Attitude Control Study For The Space Station Redocking Process

The third stage of Chinese manned space engineering will be implemented through on-orbit assembly. According to the particular technological requirements for transferring manipulator system building the Space Station, the corresponding multi-bodies kinemics model was established; the motion path and parameters were programmed. The flight attitude mode and control scheme for assemble were also designed on the basis of the characteristics, such as multi-body construction, altering structure and parameters, coupling between rigid and flexible movements. The main work is summarized as follows:1. The input conditions were determined. Considering Mir Space Station, the initial parameters for transferring manipulator system were proposed which were applicable to our condition. The mass properties and coupling coefficient for rigid and flexible movement were calculated. The parameters for SGCMG and Star sensors were given.2. The kinemics model during transferring assembly process was established. The multi-body system dynamics model, adopted the Lagrange equation, was derived, considering the large flexible appendages during transferring assembly process, and the model which is applicable to the control system was given.3. The impact for interference during the assembly process was analyzed, as well as the path planning for transferring. The interference effect between module and solar array during transferring was simulated based on the ADAMS software. The model for solar array interference analysis was derived, and the condition for interference was determined. Then the optimal transferring path was obtained finally.4. The movement parameters during transferring assembly process were investigated. The vibration movement for solar array during transferring and its resulted interferential moment were simulated and analyzed. According to the simulation results of interferential moment and angular momentum, the optimal angular velocity during transferring was obtained.5. Assembly attitude control during transferring was studied. A non-linear control algorithm with strong robustness was designed based on the Lyapunov stability theory. Although the assembly attitude sustained stable during transferring, the saturation problem for Single-gimbal Control Moment Gyro(SGCMG) was occurred. Coupling between control and construction would be arisen when whiff was in uninstalling stage. As a results, Torque Equilibrium Attitude(TEA) flight mode was designed to avoid the saturation condition. The optimal flight attitude mode and control algorithm during transferring assembly process were obtained through simulation analysis.