Identification method for transfer function of multi-DOFs motion stage

Precision motion stage with multi-DOFs is a key component of integrated circuit fabrication equipment and high performance machining tool. Its accuracy decided by the precision of transfer function impacts directly on the equipment performances. Its order and parameters determination are key questions for transfer function identification. System transfer function model is established by using additional noise according to analysis result of ideal air bearing stage. A method is described in detail to determine the model order by F testing and model parameters by least square method. The mathematical model is verified by an experiment and motion accuracy of X-axis, Y-axis and Rz-axis reach 10 nm, 10 nm and 60 nrad respectively. This method can also be used for transfer function identification of other multi-DOFs air bearing stage.