Research On The Flight Scheme Of Homing Phase In RVD Mission

Rendezvous and docking (RVD) is a necessary operational technology for space-supply, space-assembly, space-succor and so on, and is also a key technology of the second step of China manned space engineering. Homing phase is an important phase of RVD.The dynamics model, error problem and maneuver failure problem of homing phase are studied in depth in this thesis. The main achievements are summarized as follows:(1) A new guidance algorithm for homing phase of space rendezvous is studied by using the second-order nonlinear equations of relative motion. The targeting error induced by traditional C-W guidance algorithm is analyzed firstly, and the result presents that the linearization error is a predominant error factor. The second-order nonlinear equations of relative motion are derived, and the iterative correction guidance algorithm is put forward in this thesis. The proposed guidance algorithm is evaluated by simulation, and the simulation results show that the precision of new guidance algorithm has been greatly improved compared with that of the C-W guidance algorithm.(2) The flight schemes of homing phase are studied taking into account various errors. Covariance analysis method and Monte-Carlo method are introduced firstly. Secondly, the effects of navigation errors and the actuation errors typical in homing phase are analyzed by covariance analysis. Finally a few representative flight schemes of homing phase are analyzed by Monte-Carlo method, and the best flight scheme is ascertained.(3) The maneuver failure problem in homing phase is studied, and the preliminary countermeasures for impulse failure and attitude failure are provided. Based on the C-W guidance algorithm and high-precision orbit model, the maneuver failures in homing phase of RVD are simulated and analyzed, and the boundary conditions of countermeasure are given respectively according to the various constraints. The simulation results show that these countermeasures can deal with these maneuver failures well.(4) The simulation system of homing phase in RVD is developed. Guided by object-oriented (OO) methodology, the simulation system of homing phase in RVD is designed by the use of Unified Modeling Language (UML) firstly, and is coded in VC++ 6.0. The simulation results verify the rationality and rightness of the simulation system.Some problems concerning the homing phase are analyzed and studied in this thesis, and the conclusions of this thesis are well references for the second step of China manned space engineering, and they will be beneficial to Chinese rendezvous and docking technology.