摘要 |
A multi-stage system includes a stator including a plurality of electric coils; a first stage including a first magnet assembly, the first stage moveable relative to the stator; a second stage including a second magnet assembly, the second stage moveable relative to the stator; a controller configured to position the first and the second stage relative to the stator by activating, respectively, a first subset of the plurality of electric coils to interact with the first magnet assembly and a second subset of the plurality of electric coils to interact with the second magnet assembly, the controller adapted to prevent at least one electric coil, to be simultaneously shared by the first and the second subset to position the first and the second stage on the stator, from activating. |