Study of Stability of Precise Tiled-grating Device

To satisfy the high-stability requirement of a tiled grating we have analyzed and optimized the stability of a newly designed precise tiled-grating device considering three aspects: structure design, transmission chain, and control algorithms. The main structure of the device is changed from a parallel-board structure to a new tetrahedral brace design, enhancing the overall vibration stability; during the analysis of the transmission chain, the adjustment accuracy and stability of the device were ensured by slowing the growth of the error transmission factor; and for the optimization analysis of the PID control algorithms, we adopted a latch compensation method to avoid the saturated loss and a four-point central difference method to avoid the disturbances, thus enhancing the stability control of the device. To test the stability of the device, an optical experiment with a reference spot was designed. The experimental results showed that over 380 s, the ambient excitation response was always within an acceptable range. The average deflections about the X axis and Y axis are 0.243 and 0.00146 mu rad, respectively, which satisfy the stability requirement.