Surface shape precise calculation method for large-aperture mirror

Abstract

The invention particularly relates to a surface shape precise calculation method for a large-aperture mirror. The method mainly aims to solve the problem that an existing surface shape calculation method has error division, the difference between a calculation result and a real value is excessively large due to errors, and consequently a mirror surface shape result is not accurate. The method comprises the steps that (1) a coordinate system is determined; (2) a mirror digital model is established, and mirror digital model information comprises mirror node and unit information; (3) a three-dimensional model of a mirror supporting structure is established; (4) finite element meshing is performed on the mirror supporting structure; (5) a finite element mesh model of the mirror is established;(6) a constraint relation between mirror nodes and the mirror supporting structure is established in finite element software; (7) a finite element boundary condition and a load are loaded to the mirror nodes and the mirror supporting structure in the finite element software; (8) finite element solving is performed; and (9) postprocessing is performed, wherein optimal approximation surface fittingis performed on extracted mirror surface deformation data.

Description

technical field [0001] The invention relates to the field of optical precision machinery, in particular to an accurate calculation method for large-diameter reflective mirrors. Background technique [0002] With the gradual strengthening of optical processing capabilities, large-aperture mirrors have been widely used, but one of the difficulties in the application of large-aperture mirrors is to ensure that the surface accuracy of the mirrors meets the requirements under various usage conditions. Therefore, the selection of the supporting structure form of the large-aperture mirror is particularly critical. The judgment criteria of the existing supporting structure form mainly include the following steps: 1. By meshing the supporting structure of the mirror and the mirror; 2. Establishing the mirror and mirror Constraint relationship between supports; 3. Setting boundary conditions and loading of working conditions; 4. Finite element solution; 5. Post-processing, extracting ...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to solve the existing large-aperture reflector when the finite element software is used to divide the reflector grid, there is a node position error that is relatively large relative to the requirements of the optical instrument, and the error leads to a discrepancy between the calculated result of the reflector surface shape and the real value. For the problem of too large a gap, provide an accurate calculation method for the surface shape of large-aperture mirrors

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