Parametric modeling and optimization of lightweight large aperture mirror driven by support

Large aperture mirrors play an important role in ground-based telescopes, space exploration and other fields, and have always been a research hotspot for opto-mechanical structure design. Large aperture lightweight mirrors are often limited by strict performance indexes. It is difficult to optimize the design with complex structures and many design parameters. In this paper, a mirror of Φ1.2m is taken as the research object. An 18-point support parametric model of the mirror is established based on geometrical constraint solving. The optimized design is carried out for the two types of support methods, namely passive support (equal support force) and active support (unequal support force), in order to achieve a better lightweight rate and adaptability. The results show that the optimized mirror has a mass less than 96 kg and a lightweight rate more than 82.7%. Under 1 g gravity, the RMS value of the mirror is less than 6 nm. And the deformation of the mirror can be further reduced by using the active support with unequal support force. This method can provide a reference for the optimized design of large aperture lightweight mirrors.