Researches On Rigid-Flexible Coupling Dynamics Of The Flexible Multibody Satellite

With the development of aerospace technology, the large-scale spacecraft having large flexible structures appeared. The flexible structures, such as the great antenna, solar panels, large truss, had made the spacecraft configuration complex. Furthermore, the large overall motion of the spacecraft had become more complicated and diversiform. Unfortunately, the elastic deformed motion of the flexible structures aroused by the large overall motion of the spacecraft was not neglected again. Because of the coupling of the two motions, the dynamic analysis of the whole spacecraft is more difficult. What's more, the especial dynamic phenomenon, dynamic stiffening, became important in the analysis of spacecraft dynamics. Thus, research on the coupling of the large overall motion and the elastic deformed motion is important. The studies included in this thesis are as follows:Firstly, in view of the flexible beams of the spacecraft undergoing large overall motion, the rigid-flexible dynamic equations were established via the mode assumption and the finite element method. The results of numerical simulation show that the traditional dynamic modeling method can't indicate truly the dynamic action of flexible beams undergoing large overall motion. However, the dynamic model in this thesis can. Moreover, the dynamic stiffening phenomenon was verified.Secondly, in view of the flexible solar panel and large truss undergoing large overall motion, the rigid-flexible dynamic equations were established via the different methods. The results of numerical simulation show that there are some limitations in the traditional modeling method.Finally, the dynamic equations that can simulate completely the dynamic action of a flexible satellite flying on the orbit were established. It was funded that the control law of the rigid satellite's attitude can't be applied into the attitude control of the flexible satellite. Actually the attitude control system will arouse the instability of flexible satellite. Furthermore, with the effects of environment power, the traditional dynamic model can't indicate truly the dynamic action of the flexible satellite. On the contrary, the rigid-flexible dynamic model in this study can indicate the dynamic action of satellite.This research show that, the traditional dynamic model can't indicate the dynamic action of flexible satellite undergoing large overall motion because of the coupling of the rigid motion and the deformed motion. In order to indicate the dynamic action truly of the flexible satellite, it is prerequisite to establish the first order approximation rigid-flexible coupling dynamic model.