Damping Control in Magnetic Levitation of Micro Objects

In this paper, magnetic levitation of micro objects is discussed and a solution to damp vibration is presented. A magnetic levitation setup with a real-time feedback controller is built. Various tiny permanent magnets are levitated and challenges of microlevitation are discussed. Large vibrations are observed when levitated object becomes smaller. To suppress vibrations and increase precision, eddy current damping is introduced by placing conductive discs in the varying magnetic field. The damping analysis is performed and a damping coefficient formula is derived for the system. It is shown that a cylindrical permanent magnet of 0.386 g is successfully levitated in an airgap of 290 mm. The proposed system has a potential to be used for micromanipulation purposes in a motion range of 39.8 mm