Study of the Dynamic Properties of HTS Bulk Movers for Traveling Along Vertical Walls as a Three-Dimensional Actuator

We have been investigating three-dimensional actuators using bulk high-temperature superconductors (HTS) as transportation devices that move in free space. The large flux-pinning force of HTS allows motion without contact, even when the levitation force is not aligned against gravity, which could make them useful in clean or dangerous environments, such as clean rooms for semiconductor fabrication or in tunnels containing flammable gas. An actuator prototype, consisting of an HTS bulk with trapped magnetic field as a mover and a two-dimensional array of electromagnets as a stator, has been developed. In a previous study, the dynamic characteristics for traveling over floors were examined. In this study, horizontal, vertical, and oblique motions along vertical walls have been investigated. Movement characteristics have been studied for HTS bulks of two diameters and related to measurements of the axial components of their trapped magnetic fields. Maximum vertical displacements of 5.80 and 11.5 mm were achieved for HTS bulks of 60- and 46-mm outer diameters, respectively.