Electromagnetic levitation control system for a thin steel plate: optimal placement of permanent magnets for levitation assist using genetic algorithm

For thin steel plates, which are used in many industrial products including those of the automobile industry, we have proposed a magnetic levitation control system and confirmed its realization by means of a digital control experiment. However, the use of a limited number of electromagnets cannot suppress static deflection and high-order-mode elastic vibration, which are characteristics of a flexible magnetic material. To solve this problem, we have proposed a hybrid levitation control system for the thin steel plate using the magnetic force generated by permanent magnets, which have no operational costs, in the areas where the attractive force of the electromagnets is negligible. In this study, we attempt to determine the optimal placement of permanent magnets to reduce the deflection and elastic vibration of a thin steel plate under the generated magnetic field. To verify the usefulness of optimal placement of the permanent magnets, experiments concerning elastic vibration were performed on a magnetically levitated thin steel plate. As a result, it was confirmed that the control performance was improved by the optimal placement of the permanent magnets.