Optimal Design Of 2m SiC Mirror Active Adjusting Lateral Support Method And Support Mechanism

As the important optical component of ground-based telescope,the support states of the mirror influence the imaging quality of the telescope.With the development of the technology of telescope,the aperture of the mirror becomes larger,so the design of lateral support system becomes more and more important.The paper presents a design of the lateral support system based on the 2m mirror.The design meets the requirements of surface accuracy of the mirror and first-order resonant frequency of the telescope system.The author studies the development of the lateral support system by reading relevant articles.After learning basic theories and general principles of lateral support system,the author proposes a lateral support method based on the edge tangential shear principle.The lateral support system proposed in this paper contains 12 edge discrete support points.The system is based on the 18 points Whiffletree structure for axial support system used on a 2030 mm lightweight mirror in diameter;The paper designs the support position using uniform gravity support method and optimize the angle of support force by the edge tangential shear formula.The result shows that root mean square(RMS)of the mirror surface’s displacements is 15.23nm;The first-order resonant frequency of the support system is 17.7Hz.The result meets the design requirements.This paper also designs a new type of active adjusting lateral support mechanism after theoretical analysis.Firstly,the author analyses forms of common lateral supports;After that,active adjusting lateral support mechanism is designed including actuator,flexible hinge and lever system.Finally,finite element analysis of the force and displacement of the mechanism is carried.The author also designs the experiment to do stiffness and adjustment testing.The result shows that the force of displacement actuator is 70.38 N while the support force is 408.21 N,which reduces the requirements of stiffness and strength greatly.The displacement of the actuator is 0.046 mm,which is 22 times that of the suppor ting part.So the requirement of the displacement actuator is greatly reduced.The stiffness measured in the experiment is 1225N/mm,which meets design requirement.It shows that the active adjusting lateral support mechanism has good engineering application abilities.Lastly,the author analyzes the sensitivity of main parameters to simulate the influence of manufacturing and assembling.The analysis can be a reference in further study.