Decoupling Control Method for High-Precision Stages using Multiple Actuators considering the Misalignment among the Actuation Point, Center of Gravity, and Center of Rotation

High-precision stages are widely used in the semiconductor and flat panel industries. Because six degrees of freedom have to be controlled in these stages, coupling forces can degrade their control performance and stability. This paper proposes a decoupling control method from the scanning motion x to the pithing motion theta sub(y) using multiple actuators considering the misalignment of the actuation point, the center of gravity (CoG), and the center of rotation (CoR). The method proposed in this paper consists of three steps: 1) a detailed modeling of the the scanning motion x and the pitching motion theta sub(y), 2) a changeable actuation point stage, and 3) an integrated design of mechanism and control. The validity of the proposed method is demonstrated by experiments.