A Linear Table System Using Repulsive Forces of Permanent Magnets. Static Stiffness of Levitated Table and its Stabilization Using Two-Axis Control.

A linear table supported by repulsive forces between permanent magnets (PMs) can not levitate stably without a feedback control system. To make the simple-structured PM linear table system which has the minimum number of actuators, sensors and controllers, the number of controlled degrees of freedom of the table system should be minimized. In this paper, first, the PM linear table mechanism which has four short PMs attached to the bottom of the table and two fixed parallel long PMs is introduced. Then a dynamic model of the linear table mechanism is derived from equivalent current lines of the PMs. The model indicates that the active control in the two degrees of freedom is indispensable for the stabilization of the linear table. A two-axis controlled PM linear table system is designed and constructed experimentally. Finally, it is clarified that the table can levitate with two-axis PD controllers for lateral and yaw motions.