The Design Of Deployable Mechanisms Of Space Large Aperture Optical Primary Mirror

With the rapid development of space science and technology, the large aperture space optical telescope plays a significant role in deep space exploration and earth observation. Deployable segmented primary mirror, as a trend of the development of large-aperture telescope, is a possible solution in the future. This paper proposed a new deployable mechanism in large aperture space optical primary mirror, whose primary mirror is annulus-sector segmented, and is supported by three retractable tri-prism mast. The detailed structure design of deployable mechanisms, the kinematics and dynamics analysis of the deployable unit of the optical primary mirror were carried out, further more, test and analysis were made on the developed principle prototype, and the function of the deployable mechanisms was verified.A new deployable mechanism including the retractable tri-prism trussed mast and annulus-sector segmented primary mirror supported by the masts were proposed in the large aperture space optical system. The design of joint hinges and mechanical linkage of the primary mirror, as well as the optimization of the number of segmented sub-mirror were carried out. In addition, the design of a deployable mast was carried out, and the deploying, folding and locking principle were analyzed.By abstracting the deployable unit of the primary mirror into space deployable 7R mechanism, the relationship between side and angle in the deployable unit was analyzed, and the CFD-H coordinate system of 7R mechanism was established by the improved D-H method, coordinate transform matrix can be got further. The velocity and acceleration curves of arbitrary points in deployable unit can be obtained through coordinate transformation matrix. At the same time, the kinematics model was established in ADAMS software, the simulations were consistent with the theoretical results, which verified the correctness of the theoretical analysis.On the basis of kinematics analysis, derived the Lagrange function of primary mirror deployable unit, calculated the required torque when the deployable unit do uniform motion, and the correctness of the theoretical calculation was verified by simulation. The ADAMS dynamics model of the designed hinges was builted, which verified the deploying and locking reliability. Finally, the dynamic model of the entire primary mirror was established, and the dynamic characteristics of the deployable mechanism of the primary mirror were analyzed when considering the frictional damping, hinge clearance and the flexibility of linkages.Principle prototype of the deployable mechanism was developed to verify the deployable function. The experimental investigation was developed to study the static stiffness, repeated accuracy and vibration models of the mast, as well as the deployable shape precision and vibration models of the primary mirror. And the results were consistent with the simulation. These can provide reference and date support to the design of the deployable mechanism in space large aperture optical primary mirror.