Yanchun Li

Research on the Space Deployable Mechanism Driven by Twist Spring

A deployable mechanism applied in the aerospace with twist springs and links driving, locking function is described in this paper. Dynamic analysis on this mechanism has been presented, and dynamic simulation has been implemented following the results of analysis, the dynamic characteristics of mechanism have been verified.

Research on the support truss structure of foreign space remote sensor with large-scale and flexibility

The truss structure had the merits of simple configuration, reliable, flexible assembly, specific stiffness and strong design ability. It was widely used in the support structure of Space camera and large telescope at home and abroad. The article described and analyzed truss structures of ground-based telescopes, space-based telescopes and Space camera. Conclusions that some reference should be followed in the truss design process were given. Simultaneously it also introduced the basic knowledge of truss design optimization, including the optimization ideas of truss structure and optimization algorithm of truss structure, which laid a good foundation for optimal design of truss in future.

The design of support structure of mirror subassembly of space remote sensor

The support structure of large aperture mirror of space remote sensor is the key of the space remote sensor development. In this paper, the size of the large aperture mirror is Φ700mm,which is supported in the back of mirror with 3 points ,the composite structure of ball joint and flexible groove is adopted in support structure which can guarantee the mirror surface satisfy the requirement of optical design under the coupled load of gravity and heat. At the same time, the mirror subassembly should have a high enough stiffness through the reasonable lightweight to ensure the camera in transportation and launch process can withstand severe vibration condition. In order to validate the rationality of the design,the finite element analysis is done to the mirror subassembly,which indicates that the shape error variation of mirror RMS is better than λ/50 and PV is better than λ/10 in the coupling load of gravity and heat,and the first natural frequency of the mirror subassembly is higher than the design requirements. Dynamics calculation results of mirror subassembly consistent with mechanics experiment results；the surface precision of the mirror subassembly obtained from the ZYGO interferometer consistent with the results of finite element analysis and meets the design requirements.

Optimized design and research for cylindrical electrically controlled box of space camera

The object of study is the electric control box of a certain type of space remote sensor. In view of the existing shortcomings of the original electric control box, the electric control box is designed reasonably. In the result, the design of electronic control box supported by the cylindrical multi-point is proposed, which can solve the series of problem of the original program, such as the large volume, heavy weight, large signal interference. The camera control box is made of magnesium alloy which has light weight and high strength; by the structure design of stacked, the electronics system is classified integration; through the local shielding program, the problem of anti radiation and interference of electronics system is solved; by using the multi supporting structure scheme , the structural rigidity of the electric control box is improved, the modal by 57Hz increased to more than 120Hz, which meet the 100Hz technology of the design specifications; the box body is adopted by nickel for protection, which eliminating the possibility of air and humid environment on the corrosion of magnesium alloy. At present, the electric control box designed has been completed the

Space focusing mirror assembly with flexure hinges

Focusing mirror assembly (FMA) is an important component of large space telescope. It can compensate the telescopes defocus caused by environmental factors. Telescope launching vibration and shock, as well as the structure stress of kinematic movement have great impact on focusing mirror assembly. To solve the problems of defocus result from vibration, shock and other environmental factors, a focusing mirror assembly with flexure hinge structure for space telescope is developed. Analysis and tests shows that the natural frequency of mirror assembly up to 130Hz. Before and after the tests, the shape RMS error variation of focusing mirror is less than 0.002λ (λ = 632.8nm). So the flexure support can well meet the requirements of mirror assembly structure performance.

High-Precision Splicing and Testing for the FPA of Space Camera

The focal plane assembly is one of the most important components of Space camera, whose splicing accuracy the camera imaging quality. Through the analysis of CCDs splicing methods, the focal plane of space camera was staggered lap compact mechanical design, carried out high-precision splicing and testing. While splicing the image processing technology is used to CCDs pixel labelings quantization processing. The ultimate purpose is to eliminate possible errors which due to human visual impact on the stitching accuracy and improve stitching accuracy based on the focal planes character. The results show that the focal plane of CCD chip overlap error is less than 3 μm, the two rows of CCD in the parallel error is less than 3 μm, the coplanar error is less than 5 μm. Finally, according to the analysis of the image obtained from the imaging test on the ground, the camera image stitching results were coincided with the test results, which proved that the method is feasible and accurate. All the results show that the splicing and testing of the FPA for TDI CCD is achieved high-precision.

Design and analysis of structure of large aperture three-mirror off-axis optical system

On the basis of characteristics of optical system of Large aperture three-mirror off-axis, the mirrors’ support structure and the overall frame structure of the optical system was designed and investigated, the first and foremost is the lightweight of the support structure and the overall frame structure, the structure design of the three-mirror off-axis optical system was completed, which characteristic is integrative design of the overall frame structure , also the 3D model of the structure of the optical system was built, by means of the finite element analysis techniques, the modal analysis was done to the overall structure, the analysis results indicate that the first natural frequency of the overall structure is 162Hz，which is higher than 120 Hz requested by the overall structure of the optical system ,the overall structure have a high enough dynamic stiffness and reasonable distribution of modal, which ensure the overall structure in transportation and launch process to withstand severe vibration condition, and the shape error variation RMS and PV of optical mirror which are important indexes of image quality under the comprehensive influence of gravity and thermal load which is in the control range meet the design index.

Effects of environment factors on imaging performance of long focal length space camera

In course of developing, testing, launching and working in orbit, Space camera has to undergo the shock of external loads and changing environment. The optical performance of a long focal length space camera is largely determined by external mechanical loads and ambient temperature. The performance of the camera is a result of the interaction between environment factors. The performance of the optical system should be making an accurate forecast when a modern optical instrument is designed. In this paper, the research methods are reviewed firstly. Then the related technologies are described. The analysis methods of environment temperature and structural characteristics effecting space camera imaging performance are also discussed.