Research On The Key Technologies Of Micro-vibration Suppression For The Space Telescope

The field of deep space exploration is developing rapidly at present,so the development of space telescope for it is becoming more and more urgent.Stability is an important index of space telescope,the micro-vibration caused by the moving mechanism of the telescope is the main reason affecting the stability.Therefore,microvibration should be suppressed.In this paper,the micro-vibration integrated simulation,design and optimization of the vibration isolation system(VIS)for the space telescope payload and active damping vibration suppression technology are studied systematically and deeply.The details are as follows:The micro-vibration integrated simulation is studied,and the main content is the establishment of the micro-vibration integrated analysis model.Compared with the traditional structural dynamics analysis,the final output of the model is the Line-ofSight of the space telescope.The final analysis results can be used to evaluate the stability of the telescope.The micro-vibration integrated simulation model includes three important parts.The first is the FE-model based on the structure,which includes the space telescope payload,vibration isolation system and space telescope platform.The second is the optical model,which consists of the mirror rigid body displacement fitting equation and the optical sensitivity matrix of the image point.The third is the disturbance source model,mainly the force and moment of the disturbance source installation interface,which are obtained from the measurement.The integrated model can be used for modal analysis and frequency response analysis to master the dynamic characteristics of structures.It can also be used to evaluate the stability of LOS of the telescope in time domain and frequency domain.In the design of space telescope payload vibration isolation system,the stability index can be directly used as the analysis target.A vibration isolation system for space telescope is designed and optimized,including configuration,stiffness and damping of the system.In the traditional vibration isolation system configuration design process,it is assumed that the platform is in the constrained state and the mass of the satellite platform is much greater than that of the payload.However,for space telescope,the mass of the payload and the platform are close,and the boundary conditions are free-free.A calculation model of natural frequency distribution of vibration isolation system is proposed considering the above situation,and the configuration optimization is carried out to minimize the ratio of natural frequency of the 6th and 1st order of the integral modes of vibration isolation system.After the configuration optimization of the vibration isolation system is completed,a metal vibration isolator with three directional stiffness is proposed considering the mass eccentricity of the space telescope.The parameters are optimized with the above optimization objectives,and the frequency ratio is further reduced after the stiffness optimization.The verification structure of the vibration isolation system is designed and fabricated,and the simulation results are compared with the experimental results.The effectiveness of the stiffness optimization is proved by the experiment.the damping of vibration isolation system is designed,a viscous fluid damper is designed to suppress the VIS's resonance modes and its damping coefficients tested.Finally,the micro-vibration integrated simulation model is used to simulate and analyze the vibration isolation effect of the vibration isolation system which includes configuration,stiffness and damping.The comprehensive vibration isolation effect of the vibration isolation system is simulated,and the effectiveness of the vibration isolation system is proved.Two active damping control strategies based on positive position feedback are studied,which are positive acceleration feedback and positive velocity feedback based on force feedback.The research content includes three parts: firstly,the control strategy is derived,then the theoretical effect is simulated,and finally the effect is simulated based on finite element analysis.The actuating mechanism of the above two active damping control methods: active tuned mass damper is designed,and its structural characteristics are analyzed and tested.The effectiveness of the two control strategies is proved by experiments,and good results can be obtained in both time domain and frequency domain.