Method for determing a commutation offset and for determining a compensation map for a stage

摘要

A method for determining a commutation offset for a mover (250A) of a mover assembly (220C) that moves and positions a stage (220A) relative to a stage base (220B) includes controlling the mover assembly (220C) in a closed loop fashion to maintain the position of the stage (220A) along a first axis and along a second axis with the stage (220A) levitated above the stage base (220B). The method also includes the steps of (i) directing current to a coil array (240) of the mover assembly (220C) so that the mover assembly (220C) imparts a disturbance on the stage (220A); and (ii) evaluating one or more forces generated by the mover assembly (220C) as a result of the disturbance on the stage (220A) created by the mover (250A). Further, a method for generating a compensation map (1402) includes sequentially directing a plurality of excitation signals to the control of the mover assembly (220C) and determining the control commands that result from the plurality of excitation signals.

主权项

1. A method for controlling a mover assembly that moves and positions a stage relative to a stage base, the method comprising the steps of:
controlling the mover assembly with a control system to position the stage at a first test position; applying a first set of excitation signals with the control system to the mover assembly with the stage at the first test position; determining a first set of control commands for each of the excitation signals of the first set; controlling the mover assembly with the control system to position the stage at a second test position that is different than the first test position; applying a second set of excitation signals with the control system to the mover assembly with the stage at the second test position; determining a second set of control commands for each of the excitation signals of the second set; and generating a compensation map from the first set of control commands and the second set of control commands, and controlling the mover assembly with the control system utilizing information from the compensation map.