Magnetically levitated linear drive with passive stabilized axes using repulsive magnetic guidance

Abstract:
Magnetically levitated linear drives are used in applications of precision engineering as they offer high dynamics and low friction. In addition the durability of these systems is high, as there is no wear caused in the guidance. One of the main disadvantages of magnetically levitated linear drives in precision engineering is, that a constant electric current in the guidance is required to compensate the force of gravity. Also the complexity of these systems is high, as a huge amount of power and sensing electronics as well as complex control algorithms are required. In this paper, a magnetically levitated linear motor with two passive stabilized axes using a repulsive permanent magnet configuration is presented. The remaining axes are controlled by Lorentz coils, which uses the same magnetic field than the repulsive guidance. In this configuration, the complexity of the system and the amount of power and sensing electronic is reduced. As a second effect of the repulsive magnetic guidance, the force of gravity can be compensated to powerless levitation by the negative spring stiffness of the permanent magnet guidance up to a weight of 400g. Due to forces of the permanent magnet guidance and a flexure design on the armature of the motor, loads of the armature will levitate with zero watts power dissipation at a constant levitation height.