Disturbance Compensation of a Superconductor-Based Levitation Module Using a Parallel Actuator-Sensor System

Superconductor-based magnetic levitation struggles with an inherently non-stiff and lightly damped coupling between superconductor and levitation module. This means a magnet that is levitating above a superconductor can easily start oscillating if the equilibrium is disturbed. This can, for example, occur if a superconductor-based levitation module is mounted on a mechanical handling system. During motion of the handling system magnetic torques generate angular velocities of the levitation module. For production systems that may use levitation for frictionless motion this is an undesired behavior. Therefore, it is necessary to stabilize the levitation module during motion of the handling system. In this publication a feed-forward disturbance compensation control scheme is proposed using a novel parallel actuator-sensor system based on induced voltages from time varying magnetic fields. The proposed control law is validated experimentally. Angular velocities during motion can be reduced by around 50%, depending on performance metric, with respect to the uncontrolled case.