Analysis And Research On Precision And Thermal Stability Of Umbrella Anrenna Rib Delpoyment Mechanism

With the vigorous development of China space industry,more and more satellites have been launched into space to serve humanity.However,the space environment is rather harsh.With the on-orbit operation of the satellite antenna,the position and posture of the spacecraft are constantly changing relative to the Sun and the Earth,as well as the temperature field of itself.Due to the existence of such extreme temperature differences in the space,the structural deformation is caused,which seriously affect the antenna’s working accuracy.In view of this problem,this paper takes the umbrella antenna rib deployment mechanism as the research object,and the deployment accuracy and the thermal stability during the on-orbit operation are analyzed and studied.Firstly,the main error sources affecting the deployment accuracy of the umbrella antenna are analyzed,namely the dimensional machining error and the clearance fit tolerance.The Monte Carlo method was used to synthesize the error,and the distribution law of the contact points of the rotating pair with clearance was analyzed.The effective error formula of the machining size and clearance fit was established.The effective length model and the mechanism error model were established with the errors of gap and rod length.The deployment mechanism model is analyzed and simplified,establishing a dimensional chain to find the impact of each error source on deployment accuracy.By using D-H method,considering the coupling effect of dimensional machining error and clearance fit tolerance,a mathematic model of the sensitivity of each error source to the H surface deployment angle accuracy was established.Secondly,thermal analysis of the orbital space where the umbrella antenna is located is performed,and the main heat transfer methods in space are described.The temperature and load received by the umbrella antenna mainly come from the solar radiant heat,the earth’s radiant heat and the earth’s reverse heat according to its orbit.The relevant parameters,the calculation of the temperature field,provide a theoretical basis for the subsequent finite element thermal analysis.Finally,based on the actual operation of the umbrella antenna in orbit,the thermal-structural coupling analysis of the unfolding mechanism model is performed at the lowest temperature and highest temperature conditions to obtain the thermal deformation and thermal stress of the structure.Through the analysis of precision and thermal stability,it has guiding significance for the redistribution of tolerances and component materials,and improves design efficiency.Through theoretical and simulation analysis,the test cost is greatly reduced and the working reliability of the space mechanism is improved.