A novel design concept for a planar magnetic levitation stage

A new design concept has been developed for overcoming the main drawback of the planar magnetic levitation stage introduced by Dr. Kim Won-jong in his PhD thesis in 1997, which consists in the difficulty of extending the travel range of the mover. During the last two years we set up and made experiments on a similar stage structure as that presented by Dr. Kim Won-jong. A new control method has also been developed for improving the performance. The experimental results are promising, e.g. less than 1 nm RMS position noise, but only a short travel range is possible. Extending the travel range leads to unacceptable increase of stage area and power dissipation. The new design concept solves this problem and, along with the new control algorithm, enables the realization of a modular structure with distributed control. The modular concept enables us to propose, at the end of the experimental phase, a set of building blocks with which stages with different travel ranges are easily set up.