Research On Dynamic Adjustment Technology Of Secondary Mirror Truss Of Vehicle-mounted Telescope

For astronomical observation,the most important tool is the telescope,and the larger the aperture,the higher the resolving power,and the size of the observable universe is directly proportional to the telescope’s resolving power.Compared to traditional ground-based large-aperture telescopes,vehicle-mounted telescopes are more adaptable to weather and environment,and more efficient in observation.However,because the vehicle-mounted telescope must be transported by road,passing through some bridges and culverts,there are strict restrictions on its overall width and height,thus limiting its further aperture enhancement.Therefore,this paper proposes a new dynamic secondary mirror truss adjustment mechanism,which integrates the secondary mirror truss with Hexapod platform to design a new dynamic secondary mirror truss adjustment mechanism,which adjusts the secondary mirror position through the secondary mirror truss and eliminates the traditional Hexapod platform to reduce the overall height of the telescope and further enhance the maximum aperture of the vehicle-mounted telescope.The specific research of this paper is as follows:1)The kinematic modeling of the secondary mirror adjustment mechanism was carried out,and the kinematic model was analyzed for the degrees of freedom of the mechanism as well as the forward and reverse solution modeling and error modeling,and the overall design of the secondary mirror adjustment mechanism was carried out.2)Finite element modeling was performed on the 3D model,and static analysis was performed on the finite element model,and the face shape of important parts and secondary mirror was analyzed,and modal analysis was performed on the finite element model as a whole to verify the rationality of the structure.3)The prototype was assembled,the travel test and position calibration of each calibration unit were performed,the stiffness test of the vertical direction of the optical axis was performed,and the kinematic performance test of the mechanism was performed,including the resolution test,the motion accuracy test and the motion space test of the mechanism.The machining and assembly errors of the mechanism were analyzed to determine the sources of errors and their solutions.In this paper,a new dynamic secondary mirror truss adjustment mechanism is proposed and designed for the purpose of reducing the overall height of the telescope to enhance the maximum aperture of the vehicle-mounted telescope through investigation and research for major national development needs.This paper integrates the secondary mirror truss and Hexapod platform,and designs a dynamic secondary mirror truss adjustment mechanism with automatic adjustment of three degrees of freedom for deflection in X/Y two directions and movement in Z direction,and manual adjustment of two degrees of freedom for movement in X/Y two directions,which makes the secondary mirror system of large aperture telescope more compact and has certain engineering significance and reference value.