Design, Modeling, and Closed-Loop Control of a Complementary Clamp Piezoworm Stage

A novel complementary clamp piezoworm stage was developed to be integrated into a two-axis configuration for tracking profiles in different size regimes. It is based on novel clamp designs that permit complementary action using the same flexure frame in a compact arrangement. A novel direct connection to a commercial slide was used to eliminate backlash and the need for high-precision alignment of a rod and slide. A model was developed and used to design the controller structure and choose thresholds for smooth operation. Complete assessment of the closed-loop performance of a single-axis and dual-axis stage in different regimes was done. The average positioning accuracy of the stage was plusmn20 nm. For tracking applications, the average error of the two-axis stage was 8 nm in the nanometer regime, 1.72 mum in the micrometer regime, and 1.85 mum in the millimeter regime.