Research On Techniques Of Axial And Lateral Supporting Of 12-meter Large Optical-infrared Telescope (LOT) Segments

The development of astronomical observation is inseparable from the demand for telescopes.There are as many as 13 large-diameter telescopes in the world.However,the lack of large ground-based telescopes in China limits the development of astronomical observation.The design of Large Optical-infrared Telescope(LOT)and possible subsequent construction will greatly improve this shortcoming,so it is of great significance to study the key technologies in LOT.In this paper,the techniques of axial support and lateral support for a 12-meter LOT segment are reserached.Segment supporting mainly includes axial support and lateral support,for which,Whiffletree axial support point design,axial support and lateral support structure design,sensitivity analysis of axial support and lateral support,and axial support reaction experiment are mainly carried out.The research content is as follows:(1)Determining the number of axial support points and carrying out parametric design of axial support points in second chapter.The paper designs four schemes and optimize the position of support points for each scheme.Under ISIGHT,the optimization objective is to minimize the RMS of segment surface and the parameters of the parametric design of the segment are optimization variables.The optimization algorithm is selected and integrated with ANSYS and MATLAB to obtain the optimal solution of each scheme and select the best scheme.The Zernike polynomial in the regular hexagon was used to fit the surface shape and remove the rigid body displacement.Simulation was used to determine the supporting points of the small tripod and the big tripod.(2)The error sensitivity analysis of a single parameter carried out the position sensitivity analysis of the axial support point,the sensitivity analysis of the axial support force,the sensitivity analysis of the position of the small tripod and the big tripod support point,and the sensitivity analysis of the thickness of the lateral support diaphragm.The sensitivity analysis ofmultiple parameters mainly includes the global sensitivity analysis of the position parameters of the axial value support point and the global sensitivity analysis of the axial support force.By analyzing the influence of various errors,the actual surface shape is estimated.(3)Axial support structure design is carried out for support rod,flexure hinge,small tripod and large tripod,including material selection of each part,theoretical strength analysis and static simulation verification of finite element.The lateral support design is used to design the diaphragm and connection part,and the strength is analyzed by ANSYS.(4)Axial support reaction test experiment is carried out to compare the results of finite element analysis and the actual experiment results.