Research On High Stability Direction Control Technology Of Micro-Vibration On Space Telescope

With the in-depth research on deep space exploration,the detection ability and resolution of space camera are continuously improved,the focus of optical system has become longer and longer,the aperture and size of corresponding camera has been larger and larger,and the requirement for image data of spacecraft is constantly raised.However,the dynamic environment of the spacecraft is complicated.The attitude changes of the spacecraft,the overall vibration of the space camera and the vibration of various optical elements inside the spacecraft cannot be neglected.Therefore,the influence of microvibration on space optical system and the problem of space optical precise image stabilization control are of great significance to improve the imaging quality of space telescope.The main research object of this paper is space telescope.With the goal of improving the optical imaging quality,the sources of micro-vibration interference faced by the space telescope during its orbital operation are analyzed firstly.Using finite element method,dynamic response analysis of space telescope under disturbance load is carried out and the rigid body displacement response of each optical element of space telescope in six degrees of freedom direction under disturbance is determined.Secondly,static analysis is carried out on the optical model of space telescope to compare the effects of steady-state response on optical system under load.Considering the exposure time of space telescope,the imaging of optical system is analyzed dynamically,and the motion of image points in integration time is evaluated by the radius of motion envelope circle.The results show that the image point displacement changes with time and has no regularity.Finally,with image motion compensation algorithm,a precise image stabilization scheme based on fast piezoelectric yaw mirror is designed by using ideal second-order function PID method and internal model control method.The simulation experimental system of image motion compensation system is designed and established,and the experimental results are evaluated with optical dynamic transfer function as index.The results show that both control systems are effective,and the optical system controlled by internal model has better image quality and control effect.It verifies the scheme of optical axis compensation control system for the swing mirror is effective and feasible.