Lightweight airborne TPMS-filled reflective mirror design for low thermal deformation

Abstract

In recent decades, unmanned aerial vehicle airborne optical systems have gained a booming development. With the continuous pursuit of optical system performance, the thermal deformation of the reflector during temperature change constrains the further improvement of the system performance. Traditional open-back mirrors have difficulty meeting high-performance targets under temperature change. With the rapid development of 3D printing technology, the complex structures represented by TPMS have significantly increased the freedom of optical reflector design. This paper proposes a TPMS structure optimization design approach based on the homogenization performance model, which can accurately describe the TPMS structure performance and obtain structures with outstanding performance with minimal computing cost. A TPMS-filled reflector with a diameter of 400 mm and a height of 60 mm was designed with a mass reduction of about 70 %. Results show that the final shape deviation of the mirror is below 20 nm RMS at room temperature and below 30 nm RMS at 50 ℃. Compared to open-back mirrors, TPMS-filled mirrors perform significantly better at high temperatures. This method helps with the application of TPMS in the design of opto-mechanical structures.