Development of Electromagnetic Levitation System for Thin Steel Plates with Electromagnets and Permanent Magnets for Levitation Support (Experimental Consideration of Vibration Characteristics of Levitated Steel Plates)

Contact conveyance by rollers is used in thin steel-plate production lines, and scratches on the surface of the plates and plating defects may occur. Therefore, noncontact magnetic levitation conveyance of thin steel plates using the attractive force of electromagnets has been proposed. We previously studied a magnetic levitation system for thin steel plates using both electromagnets and permanent magnets. However, the vibration characteristics of levitated steel plates have not yet been studied. In this study, magnetic levitation experiments were conducted on steel plates using the optimum arrangement of permanent magnets for each condition obtained by the genetic algorithm, and the stability of levitation was experimentally investigated. The results confirmed that the levitation performance of the steel plates was different for each gap. As the gap increased and approached the optimum gap obtained in the GA search, the attractive force of the permanent magnet became appropriate for assisting levitation. This optimized arrangement of permanent magnets reduces the deflection of the levitated steel plate, and the vibration could be suppressed. Thus, the proposed method can change the vibration characteristics of a levitated steel plate and improve levitation stability.