The curved prisms have been widely used as a light splitting element because of its own focal power and can be set in nonparallel light path. When the effective light transmission area of large-size curved prism is rectangular or elliptical, it can be processed into rectangular optical elements during processing, which can reduce the volume and mass of the instrument on the one hand, and effectively block the stray light outside the field of view on the other hand. Adhesive fixation is one of the common fixation methods of optical elements, which is applied in many launched spaceborne remote sensors. However, the adhesive bonding process and adhesive strength are unstable and the bonding reliability is poor, resulting in the calculated theoretical bonding area and adhesive layer thickness are often difficult to meet the requirements of complex mechanical and thermal environment. The rigid-flexible dual mode coupling support structure for space-based rectangular curved prism was firstly introduced. And then the tensile and shear tests on the epoxy adhesive used in this project was carried out and the bonding area based on the strength test was designed. On this basis, the mechanical test of the simulator mirror group was carried out to verify the reliability of the bonding area and the design of the support structure. Finally, three bonding postures were simulated analysis and tests including prone, lateral and vertical bonding. The results showed that the vertical bonding was the smallest surface shape errors of the curved prism. Based on this bonding attitude, the bonding and mechanical tests of the curved prism were completed to verify the reliability and rationality of the bonding process.
With the increasing demand of infrared detection, the infrared cold optical technology has developed rapidly in recent decades. The low temperature deformation of infrared optical elements is one of the key factors restricting the development of infrared cold optical technology. The processing and assembly of optical subassemblies and support structures are carried out at room temperature and pressure, while the actual working environment of infrared system is relatively low temperature environment, which can vary by 200 degrees Kelvin or more. Therefore, the temperature adaptability of the support structure is strictly required. The optimal design flexible support of the 70mm diameter single crystal lens made by germanium was carried out to ensure that the component surface shape reached (1/6) λ and the natural frequency was above 200HZ at 100K low temperature in this paper. At the same time, the ISIGHT integrated optimization method was used to optimize the flexible support structure. The multi-objective integrated optimization of key dimensions of flexible support was completed, aiming at maximizing the fundamental frequency of the system and minimizing the lens surface shape errors. Finally, the optimal size was selected to complete the flexible structure design. In this paper, an adaptive flexible support structure for cold optical lens with three layers of stress release was designed by multi-objective integrated optimization method. Meanwhile, its performance was verified by low temperature tests. The results verified the reliability and the feasibility of the structure design and analysis.
From the special structure, processing technology and function of Fery prism in spectral imager, and the structural design features of a certain research spectral imager project, an assembly measurement method based on CMM, PSM and high precision rotating device is proposed, which combines the principles of space measurement, point source collimation and 3D mathematical modeling, the on-line inspection and alignment technology of Fery prism assembly are studied. Firstly, the key parameters of a single curved prism, such as curvature radius of surface, spherical coordinates, deflection angle of optical axis and off-axis are measured by CMM. Secondly, the Fery prism assembly is assembled by CMM, PSM and high precision rotating device. The space coordinates between the components are measured by CMM, and the position of the Spherical Center and the deflection angle are precisely determined by point source microscope. Finally, the actual assembly effect of the Fery Prism Assembly is reappeared through the data processing of the computer software, and the directional offset between the Fery prism assembly and the theoretical model is given, the precision assembly of Fery prism aseembly is completed by azimuth rotation and trimming mat processing. It provides a new technology method for on-line precision assembly of Fery prism module in Spectral Imager, which has strong operability and high measurement precision, and is suitable for precision detection and assembly of Fery prism module of different sizes.
To ensure the high surface accuracy and high thermal stability of space mirror, a lightweight design for the Φ514mm ULE primary mirror of a space remote sensor and flexible support structure with three-point was carried out. By further optimizing the parameters of the flexible supporting structure, the requirements of the optical index were met. The finite element model of the mirror assembly was established, and the static and dynamic characteristics of the assembly were analyzed. The results showed that the surface shape accuracy (RMS) of the mirror assembly is better than 8 nm under a load case of 1g gravity when the optical axis is level, and the first-order natural frequency of the component is 254 Hz. Finally, a mechanical test was carried out on the mirror assembly. The test results showed that the first-order frequencies of the three directions of the mirror assembly are all greater than 100 Hz , the error between the test data and the finite element analysis results does not exceed 10%. Analysis and test results showed that, the reasonable support structure design can effectively lower the change of the mirror surface shape caused by assembly stress and thermal stress, and has good dynamic performance. It is verified that the mirror and its supporting structure designed in this paper are reasonable, which provides reference and ideas for the design of flexible supporting structure of similar space mirror.
To minimize the assembly stress and thermal stress introduced by the support structure, and ensure the high surface accuracy and high thermal stability of space mirror. An ultra-lightweight design of secondary mirror was carried out for some space remote sensor, and three tangential bipods were used for quasi-kinematic support. Firstly, the design principle of quasi-kinematic support structure was investigated, and advantages of bipod kinematic support were analyzed from the angle of degree of freedom decoupling. Based on structure designed above, the finite element model was established. Taking surface accuracy of the mirror as optimization objectives, the integrated optimization method was adopted to extract the structural parameters with high sensitivity on the surface accuracy in the flexible support structure, and parameters optimization design was carried out. Finally, the static and dynamic characteristics of the optimized mirror assembly were analyzed. The analysis results showed that the surface shape accuracy (RMS) of the mirror assembly is better than 1 nm under a load case of 1g gravity when the optical axis is level. Surface accuracy (RMS) is better than 2 nm under the load case of 4℃ uniform temperature rise. The first-order natural frequency of the secondary mirror assembly is 587 Hz. The optimized mirror support structure can well unload the additional deformation caused by the support structure, and has good dynamic stiffness, which verifies that the designed mirror and its support structure are reasonable, and the optimization design method is reliable. This paper provides a reference and idea for the design of flexible support structure of space mirror.
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