Integrated design of mechanism and control for high-precision stages by the interaction index in the Direct Nyquist Array method

Abstract

High-precision stages are widely used in the semiconductor and flat panel industry. Because these stages have six degrees of freedom to control, coupling forces can deteriorate its control performance and stability. If heights of the center of gravity (CoG), the center of rotation (CoR), the actuation point, and the measurement point are not the same, couping between the x and θ y motions occurs. In this paper, integrated design method of mechanism and control is proposed utilizing the Direct Nyquist Array (DNA) method and a changeable actuation height stage by means of multiple actuator arrangement in the x direction. Due to the model analysis and the optimal actuation height, the coupling can be reduced with a simple precompensator. By drawing the Generalized Gershgorin Band (GGB), the effectiveness of the proposed method is verified through experiments.