| With aerospace techniques widely used in various fields, the numbers and types of satellites are growing rapidly. Satellites trend to be flexible and large-scale, so designing flexible satellite attitude control system has important significance. The single-axis flexible satellite is controlled as the research object in this thesis, we researched on the model of flexible satellites, attitude control and suppressing the vibration of flexible appendages. It includes the following aspects:Firstly we analyzed the differences of the frequency between non-binding mode and constraint mode of the flexible appendages, on this basis, the dynamic model of flexible satellite is given. We applied input shaping to the vibration suppression of flexible appendages, briefly described the principles and concepts of the input shaping.Considering the uncertainties that exist in flexible satellites, we designed variable structure control which needs only output information, and combined with the input shaping method. Simulation results show that the composit- e control method improves the control accuracy of flexible satellite while the modal vibration is suppressed.Considering parameter uncertainty of the flexible satellite system, disturba- nce uncertainty and the chattering problem that exist in traditional variable struc- ture control, we designed a variable structure controller of RBF neural network and a variable structure controller with adaptive bound which learn from RBF network . On the basis of the above methods , we designed an adaptive variable structure controller of RBF neural network. Analysis of simulation results shows the method can reduce vibration of flexible appendages effectively and improve the accuracy of the system control, system has strong robustness. In addition, we designed a simulation software which facilitates algorithms and comparison of the simulation results under various control. On this basis, we gived the simulations of various algorithms and analyzed the results. |
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