Reduction in the amplitude of the primary resonance combined with the parametrically excited horizontal oscillation in a high-tc superconducting levitation system

This research proposes reduction in the amplitude of the primary resonance combined with the parametrically excited horizontal oscillation in a High-Tc superconducting levitation system. High-Tc superconducting levitation systems have very low damping and stable levitation without control. However, in such low-damped systems, complicated phenomena of dynamics can be easily generated by nonlinearity of the magnetic force. Our previous research showed that, when the frequency of vertical excitation is in the neighborhood of double the natural frequency in the horizontal direction, horizontal oscillation can occur parametrically through nonlinear coupling between vertical motion and horizontal motion. This research discusses on effects of the parametrically excited horizontal resonance on the primary resonance. We discussed possible nonlinear interaction called internal resonance between the vertical motion and the horizontal motion whose natural frequency is chosen as half that of the vertical motion. The primary resonance reduction based on this mechanism was successfully verified numerically. This kind of nonlinear oscillation can be useful for reducing resonance of a high-Tc superconducting levitation system.