Development of Electromagnetic Levitation Control Device for a Rectangular Sheet Steel.

Abstract

This paper proposes a levitation control device for a rectangular sheet steel by the hybrid actuator using five electromagnets and thirty permanent magnets. The five electromagnets are independently controlled by feedback signals from gap sensors to stabilize a levitation behavior. The thirty permanent magnets are installed to support the static deflection of the sheet steel. In addition, it is found that the permanent magnets increase the damping factor of elastic vibration and work effectively for the electromagnetic levitation. In this study, the attractive force of the permanent magnets is analyzed by using the finite element method and the elastic vibration of the sheet steel is calculated by the finite difference method. To verify usefulness of the proposed levitation control system, an experiment applying the digital optimal control theory was performed for the rectangular sheet steel (length: 800 mm, width: 600 mm, thickness: 0.3 mm). As a result, in comparison with the system only using the electromagnets, it was confirmed that the control performance was improved by using the permanent magnets.