Investigation On The Attitude Dynamics And Control Method Of The Space Station At Lagrange Point

With the development of deep space exploration technology,the utilization potentiality and significance of three-body libration points attract more and more attention.When established at libration point,a large long-term space station is more advantageous for interplanetary spacecraft to execute on-orbit residence,maintenance,fueling missions.However,for the complex configuration and the peculiar mass distribution,there are many new researches demands in attitude dynamics and control problems near libration points.On the background of the libration point missions,the attitude dynamics and control problems of large space stations with control torque gyro are investigated.The main results achieved in this dissertation are summarized as follows.A solution method of the torque equilibrium attitude for three-body libratioin points is proposed and the distribution of the equilibrium attitude is developed.1)The solution and analysis method of the torque equilibrium attitude for space station at libration points is established;2)the torque equilibrium attitude at libration points are calculated and the results are analyzed combined with the configuration parameters of the space station.3)the distribution of the torque equilibrium attitude in a three-body space is studied and a special point near the second main celestial body is discovered.When a certain configuration condition is satisfied,there are infinite torque equilibrium attitudes at the special point.The stability of the initial attitude and spinning motion of the space station in periodic orbits are studied.1)The effects of the orbital altitude of planar periodical orbits and the configuration of space station on attitude motions are investigated;2)The attitude motions of space station on Halo periodical orbits are simulated and the simulation results are drawn in pictures and analyzed.3)Based on spin attitude motion mode,the attitude stability of space station on libration points or periodical orbits near the libration points are studied,which provides reference for space station missions in practical three-body environment.An initial value optimization method for the attitude motion of the space station at libration points based on the phase plane constraints is proposed.1)Based on the phase trajectory of attitude motion,the stability condition of attitude motion is analyzed,and the path constraint to ensure the stable motion of attitude is proposed.2)The optimization objective function considering the ideal attitude is constructed,the initial value optimization problem is transformed into the optimal path planning proble.The basic model of the problem is established,and the solution strategy based on the pseudogeneralization method is proposed.3)The effectiveness of the proposed method is verified,and the influence of orbital parameters and space station configuration parameters on the initial value optimization solution is analyzed.4)The event constraint conditions are proposed,and a series of single-period,multi-period attitude-orbit naturally coupled periodical solutions are gained.A method of attitude maneuver path planning and tracking control for space station at libration points is proposed.1)The optimal attitude maneuver path considering the control torque is planned,and the attitude maneuver time and the maximum angular momentum of the gyroscope are taken as optimization targets.2)The existence condition of attitude maneuver path is deduced from the angular momentum exchange capacity of the gyroscope.3)The controller of attitude modification and tracking and the feed-forward steering law of the gyroscope are designed,which can be used to eliminate the angular momentum deviation and the influence of environmental disturbance.4)The idea of configuration-changeable SGCMG is proposed and the optimal strategy is designed.The configuration parameters of the gyroscopes can be optimized according to different mission demands,which makes it adaptable for many complicated attitude motion missions.The dissertation develops the torque equilibrium attitude solving and analysis method,the initial value optimization method on the periodic orbits and the attitude control method in the three-body problem,which greatly enriches the attitude control problem and the research results in the three-body problem.The proposed method is of great theoretical and practical application value for attitude prediction and effective attitude control of large space station at libration points.