A Novel Kind Of Parallel Pointing And Stability Technology For Space Optical Payload

Reflective telescope is one of the most important tools for modern scientists to explore the universe.It is mainly composed of primary mirror,secondary mirror and mirror support structure.The internal and external factors such as gravity and vibration existing in the reflection telescope have a great interference to the imaging effect.Therefore,the positional relationship between the primary and secondary mirrors must be fine-tuned.Generally,the weight and volume of the secondary mirror are small.Therefore,the secondary mirror adjustment scheme is adopted.In the early stage of this paper,the XX large-scale ground-based telescope was taken as the research background,and the sub-mirror precision pointing parallel platform was studied.The sub-mirror precision pointing parallel platform designed in this paper mainly refers to the basic configuration of Gough-Stewart parallel platform.A new off-set hinge is used.The inverse kinematics model of the parallel platform is derived by using Newton method and vector analysis method,and the workspace was analyzed using a numerical search method.With the continuous development of space optical load technology,the requirements for the range and stability of the adjustment mechanism are getting higher and higher.For this reason,this paper,based on the previous research of precision pointing parallel platform,intends to make full use of the optical characteristic that the pointer of the optical axis of the optical load is sensitive to pitch and yaw motion and insensitive to rotation and translation.A new type of coarse and precise parallel pointing and stable integration technology is proposed.The technology utilizes coarse-level control to achieve large-scale adjustment,and uses fine-level control to compensate for optical axis shake caused by factors such as satellite platform vibration,thereby improving stability.The coarse and fine two stages are in parallel,and the motion decoupling is realized through coordinatedcontrol.Compared with the traditional coarse-precision series pointing and stabilization technology,the coarse-level and fine-level parallel pointing and stable integration technology of this paper has the advantages of compact structure,small weight and small size,and is more suitable for space applications.The coarse actuator of the platform mainly realizes the change of the position of the platform by controlling the servo motor to drive the small lead precision ball screw movement.The precision actuator mainly realizes the stability of the platform through the action of the voice coil motor and the internal spring piece.This paper design the structure of the platform,optimize the design of the parallel platform,establish the kinematics and dynamics model,and verify the rationality of the structural design through the mechanical finite element simulation method.The research and implementation of this project can accumulate experience provide and theoretical basis for the development of high-precision spatial optical load directivity technology in China.