Rigid-body displacement separation of optics in optical-structural-thermal integrated analysis

The deformation of opto-mechanical system caused by environmental load has a serious effect on the performance of the optical system. Thermal-structural-optical integrated analysis is an effective method to evaluate this kind of effect. To reduce the impact of the rigid body displacement of optical system on the deformed optical face fitting, a method based on homogeneous transformation and least square method was studied in optical-structural-thermal integrated analysis. Firstly, the homogeneous transformation was employed to express rigid-body displacement in deformed surface data. Then, least square method was adopted to resolve the rigid-body displacement parameters. An off-axis parabolic mirror under cryogenic environment was analyzed by this method. The deflections of the mirror were small to the magnitude of μrad. Also, analysis of the resolving precision was made. The results indicate that the resolution error is less than 1% with the rigid rotation less than 0.01 rad and it meets the demand of precision in optical-structural-thermal integrated analysis.