Unloading Method Of Tetrahedral Deployable Antenna And Experimental Research

With the development of economy and society,people explore the universe frequently,and various space activities are carried out one after another.Due to the special space mission and the high price of equipment,it is necessary to improve its reliability,economy and safety,and to carry out zero gravity environment simulation in advance on the ground.This paper focuses on the gravity unloading problem of symmetric and asymmetric tetrahedral antennas,including kinematics and dynamics analysis,unloading scheme design,simulation analysis,and experimental verification.The main research contents are as follows:Firstly,based on the kinematics analysis of the positive-fed symmetrical tetrahedron deployable antenna mechanism,the unloading index is determined,and three feasible schemes are provided,and their advantages and disadvantages are compared and analyzed.In this paper,the same unloading index and scheme are adopted for the partial feed asymmetric tetrahedral deployable antenna mechanism.Based on the original unloading point,the optimization analysis of unloading point is carried out and a new unloading point is established.Through the analysis of two kinds of different mechanisms,a general scheme suitable for tetrahedral deployable antenna mechanism is obtained.Then,the stiffness of the unloading rope is optimized,and the simulation model of tetrahedral deployable antenna under gravity unloading condition,gravity no-unloading condition and microgravity condition is established in ADAMS software.According to different unloading methods,the simulation results under gravity unloading condition are compared,and the advantages and disadvantages of different unloading methods are analyzed from the antenna unloading force,stationary state and other indicators,and the optimal scheme is selected.The simulation results of gravity unloading condition,gravity no-unloading condition and microgravity condition of the preferred scheme are compared,and the unloading force and stationary state of the antenna are analyzed.Finally,the unloading device is set up for experimental research.Based on the calculated stiffness of the unloading rope and considering the variable position of the unloading point,the unloading experimental platform was built to analyze the variation of the antenna deployment pose and stability under the unloading condition,so as to verify the effectiveness of the proposed unloading method.