Implementation of a dual disturbance observer for pneumatic stage

This paper treats a pneumatic stage used in semiconductor exposure apparatus as a research subject. Pneumatic positioning is slow due to the compressibility of air. Moreover, there are several causes that prevent the high-precision positioning. In particular, the flow disturbance induced by the air pipe supplying compressed air, and the mechanical disturbance generated by rolling guide are the main cause. This paper proposes “Dual Disturbance Observer” as a method of removing two disturbances to realize high-precision positioning.