Design of a kinematic flexure mount for precision instruments based on stiffness characteristics of flexural pivot

Abstract Precision components in optical instruments enjoy the benefits of kinematic flexure mount, owing to its excellent performance evident in space telescope and lithography equipment. The stiffness behavior of a flexure mount is important for releasing thermal stress and resisting displacement. However, they still need enough investigation and design guidance. In this paper, a novel kinematic flexure mount comprising three identical chains, is proposed based on exact constraint principles. Considering radial translational and supporting stiffnesses, a single chain of the mount is designed using the cross-spring pivots. Then, the stiffnesses are analyzed to better evaluate the influences of configuration parameters. Stress analysis is also implemented by stress checking to fulfill large motion range. Moreover, a practical case for supporting a 1-m primary mirror is designed to validate the effectiveness of the design, and stiffnesses for a single chain are verified by finite element analysis (FEA). For design validation, the system is simulated and compared with traditional three-bipod mount. The results show that the proposed mount is capable of greatly releasing thermal stress introduced into the mirror and provides adequate supporting stiffness.

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