Research On On-orbit Deployment Dynamics And Control Method Of Large Space Antennas

As countries continue to carry out major aerospace science and technology projects such as manned space flight,space science communication and deep space exploration,space antennas have become a hot topic of research as a platform for information interaction between space and ground.Studies have shown that as the antenna aperture increases,its signal gain and effective propagation distance will multiply.However,limited by the capacity limitations of the transmitter,the space antennas are mostly designed in a deployable form.Complex dynamics issues will be involved in the antenna deployment process,which has a crucial impact on the success or failure of the antenna.This paper will study the dynamics and process control methods before and after the deployment of a large-scale space antenna,and lay a solid theoretical foundation for the development of new space antennas.The antenna and the satellite body are connected by deployable supporting arms.Before the antenna is deployed,the supporting arms are deployed firstly.The supporting arms are elongated structure,which will have certain flexibility during the deployable process,which inevitably causes the occurrence of vibration and other phenomena.Therefore,this paper adopts a novel soft multi-body dynamics modeling method-absolute node coordinate formulation-to model the antenna supporting arms,analyze its dynamic performance during the development process,and predict some phenomena and propose improvement measures.After the antenna supporting arms are deployed,it will be the deployment process of the reflector.The reflector consists of a rigid truss,a flexible cable net system and a drive unit.It is a typical multi-body system.Dynamic modeling of the deployment process of the reflector is a core problem.Based on the Lagrange multibody system dynamics equation,the dynamic differential equation of the system is established.In addition,using the optimization algorithm,the optimal deployment trajectory of the reflector is planned.Based on the dynamic equation and the optimal trajectory,the dynamic performance of the reflector is studied.After the antenna is deployed,it will be locked with the supporting arms,the satellite body,and the solar panel.The entire spacecraft system contains a large number of flexible structures.In order to avoid the occurrence of resonance in the system,this paper uses the entire spacecraft as the object for finite element analysis,including modal analysis,harmonic response analysis and shock response analysis of the system.The influencing factors of the modal fundamental frequency are explored and some data vital to the system are obtained.The space deployable antenna system is a complex multi-body system.In this paper,the antenna deployment controllers are designed.There are many complex and unknown dynamic disturbances in the space environment,and there are some inaccuracies in the modeling of the system.Therefore,in order to ensure the smooth development of the antenna,two controllers-adaptive sliding mode controller and fuzzy PID controller-are designed for different precision dynamic models,and verified the feasibility of these two controllers through simulation.