Cooperation Motion Control Of Simulated Star Based On Air-floating Platform

In space missions,the status of spacecraft on-orbit service technology is gradually improving,and there is more and more research on cooperative control of combined spacecraft.Before the mission,the related aerospace equipment must be tested under certain conditions,and the most critical factor is weightlessness.Because of its low cost,small disturbances and long experiment time,the air-floating simulation experiment platform can effectively test the effect of the control strategy running on the spacecraft,and it has become an important means to simulate the rendezvous and docking,attitude control,on-orbit capture and other technologies of spacecraft in space.This paper mainly studies the motion control of the 3-DOF simulated star in the experiment of air-floating platform,including two cases of single simulated star and combined simulated stars,and considers two control modes of single star control and cooperative control for the combined simulated stars.First,the basic environment information of the air-floating platform and the hardware composition of the simulated star equipment are briefly introduced.After analyzing the actual motion characteristics of the simulated star,the inertial coordinate system(ICS)and the body coordinate system(BCS)fixed to the simulated star are defined.Through the force analysis of single simulated star,the equivalent mechanical model in the BCS is established,and the dynamic models of single simulated star and combined simulated stars in the ICS are derived respectively.Next,according to the existing experimental motion control system,the software framework part and some basic modules under it are analyzed and designed.By analyzing the overall process of simulated star movement,a navigation module is designed.According to the simulated star dynamic model,the digital PID controller is adopted and designed.The thrust distribution strategies of single simulated star and combined simulated stars are designed respectively based on the equivalent mechanical model.Finally,some typical motion forms in the research of air-floating platform are listed,including fixed-point flight and tracking of straight line,circle and sector trajectories.For single simulated star,the simulation and experiment of the above movements are realized,and the good signal tracking performance and anti-interference performance verify that the design of the control module meets the basic requirements;for combined simulated stars,due to the limitation of the existing resources,only the simulation of the above movements is realized by software.The good response speed and accuracy verify the correctness of the combination method selection and thrust distribution strategy.In addition,the better control effect and lower energy consumption of cooperative control also verify the practical significance of its theory.