Variable Stiffness Approach to Reduce Vibration Induced in Passively-supported Directions of an Active Magnetic Suspension System

This study focuses on the vibration reduction in lateral directions by varying the stiffness of the system in a vertically active magnetic suspension system. Vibration can easily be induced in the lateral directions while the normal directions are actively controlled with a pair of electromagnets working in a differential driving mode. Switching stiffness control is applied to such a system to reduce the lateral vibration of a floator that is a 25 mm ferromagnetic ball. The normal position of the floator is unchanged even if the stiffness control is applied to the system. The efficacy of the control is evaluated by several experiments which show the reduction of lateral vibrations.