Lianqiang Wang

Aiming at the inherent nature and complexity of the influence of in-orbit micro-vibration in the imaging quality of segmented telescopes, a dynamic full-link opto-mechanical integration analysis method is proposed. The method is based on the measured micro-vibration signals of the infrared refrigerator, using the finite element method to perform the transient response analysis of the opto-mechanical system in Patran/Nastran software. The interface tool is written by Matlab to achieve the calculation of rigid body displacement and real-time data interaction with Zemax. The results show that when the working wavelength is 1 μm, the optical system has a wavefront error Root-Mean-Square value of less than 0.071λ in 4 s. Evaluating the effect of micro-vibration on the imaging quality of the system in terms of the peak ratio of the point spread function. When the exposure time was 2 s, the ratio maximum values of 0.4628 and 0.6207 were reached for the X-axis and Y-axis, respectively. The method provides an important reference basis for the evaluation of imaging quality of an optical system under micro-vibration environment with a long exposure time.

A hydraulic in-situ support system is commonly used in the optical testing of mirrors, since it is convenient to unload the gravity of a mirror to be measured without the risk of being turned over or moved to another place. The existing supporting structures have several disadvantages, such as the problem of the output force deviating from the axis, being sensitive to machining loads, its flexible components easily leading to fatigue damage by cyclic loads and so on. A new single-cylinder hydraulic supporting unit with a ball hinge was proposed, analyzed and verified in this paper. A finite simulation based on four structural parameters’ effect on the stiffness of the proposed hydraulic supporting unit showed that increasing the thickness, elastic modulus and convolution width of the rolling diaphragm and decreasing the height of the rolling diaphragm to some extent was beneficial to a high stiffness. Moreover, it could be concluded from experiments that, in order to decrease the stiffness dispersion, the air ratio should be as low as possible and the values of the initial pressure and press speed should be as high as possible. These results are conducive to maintain a high stiffness of HSU to bear the processing load and reduce the low-order aberrations of mirror which provide a reference for future hydraulic supporting unit designs.