Stroboscopic Imaging System for Studying the Dynamics of Superconducting Levitation Bearings

Passively stable contactless high-speed bearings based on a magnetic rotor levitating above a high-temperature superconductor are desirable for many applications. Understanding the dynamics of spinning superconducting bearings is critical to their design, however, motion blur in video footage makes it difficult to analyse vibrations, oscillations and precession. Here we present a cost-effective stroboscopic imaging system synchronised with the rotor frequency. This makes the rotor appear frozen about the axis of spin, allowing changes in rotor position and tilt angle to be clearly observed. Position and orientation is automatically determined by computer vision tracking of an ArUco marker attached to the rotor. A trial of the system in a spin-down experiment shows that it is able to capture all six degrees of freedom of the rotor during its decoupling from the drive shaft at 6000 rpm. To our knowledge, this marks the first use of the stroboscopic method applied to the study of superconducting bearings.