Effect of Gyroscopic Damper on Secondary Resonance of Superconducting Levitation

This study aims to verify the effectiveness of a gyroscopic damper on the nonlinear resonances of a magnetic levitation system with superconductors at several resonance points. Magnetic levitation systems using high-temperature superconductors provide controlled and stable levitation, but because they are non-contact, they have low damping and are easily affected by external disturbances. In addition, the magnetic force of superconductivity tends to cause nonlinear vibrations, and reducing these vibrations is an important development issue from the perspective of structural safety in system adaptation. We focus on the use of gyroscopic damper as a passive vibration suppression method that takes advantage of the property of the superconducting magnetic levitation system to be stable without control. Our previous studies have shown that gyroscopic damper is effective for simultaneous vibration suppression in the translational and tilting directions by optimizing the setting parameters of the gyroscopic damper. The vibration suppression effect in primary resonance has also been theoretically and experimentally confirmed. In this study, in addition to a reduction of approximately 10% in both the translational and tilting directions with respect to the excitation frequency component of secondary resonance, it was confirmed that the amplitude of what appears to be a subharmonic component oscillating at 1/2 and 3/2 of the excitation frequency was reduced by almost 100%. Thus, it was demonstrated that the gyroscopic damper can suppress secondary resonance in addition to primary resonance.