A control scheme for the motion of a magnet supported by type-II superconductor

Levitation systems including superconducting effects constitute a theoretically interesting and practically important class of magnetic suspension. The dynamics of such systems can be described by a second-order nonlinear ordinary differential equation, which involves a hysteresis and stiffness function. In this work, the design of a continuous robust strategy to control the motion of superconducting magnetic levitation with least prior knowledge is presented by assuming that exact model of the levitation system and external excitation force are not known. Controller comprises a linearizing-like feedback (i.e., the controller induces an input-output linear behavior in the motion of the levitation system) and an uncertainty estimator. Simulations are provided to illustrate the performance of the proposed controller.