Research On Pursuit And Evasion Strategy Of Two Spacecraft In Near Earth Orbit Based On Integrated Attitude-orbit Modeling

With the diversification of spacecraft missions and the development of spacecraft technology.Spacecraft rendezvous and docking mission,as the basis and premise of tracking spacecraft close-range operation,puts forward new requirements for the modeling and control strategy of spacecraft kinematics and dynamics.Based on spacecraft orbit dynamics,attitude kinematics equation and dynamics equation,optimal control theory,this paper combines Euler fourelement attitude dynamics model with relative orbit dynamics model in tracking spacecraft body coordinate system.The integrated attitude-orbit model in this paper takes into account the perturbation term and other bounded perturbation terms caused by the uneven shape of the earth.。 The optimal control strategy of two spacecrafts in near-Earth circular orbit based on integrated attitude-orbit modeling is systematically studied,and the relevant parameters and expected states are given to simulate and verify the control strategy proposed in this paper.The main achievements of this paper are as follows:1.The integrated attitude-orbit modeling of two spacecraft in near-Earth circular orbit is studied.Firstly,the relative orbit dynamics model of near-Earth circular orbit is introduced.Then,the concept of quaternio n,the operation relationship and the transformation relationship between quaternion and Euler angle are introduced.Based on quaternion,the relative attitude dynamics equation and the relative orbit dynamics equation of two spacecraft in near-Earth circular orbit are given.Then the relative orbit dynamics model and the relative attitude dynamics model are combined.An integrated attitude-orbit model of two spacecrafts based on near-earth circular orbit is proposed.2.The optimal control theory is introduced.Firstly,aiming at the rendezvous and docking problem of two spacecrafts in circular orbit,based on the performance index of energy minimization principle,an example of the optimal control theory is verified,which lays a foundation for the study o f the optimal control strategy of the integrated model of near-Earth circular attitude and orbit.In order to eliminate the coupling effect caused by the change of attitude and orbit independent control,a cubic thruster is designed for the integrated model of near-Earth circular attitude and orbit,and then the optimal control strategy is studied to achieve the convergence of attitude and tracking error.3.Firstly,the general orbital parameters of spacecraft and their conversion relations are introduced,and the orbital parameters of target spacecraft are given.The initial expected tracking error of tracking spacecraft and the expected state and disturbance moment of target spacecraft are simulated numerically,and the simulation results are analyzed to verify the effectiveness of the optimal control strategy。...