance mass moments with phase difference of π were identical, the feedforward restraint simulations were implemented at the speed of 8 000 r/min. The results show that the rotor's radial and axial amplitudes decrease from 13.8 μm and 21.6 μm to 3.3 μm and 5.6 μm, which are reduced by 76.1% and 74.1%, respectively. The tests results have a good agreement with those of the simulations, which indicates the dynamic model is correct and feedforward restraint method is effective.