Application of Kitamori's Method to Stage Positioning Control

Abstract

The precise positioning stage is ordinary mounted on the isolated table. For the positioning of its stage, PID compensator is widely used. There are many PID tuning methods, such as the ultimate sensitivity method. However, these methods are effectively applied to the plants described by "first-order lag+dead time". Then, it is difficult to realize the desirable positioning for the stage mounted on the isolated table by the simple applying of these method. Therefore, the knowledge based adhoc parameter tuning has been carried in the production field. However, this tuning easily introduces the tradeoff between the command and disturbance responses and then an adequate compromise is required. In this circumstances, we have doubts whether absolute positioning ability inherent in the stage itself is actively used. In this paper, in order to progress the positioning performance of the stage, we try to derive the tuning formulas based on Kitamori's method. The command and disturbance designated formulas are derived. Through the numerical simulation, it is clear that the practical formulation can be derived.